Android: Array index when i first click the button it doesn't show my first index but it show the second index

Question

I'm creating an app on android for viewing the image with the sound.I got problem when i first click the next button it doesn't show the my first index image with sound but it show my second index. i want to show my first index when i first click on the next button.

   public void btn_click(View v){
  ImageView imageview = (ImageView)findViewById(R.id.ImageViewPreview3);
  if (v == btn_next) {
          try {
              currentimageindex = (currentimageindex + 1) % IMAGE_IDS.length;
              currentsoundindex = (currentsoundindex + 1) % myMusic.length;
          } catch (Exception e) {
              Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
          }
      }
  if (v == btn_back) {
          try {
              currentimageindex = (currentimageindex + IMAGE_IDS.length - 1) % IMAGE_IDS.length;
              currentsoundindex = (currentsoundindex + myMusic.length - 1) % myMusic.length;
          } catch (Exception e) {
              Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
          }
      }
  imageview.setImageResource(IMAGE_IDS[currentimageindex]);
  mp = MediaPlayer.create(this, myMusic[currentsoundindex]);
  mp.start();
  }
}

Answer 1

使用equals（Object）代替==

if (v.equals(btn_next)) {
          try {
              currentimageindex = (currentimageindex + 1) % IMAGE_IDS.length;
              currentsoundindex = (currentsoundindex + 1) % myMusic.length;
          } catch (Exception e) {
              Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_SHORT).show();
          }
      }

等等。