java - 如何将 gif 转换为动态壁纸以在 Android 应用程序中使用

Question

我不需要随手机移动的精美壁纸，我只想使用 gif 作为移动的“动态”壁纸。这可能吗？如果可以，谁能向我解释它是如何完成的，或者给我指出一个演示如何做的资源？到目前为止，我一直找不到。

Answer 1

参见 GIFLiveWallpaper demo 看看github repo

public class GifLiveWallPaper extends WallpaperService {

static final String TAG = "LIVE_WALLPAPER";
static final Handler liveHandler = new Handler();

@Override
public Engine onCreateEngine() {
    try {
        return new WallPaperEngine();
    } catch (IOException e) {
        Log.w(TAG, "Error creating WallPaperEngine", e);
        stopSelf();
        return null;
    }
}

class WallPaperEngine extends Engine {

    private Movie liveMovie;
    private int duration;
    private Runnable runnable;
    float mScaleX;
    float mScaleY;
    int mWhen;
    long mStart;

    public WallPaperEngine() throws IOException {

        InputStream is = getResources().openRawResource(R.raw.sam);

        if (is != null) {

            try {
                liveMovie = Movie.decodeStream(is);
                duration = liveMovie.duration();

            } finally {
                is.close();
            }
        } else {
            throw new IOException("Unable to open R.raw.hand");
        }
        mWhen = -1;
        runnable = new Runnable() {
            public void run() {
                nyan();
            }
        };
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        liveHandler.removeCallbacks(runnable);
    }

    @Override
    public void onVisibilityChanged(boolean visible) {
        super.onVisibilityChanged(visible);
        if (visible) {
            nyan();
        } else {
            liveHandler.removeCallbacks(runnable);
        }
    }

    @Override
    public void onSurfaceChanged(SurfaceHolder holder, int format,
            int width, int height) {
        super.onSurfaceChanged(holder, format, width, height);
        mScaleX = width / (1f * liveMovie.width());
        mScaleY = height / (1f * liveMovie.height());
        nyan();
    }

    @Override
    public void onOffsetsChanged(float xOffset, float yOffset,
            float xOffsetStep, float yOffsetStep, int xPixelOffset,
            int yPixelOffset) {
        super.onOffsetsChanged(xOffset, yOffset, xOffsetStep, yOffsetStep,
                xPixelOffset, yPixelOffset);
        nyan();
    }

    void nyan() {
        tick();
        SurfaceHolder surfaceHolder = getSurfaceHolder();
        Canvas canvas = null;
        try {
            canvas = surfaceHolder.lockCanvas();
            if (canvas != null) {
                drawGif(canvas);
            }
        } finally {
            if (canvas != null) {
                surfaceHolder.unlockCanvasAndPost(canvas);
            }
        }
        liveHandler.removeCallbacks(runnable);
        if (isVisible()) {
            liveHandler.postDelayed(runnable, 1000L / 25L);
        }
    }

    void tick() {
        if (mWhen == -1L) {
            mWhen = 0;
            mStart = SystemClock.uptimeMillis();
        } else {
            long mDiff = SystemClock.uptimeMillis() - mStart;
            mWhen = (int) (mDiff % duration);
        }
    }

    void drawGif(Canvas canvas) {
        canvas.save();
        canvas.scale(mScaleX, mScaleY);
        liveMovie.setTime(mWhen);
        liveMovie.draw(canvas, 0, 0);
        canvas.restore();
    }
}
}