[英]Setting setInterval to call multiple times but gets only called once in react native
[英]Video-React: handleStateChange gets called multiple times when it should be called only once
我正在使用Video-React在我的项目中实现视频播放功能:
<Player
ref={(player) => {
this.state.player = player;
}}
src={videoURL}
></Player>
我正在跟踪 state 改变这种方式:
componentDidUpdate(prevProps, prevState) {
if (this.state.player) {
this.state.player.subscribeToStateChange(
this.handleStateChange.bind(this)
);
}
}
handleStateChange(state, prevState) {
const userHasJustPlayedVideo = prevState.paused && !state.paused;
const userHasJustPausedVideo = !prevState.paused && state.paused;
if (userHasJustPlayedVideo) {
console.group("userHasJustPlayedVideo: PREVIOUS STATE");
console.log("previous state: ", prevState);
console.groupEnd();
console.group("userHasJustPlayedVideo: CURRENT STATE");
console.log("state: ", state);
console.groupEnd();
}
if (userHasJustPausedVideo) {
console.group("userHasJustPausedVideo: PREVIOUS STATE");
console.log("previous state: ", prevState);
console.groupEnd();
console.group("userHasJustPausedVideo: CURRENT STATE");
console.log("state: ", state);
console.groupEnd();
}
}
问题:当我暂停/播放视频时, handleStateChange
被多次调用,它遵循这种模式。
换句话说, state属性paused
了从 true 到 false 或从 false 到 true 的转换,对于那个STATE TRANSITITON , handleStateChange
被多次调用并递增(参见下面的评论)。
// After I play and pause the 1st time
// userHasJustPlayedVideo block gets logged 1 time
// userHasJustPausedVideo block gets logged 2 times
// After I play and pause the 2nd time
// userHasJustPlayedVideo block gets logged 2 times
// userHasJustPausedVideo block gets logged 3 times
// After I play and pause the 3rd time
// userHasJustPlayedVideo block gets logged 3 times
// userHasJustPausedVideo block gets logged 4 times
// And so on and so forth
// Everytime there's an extra log
// It seems that handleChange gets called one extra time
// Everytime I play and pause
// Which doesn't make sense
我只需要在这里执行一次逻辑:
if (userHasJustPausedVideo) {
// LOGIC TO BE EXECUTED ONCE
}
但是,对于当前的实现,该逻辑将被执行多次。
知道我做错了什么吗?
我猜每次 state 更新时,您都会再次订阅 state 更改。 所以你看到了这种行为模式。
您应该订阅 state 更改componentDidMount
而不是componentDidUpdate
,所以它只注册一次。
查看文档方法部分中的subscribeToStateChange(listener)
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