code: public void updateVolume(int volumeValue) {
          if (null != dialog && dialog.isShowing()) {
              int index = volumeValue / 600;
              if (index >= volumes.length - 1) {
                  index = volumes.length - 1;
              }
              mImageView.setImageResource(volumes[index]);
          }
      }
docs: 更新音量大小