如何在Android应用中覆盖相机的缩放按钮？

Question

I'm having zxing app for barcode scanning . It's having auto-focus but i need to set zoom in/out in my app.

It will be better if i can override volume control buttons in android device for zooming in the app.

How can i implement zooming in my app using volume control buttons?

Please share your thoughts..

Answer 1

public boolean onKeyUp(int keyCode, KeyEvent event) 
{ 
   if (keyCode == KeyEvent.KEYCODE_VOLUME_DOWN) { 
       // increase your zoom
       return true;
   } else if(keyCode ==  KeyEvent.KEYCODE_VOLUME_UP){
       // decrease your zoom 
       return true;
   }
   return super.onKeyUp(keyCode, event); 
}

you can use the above onKeyUp() event to do you task:::

Answer 2

See here for how to override the volume control buttons. You can perform zoom when you capture the event.

Answer 3

Try to use dispatchKeyEvent by putting the following code in your activity.

      public boolean dispatchKeyEvent(KeyEvent event) {
        int keyCode = event.getKeyCode();
        switch (keyCode) {
        case KeyEvent.KEYCODE_VOLUME_UP:
            addIntensityLvl();
            return true;
        case KeyEvent.KEYCODE_VOLUME_DOWN:
            subtractIntensityLvl();
                return true;
        default:
            return super.dispatchKeyEvent(event);
        }
    }