Step 1: Create a database-using application:

For example, as follows:

Application: TestDatabase

Package Name: com.android.TestDatabase

Database Name: TestingDatabase

Table Name: TestingTable

Step 2: Launch the application to create a database for the application.

Step 3: Open a command prompt. For example, on Windows, go to Start > Run and type “cmd”

Step 4: Navigate to the tools folder in the Android SDK.

Step 5: Input the following at the command prompt:

d:\android-sdk\tools>adb shell

# cd data/data

# cd com.android.TestDatabase

# cd databases

# sqlite3 TestingDatabase;

sqlite3 TestingDatabase

SQLite3 version x.x.x

Enter ".help" for instructions

sqlite>

Step 6: From here you can fire your queries.

For example:

sqlite> select * from TestingTable;

Step 7: To exit, press ctrl+c

Step 8: Then you can check the directories inside the folder.

For example, let’s check all the databases created in the folder “databases”

Type:

# cd databases

# ls

ls

TestingDatabase

Thanks for reading, and I hope this helps.  If you have any questions about this specific tutorial or any other issues re: coding for Android, drop us a line any time from our contact page!

Nirav Shah
Software Engineer
Sourcebits Tech Pvt Ltd.

Whenever a user launches an Android application, a thread called “main” is automatically created. This main thread, also called the UI thread, is crucial since it’s responsible for dispatching events to various widgets, including the drawing events. For careless Android developers, this single thread can be the overarching reason for poor app performance. With so much riding on a single thread performing long operations like network access or database queries, any interference on this thread will block up the entire user interface. No events can be dispatched – including drawing events – while long operations are underway, and from the user’s perspective, the application appears hung. Even worse, if the UI thread is blocked for more than a few seconds (about 5 seconds currently) the user will encounter the dreaded “application not responding” (ANR) dialog.

BaseAdapter is an Adapter object that acts as a bridge between an AdapterView and the underlying data for that view. The Adapter provides access to specific data points and is also responsible for making a View for each point in the data set. So, taking the example of downloading an image over HTTP, there may be some slowdown in our application with the Main UI thread getting blocked for more than a few seconds, and users might be presented with the ANR dialog. To avoid this situation I have some suggestions:

1. Use ExecuterService (Thread pool)
2. Use AsynTask
3. Use SoftReference Drawable Object
4. Create the ListView first, then download images
5. Make use of OnScrollListener Interface

I’ve written a sample application to help Android developers visualize this implementation.

Here we have AbastractListAdapter, an extension of BaseAdapterClass:

public abstract class AbstactListAdapter extends BaseAdapter {
	public AbstactListAdapter(Context context) {
		this.context = context;
	}
	public abstract void setScrollStatus(boolean scroll);
	public abstract void scrollIdle(AbsListView view);
}

There are two methods of implementation for Class ListAdapterScrollListener and Onscrollistner.

public void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount) {
		adapter.setScrollStatus(true);
	}
public void onScrollStateChanged(AbsListView view,intSrollState) {
		switch (scrollState) {
		case OnScrollListener.SCROLL_STATE_IDLE:
			adapter.scrollIdle(view);
			break;
		case OnScrollListener.SCROLL_STATE_TOUCH_SCROLL:
			adapter.setScrollStatus(true);
			break;
		case OnScrollListener.SCROLL_STATE_FLING:
			adapter.setScrollStatus(true);
			break;
		}
}

In my onCreate method I set up and configure the list view to load the views and set the listner for Scroll.

public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Adapter mAdapter=new Adapter(this);
        setListAdapter(mAdapter);
        getListView().setOnScrollListener(new 		ListAdapterScrollListener(mAdapter));
      }

I use an Adapter class to extend AbstractAdapterClass and implement BaseAdapter, both of which help to load images when scrolling is idle.

The image is loaded in a separate threadpool. I have used Executerservice and assign a threadpool to download images. This method employs a runnable which will extend Assigntask. This ImageLoader class has a subclass, workerthread, which extends Assyntask and implements runnables. This class uses ExecutorService, and assigns 5 threads to do the work. Other implementations of this kind launch a separate thread per image, meaning that the network connection will become clogged with any image load. Assigning the task to the workerthread subclass and using onprogressupdate to notify the adapter to display the image reduces the burden.

You’ll notice the use of SoftReference here. While this appears to work well, I haven’t done any significant load or performance testing, so it may not be necessary. Since bitmap/drawable objects require memory, and Android supports 16mb of heap, it’s better to classify those objects as SoftReference objects. SoftReferences pointing to softly reachable objects are guaranteed to be cleared before the VM triggers an OutOfMemoryError. This can be written as follows:

 public class ImageLoader {

private class WorkerThread extends AsyncTask implements Runnable{
		public WorkerThread(String url,int pos) {
			this.url=url;
			intex=pos;
			}
		@Override
		protected void onProgressUpdate(Void... values) {
			mAdapter.notifyDataSetChanged();
			super.onProgressUpdate(values);
		}
		@Override
		public void run() {
			Cache.put(intex,new SoftReference(readDrawableFromNetwork(this.url)));
			publishProgress();
		}
	}

	public Drawable getDrawble(int pos)
	{
		SoftReference mReference=Cache.get(pos);;
		if(mReference!=null)
			return mReference.get();
		else
			return null;
	}

/*method to get Image if already or to start new task to download*/
	public void loadImage(int First,int Last) {
			try{
					_exec = Executors.newFixedThreadPool(5);
				for(int pos=First;pos<=Last;pos++){
					if(Cache.containsKey(pos)){
						if(Cache.get(pos).get()==null)
							_exec.execute(new  WorkerThread(Dataset.mStrings[pos],pos));
					}else{
						_exec.execute(new  WorkerThread(Dataset.mStrings[pos],pos));
					}
				}
			}catch (Exception e) {
				_exec.shutdown();
			}

	}//end of method

	private static Drawable readDrawableFromNetwork(String url ) {
	   Write code here to downlaod image from network.
	}//end of method
}

And that’s it!

For your reference, the code has been packaged for you to download and inspect here.

Anyone with significant time in mobile application development understands the challenges of writing portable applications. There are tons of reasons for this, but probably the biggest hurdles we face are:

• Varying screen sizes
• Varying screen resolutions
• Varying hardware configurations
• Varying media formats; such as for images, audio, video
• Varying input methods; e.g. touch screen, T9 key pad, qwerty keypad
• Non-standard, device-specific hardware keys

And so on and so forth >_<

Android engineers, anticipating the witches brew of OEM handsets they would encounter, took steps to try and alleviate the situation by standardizing some key features:

• A very rich widget set that can scale according to needs
• Standardized way of implementing custom widgets
• Standardized user interface conventions for touch screen devices
• Standardized image capture formats {still buggy from time to time}
• Standardized mechanism for sharing code across different components; such as user interface elements, fixed content or a specific activity
• Standardized on a base set of hardware keys; e.g. Home, Back, End, and Trackball

Above notwithstanding, with screen sizes and resolutions still very much device dependent {see: T-Mobile G1, Motorola Droid, Google Nexus One, HTC Hero and so on}, creating a consistent UI that both looks good and works well on all platforms has been a slog. For Android developers or those just interested in Android application development, here we present a method and a design pattern that can be utilized to achieve precisely that. The focus points are as follows:

• Understand the functionality that needs to be replicated per device. This can be represented by a Java interface to achieve, for example, scaled UI elements across varying screen sizes and resolutions.
• Separate device-specific features into device-specific implementations. For example, each phone {including from the same manufacturer} might have different hardware keys, or even different keypads (such as T9, QWERTY, or SureType). If an application is to work on different phones with different input mechanisms, it must take into account these differences when implementing.
• A Class Factory that can intelligently instantiate the device-specific components of multiple handset designs.

Let’s take for example the case of displaying a splash screen at application launch. Here we address the issue of supporting for multiple devices. The first act of separating the functionality begins with this interface:

public interface SplashableScreen {
public void showSplashImage(ImageView mView);
public void startSpalshing() throws Exception;
public void SetSplashDuration(int time);

}

Any screen that can be shown as a splash has the functionality as described by the methods indicated.

A device-specific implementation / screen-specific implementation can be written as follows:

public class SplashScrren_320_480 implements SplashableScreen{
public void showSplashImage(ImageView mView){
// Write code speficic to this resolution.
}

}

And a proper implementation can be instantiated and used as follows:

public class SplashFactory{
public static SplashableScreen getSplashScreen(){
// Given a device metrics, instantiate appropriate class and return.
}
}

We’re pleased to offer the full code for this useful application for download here.

Android facebook users, you don’t have to feel left out of the facebook juggernaut anymore – you get the same easy to use, popular facebook that is making waves on the iPhone, on your Android.

The Design follows the same popular features of facebook you are used to, and far superior to the clones that are a dime a dozen on the android market.

Of course you have to use certain features like registering for an account and editing your profile settings on the popular facebook website , but this app comes very close to the home grown iPhone app. Actually, it beats it in looks and some features of user-intuitiveness.

Facebook opened up its API for 3^rd party development, saying they were not interested to pursue other platforms after having developed an in-house version for the iPhone. RIM engineers also collaborated with Facebook to develop one for the blackberry. One is not aware of the reason why this step motherly treatment for Android, but it is. This could be due to Google going the MySpace way, but it is true that Facebook has even stopped building their API in java since mid 2008.

Facebook has not opened up its API fully. It is still holding on to Chat and Inbox APIs. A lot of Android and 3^rd party apps out there are only catering to obtaining News Feeds, friend -lists from Facebook and sending SMSs in the form of status updates, and thats about it!.

AndroidBook has broken the barrier, it is the closest you can get to the iPhone app developed by Facebook. We did it the tough way – but we did it!. This despite the fact that facebook for iPhone is a homegrown application, which had access to the closed facebook APIs.

Features of AndroidBook:

• Login – Login to Facebook, and provide link to Facebook website for Sign Up

Home:

• News Feeds (Status Updates and Links)
• Notifications (Updates to Photos)
• Requests (Friend requests)

Profile:

• Wall (Compose status updates on wall)
• Info (Information of Logged in User)
• Photos, Take, Replace and Upload to personal Album.

Friends:

• Friends Search and Friends Profile

Chat:

• Chat with Available friends

E-mail:

• Inbox (Select, Compose, Reply and Send)
• Sent (Delete)
• Updates (Events Notifications)

Take Photo, Cancel, Replace or Save photo (store locally or upload to personal album)
Logout

Compared to investments of Apple, which has a $100 million fund to seed iPhone applications, and RIM, which has $150 million fund to seed Blackberry applications, the Google investment is a far cry away.

Judging for ADC 2 is different from ADC 1 in that there will be 30 winners against the 50 last year, and 45% of weightage for an application is decided by the community vote and 55% by the judges.
It is mandatory to submit applications that run on Android 1.5 and be in English, and those that are unpublished and non-upgraded.

ADC2 will have two rounds of judging, the first round results in 200 apps total(in 10 categories), that will proceed to the second round. Out of which 30 entries will be winners with 3 entries within the 30 picking up the prizes in the overall winners category.

The contest is expected to start in August 09 and winning entries declared by November 09. We could see a drop in the Android market uploads, as the opportunity cost of waiting is pretty high. We could also see a host of entries in the Lite version (Full-featured with expiry time), so popular applications could potentially rake in money in both places (ADC 2 and The Android Market).

One bone of contention is the ‘Supposed ban on Open Source apps ‘ My comments here.

‘The Plateau‘ takes Android’s touch screen capabilites to a whole new level.
Code is performance optimized, so lag is non-existant as you un-entangle the crossed lines by moving the orbs. To top it all, the background music is bound to leave you in a trance.

There are two modes of ‘The Plateau‘ – Challenge and Arcade.
In the non-timed Challenge mode, you can leisurely work out each level and thus help build your own strategies.
The strategy skills that you have thus acquired will help you beat the time for each level in the Arcade mode.

Every level has orbs that randomly change their color – your perceptiveness and responsiveness can help you alter your score to your advantage.
You can resume every level where you ended, you can submit your score and check your position in the high scores list – fight against yourself or the competition, which you will have in plenty,  i.e.,  if you can let go.

Be warned, this game is highly addictive, and promises to entangle you in its web and launch you to a rarefied atmosphere in outer space.