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[英]Can't call setState (or forceUpdate) on an unmounted component. Memory leak on react-image-gallery
[英]Can't call setState (or forceUpdate) on an unmounted component. React
Gutentag,伙計們!
卸載組件后,我不斷從應用程序中收到此錯誤消息:
Warning: Can't call setState (or forceUpdate) on an unmounted component. This is a no-op, but it indicates a memory leak in your application. To fix, cancel all subscriptions and asynchronous tasks in the componentWillUnmount method.
in Header (at index.js:27)
現在,這里是Header組件的代碼:
class Header extends Component {
isCancelled = false;
state = {
someStateVars: x,
separateColumns: 'true',
}
handleChange = (event) => {
const target = event.target;
const value = target.type === 'checkbox' ? target.checked : target.value;
const name = target.name;
if (!this.isCancelled) {
this.setState({ //######THIS IS LINE 27######
[name]: value
});
}
}
handleDisplayChange = (event) => {
const value = event.target.value;
const name = 'separateColumns';
if (!this.isCancelled) {
this.setState({
[name]: value
}, () => {
this.props.displayChange();
});
}
}
serversRefresh = () => {
if (!this.isCancelled) {
setTimeout(() => {
this.setState({refreshed: false});
}, localStorage.getItem('seconds')*1000); //disable refresh for 15 seconds
}
}
reactivateButton = () => {
if (!this.isCancelled) this.setState({refreshed: false});
}
componentDidMount() {
if(localStorage.getItem('seconds')>5 && !this.isCancelled){
this.setState({refreshed: true});
}
}
componentWillUnmount() {
this.isCancelled = true;
}
}
當我看到此錯誤時,我添加了isCancelled變量,該變量在componentWillUnmount()函數中更改為true。
卸載Header組件后,15秒鍾后,重新激活serversRefreshbutton時,出現此錯誤消息。
我該如何解決?
在遇到此問題的另一個組件上,“ isCancelled” var確實起到了幫助,但是在這里我看到它沒有任何影響,問題仍然存在。
只需將超時存儲在變量中,例如
this.timeout = setTimeout(/* your actions here*/, /* your timeout */)
然后在componentWillUnmount
清除超時
componentWillUnmount() {
clearTimeout(this.timeout)
}
它應該解決您的問題,而不會像this.isCancelled
這樣this.isCancelled
。 檢測組件的安裝狀態是無操作的,因為即使卸載后它仍會從內存中卸載。
setTimeout
返回計時器的ID,以后可以使用該ID取消。 clearTimeout
通過其ID取消超時(如果尚未執行)。
有關您的案例的更多信息,您可以在這里閱讀: 為什么isMounted是antipattern 。
有關MDN上的計時器的更多信息。
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