模糊挖洞

public class MainActivity extends Activity {
    Context mContext;

    int count = 0;

    ImageView image;
    TextView blurview;
    View text;

    TextView clear;
    int x = 500;
    int y = 300;
    int length = 280;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mContext = this;

        setContentView(R.layout.activity_main);

        findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                count++;
                if (count % 2 == 1) {
                    findViewById(R.id.button).setBackgroundColor(Color.parseColor("#9F3730"));
                } else {
                    findViewById(R.id.button).setBackgroundColor(Color.parseColor("#303F9F"));
                }
            }
        });

        findViewById(R.id.button2).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                findViewById(R.id.button2).setVisibility(View.GONE);
            }
        });

        findViewById(R.id.button3).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // findViewById(R.id.button2).setVisibility(View.VISIBLE);
                Bitmap bitmap = getCircularBitmap(
                        ((BitmapDrawable) image.getDrawable()).getBitmap());

                clear.setBackground(new BitmapDrawable(
                        getResources(), bitmap));
            }
        });

        image = (ImageView) findViewById(R.id.picture);
        blurview = (TextView) findViewById(R.id.blur);
        clear = (TextView) findViewById(R.id.clear);
        text = findViewById(R.id.text);

        applyBlur();

    }

    private void applyBlur() {
        image.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {

            @Override
            public boolean onPreDraw() {

                image.getViewTreeObserver().removeOnPreDrawListener(this);
                image.buildDrawingCache();
                Bitmap bmp = image.getDrawingCache();
                blur(bmp, text);

                return true;
            }
        });
    }

    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
    private void blur(Bitmap bkg, View textview) {
        float radius = 25;

        Bitmap overlay = Bitmap.createBitmap((int) (image.getMeasuredWidth()),
                (int) (image.getMeasuredHeight()), Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(overlay);

        canvas.drawBitmap(bkg, 0, 0, null);

        RenderScript rs = RenderScript.create(mContext);

        Allocation overlayAlloc = Allocation.createFromBitmap(
                rs, overlay);

        ScriptIntrinsicBlur blur = ScriptIntrinsicBlur.create(
                rs, overlayAlloc.getElement());

        blur.setInput(overlayAlloc);

        blur.setRadius(radius);

        blur.forEach(overlayAlloc);

        overlayAlloc.copyTo(overlay);

        blurview.setBackground(new BitmapDrawable(
                getResources(), overlay));

        rs.destroy();
    }

    public Bitmap getCircularBitmap(Bitmap bitmap) {
        FrameLayout.LayoutParams lp = new FrameLayout.LayoutParams(length, length);
        lp.leftMargin = x;
        lp.topMargin = y;
        clear.setLayoutParams(lp);

        Bitmap output;

        output = Bitmap.createBitmap(length, length, Bitmap.Config.ARGB_8888);

        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect1 = new Rect(0 + x, 0 + y, 280 + x, 280 + y);
        final Rect rect2 = new Rect(0, 0, 280, 280);

        float r = 140;

        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        paint.setColor(color);
        canvas.drawCircle(r, r, r, paint);
        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect1, rect2, paint);

        return output;
    }
}