Android-如何检测自定义形状按钮的单击区域的透明度

Question

I have some irregular shaped buttons, created as ImageButtons. The "android:src" attribute of the ImageButtons are .PNG files with transparent backgrounds. And the parent layout of these ImageButtons, has a custom background image, which is defined with "android:background" attribute. So the background of the activity is not transparent or just black.

My question is; how can I detect if a click on a button is on the transparent area of the source image, or on the visible part of the source image?

I tried using onTouchListener to get the coordinates of the event and make a decision according to the color of the pixel; but since the background is colorful, I couldn't get to a point.

Any help is very much appreciated. Thanks in advance!

Answer 1

Hi bro i think this link may help you.

http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/1.5_r4/android/view/View.java#View.dispatchTouchEvent%28android.view.MotionEvent%29

You need to override this method in your custom button to return false if point is not in the desired area. I suggest you go about it like this:

public static class MyButton extends ImageButton {
    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        int iX = (int) event.getX();
        int iY = (int) event.getY();

        // TODO Or use a more sophisticated, pixel value-based condition
        if (!(iX >= 0 & iY >= 0 & iX < TheBitmap.getWidth() & iY < TheBitmap.getHeight())) {
            return false;
        }
        return super.dispatchTouchEvent(event)
    }
}