Divide and Conquer

Years ago I was addicted to a simple game that I played on my then state-of-the-art Pentium-75. In this game, balls would bounce around, and I would try to partition them into small enough spaces so that I could go to the next level where more and more balls would be added. As of a couple of months ago, for the life of me, I couldn't remember the name of this game. So when I sat down to write an application for Android in my 20% time, I thought, why not try to recreate something similar? After completing most of the game and showing it to some of my friends at work, one of them said, "Oh, this reminds me of JezzBall!" Eureka! If working on this game does nothing more than reveal the name of one of the favorite games of my youth, I'll call it a success, but in the meantime, I'm happy to announce that the source of this application, named Divide and Conquer, is now available on apps-for-android.

The game starts with instructions:

and begins simply enough with one ball bouncing around. You drag your finger in a horizontal or vertical gesture on the screen to initiate a line that extends until it reaches the edges:

In each level, once you've shaved off 80% of the original area, you move to the next level. Here's a screen shot of level 6:

If a ball hits a line in progress, you lose a life:

Once you are out of lives, it is game over:

While this game isn't going to win any awards for cutting edge graphics, it demonstrates use of several Android features and APIs:

• custom drawing and animation
• touch input based gesture detection


• overriding the default behavior of the back key in some situations (to pause the game)


• creating custom Dialogs


• configuring an application to be full screen with no title or status bar
• use of the preferences framework


• use of the vibrator API

DivideAndConquerView is a custom View that implements its own onDraw method using the Canvas methods, and gesture detection using onTouchEvent and a helper class DirectionPoint. It keeps track of the state of the game using BallEngine, and reports relevant events back to the main activity of the application, which, in turn, keeps track of and controls the state of the game. The application is configured to be full screen in its AndroidManifest.xml file.

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Three new Samples: Triangle, SpriteText and Downloader

I've posted three new open source samples to the apps-for-android project: Triangle, SpriteText and Downloader.

The first two samples, Triangle and SpriteText, show techniques that would be useful to anyone using the OpenGL ES 3D graphics APIs to write Android applications. The samples contain several reusable classes that may eventually be incorporated (in some form) into the SDK. Chief among these is the GLView class, which abstracts the OpenGL ES book-keeping code from the rest of the application. GLView helps handle the extra work OpenGL ES applications have to do when the activity is paused and resumed, and when the display goes to sleep and wakes up. In the Pause/Resume case the OpenGL surface has to be recreated. In the display sleep / wake-up case the entire OpenGL context has to be recreated.

Triangle

The first sample, Triangle, shows how to use the GLView class and the OpenGL ES 3D library to display a spinning textured triangle. Think of it as the "hello, world" of OpenGL ES apps. Because it's relatively simple, it's a good place to start when experimenting with the OpenGL ES API.

SpriteText

The second sample, SpriteText, shows how to efficiently display screen-aligned text using the GL11Ext.glDrawTexiOES method. SpriteText contains a reusable LabelMaker class for drawing static text and screen-aligned images, as well as a Projector class for finding the 2D screen coordinates corresponding to a 3D point, and a MatrixTrackingGL class for keeping track of the current transformation matrix. Finally, it shows how to use these classes to display a milliseconds per frame counter. A ms/f counter can be helpful for tuning graphics performance.

Downloader

The third sample, Downloader, shows how to add a downloader activity to your application. The downloader activity runs at the beginning of your application and makes sure that a set of files have been downloaded from a web server to the phone's SD card. Downloader is useful for applications that need more local data than can fit into an .apk file. For example a game could use Downloader to download the game's artwork, sound effects, and level data. The Downloader activity is designed to be a drop-in addition to your application. You customize it by supplying the URL of an XML configuration file which lists the data files that need to be downloaded.

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Android Photostream

I'm pleased to announce that a new open source sample application—called Photostream—has been added to the apps-for-android project. Photostream is a simple photos browser and viewer for Flickr. All you need to use it is a Flickr screen name or user name (the application offers a default user name if you just want to try it.)

This application serves as an illustrative example of several Android features and APIs:

• Activity aliases


• Adding custom shortcuts to Home


• Adding a new wallpaper chooser to the system


• Custom layouts


• Custom XML attributes


• Use of themes


• Use of styles


• Use of text colors


• Use of <include>


• Use of bitmap and layer drawables from XML


• Use of HttpClient


• Proper interaction between background threads and the UI thread


• Efficient display rotation (using the new onRetainNonConfigurationInstance() API)


• Animations and layout animations


• Cropping an image


• Image manipulation

My favorite feature is the ability to add a new shortcut type in Home, to create a shortcut to any Flickr account. The shortcut shows a custom icon, downloaded from the Flickr user profile:

If you plan on reusing the source code to access Flickr in your own application, you should modify the Flickr.java file to replace the existing API key with your own. The application source code also contains a very handy class called UserTask.java. This class is designed to help you easily write background operations that interact with the UI thread.

You have read this article Apps with the title . You can bookmark this page URL https://azaquery.blogspot.com/2008/09/android-photostream.html. Thanks!