React Native-將父級狀態傳遞給子級時遇到麻煩

Question

一個React新手，在通過父組件（在此情況下為App ）傳遞狀態和功能以及從子組件（在此情況下為Main ）訪問狀態和功能時遇到了一些問題。 我確定這是一兩個非常簡單的錯誤，我在哪里絆倒了？

這是項目結構：

App
 |__ Rootstack
       |
       |__Favorites
       |__Main

這是精簡的代碼：

class Main extends React.Component {
  render() {
      return (
      <View>
         <Text>{this.props.favoritesList.length}</Text>
         <Card>
              onSwiped={() => {this.props.updateArray}} //the idea being that on a swipe, updateArray would add 1 to the 'favoriteList' in the parents state, and the favoritesList.length would update by +1.
         </Card>
      </View>
        );
    }
}

class Favorites extends React.Component {
          ....
    }

const RootStack = StackNavigator(
  {
    Main: {
      screen: Main},
    Favorites: {
      screen: Favorites}
  },
  {
    initialRouteName: 'Main'
  }
);


export default class App extends Component<{}> {
  constructor(props) {
      super(props);
      this.state = {
        favoritesList: []
      };
    this.updateArr = this.updateArr.bind(this); //don't know if this is necessary?
    }

  updateArr=()=>{this.setState({ favoritesList: 
      [...this.state.favoritesList, 'new value']})};

  render() {
      return <RootStack {...this.state} updateArray={this.updateArr}/>;
    }
  }

我得到的錯誤是 - 有任何想法嗎？ 提前致謝！

Answer 1

1-

這是不對的

       <Card  ... props should be here!!---  >
          onSwiped={() => {this.props.updateArray}} //the idea being that on a swipe, updateArray would add 1 to the 'favoriteList' in the parents state, and the favoritesList.length would update by +1.
     </Card>

正確答案是：

     <Card  
       onSwiped={() => {this.props.updateArray}} //the idea being that on a swipe, updateArray would add 1 to the 'favoriteList' in the parents state, and the favoritesList.length would update by +1.
      >
    </Card>

錯誤的含義是Card的子級應該是對象而不是...

2

this.updateArr = this.updateArr.bind(this); 不需要，因為updateArr = () => ...寫在es6中