小编Roo*_*Roo的帖子

我在另一个线程中启动NSURLConnection:

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0),
        ^{
            NSURLConnection *connection = [NSURLConnection connectionWithRequest:[request preparedURLRequest] delegate:self];
            [connection start];
         });

但是我的委托方法没有被调用:

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData*)data;

在主线程上运行时一切都很好.如何在另一个线程上运行连接并获取在同一线程上调用的委托方法？

我StaggeredGridLayout为我做了这个RecyclerView:

这是代码:

 @Override
public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, final int position) {

    Photo photo = mPhotos.get(position);

    TextView titleView = ((CellViewHolder) viewHolder).titleTextView;
        titleView.setText(photo.getTitle());

    TextView subTitleView = ((CellViewHolder) viewHolder).subtitleTextView;
        subTitleView.setText(photo.getName());

    Picasso.with(mContext).load(photo.getPhotoUrl()).into(((CellViewHolder) viewHolder).imageView);

    ImageView userImageOverlay = ((CellViewHolder) viewHolder).userImageOverlay;

    StaggeredGridLayoutManager.LayoutParams layoutParams = (StaggeredGridLayoutManager.LayoutParams) viewHolder.itemView.getLayoutParams();

    if (position == 0 || position % 4 == 0) {
        layoutParams.setFullSpan(true);
        layoutParams.height = Math.round(Utils.convertDpToPixel(202.67f, mContext));
        titleView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 21.67f);
        subTitleView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 12.00f);
        userImageOverlay.setVisibility(View.VISIBLE);
    } else if ((position - 1) % 4 == 0) {
        layoutParams.setFullSpan(false);
        layoutParams.height = Math.round(Utils.convertDpToPixel(360.00f, mContext)); …

我有一个简单的两屏应用程序，其中包含redux和React-Native-Navigation V2。我尝试将项目从列表传递到另一个视图作为道具。不幸的是，我得到一个错误：

TypeError：无法读取未定义的属性“ id”

该项目已通过但未在第二视图中作为道具被接收。在没有Redux的情况下，一切正常。我是否正确注册了视图？

查看注册：

export default (store) =>  {
  Navigation.registerComponent('example.app.FirstScreen', reduxStoreWrapper(FirstScreen, store));
  Navigation.registerComponent('example.app.SecondScreen', reduxStoreWrapper(SecondScreen, store));
}

function reduxStoreWrapper (MyComponent, store) {
  return () => {
    return class StoreWrapper extends React.Component {
      render () {
        return (
          <Provider store={store}>
            <MyComponent />
          </Provider>
        );
      }
    };
  };
}

第一视图：

class FirstScreen extends Component {
  componentDidMount() {
    this.props.listItems();
  }

  onItemPress = (item: Item) => {
    Navigation.push(item._id, {
      component: {
        name: 'example.app.SecondScreen',
        passProps: {
          item: item
        }
      }
    });
  };

  render() { …

我得到两个字节,例如0xFE和0x70,它应该代表-400的值.我怎么能把这些字节转换成有符号的短？它甚至可能吗？