Warning: file_get_contents(/data/phpspider/zhask/data//catemap/9/javascript/453.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181

Warning: file_get_contents(/data/phpspider/zhask/data//catemap/3/reactjs/21.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181

Warning: file_get_contents(/data/phpspider/zhask/data//catemap/5/date/2.json): failed to open stream: No such file or directory in /data/phpspider/zhask/libs/function.php on line 167

Warning: Invalid argument supplied for foreach() in /data/phpspider/zhask/libs/tag.function.php on line 1116

Notice: Undefined index: in /data/phpspider/zhask/libs/function.php on line 180

Warning: array_chunk() expects parameter 1 to be array, null given in /data/phpspider/zhask/libs/function.php on line 181
Javascript 如何在react native中渲染对象?_Javascript_Reactjs_React Native - Fatal编程技术网

Javascript 如何在react native中渲染对象?

Javascript 如何在react native中渲染对象?,javascript,reactjs,react-native,Javascript,Reactjs,React Native,我正在使用react native开发一个链接到firebase的简单应用程序。我有一个类,其中有几个方法,就我在线搜索这个问题所知,它似乎与渲染函数中的输出有关。但是我检查了我的方法,我无法确定确切的问题 这是我的班级: class ToDo_React extends Component { constructor(props) { super(props); var myFirebaseRef = new Firebase(' '); this.itemsRef = m

我正在使用react native开发一个链接到firebase的简单应用程序。我有一个类,其中有几个方法,就我在线搜索这个问题所知,它似乎与渲染函数中的输出有关。但是我检查了我的方法,我无法确定确切的问题

这是我的班级:

class ToDo_React extends Component {
  constructor(props) {
    super(props);
  var myFirebaseRef = new Firebase(' ');
  this.itemsRef = myFirebaseRef.child('items');

  this.state = {
    newTodo: '',
    todoSource: new ListView.DataSource({rowHasChanged: (row1, row2) => row1 !== row2})
  };

  this.items = [];
}
componentDidMount() {
  // When a todo is added
  this.itemsRef.on('child_added', (dataSnapshot) => {
    this.items.push({id: dataSnapshot.key(), text: dataSnapshot.val()});
    this.setState({
      todoSource: this.state.todoSource.cloneWithRows(this.items)
    });
  });
  this.itemsRef.on('child_removed', (dataSnapshot) => {
      this.items = this.items.filter((x) => x.id !== dataSnapshot.key());
      this.setState({
        todoSource: this.state.todoSource.cloneWithRows(this.items)
      });
  });
}
    addTodo() {
  if (this.state.newTodo !== '') {
    this.itemsRef.push({
      todo: this.state.newTodo
    });
    this.setState({
      newTodo : ''
    });
  }
}
    removeTodo(rowData) {
  this.itemsRef.child(rowData.id).remove();
}
render() { return (
<View style={styles.appContainer}>
  <View style={styles.titleView}>
    <Text style={styles.titleText}>
      My Todos
    </Text>
  </View>



<View style={styles.inputcontainer}>
    <TextInput style={styles.input} onChangeText={(text) => this.setState({newTodo: text})} value={this.state.newTodo}/>
    <TouchableHighlight
      style={styles.button}
      onPress={() => this.addTodo()}
      underlayColor='#dddddd'>
      <Text style={styles.btnText}>Add!</Text>
    </TouchableHighlight>
  </View>
  <ListView
    dataSource={this.state.todoSource}
    renderRow={this.renderRow.bind(this)} />
</View>
);
}
renderRow(rowData) {
return (
<TouchableHighlight
underlayColor='#dddddd'
onPress={() => this.removeTodo(rowData)}>
<View>
<View style={styles.row}>
  <Text style={styles.todoText}>{rowData.text}</Text>
</View>
<View style={styles.separator} />
</View>
</TouchableHighlight>
);
}
}
类ToDo\u组件{
建造师(道具){
超级(道具);
var myFirebaseRef=新的Firebase(“”);
this.itemsRef=myFirebaseRef.child('items');
此.state={
纽托德:“,
todoSource:new ListView.DataSource({rowHasChanged:(row1,row2)=>row1!==row2})
};
此参数为.items=[];
}
componentDidMount(){
//添加待办事项时
this.itemsRef.on('child_added',(dataSnapshot)=>{
this.items.push({id:dataSnapshot.key(),text:dataSnapshot.val()});
这是我的国家({
todoSource:this.state.todoSource.cloneWithRows(this.items)
});
});
this.itemsRef.on('child_removed',(dataSnapshot)=>{
this.items=this.items.filter((x)=>x.id!==dataSnapshot.key());
这是我的国家({
todoSource:this.state.todoSource.cloneWithRows(this.items)
});
});
}
addTodo(){
如果(this.state.newTodo!=''){
此.itemsRef.push({
托多:这个。州。纽托多
});
这是我的国家({
新主题:“”
});
}
}
removeTodo(行数据){
this.itemsRef.child(rowData.id).remove();
}
render(){return(
我的待办事项
this.setState({newTodo:text})值={this.state.newTodo}/>
this.addTodo()}
参考底色='#dddddd'>
添加
);
}
renderRow(行数据){
返回(
this.removeTodo(rowData)}>
{rowData.text}
);
}
}

问题在于您的
renderRow
方法,其中您渲染:

<Text style={styles.todoText}>{rowData.text}</Text>
请注意,
val()

因此,您可能想在这里执行的操作是推送
this.state.newTodo
而不是对象

this.items.push({id: dataSnapshot.key(), text: dataSnapshot.val()});
this.itemsRef.push({
  todo: this.state.newTodo
});