我已经将一个组件分割为父元素和子元素。我通过状态将父数据传递给孩子,但接收到Uncaught TypeError:无法读取null的属性'imageSource',这很奇怪,因为我遵循与应用程序的另一个元素相同的过程。我也遵循组件和道具文档,但仍然有点难住。反应:父类和子元素之间的未捕获类型错误
如果我已经定义了状态,将其设置并添加为属性给孩子,状态如何仍然null?
class Parent extends React.Component {
constructor(){
super();
this.state = {
imageSource: [],
imageTitles: [],
}
}
componentDidMount(){
...
...
// grabbing stuff from Dropbox API
...
...
.then(function(){
that.setState({
imageSource: sources,
imageTitles: titles,
});
});
render(){
return(
<Child imageSource={this.state.imageSource} imageTitles=
{this.state.imageTitles} />
);
}
}
class Child extends React.Component{
render(){
if(!this.state.imageSource.length)
return null;
let titles = this.state.imageTitles.map((el, i) => <p>{el}</p>)
let images = this.state.imageSource.map((el, i) =>
<div className="imageContainer">
<img key={i} className='images' src={el}/>
<div className="imageTitle">{titles[i]}</div>
</div>
)
return (
<div className="ChildWrapper">
{images}
</div>
);
}
}