SeekBar.java 文件源码

/**
 * Converts a drawable to a tiled version of itself. It will recursively
 * traverse layer and state list drawables.
 */
private Drawable tileify(Drawable drawable, boolean clip) {
    if (drawable instanceof DrawableWrapper) {
        Drawable inner = ((DrawableWrapper) drawable).getWrappedDrawable();
        if (inner != null) {
            inner = tileify(inner, clip);
            ((DrawableWrapper) drawable).setWrappedDrawable(inner);
        }
    } else if (drawable instanceof LayerDrawable) {
        LayerDrawable background = (LayerDrawable) drawable;
        final int N = background.getNumberOfLayers();
        Drawable[] outDrawables = new Drawable[N];

        for (int i = 0; i < N; i++) {
            int id = background.getId(i);
            outDrawables[i] = tileify(background.getDrawable(i),
                    (id == android.R.id.progress || id == android.R.id.secondaryProgress));
        }
        LayerDrawable newBg = new LayerDrawable(outDrawables);

        for (int i = 0; i < N; i++) {
            newBg.setId(i, background.getId(i));
        }

        return newBg;

    } else if (drawable instanceof BitmapDrawable) {
        final Bitmap tileBitmap = ((BitmapDrawable) drawable).getBitmap();
        if (mSampleTile == null) {
            mSampleTile = tileBitmap;
        }

        final ShapeDrawable shapeDrawable = new ShapeDrawable(getDrawableShape());
        final BitmapShader bitmapShader = new BitmapShader(tileBitmap,
                Shader.TileMode.REPEAT, Shader.TileMode.CLAMP);
        shapeDrawable.getPaint().setShader(bitmapShader);
        return (clip) ? new ClipDrawable(shapeDrawable, Gravity.LEFT,
                ClipDrawable.HORIZONTAL) : shapeDrawable;
    }

    return drawable;
}