docs: @Override
      public boolean onMenuItemClick(MenuItem item) {
          boolean handled = false;
  
          ShareTarget target = mShareTargets.get(item.getItemId());
  
          // 首先响应target自带的listener
          if (target.listener != null) {
              handled = target.listener.onMenuItemClick(item);
          }
  
          if (handled) {
              return true;
          }
  
          // 其次响应外部设置的listener
          if (mOnMenuItemClickListener != null) {
              handled = mOnMenuItemClickListener.onMenuItemClick(item);
          }
          if (handled) {
              return true;
          }
  
          if (target.packageName == null || target.className == null) {
              return true;
          }
  
          // 最后响应默认的intent
          ComponentName chosenName = new ComponentName(
                  target.packageName,
                  target.className);
          Intent intent = new Intent(mIntent);
          intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
          intent.setComponent(chosenName);
          if (DEBUG) {
              Log.v(TAG, "onMenuItemClick() target=" + chosenName);
          }
          try {
              mContext.startActivity(intent);
          } catch (Exception e) {
              Log.e(TAG, "onMenuItemClick() error: " + e);
              Toast.makeText(mContext, R.string.share_action_provider_target_not_found, Toast.LENGTH_SHORT).show();
          }
          return true;
      }