使用Loaders

public class CustomGalleryView extends FragmentActivity implements LoaderManager.LoaderCallbacks<Cursor>{

	private static final int LOADER_ID = 1;
	private Config config;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.layout_gallery_main);
		Intent clientIntent = getIntent();
		Log.i("INFO", "CustomGalleryView onCreate...");
		String windowTitle = clientIntent.getStringExtra(AppConstant.WINDOW_TITLE);
		if(!TextUtils.isEmpty(windowTitle)) setTitle(windowTitle);
		int defaultCheckResId = R.drawable.checkbox_up;
		int defaultCheckedResId = R.drawable.checkbox_selected;
		int checkboxCheckResId = clientIntent.getIntExtra(AppConstant.CHECKBOX_CHECK_RESOURCE, defaultCheckResId);
		int checkboxCheckedResId = clientIntent.getIntExtra(AppConstant.CHECKBOX_CHECKED_RESOURCE, defaultCheckedResId);
		String[] projection = { MediaStore.Images.Media.DATA,
				MediaStore.Images.Media._ID };
		String sortOrder = MediaStore.Images.Media._ID;
		Uri uri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
		config = new Config(checkboxCheckResId, checkboxCheckedResId, uri, projection, null, null, sortOrder);
		getSupportLoaderManager().initLoader(LOADER_ID, null, this);
	}

	@Override
	public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
		Log.i("INFO", "Loader_id:"+arg0+" onCreateLoader");
		CursorLoader cursorLoader = new CursorLoader(this, config.getUri(), config.getProjection(), config.getSelection(), config.getSelectionArgs(), config.getSortOrder());
		return cursorLoader;
	}

	@Override
	public void onLoadFinished(Loader<Cursor> arg0, Cursor cursor) {
		if(cursor != null){
			if(cursor.moveToFirst()){
				do {
					String path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
					int id = cursor.getInt(cursor.getColumnIndex(MediaStore.Images.Media._ID));
					Log.i("INFO", path+":"+id);
				} while (cursor.moveToNext());
			}
		}
	}

	@Override
	public void onLoaderReset(Loader<Cursor> arg0) {
		// TODO Auto-generated method stub
	}

}

    再来看看横竖屏切换时打印的情况。我们可以发现此时Activity重新onCreate，而Loader并没有重新创建，也就是说Activity为我们保存好了Loader的状态，当发生配置项改变时不用重新去创建Loader，重新加载数据。做到及时的响应用户。