类型错误：未定义不是对象 this.prop

Question

收到错误 TypeError: Undefined is not an object(evaluating 'this.props.track[this.state.selectedTrack]')尝试为 iOS 运行我的模拟器时。我正在构建播放器。我在启动时收到的错误如下。并且代码将在播放器的正下方任何指导将不胜感激。import React, { Component } from 'react';import {Player as PodCast} from './PodcastLayers/Player';export const TRACKS = [{title: 'Stressed Out',artist: 'Twenty One Pilots',albumArtUrl: "http://36.media.tumblr.com/14e9a12cd4dca7a3c3c4fe178b607d27/tumblr_nlott6SmIh1ta3rfmo1_1280.jpg",audioUrl: "http://russprince.com/hobbies/files/13%20Beethoven%20-%20Fur%20Elise.mp3",},];export default class PodCastScreen extends React.Component {render() {return <PodCast tracks={TRACKS}/>}}

Answer 1

2 状态可能正在发生：

1. 你没有在你的道具中传递“轨道”

2. 您正在传递带有 null 或 undefined 值的“track”

Answer 2

您发布的第二个问题，您应该将类导入 PodCastScreen为import PodCastScreen from'./PodcastLayers/Player';