使用setState与setParams反应Native [英] React Native using setState with setParams

问题描述

我正在开发一个本机应用程序，我希望能够从静态navigationOptions更改状态。我跟着这个： https://github.com/react-navigation/react -navigation / issues / 1789

I'm working on a react native app where I'd like to be able to change the state from the static navigationOptions. I was following this: https://github.com/react-navigation/react-navigation/issues/1789

并实施了以下解决方案之一：

And have implemented one of the solutions as follows:

static navigationOptions = ({navigation}) => {
    const { state } = navigation;
    const {params = {}} = navigation.state;
    navigation.params = {title: "", description: "", points: 0, image: {}, saveImage: true};
    return {
      headerRight: ( <Button transparent onPress={()=> params.create()}><Icon name="ios-add" style={{color: 'white'}}/></Button>)
    };
  };

  componentDidMount() {
    this.props.navigation.setParams({
        create: this.openCreateModal
    });
  }

  openCreateModal() {
    this.setState({createModalVisible:true});
  }

不幸的是，当我按下按钮调用openCreateModal函数时，我收到错误 this.setState不是函数。

Unfortunately when I call the openCreateModal function by pressing the button, I get the error this.setState is not a function.

我很感激任何帮助。

推荐答案

您的 openCreateModal（）方法未绑定。在该问题上进一步了解并且有人指出那个错误。

Your openCreateModal() method is not bound. Look further down in that issue and someone points out that mistake.

要解决此问题，您需要显式绑定它，以便它可以访问正确的 this 上下文，例如在你的构造函数中：

To fix this, you either need to explicitly bind it so it has access to the correct this context, for example in your constructor:

constructor(props) {
  super(props);

  this.openCreateModal = this.openCreateModal.bind(this);
}

或者你可以将它转换成ES6箭头函数，它会自动绑定它像这样的类的上下文：

Or you can convert it to an ES6 arrow function which would auto-bind it to the class's context like so:

openCreateModal = () => {
  this.setState({createModalVisible:true});
}

这篇关于使用setState与setParams反应Native的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！