Reactjs React本机回调函数/方法不起作用
我读了一些教程,但我不明白为什么传递回调函数和回调方法都不起作用 当I console.log时,回调函数未定义 请帮忙Reactjs React本机回调函数/方法不起作用,reactjs,react-native,callback,react-native-ios,Reactjs,React Native,Callback,React Native Ios,我读了一些教程,但我不明白为什么传递回调函数和回调方法都不起作用 当I console.log时,回调函数未定义 请帮忙 import React, { Component } from 'react'; import { FlatList } from 'react-native'; import { RecipeCard } from '../RecipeCard/RecipeCard'; import recipeData from '../../config/SampleDataReci
import React, { Component } from 'react';
import { FlatList } from 'react-native';
import { RecipeCard } from '../RecipeCard/RecipeCard';
import recipeData from '../../config/SampleDataRecipeList.json';
class RecipeList extends Component {
constructor(props) {
super(props);
this.handlePress = this.handlePress.bind(this);
}
state = {};
handlePress() {
console.log('Handle Press');
}
handleClick = () => {
console.log('Handle Click');
};
renderItem({ item }) {
return (
<RecipeCard
title={item.title}
persons={item.persons}
time={item.time}
uri={item.uri}
onPress={this.handlePress}
/>
);
}
render() {
return (
<FlatList
data={recipeData}
renderItem={this.renderItem}
keyExtractor={(item, index) => index.toString()}
/>
);
}
}
export { RecipeList };
import React,{Component}来自'React';
从“react native”导入{FlatList};
从“../RecipeCard/RecipeCard”导入{RecipeCard};
从“../../config/SampleDataRecipeList.json”导入recipeData;
类RecipeList扩展了组件{
建造师(道具){
超级(道具);
this.handlePress=this.handlePress.bind(this);
}
状态={};
女佣(){
console.log('handlepress');
}
handleClick=()=>{
log('handleclick');
};
renderItem({item}){
返回(
);
}
render(){
返回(
index.toString()}
/>
);
}
}
导出{RecipeList};
解决方案是将其更改为在构造函数中绑定renderItem,或者将其更改为胖箭头函数,如
renderItem = ( ) => {...}
我建议使用如下箭头函数:
renderItem = item => {
return (
<RecipeCard
title={item.title}
persons={item.persons}
time={item.time}
uri={item.uri}
onPress={this.handlePress}
/>
);
renderItem=item=>{
返回(
);
BindrenderItem
在你的constructor.works中。非常感谢。不用担心,我建议你使用箭头函数,这样你就不必一直绑定。要做到这一点,请将所有函数从handlePress(){…}
更改为handlePress=()=>{…}
argh。是的,您是对的。react native flatlist文档也可以做到这一点。非常感谢。谢谢。就这样