Live wallpaper using animated gif ( with centercrop scaletype)

Question

How to create a simple live wallpaper using animated .gif image? I'm getting .gif image not proportioned to the screen. How to make it centercrop?

Answer 1

In my opinion the selected answer is somewhat incomplete and not generic as it mentions hard coded values and doesn't keep in mind different screen sizes. It would be much easier to just get the values sent by onSurfaceChanged method and to use them to scale the Canvas object.

Basically, we take the ratio of the screen width to the movie(GIF) width and the ratio of the screen height to the movie height. These two variables are then used to scale the canvas to fill across the screen perfectly.

Firstly, store the width and height you get from onSurfaceChanged method globally.

@Override
public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    super.onSurfaceChanged(holder, format, width, height);
    this.width = width;
    this.height = height;
    //GLOBALLY DECLARED
}

onSurfaceChanged runs right after onCreate runs so don't worry, the values will be stored in variables width and height before they are used.

Later when you are initializing the canvas, scale it by using the ratio of the screen size to the movie size. PS - movie is a Movie object associated with the GIF we are working with.

float x = (float)width / (float)movie.width();
float y = (float)height / (float)movie.height();
canvas.scale(x,y);

Answer 2

Your activity file

public class GIFWallpaperService extends WallpaperService {

@Override
public WallpaperService.Engine onCreateEngine() {
    try {
        Movie movie = Movie.decodeStream(
                getResources().getAssets().open("owlinsnow.gif"));

        return new GIFWallpaperEngine(movie);
    }catch(IOException e){
        Log.d("GIF", "Could not load asset");
        return null;
    }
}

private class GIFWallpaperEngine extends WallpaperService.Engine {

    private final int frameDuration = 20;

    private SurfaceHolder holder;
    private Movie movie;
    private boolean visible;
    private Handler handler;

    public GIFWallpaperEngine(Movie movie) {
        this.movie = movie;
        handler = new Handler();
    }

    @Override
    public void onCreate(SurfaceHolder surfaceHolder) {
        super.onCreate(surfaceHolder);
        this.holder = surfaceHolder;
    }

    private Runnable drawGIF = new Runnable() {
        public void run() {
            draw();
        }
    };


    private void draw() {
        if (visible) {
            Canvas canvas = holder.lockCanvas();
            canvas.save();
            // Adjust size and position so that
            // the image looks good on your screen
            canvas.scale(2f, 2f);
            movie.draw(canvas, -100, 0);
            canvas.restore();
            holder.unlockCanvasAndPost(canvas);
            movie.setTime((int) (System.currentTimeMillis() % movie.duration()));

            handler.removeCallbacks(drawGIF);
            handler.postDelayed(drawGIF, frameDuration);
        }
    }

    @Override
    public void onVisibilityChanged(boolean visible) {
        this.visible = visible;
        if (visible) {
            handler.post(drawGIF);
        } else {
            handler.removeCallbacks(drawGIF);
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        handler.removeCallbacks(drawGIF);
    }
}
}

Manifest file

<application android:allowBackup="true" android:label="@string/app_name"
    android:icon="@drawable/owl" android:theme="@style/AppTheme">

    <service
        android:name=".GIFWallpaperService"
        android:enabled="true"
        android:label="Owl in Snow"
        android:permission="android.permission.BIND_WALLPAPER" >
        <intent-filter>
            <action android:name="android.service.wallpaper.WallpaperService"/>
        </intent-filter>
        <meta-data
            android:name="android.service.wallpaper"
            android:resource="@xml/wallpaper" >
        </meta-data>
    </service>

</application>

<uses-feature
    android:name="android.software.live_wallpaper"
    android:required="true" >
</uses-feature>

Create xml directory under res and wallpaper.xml inside it.

<?xml version="1.0" encoding="UTF-8"?>
<wallpaper
xmlns:android="http://schemas.android.com/apk/res/android"
android:label="GIF Wallpaper"
android:thumbnail="@drawable/owl">
</wallpaper>

Make sure you place the gif image inside assets folder. To create an asset folder click on file->New->Folder->assets