Reactjs 通过道具对组件进行反应
我试图将道具传递给一个在使用componentWillReceiveProps时工作的组件,但一旦计数器完成,它就会调用Reactjs 通过道具对组件进行反应,reactjs,Reactjs,我试图将道具传递给一个在使用componentWillReceiveProps时工作的组件,但一旦计数器完成,它就会调用clearInterval(this.intervalId)但是,一旦我再次更改输入,计数器不会再次启动。如何将更新的道具传递回组件 组件代码 class Stopwatch extends Component { constructor(props) { super(props); this.state = { c
clearInterval(this.intervalId)代码>但是,一旦我再次更改输入,计数器不会再次启动。如何将更新的道具传递回组件
组件代码
class Stopwatch extends Component {
constructor(props) {
super(props);
this.state = {
currentCount: this.props.counter,
hours: 0,
minutes: 0,
seconds: 0
}
}
componentWillMount() {
this.timer(this.props.counter);
}
timer() {
this.setState({
currentCount: this.state.currentCount - 1
})
const seconds = Math.floor(this.state.currentCount % 60);
const minutes = Math.floor((this.state.currentCount/60) % 60);
const hours = Math.floor((this.state.currentCount/3600) % 3600);
this.setState({hours, minutes, seconds});
if (this.state.currentCount < 1) {
clearInterval(this.intervalId);
}
}
componentDidMount() {
this.intervalId = setInterval(this.timer.bind(this), 1000);
}
leading0(num) {
return num < 10 ? '0' + num : num;
}
componentWillReceiveProps(nextProps){
if(nextProps.counter !== this.props.counter){
this.setState ({currentCount: nextProps.counter})
}
}
render() {
return (
<div>
<div>Hours {this.leading0(this.state.hours)}</div>
<div>Minutes {this.leading0(this.state.minutes)}</div>
<div>Seconds {this.leading0(this.state.seconds)}</div>
</div>
)
类秒表扩展组件{
建造师(道具){
超级(道具);
此.state={
currentCount:this.props.counter,
小时:0,
分钟:0,
秒:0
}
}
组件willmount(){
this.timer(this.props.counter);
}
计时器(){
这是我的国家({
currentCount:this.state.currentCount-1
})
const seconds=Math.floor(this.state.currentCount%60);
const minutes=Math.floor((this.state.currentCount/60)%60);
常数小时=数学地板((this.state.currentCount/3600)%3600);
this.setState({hours,minutes,seconds});
if(this.state.currentCount<1){
clearInterval(此为有效期);
}
}
componentDidMount(){
this.intervalId=setInterval(this.timer.bind(this),1000);
}
领先0(个){
返回数值<10?'0'+num:num;
}
组件将接收道具(下一步){
if(nextrops.counter!==此.props.counter){
this.setState({currentCount:nextrops.counter})
}
}
render(){
返回(
小时数{this.leading0(this.state.Hours)}
分钟数{this.leading0(this.state.Minutes)}
秒数{this.leading0(this.state.Seconds)}
)
主代码
class App extends Component {
constructor(props) {
super(props);
this.state = {
deadline: 'December 25, 2018',
newDeadline: '',
counter: 75,
newCounter: ''
};
}
changeDeadline() {
this.setState({deadline: this.state.newDeadline});
}
changeNumber(e) {
this.setState({counter: this.state.newCounter});
}
render() {
return (
<div className='App'>
<div className='App-title'>Countdown to {this.state.deadline}</div>
<Clock
deadline={this.state.deadline}
/>
<Form inline>
<FormControl
className="Deadline-input"
placeholder='New Date'
onChange={event => this.setState({newDeadline: event.target.value})}
/>
<Button onClick={() => this.changeDeadline()}>Submit</Button>
</Form>
<div>Stopwatch From { this.state.counter } Seconds</div>
<Stopwatch
counter={this.state.counter}
/>
<Form inline>
<FormControl
className="Deadline-input"
placeholder='New Number'
onChange={event => this.setState({newCounter: event.target.value})}
/>
<Button onClick={() => this.changeNumber()}>Submit</Button>
</Form>
</div>
)
}
类应用程序扩展组件{
建造师(道具){
超级(道具);
此.state={
截止日期:“2018年12月25日”,
新截止日期:'',
柜台号码:75,
新计数器:“”
};
}
更改截止日期(){
this.setState({deadline:this.state.newDeadline});
}
更改编号(e){
this.setState({counter:this.state.newCounter});
}
render(){
返回(
{本州.截止日期}倒计时
this.setState({newDeadline:event.target.value})
/>
this.changeDeadline()}>提交
来自{this.state.counter}秒的秒表
this.setState({newCounter:event.target.value})
/>
this.changeNumber()}>Submit
)
}
提前感谢componentDidMount
函数调用一次,如果要重置道具更改上的计数器,应在componentWillReceiveProps
函数中执行
类秒表扩展组件{
// ...
重置间隔(){
如果(本条有效){
clearInterval(此为有效期);
this.intervalId=null;
}
this.intervalId=setInterval(this.timer.bind(this),1000);
}
组件将接收道具(下一步){
if(nextrops.counter!==此.props.counter){
this.setState({currentCount:nextrops.counter})
//重置间隔
这是resetInterval()
}
}
//...
}