这里我们使用一个自定义view来为图片蒙层。该方法投机取巧，直接把一张有透明效果的图片直接画到原图上。tranparent.png那张图片可以换成用bitmap自己画，以后改进。先上效果图:上面是原图，下面是蒙层后的效果
public class CenterImage extends ImageView {
private Paint paint;
private boolean isCenterImgShow;
private Bitmap bitmap;
public void setCenterImgShow(boolean centerImgShow) {
isCenterImgShow = centerImgShow;
if (isCenterImgShow) {
bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.transparent);
invalidate();
}
}
public CenterImage(Context context) {
super(context);
init();
}
public CenterImage(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public CenterImage(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
paint = new Paint();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (isCenterImgShow && bitmap != null) {
//从中心点开始画
canvas.drawBitmap(bitmap, getMeasuredWidth() / 2 - bitmap.getWidth() / 2, getMeasuredHeight() / 2 - bitmap.getHeight() / 2, paint);
}
}
}<com.epos.testrxjava.CenterImage
android:layout_below="@id/image"
android:id="@+id/goodsImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/dog" />调用：
CenterImage mGoodsImg =(CenterImage)findViewById(R.id.goodsImage);
mGoodsImg.setCenterImgShow(true);透明图片：
