@Override
 protected void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   mContext = this;
   setContentView(R.layout.activity_file_manage);
   mFileTask = new FileTask();
   mFileTask.executeOnExecutor(PoolThread.THREAD_POOL_EXECUTOR, "");
   initView();
 }
 @Override
 protected void onPause() {
   super.onPause();
   if (mThumbnailTask != null && mThumbnailTask.getStatus() == Status.RUNNING) {
     mThumbnailTask.cancel(true);
   }
   if (mFileTask != null && mFileTask.getStatus() == Status.RUNNING) {
     mFileTask.cancel(true);
   }
 }
 @Override
 protected void onResume() {
   super.onResume();
 }