javascript - setState 方法未被调用

Question

我的 setState 方法没有被调用，而打印 setState 之后的值总是打印默认值。我正在使用博览会

从'react'导入React；

从 './KeyboardShift' 导入 KeyboardShift；从 'react-native-floating-labels' 导入 FloatingLabel；

export default class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      focusDescriptionInput: false
    }
  }
  render() {
    return (
      <SafeAreaView style={styles.container}>
        <KeyboardShift>
          { () => (
            <View>
              <FloatingLabel 
              labelStyle={styles.labelInput}
              inputStyle={styles.input}
              style={styles.formInput}
              returnKeyType={"next"}
              onSubmitEditing={() => {
                console.log(this.state.focusDescriptionInput)
                context.setState({
                  focusDescriptionInput:true
                })
                console.log(this.state.focusDescriptionInput)
              }}>
                Email
            </FloatingLabel>
            <FloatingLabel
              labelStyle={styles.labelInput}
              inputStyle={styles.input}
              style={styles.formInput}
              focus={this.state.focusDescriptionInput}>
                Email 2
            </FloatingLabel>


            </View>
          )}

          </KeyboardShift>
      </SafeAreaView>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent:"center",
    alignItems:"center",
    marginTop: 50
  },
  textInput: {
    fontSize: 16,
    height: 40,
    marginTop: 16
  },
  labelInput: {
    color: '#673AB7',
  },
  formInput: {    
    borderBottomWidth: 1.5, 
    marginStart: 20,
    marginEnd:20,
    borderColor: '#333',       
  },
  input: {
    borderWidth: 0
  }
});

Answer 1

使用 this.setState 代替 context.setState。

并且在你的代码中如果你想在setState之后打印状态的值，它应该是:

            onSubmitEditing={() => {
                console.log(this.state.focusDescriptionInput)
                this.setState({
                  focusDescriptionInput:true
                }, () => {
                   console.log(this.state.focusDescriptionInput)
                })

              }}>

为什么？请记住，setState 是异步。所以，在这个例子中我只是使用了setState的回调函数。希望这对您有所帮助!