Android 界面置灰

1.Activity中：在Activity的OnCreate方法中设置

setViewGray(getWindow().getDecorView());

public void setViewGray(View view) {
    Paint paint = new Paint();
    ColorMatrix cm = new ColorMatrix();
    cm.setSaturation(0f);
    paint.setColorFilter(new ColorMatrixColorFilter(cm));
    view.setLayerType(View.LAYER_TYPE_HARDWARE, paint);
}

2.Dailog：直接调用 
setViewGray(dialog的View);  就行了