Question

In my application, I have some images and when I tap on that image, it should be rotated by 90 degree. I am able to rotate image once but can’t rotate on second tap. Can anyone help me to solve this problem? How can I rotate image on every touch event?

if (event.getAction() == MotionEvent.ACTION_DOWN) {
    Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.quartercircle1);
        Matrix m = new Matrix();
        imgvwQrtr1.setScaleType(ScaleType.MATRIX);

        m.setRotate(90f, imgvwQrtr1.getDrawable().getBounds().width()/2, imgvwQrtr1.getDrawable().getBounds().height()/2);
        bm = Bitmap.createBitmap(bm, 0, 0, bm.getWidth(), bm.getHeight(), m, true);
        imgvwQrtr1.setImageBitmap(bm);


        ClipData data = ClipData.newPlainText("", "");
        DragShadowBuilder shadowBuilder = new DragShadowBuilder(v);
        v.startDrag(data, shadowBuilder, v, 0);
        return true;
    }

Answer 1

you need to create global variable like:

int degree = 0;

and in the code

.....
//shortest way
degree = degree + 90;
if(degree % 360 == 0) {
   degree = 0;
}
//if(degree >= 270) {
   //degree = 0;
//} else {
   //degree+=90;
//}
m.setRotate(degree, imgvwQrtr1.getDrawable().getBounds().width()/2,
imgvwQrtr1.getDrawable().getBounds().height()/2);
....