@Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (mViewImage.mPaused) return false; // Don't respond to arrow keys if trackball scrolling is not enabled if (!mEnableTrackballScroll) { if ((keyCode >= KeyEvent.KEYCODE_DPAD_UP) && (keyCode <= KeyEvent.KEYCODE_DPAD_RIGHT)) { return super.onKeyDown(keyCode, event); } } int current = mViewImage.mCurrentPosition; int nextImagePos = -2; // default no next image try { switch (keyCode) { case KeyEvent.KEYCODE_DPAD_CENTER: { if (mViewImage.isPickIntent()) { IImage img = mViewImage.mAllImages .getImageAt(mViewImage.mCurrentPosition); mViewImage.setResult(ReviewImage.RESULT_OK, new Intent().setData(img.fullSizeImageUri())); mViewImage.finish(); } break; } case KeyEvent.KEYCODE_DPAD_LEFT: { if (getScale() <= 1F && event.getEventTime() >= mNextChangePositionTime) { nextImagePos = current - 1; mNextChangePositionTime = event.getEventTime() + 500; } else { panBy(PAN_RATE, 0); center(true, false); } return true; } case KeyEvent.KEYCODE_DPAD_RIGHT: { if (getScale() <= 1F && event.getEventTime() >= mNextChangePositionTime) { nextImagePos = current + 1; mNextChangePositionTime = event.getEventTime() + 500; } else { panBy(-PAN_RATE, 0); center(true, false); } return true; } case KeyEvent.KEYCODE_DPAD_UP: { panBy(0, PAN_RATE); center(false, true); return true; } case KeyEvent.KEYCODE_DPAD_DOWN: { panBy(0, -PAN_RATE); center(false, true); return true; } case KeyEvent.KEYCODE_DEL: MenuHelper.deletePhoto( mViewImage, mViewImage.mDeletePhotoRunnable); break; } } finally { if (nextImagePos >= 0 && nextImagePos < mViewImage.mAllImages.getCount()) { synchronized (mViewImage) { mViewImage.setImage(nextImagePos, true); } } else if (nextImagePos != -2) { center(true, true); } } return super.onKeyDown(keyCode, event); }