Reactjs 当用户按下React上的键时,如何执行函数?
当用户按键时,我需要我的react组件执行一个函数,但我有下一个错误:Reactjs 当用户按下React上的键时,如何执行函数?,reactjs,react-hooks,keyboard-events,Reactjs,React Hooks,Keyboard Events,当用户按键时,我需要我的react组件执行一个函数,但我有下一个错误: react-dom.development.js:55 Uncaught Invariant Violation: Too many re-renders. React limits the number of renders to prevent an infinite loop. 我正在使用事件键盘的挂钩: function useKey(key) { const [pressed, setPressed] =
react-dom.development.js:55 Uncaught Invariant Violation: Too many re-renders.
React limits the number of renders to prevent an infinite loop.
我正在使用事件键盘的挂钩:
function useKey(key) {
const [pressed, setPressed] = useState(false)
const match = event => key.toLowerCase() == event.key.toLowerCase()
const onDown = event => {
if (match(event)) { setPressed(true) }
}
const onUp = event => {
if (match(event)) { setPressed(false) }
}
useEffect(() => {
window.addEventListener("keydown", onDown)
window.addEventListener("keyup", onUp)
return () => {
window.removeEventListener("keydown", onDown)
window.removeEventListener("keyup", onUp)
}
}, [key])
return pressed
}
和我的组件:
function App() {
const [state, setState] = useState("state")
const key = useKey('ArrowUp')
if(key){
// TODO
setState({...state})
}
return (
<div className="App">
<h1>Hello CodeSandbox</h1>
<h2>Start editing to see some magic happen!</h2>
{state}
</div>
);
}
函数应用程序(){
常量[状态,设置状态]=使用状态(“状态”)
const key=useKey('ArrowUp')
如果(关键){
//待办事项
setState({…state})
}
返回(
你好,代码沙盒
开始编辑,看看神奇的发生!
{state}
);
}
代码在这里是您的设置状态导致了问题。在useEffect钩子中移动状态更新,每当密钥发生更改时,检查密钥是否为true,然后更新您的状态
function App() {
const [state, setState] = useState("state")
const key = useKey('ArrowUp')
useEffect(() => {
if(key) setState({...state});
}, [key])
return (
<div className="App">
<h1>Hello CodeSandbox</h1>
<h2>Start editing to see some magic happen!</h2>
{state}
</div>
);
}
函数应用程序(){
常量[状态,设置状态]=使用状态(“状态”)
const key=useKey('ArrowUp')
useffect(()=>{
if(key)setState({…state});
},[键])
返回(
你好,代码沙盒
开始编辑,看看神奇的发生!
{state}
);
}