BGASwipeBackLayout.java 文件源码

private void dimChildView(View v, float mag, int fadeColor) {
    final LayoutParams lp = (LayoutParams) v.getLayoutParams();

    if (mag > 0 && fadeColor != 0) {
        final int baseAlpha = (fadeColor & 0xff000000) >>> 24;
        int imag = (int) (baseAlpha * mag);
        int color = imag << 24 | (fadeColor & 0xffffff);
        if (lp.dimPaint == null) {
            lp.dimPaint = new Paint();
        }
        lp.dimPaint.setColorFilter(new PorterDuffColorFilter(color, PorterDuff.Mode.SRC_OVER));
        if (ViewCompat.getLayerType(v) != ViewCompat.LAYER_TYPE_HARDWARE) {
            ViewCompat.setLayerType(v, ViewCompat.LAYER_TYPE_HARDWARE, lp.dimPaint);
        }
        invalidateChildRegion(v);
    } else if (ViewCompat.getLayerType(v) != ViewCompat.LAYER_TYPE_NONE) {
        if (lp.dimPaint != null) {
            lp.dimPaint.setColorFilter(null);
        }
        final DisableLayerRunnable dlr = new DisableLayerRunnable(v);
        mPostedRunnables.add(dlr);
        ViewCompat.postOnAnimation(this, dlr);
    }
}