The crew that brought you the Arduino is always hard at work trying to bring the community closer together and to foster collaborative development. They recently rolled out a new feature on their site that is sure to be of interest to Arduino veterans and neophytes alike.

Arduino Labs is a platform which the team plans on using as an incubator of sorts, for projects that are underway, but not fully baked. Currently, they have highlighted two in-progress initiatives, including the Arduino Mega ADK, as well as a GSM/GPRS shield that the team has been developing in collaboration with Telefonica I+D.

As of right now, the site looks to be a one-way information outlet for the Arduino team to the community, but they stress that their aim is to create a more open development process within the Arduino project. While there is no official statement on the matter, we hope that the site will eventually allow members of the community to offer both their feedback and lend manpower to forthcoming projects.

[via Adafruit blog]

Filed under: arduino hacks, news

In his line of work, Hackaday reader [Pedantite] often has to monitor the build status of several continuous integration servers throughout the day. One afternoon, he got the idea to install a set of stop lights in the office in order to monitor the status of the servers, but filed it away as a “wouldn’t it be cool if…” project.

After some time had passed, he was bitten by the idea bug again and decided he would build a physical device to display the status of his build processes. This time around, he brainstormed on a smaller scale and the result is the “Indictron” you see above.

He built a simple LED board made up of four rows of four LEDs to display the build processes. Different LEDs are lit depending on the project’s current build status as well as the results of the previous build. The board uses an ATmega88, and interfaces with a compiler watchdog application using a virtual USB package made specifically for AVR micro controllers.

The end result is a simple, yet useful status board that “just works”. He does not seem to have code or schematics posted on his site at the moment, but we’re pretty sure he would share them upon request.

If you’re interested in a bit more of [Pedantite's] work, check out his “Good Times” parental timer we featured last week.

Filed under: led hacks, Software Development

We asked for responses to our last Development Board post, and you all followed through. We got comments, forum posts, and emails filled with your opinions. Like last time, there is no way we could cover every board, so here are a few more that seemed to be popular crowd choices. Feel free to keep sending us your favorite boards, we may end up featuring them at a later date!

The Popular:

Parallax Propeller: We heard the loudest cries from the Parallax fans out there. The Propeller is a unique chip, in that it contains 8 cores called cogs which each take turns executing separate code. This design allows for disregarding of interrupt style programming in favor of assigning each core a specific task. There are a number of boards available, including Gadget Gangster’s platform as well as boards from Parallax. Thinking in terms of 8 cores rather than one may present a learning curve to some embedded programmers, though there are a number of code examples to pull from online to get beginners on their feet.

Atmel’s AT90USB and AT32U4 based boards: Atmel’s AT90USB and ATmega32U4 chips are common on low part count boards like the Teensy/Teensy++ because of their built-in hardware USB support, which means no FTDI or equivalent chip required. These development boards tend to be low-cost, easy to implement on a breadboard, and in cases such as the Teensy, are Arduino IDE compatible. The chips these boards are based on are also an excellent place for those trying their hand out at microcontroller circuit design for the first time because of their simplicity and low hardware requirements.

Microchip’s PIC line: Somehow, we managed to leave the entire Microchip crowd in the cold last time. A popular set of microcontrollers with a similar market segment to Atmel’s chips, these chips vary from the low-end and low-cost 8-bit series to the higher end 16 and 32-bit models. We received a good number of development board recommendations, all ranging in price, features, and ease of use. We’ll rely on comments and forum posts to help convince you what specific model to try.

[edit: Added the PicKit3 as per popular request]

The Powerful:

mbed: Possibly one of the most popular hobby development boards for ARM’s Cortex-M3 chip, the mbed features a similar footprint to the Teensy, but with a huge jump forward in power. The mbed includes hardware for a number of peripherals, including support for ethernet with the addition of an RJ-45 port. The major difference between the mbed and other similar boards is the entirely web-based IDE. We have previously reviewed the mbed, so for more details be sure to check it out.

Renesas’ RX62N RDK: Whenever a company gives away development boards for free, the community often jumps on the offer. Rather than the normal free barebones boards though, the RDK has a good number of on board peripherals, including an Ethernet port as well as a 3 axis accelerometer. Unfortunately you can’t get one for free anymore (at least not this contest), but from all we have heard from our readers, it may be worth investing in anyway.

The Maple: The Maple from LeafLabs is an excellent example of the effect open hardware tools such as the Arduino have had on the hobbyist environment. Featuring an ARM Cortex-M3, the Maple has plenty of processing power and also can brag that it has the same header layout as the Arduino. This means that almost all commercially available Arduino shields will work on the Maple, a major selling point for anyone who has invested into a well stocked Arduino setup but needs an injection of performance.

Bonus Points:

OpenWRT based routers: Often, projects need to be networked either by wire or wirelessly to operate as desired. Rather than buying a high-end development board with ethernet or Wi-Fi built-in, many readers suggested buying (or salvaging) any one of a number of low-cost wireless routers, and installing a custom linux based firmware on them. These boards often tend to have UARTs or USB ports originally meant for debugging available for expansion with sensors or other low-end microcontrollers. A hack in the true sense of the word, we applaud this sort of creativity. Some popular firmwares to check out would include DD-WRT, OpenWRT, and the Tomato firmware. Be sure to make sure support exists for your device before you go buying anything though.

FPGA boards: When we set out to cover development boards, we had microcontrollers in mind. However when it comes to signal processing, custom high-speed logic, or flexibility, FPGAs are an excellent choice. The two major players for hobbyists these days are Xilinx with their Spartan line, and Altera with their Cyclone line. Both companies offer their IDE for free, and it comes down to personal preference when choosing which way to go. Both companies also support SoC designs to implement virtual microcontrollers on the FPGA, which adds an additional layer of flexibility for any hobbyist or engineer. Chances are, most hobbyists will not need the performance of cutting edge FPGAs (or CPLDs), so keep an eye out for older development boards on sale, or development boards made by third parties.

Build your own: Although it may appear as a sort of “Get off my lawn” answer to our question, there is a lot to be said about building a development board from scratch. These days, many 8-bit or 32-bit microcontrollers require few if any external components to run in a basic mode, and can be combined with a JTAG or FTDI cable for programming and communication. There are countless tutorials on using perf-board or etching a board to make a custom circuit, and the experience is invaluable for breaking away from high cost development boards in simple projects.

Filed under: parts

Here at Hackaday, we see microcontroller based projects in all states of completion. Sometimes it makes the most sense to design systems from the ground up, and other times when simplicity or a quick project completion is desired, pre-built system boards are a better choice. We have compiled a list of boards that we commonly see in your submitted projects, split up by price range and with a little detail for reference.

After reading our list, sound off in the comments or on this forum post, and we may include your board in a follow-up guide at a later date. We will also be giving away 10 Hackaday stickers to the most insightful, the most original, and most useful advice given on the forum, so if you haven’t registered yet, now would be a perfect time. Winners of the sticker giveaway will be selected from the forum thread, and the final decision for prizes will be judged by the wit and whim of the Hackaday writing team. More prize details to follow in the thread. Read on for our guide based on past project submissions.

The Cheap ($0-$50):

When it comes to cheap boards, users can expect a simple breakout board, usually with some debugging facilities and minimal extra components. These boards tend to be aimed at hobbyists and the education crowd rather than companies who can afford full featured development setups for their engineers. Unfortunately, boards that come directly from manufacturers tend to have locked down or overly simplified IDEs or debugging software, though low price points often inspire the open source communities to write their own to take advantage of all the features.

• TI’s MSP430 Launchpad: Coming in at $4.30, TI’s Launchpad board is definitely a bargain. For your money, you get a set of 16-bit MSP430 processors, a mini-USB debugger and programming interface, and a set of Windows IDEs to choose from. Not much more to write home about, but we have featured a number of projects with this family of microcontrollers running the show.
• STMicroelectronic’s Discovery: Costing you a paltry $11.85, This 32-bit ARM processor may be one of the best performance to cost values. Similar to the Launchpad, the Discovery has a mini-USB interface, a breakaway programmer and debugger, and a few locked down IDEs to select. For students or professionals looking for experience with the ARM architecture, this Cortex-M3 based system would be a great place to start.
• The Arduino Family: Needing no introduction, these 8-bit AVR based systems have been displayed by us numerous times. Due to an open source hardware and software design, these boards are available for as low as $20 or so for Arduino Compatable clones, or any price range up depending on included peripherals. Because of the simple IDE and coding environment familiar to anyone familiar with C, C++, or Java, the Arduino is a common choice for beginners, non-engineering types, and professionals alike.

Mid-Range Boards ($50-$150):

For a little more money, more can be expected from a development board. Often featuring higher I/O pin counts, more complex interfaces such as host USB ports, Ethernet, or Video-Out, these boards are a great place for a little computational and functional muscle. However, with a higher cost, it is more difficult to just throw one of these boards at any one-off project. More costly boards are often supported better as well, because they are used by engineers who will decide on important purchasing decisions. This area is also a transition area from more hardy microcontroller type boards into the more powerful microprocessor type systems (such as shifting from the Cortex-M to the Cortex-A series of ARM processors).

• The Arduino Mega: For all the same reasons as the original Arduino, the Arduino Mega has its place in a prototyping or development environment. For a bit more money than the original, extra code space, processing power, and I/O pins are gained, with the same comfortable, familiar, and similar development tools. The Arduino Mega runs at $65, which makes for a costly 8-bit system.
• The Chumby Hacking Board: An interesting example of a product going from production to prototyping as an afterthought, this board is based on the guts of the Chumby One, featuring a 32-bit Freescale i.MX ARM processor at 454 MHz. This system has video out, as well as a trio of USB ports for all the peripherals you can find or write your own drivers for. The Chumby Hacking board clocks in at a reasonable $90 or so, though supplies seem to be dwindling, so act fast if interested.
• The Original BeagleBoard: At the top of the price range, the BeagleBoard (Revision C4) features a 600 MHz Cortex-A8 ARM processor capable of running a number of Linux systems, including Angstrom and Ubuntu. Designed to interface with cool toys like touchscreens, this board also features a powerful DSP chip for crunching numbers, as well as processing video and sound. For a newly discounted rate of $125, this compact powerhouse could be yours.

The Upper Crust ($150+)

At this price range, these boards often contain ARM processors from the Cortex-A series, and have more in common with high-end smartphones than the microcontrollers usually seen on Hackaday and in day-to-day life. Boards like these are a real investment, and often cost and perform similar to many older or low-end PCs and netbooks at a considerably more efficient performance to power use ratio in most cases. These boards tend to run Linux-based operating systems, including Android as well as others.

• The BeagleBoard xM: Coming in at just around $150, this big brother to the first BeagleBoard adds parts such as onboard Ethernet, an additional 2 USB ports, and a bump to a 1 GHz processor. Although the MSRP is listed at $149, a high demand has pushed the cost well above that at places where stocks are even available. Because of a strong similarity to the original BeagleBoard, the existing community is strong, and full of examples and guides to get the board going
• The PandaBoard: With features as far away from an 8-bit microcontroller as imaginable, this board comes dressed to the nines featuring a dual-core 1 GHz processor capable of handling 1080P video stream. We realize this is probably out of the ballpark of just about any “hack” level project at $174, but we know there are some engineers out there very excited to see this.

In Summary:

We know that brand and experience preference can be a strong motivator, so be productive with your advice and sound off in our forum with your picks for our follow-up post(s). We will do our best to wrap up all the information you provide into a more definitive, and hopefully even more informative guide for beginners and professionals alike.

Filed under: parts

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 private void rbFemale_CheckedChanged(object sender, EventArgs e)
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 else
 rbMale.Checked = true;
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private void main_Load(object sender, EventArgs e)
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}

private void cbMonth_SelectedValueChanged(object sender, EventArgs e)
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 for (int i = 1; i <= 30; ++i)
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 else if (cbMonth.Text == "January" || cbMonth.Text == "March" || cbMonth.Text == "May" || cbMonth.Text == "July" || cbMonth.Text == "August" || cbMonth.Text == "October" || cbMonth.Text == "December")
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Filed under: Software Development

In this tutorial we will be pivoting from our last tutorial on Graphical Elements to start focusing on databases in Android development. The android platform uses SQLite databases in its applications and is one of five data storage options in android development. We will only be focusing on SQLite development in android because it is key to the construction of a workable/functional program. After this tutorial you should be able to implement a SQLite database that you are then able to insert and select items from tables in the database.

For this project we will be creating a Random Quote generator that has you enter quotes or sayings in a textbox and press a button to insert them into the database. We will issue a confirmation toast that allows us to see if the data was entered into the database successfully and the textbox will be blank. If a second button is pressed, the database will be accessed and told to select a random quote from the database to show in a toast on the screen.

To start off we will make a new project called RandomQuotes. In part one of the series we stepped through making a new project so we wont walk through all of the steps again but instead I will just give you the information you need. The information to get this project up and running bare bones is as follows:

• Project Name: RandomQuotes
• Build Target: Android 1.5
• Application Name: RandomQuotes
• Package Name: com.gregjacobs.randomquotes
• Create Activity: QuotesMain
• Min SDK Version: 3

After inserting these values and you have pressed Finish we will start by making a class file in our com.gregjacobs.randomquotes package. To do this we will right click on the package and navigate to New then to Class. When the new window pops up the only data we will enter is the Name section filling it with DBAdapter. After this is done we press Finish and are presented with a bare bones class file that we will quickly start to modify. This tutorial will be like the last in the sense that code will be posted and I will explain the important parts and what functions are doing. The only difference from the previous tutorial code will be that I include text files as well as documenting the code here so you are able to download and compare. We will start off with the DBAdapter.java file:

package com.gregjacobs.randomquotes;

import java.util.Random;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

We will start off by importing all of the tools required to get this SQLite Database up and running. All of these might be straightforward for database programmers but we will discuss them anyways. ContentValues allow us the ability to store a set of values for insert statements, Context as explained in the last post allows us access to the application environment. Cursor is probably the most vital import we will need next to the SQLite imports. Cursor allows us access to the data returned to the cursor from a database query. SQLException allows us to throw SQL exceptions if there is ever an error, these messages provide more insight as to what the problem may be. SQLiteDatabase gives us the ability to manage a SQLite database using methods. SQLiteOpenHelper is basically a helper class that allows for creation and version management of a database. Log will basically log output in case there is an error.

public class DBAdapter
{
    int id = 0;
    public static final String KEY_ROWID = "_id";
    public static final String KEY_QUOTE = "Quote";
    private static final String TAG = "DBAdapter";

    private static final String DATABASE_NAME = "Random";
    private static final String DATABASE_TABLE = "tblRandomQuotes";
    private static final int DATABASE_VERSION = 1;

    private static final String DATABASE_CREATE =
        "create table tblRandomQuotes (_id integer primary key autoincrement, "
        + "Quote text not null );";

    private final Context context;

    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

Here we define all of our variables to be used in the database from the database name right down to the database create statement. We are using final variables because they will never change values and making a variable for table names and the like will later on make our lives easier than hard-coding all of our values and commiting too much (remember the re-usability).

    public DBAdapter(Context ctx)
    {
        this.context = ctx;
        DBHelper = new DatabaseHelper(context);
    }

	private static class DatabaseHelper extends SQLiteOpenHelper
    {
        DatabaseHelper(Context context)
        {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db)
        {
            db.execSQL(DATABASE_CREATE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion,
                              int newVersion)
        {
            Log.w(TAG, "Upgrading database from version " + oldVersion
                  + " to "
                  + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS tblRandomQuotes");
            onCreate(db);
        }
    }
    

Above we define a constructor to grab the context of the application and extend that to our DatabaseHelper just under the constructor. The DatabaseHelper class extends our SQLiteOpenHelper which will add greater functionality to management of our SQLite database. The key function that we will see used later on will be onCreate which will allow us to execute a SQL statement to create our database.

    //---opens the database---
    public DBAdapter open() throws SQLException
    {
        db = DBHelper.getWritableDatabase();
        return this;
    }

    //---closes the database---
    public void close()
    {
        DBHelper.close();
    }
    

Above we have two key functions that allow us to open and close the database that can be referenced when calling them in our main .java file.

    //---insert a title into the database---
    public long insertQuote(String Quote)
    {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_QUOTE, Quote);
        return db.insert(DATABASE_TABLE, null, initialValues);
    }

The function above will be processing our quotes when we call them in the main .java file. It will also be getting them ready for entry into the database by putting the string Quote into a ContentValues called initialValues which is then inserted into the database table.

    public int getAllEntries()
    {
        Cursor cursor = db.rawQuery(
                    "SELECT COUNT(Quote) FROM tblRandomQuotes", null);
                if(cursor.moveToFirst()) {
                    return cursor.getInt(0);
                }
                return cursor.getInt(0);

    }
    

This function will be querying the database table for the number of quotes entered so it can assist the random number generator in how high a number to choose so that we don’t throw an exception. We are using a rawQuery for the most part because I am personally not a huge fan of the way Android handles their queries ( having you enter in different parts of the statement in segments and separate them with commas) but I am impressed that they allow you to have full functionality with a native SQL query. The if statement will move the cursor to the first result (if there are many results) and grab the first integer it sees there. If the if statement is not true it will grab the result from the starting position anyways.

    public String getRandomEntry()
    {

    	id = getAllEntries();
    	Random random = new Random();
    	int rand = random.nextInt(getAllEntries());
    	if(rand == 0)
    		++rand;
        Cursor cursor = db.rawQuery(
                    "SELECT Quote FROM tblRandomQuotes WHERE _id = " + rand, null);
                if(cursor.moveToFirst()) {
                    return cursor.getString(0);
                }
                return cursor.getString(0);

    }

}

This function will be called by the main .java program to return a random result based on the number of entries into our database. We use the function getAllEntries to get the number of quotes and we then tell our random variable that it can go no higher than id. In our select statement we then tell it to look for quote WHERE _id = rand which is our random number.

After this class file is completed, we have a fully reusable database adapter that is ready to start inserting quotes into the database. We now need to focus on both of the XML files which will be a quick trip down memory lane so code and pictures will be posted and we shouldn’t have to review as everything is basically from the last post. Here is the main.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="@string/Quote"
/>
<EditText
android:id="@+id/Quote"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Button
android:id="@+id/go"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/press"
/>
<Button
android:id="@+id/genRan"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/genRan"
/>
</LinearLayout>

Here is the strings.xml file:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="Quote">Please Enter A Quote:</string>
    <string name="app_name">Random Quotes</string>
    <string name="press">Press Me!</string>
    <string name="genRan">Generate Random Quote!</string>
</resources>

Both are pretty straight forward and the only difference from these files and the previous posts is the additional string node in strings.xml and the extra button in main.xml. Now we have the layout in place with everything where we want it to be it is now our task to code the QuotesMain.java file. This file will register our two buttons and attach them to one event handler using a switch statement. Here is the code for our QuotesMain.java file:

package com.gregjacobs.randomquotes;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

Here we are importing all of the required items to be able to pull this project together. All of these should be familiar to you from Graphical Elements and if they aren’t it is a good post to start on and work your way here.

public class QuotesMain extends Activity {
	DBAdapter db = new DBAdapter(this);
	EditText Quote;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        // Capture our button from layout
        Button setButton = (Button)findViewById(R.id.go);
        Button getButton = (Button)findViewById(R.id.genRan);
        // Register the onClick listener with the implementation above
        setButton.setOnClickListener(mAddListener);
        getButton.setOnClickListener(mAddListener);
    }

We now have to buttons being referenced by id and they are getButton (which gets the information from the text box and inserts it into the database) and setButton (which retrieves a random quote from the database depending on the number of items in the database). These both have the same event handler and decisions on what code to run are made below.

    // Create an anonymous implementation of OnClickListener
    private OnClickListener mAddListener = new OnClickListener()
    {
    	public void onClick(View v)
    	{
    		switch(v.getId())
    		{
    		case R.id.go:
				db.open();
				long id = 0;
				// do something when the button is clicked
				try
				{
					Quote = (EditText)findViewById(R.id.Quote);
					db.insertQuote(Quote.getText().toString());

					id = db.getAllEntries();

					Context context = getApplicationContext();
					CharSequence text = "The quote '" + Quote.getText() + "' was added successfully!\nQuotes Total = " + id;
					int duration = Toast.LENGTH_LONG;

					Toast toast = Toast.makeText(context, text, duration);
					toast.show();
					Quote.setText("");
				}
				catch (Exception ex)
				{
					Context context = getApplicationContext();
					CharSequence text = ex.toString() + "ID = " + id;
					int duration = Toast.LENGTH_LONG;

					Toast toast = Toast.makeText(context, text, duration);
					toast.show();
				}
				db.close();
				break;

In the above case statement we can see that we grab the text from the textbox and insert the data into the database using db.insertQuote from the DBAdapter java class. After a successful insertion we will display a toast that allows us to see what quote was entered in successfully and what the number of quotes in the database are.

    		case R.id.genRan:
    			db.open();
    			//long id1 = 0;
    			// do something when the button is clicked
    			try
    			{
    				String quote = "";
    				quote = db.getRandomEntry();
    				Context context = getApplicationContext();
    				CharSequence text = quote;
    				int duration = Toast.LENGTH_LONG;

    				Toast toast = Toast.makeText(context, text, duration);
    				toast.show();
    			}
    			catch (Exception ex)
    			{
    				Context context = getApplicationContext();
    				CharSequence text = ex.toString();
    				int duration = Toast.LENGTH_LONG;

    				Toast toast = Toast.makeText(context, text, duration);
    				toast.show();
    			}
    			db.close();
    		}
		}
    };
}

This case uses a string variable to reference the random entry we are pulling out of the database using db.getRandomEntry. We then display that data in a toast to show that the information was actually grabbed. All of this code when pulled together and displayed on an android screen should look like this:

Entering Text:

Displaying Random Entries:

With an introduction to databases for android covered you can start writing applications that require data storage such as the final product mentioned in the first post. There are a plethora of other features to cover in SQLite databasing for android. More of those will be covered in the next tutorial. Things such as updating your database, deleting entries and getting to know your way around the DDMS (Dalvik Debug Monitor Service) are all an essential part of android programming. If you can’t wait till the next article to check these articles on DDMS and Updating and Deleting.  As always if anyone has problems, questions or issues don’t hesitate to ask and I will try my hardest to get back to you before the next post! Until the next time, Happy Hacking!

Text files of code for comparison:

DBAdapter | strings | main | QuotesMain

Articles used for reference:

DevX – Creating and Using Databases in Android
Android Developers – Reference Guide

In this tutorial, we will be continuing from where we left off with the “hello world” application.  This time adding a graphical user interface (GUI) and a “toast”. The GUI will consist of a button, textbox and a label. The “toast” will be issued onto the screen when the button is pressed.

Some may wonder what a toast is.  Well, for non-programmers, a toast is a text notification that for the most part is used only to display an error on the screen (I am a big fan of using toasts instead of an alert on the screen as its less intrusive).  For this article we will use a toast to display a message on the screen that will take the text in the textbox and issue a “Hello Greg” onto the bottom of the screen.  After this article completed you will be able to successfully make toast commands, design the layout of the hello world program, and pull text from a textbox.

We are going to start off by copy our existing Hello World project so that we can use the original in every way but have two separate projects to show the difference and both can be used as references.  To do this we will right click on the root of our HelloWorld project in the right hand pane (Navigation Explorer), navigate to copy (not Copy Qualified Name) and click it.  Then find a blank space in the Navigation Explorer, right click again and click paste.  You will be asked to supply a new name for this project and whether to use the default location.  We will name the new project ImprovedHelloWorld and we will leave the checkbox checked that says “use default location”.  Press OK and the new project will be generated from the old one.

The first thing we are going to accomplish is changing the strings.xml file to add another node under app_name.  We will do this by copying the node above it and pasting the copied material directly under the last </string> element.  Then we will change the name of the string to press and in between we will write Press Me!.  Next we will alter the hello node and change the text to say Enter Your Name Here: instead of Hello Android, Hello World!. This being accomplished we now need to design the GUI (Graphical User Interface).

To do this navigate to main.xml and we are going to go over what everything does up to this point.  We first off have a node called LinearLayout which essentially creates a space for adding objects such as textboxes, buttons and the like and will format the layout for us.  So LinearLayout will organize one thing right after the other in a one column and one row type of deal.  Next we have a TextView which in any other label we could call a label.  Now to go over what all of the parameters are in the nodes we just mentioned.  android:layout_width & android:layout_height are used to determine what will happen to an object when it is used within a layout.  There are two options when using this and they are fill_parent or wrap_content.  fill_parent will do exactly as it states, it will size the object so that it will fill the screen either vertically or horizontally.  wrap_content will format the object to expand or shrink to the size of the content displayed within.  Both of these variables can be used in many different objects including but not limited to Layouts, Text Views, Text Boxes, and Buttons.  android:text is used in certain objects like TextViews and TextBoxes to display text to the user.  As of right now, we are presenting the user with text but calling it from strings.xml instead of entering the text right in the node itself.  To reference strings.xml all that is needed is to put @string/press, where press is the name of your variable, inside the quotations.

Now that we are familiar with the terms, we will need to modify this to first house a label, textbox and finally a button.  To do this we will simply add a textbox and button since we already took care of the label in the string.xml.  To add a Textbox we will start on a new line under ending of the <TextView /> node.  Just to be clear I will add code inline and explain why we are adding it afterwards. <EditText android:id=”@+id/helloName” android:layout_width=”fill_parent” android:layout_height=”wrap_content” />.  EditText will be our textbox in this instance.  Also when giving items an ID it is best to follow these practises of adding @+id/ before your variable name which makes it possible to tie into your .java file later.  Next we will add <Button android:id=”@+id/go” android:layout_width=”fill_parent” android:layout_height=”wrap_content” android:text=”@string/press” /> directly underneath the ending of our EditText node.  Notice we are referencing the string.xml and calling the node that says Press Me! which will appear on our button now.  If you were to run this project now you would be able to see the layout of the program we just made but we are unable to get it to do anything except enter text in the textbox.

This next section will contain a lot of code and I will provide most of the screenshots of the code to help you through.  First, it is good to realize every time you would like to reference an object in your layout we need to import it.  We will need to add imports for our button and textbox.  We can do that bu adding these lines of code to the imports section at the top:

import android.widget.Button;
import android.widget.EditText;

After that we will need to include four more imports, the first being for event listen to add to our button, the second will be for the toast that we will call when the event handler runs, the third being the context of the application and the fourth to get the view of the application and handle the layout and interaction.  These imports can be added under the previous ones and will look like this:

import android.view.View.OnClickListener;
import android.widget.Toast;
import android.content.Context;
import android.view.View;

After these are added to your imports we are ready to get into coding the event handler for our button and the onCreate functions, which is called when the program is started.  To make things easier and to complement the screenshot, I will post the rest of the code and explain what the important lines are doing and why we are using them.

public class HelloMain extends Activity {

EditText helloName;

We are creating a reference to our textbox above any function so that it only has to be declared once but instantiated many times if need be.

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

// Capture our button from layout

Button button = (Button)findViewById(R.id.go);

// Register the onClick listener with the implementation above

button.setOnClickListener(mAddListener);

}

Above we capture the button from the layout using a variable.  With this variable we are going to assign it an onClick Event Handler as shown on the last line above.  Below we are creating the Event Handler for it to be hooked in above.  After creating this function it will be able to pull the text from the TextBox and display it with static text.

// Create an anonymous implementation of OnClickListener

private OnClickListener mAddListener = new OnClickListener()

{

public void onClick(View v)

{

long id = 0;

// do something when the button is clicked

try

{

helloName = (EditText)findViewById(R.id.helloName);

Here we instantiate the TextBox we declared earlier and capture the Textbox in the layout by finding it by the ID that we gave it.

Context context = getApplicationContext();

CharSequence text = “Hello ” + helloName.getText() + “!”;

int duration = Toast.LENGTH_LONG;

Toast toast = Toast.makeText(context, text, duration);

toast.show();

The above code will take Context (the facet to our applications enviroment) and and add it to our Toast along with our dynamic CharSequence text and the length the Toast will appear onscreen, which in this case we want it to be longer.  It is key to note how to make a Toast as it is more efficient that popping up textboxes to the user as well as it is less distracting.

}

catch (Exception ex)

{

Context context = getApplicationContext();

CharSequence text = ex.toString() + “ID = ” + id;

int duration = Toast.LENGTH_LONG;

Toast toast = Toast.makeText(context, text, duration);

toast.show();

}

}

};

}

The last thing we are doing for this function is putting all the important stuff mentioned above into a try catch statement which will try our important code and if there is an error it will display a Toast letting us know there was an error and a message about that error.  For functions such as these is it crucial to have precautions in place to catch errors and not have a program force close.  It is important to put the user first in thinking about UI and any error messages that might occur.  If an error somehow sneaks into your program try catch statements will catch the error and make it “cute and fuzzy” for the user.

Top half of code:

Bottom half of code, elapsed by previous view of code:

After we have coded the main content for our .java file, we can now proceed to run the application and view our completed Improved Hello World program.  Notice that when you press the button and your textbox has not text in it that the program will still function correctly.  This is a good feature to have so that you don’t start seeing Toasts containing error messages.  The completed product should look like this when the button is pressed:

This would conclude our Improved Hello World example but the learning is far from over.  Next post we will examine Databases and a look into some simple queries as well as building a database from the ground up.  As always, if you have any problems with coding this article, feel free to leave a comment and I will assist in any way possible! If you can’t wait for the next post you can read up on databases before the next posting.  Until next time, Happy Hacking!

This article will focus on developing a simple hello world program for android using Java. Google has recently released a “cute and fuzzy” programming environment for beginners to get into but I haven’t had the chance to try it, so we will be focusing on the Eclipse IDE here, which you should have set up in the last post.  When creating a text based project there are two very important items.  It will involve creating an android project, going through the necessary steps to complete both the (1) XML files and the (2) Java file and get this project ready for production and eventually deployment.  The requirements of this project are simple, know the basis of XML (for new comers if you don’t that’s OK too, you will learn) and know Java (very basic knowledge but you will learn as we go and we will modify a few parts of the java file today).

Start by firing up Eclipse and clicking File, New then Project. We are going to navigate to Android folder and select Android Project and click next. If you have updated your Android SDK correctly, your next screen will look like this. This screen requires we enter all data correctly including Project Name, Build Target, Application Name, Package Name, Create Activity, and Min SDK Version. These are important terms to know because they will control what keywords you can access and what your project looks like when you first create it. So to summarize:

• Project Name: Will be the name you would like to use for your new project. In this instance we will use “HelloWorld” (I am a programmer and loath spaces you might choose to have them but it shouldn’t make a difference)
• Build Target: This will specify what API you will be utilizing in your projects. It is key to choose wisely or you may lose out on a wider audience than anticipated. It is always best to think of what your program will use and see if a lower build will support those functions before cornering yourself with a higher API. For this program we are going to choose Android 1.5
• Application Name: Will be the name you choose for your Application to be called. This can be changed later on and for right now we make that field equal Hello World.
• Package name: The package name will consist of your company’s standard package name that you would use or in my case I use my entrepreneurial one. For this I am entering in com.gregrjacobs.helloworld but you can enter in anything you wish. Also, make sure it is in all lower case for good coding practices.
• Create Activity: You will want to make sure that the box is checked before Create Activity because this option will do most of the work you just have to give it a name. NOTE: do not call this “Activity” as your project will cease to function and you have to go through the pain of making it all over again or manually correcting it. I am going to use HelloMain as my activity name, again use what you wish though.
• Min SDK Version: This will have to be a number you enter denoting the platform you would like to target and if this application will show up in the marketplace of certain devices. If you look to the build target devices after platform tab on Android 1.5 you will see the number 3 and that will be our minimum SDK Version. Once everything is filled out press Finish.

This will create the core of our project ranging from the Android 1.5 JAR file to our Java and XML files. The most important things right now are the files in the src/com.gregjacobs.helloworld/ folder and the files in the res/ folder. First we will look at the main.xml which is located in res/layout/. This file will hold the layout of your application including textboxes, labels, dateTimePickers and the like. In the main.xml we will see that we are using a LinearLayout which will organize items into a single row or column. This can be handy sometimes (other times not so much) and for this example it will work, so leave it like this because we will be displaying text so it makes no difference. Next is the strings.xml file which will conveniently house
all of strings in the application. This is especially useful to keep the clutter out of your Java and main.xml file. We are actually going to change the string called “hello” from Hello World, HelloMain! to Hello Android, Hello World! And our string named app_name can stay how it is.

After doing this we are going to navigate to the package name we created and open HelloMain.java and this will contain the code to run the XML files we were just looking at. The first line will contain our package name that the java file is associated with. Next, in the picture above, we have imported the OS bundle and the activity function that will run our app. Later on when we explore adding textboxes and labels we will be importing widgets into our files and we will put the imports just under these two shown above. Next is our class that basically says when the application starts up, set the view of the screen to the layout labeled main. This is interesting in the sense that you can design many different layouts depending on the state you application is in. Of course with a hello world program we only need this one layout but the option is there for you to experiment with.

When we are done tweaking everything we wanted, we are going to build the application and run it on the emulator we created last post. To do this we go to the top of the eclipse screen and navigate to the button that looks like thisand press it. This will prompt you to say what type of project you would like to run. We want to run an Android Application and press ok.
The emulator should pop up onto your screen and load up. The first load time of your emulator will be atrocious but after that you should have no problems with load. When the emulator is done loading it may ask you to press Menu to unlock, do so by pressing menu just under the screen. You don’t have to navigate to load your project it will do it by itself it just has to load the rest of the software and you should end up with a result like this:

When working with tools like the eclipse IDE and AndroidSDK, making simple text based programs is a breeze. The next post coming to this series will get somewhat more difficult by developing a database class that will be reusable for most database driven applications. If anyone had any problems with this today make sure to leave a comment and I will try to get back to you before the next post. If you can’t wait to look ahead to designing an interface for your android application or looking into databases, these are the places to go; Data Storage and User Interface. Until next post, happy hacking.

Android is the prime OS for developing applications in today for many reasons. The main reasons being that it is Open Source and Intuitive. In addition it uses Java for development, which is quite an easy language to get used to and develop in. This being said, a lot of you have great ideas for Android applications or applications in general but don’t know where to start. This series will take you behind the scenes and introduce you to the software that will be your best friend while developing for android. On this journey we will start with a “Hello World” and move on from there to create a database driven application with a touch and scroll interface. The final result will look something like this:

Working with tools to develop Android applications will be your greatest asset as you will come to realize early on. All of the tools I use will be listed to make development speedy and efficient while still looking good along the way. At best you will need to acquire Eclipse, I recommend the Eclipse IDE for Java EE Developers version as it is amazing for other types of development as well. The next tools you will get are the Android SDK, which allows you to hook the SDK into eclipse to reference its API and design an efficient functioning program. After that, this part is optional, look into DroidDraw which is essentially a GUI for designing the interface side of things so that you don’t have to blindly hack your way through the Android SDK and Java jungle.

Eclipse is fairly straightforward to setup and start using the Android SDK, you just have to download a package to include the SDK to Eclipses referenced files. To do this we will go to Help and then to Software Updates which will have a tab that says Available Software. We want to Add Site to be able to look up just Google’s packages they want us to download. In the location field enter https://dl-ssl.google.com/android/eclipse and click OK. Check both boxes and proceed to the next screen. You should make sure Android DDMS and Android Development Tools are both listed before going on. Accept license agreements and click Finish. You will have to restart Eclipse but after that your hook in is ready to be setup.

Android SDK is fairly straight forward to download for any system but updating it and hooking it into Eclipse is the key. After downloading the zip file (I’m using Windows/Linux but Windows examples will be default), unzip it to your C Drive and label the folder it will enter AndroidSDK. After entering said folder double click on the setup icon which will take you to the screen that shows you all the updates available for download. Download the latest updates and proceed to the top option Virtual Devices where you will make your first emulator. NOTE: if an update list does not show you will have to set the setup client to use http instead of https. When creating the emulator the name doesn’t matter and all you really need to set is a version you want to develop on. We will pick Android 1.5 from the list because if you decide to market an application you can reach more people and for the API’s we will use we don’t need 2.1 or 2.2. After setting up your emulator you are ready to have the two meet for the first time.

Going into Eclipse you will click the Window button and navigate to the Preferences option and click it. Select the Android option on the left and there will appear in the right side of the window a blank screen with a browse button. Click the button and find your AndroidSDK directory in the C drive and select that folder. Clicking Apply will make the blank window you were looking at show many different versions of the Android SDK and if you are able to see it you are on the right track. Click OK and we are ready to start developing.

NOTES: DroidDraw will be spoken about in another post in this series and we will use it to make part of our interface and the other half we will code ourselves. For everyone else developing in Linux I have found an awesome post that will describe how to set up your environment for Ubuntu and can possibly be transitioned for Red Hat and the like. Anyone who is having trouble feel free to let me know the issues you are having and I will try my best to not leave you behind before the next post.

If you can’t wait for the next post, browse the examples on the Android Developers website.

Articles used for reference:

Android Developers – Installing ADT Plugin