Question

我从我的API获得一个大小，该大小适用于邮递员，也适用于该应用程序。我将其分配给我的尺寸状态，如果我写console.warn(this.state.size)，将出现一个空警告，这表示此尺寸为空；如果我写console.error(this.state.size)，则将出现数字2，即答案。

我只是想从API分配一些变量，但是如果我将它们声明为状态，则会在状态上产生问题循环，因此我将它们设置为全局数组。我不知道是什么引起了问题，但是从0到大小的loadnum将从1到2。

UNSAFE_componentWillMount() {
this.setState({loading : true});
    fetch(API_URL + '/auth/getsize', {
      method: 'GET',
      headers: {
        Accept: 'application/json',
        'Authorization' : 'Bearer ' + window._token,
      },
    })
    .then((response) => response.json())
    .then((responseJson) => {
        this.setState({loading : false});
      response = ""+responseJson.message;
      if(response == "Unauthenticated."){
        console.warn(responseJson.message);
        }else {
          this.setState({size : responseJson.size}, function () {console.error(responseJson.size)});
      }
    })
    .catch((error) => {
      console.error(error);
    });

}

render() {
return (
  <Container>
    <Header> 
    <Left>
        <Button
          transparent
          onPress={() => {
            this.props.navigation.openDrawer()}}
        >
          <Icon name="menu" />
        </Button>
      </Left>
        <Body style = {{
          justifyContent: "flex-end",
          alignItems: "flex-end"}}>
        <Title>صفحه اصلی</Title>
      </Body>
    </Header>
    <Content>
    <ListView  enableEmptySections={true}  dataSource={ 
        new ListView.DataSource(
            {
                rowHasChanged: (r1, r2) => r1 !== r2
            }
            ).cloneWithRows(global.num)} 
        renderRow={
            (rowData) => 
            <ListItem avatar>
              <Left>
              <Thumbnail source={require('../img/avatar.jpg')} />
            </Left>
            <Body>
              <Text>{global.title[rowData-1]}</Text>
              <Text note>{global.author[rowData-1]}</Text>
            </Body>
            <Right>
              <Text note>1:06 pm</Text>
            </Right>
          </ListItem>
        } />
    </Content>
    <Button style = {{marginBottom : 5}}onPress={()=>{
      this.fetchContent();
    }}>
    <Icon name ="refresh"/>
    </Button>
  </Container>
);

} }

export default class ListAvatarExample extends Component {
constructor(props) {
super(props);
this.state = {size:0 ,loading : false};
global.title = [];
global.num = [];
global.data = [];
global.author = [];
global.imageurl = [];
  }
  loadnum = 0;

addNum(id){
  global.num.push(id);
}
addTitle(newTitle) {
  global.title.push(newTitle);
}
addAuthor(newAuthor) {
  global.author.push(newAuthor);
}
addData(newData) {
  global.data.push(newData);
}
addImgurl(newImgurl) {
  global.imageurl.push(newImgurl);
}



fetchContent() {
this.setState({size :2}, function () {
  for(this.loadnum ; this.loadnum < this.state.size; this.loadnum++)
{
    fetch(API_URL + '/auth/getcontent/' + this.loadnum, {
      method: 'GET',
      headers: {
        Accept: 'application/json',
        'Authorization' : 'Bearer ' + window._token,
      },
    })
    .then((response) => response.json())
    .then((responseJson) => {
        this.setState({loading : false});
      response = ""+responseJson.message;
      if(response == "Unauthenticated."){
        console.warn(responseJson.message);
        }else {
          this.addNum(this.loadnum);
          this.addTitle(responseJson.title);
          this.addAuthor(responseJson.author);
          this.addData(responseJson.data);
          this.addImgurl(responseJson.imageurl);
      }
    })
    .catch((error) => {
      console.error(error);
    });     
  }
   console.warn(JSON.stringify(global.title));
   console.warn(this.loadnum)
   this.setState({ loading : !this.state.loading});
  });

 }

反应本机变量不会及时分配

0 个答案: