Javascript 在arrow函数中调用setState不改变状态?
在我的程序中,我必须在箭头函数中调用setState。函数应将IssummaryAccordinactive的状态设置为true,以便调用另一个函数。但是,当我在箭头函数中设置状态时,状态不会改变。它在控制台中仍然显示为false 下面是代码:Javascript 在arrow函数中调用setState不改变状态?,javascript,reactjs,Javascript,Reactjs,在我的程序中,我必须在箭头函数中调用setState。函数应将IssummaryAccordinactive的状态设置为true,以便调用另一个函数。但是,当我在箭头函数中设置状态时,状态不会改变。它在控制台中仍然显示为false 下面是代码: class TabMenuButtons extends Component { constructor(props) { super(props); this.state = {
class TabMenuButtons extends Component {
constructor(props) {
super(props);
this.state = {
rendersummaryAccordions: false,
renderservicesAccordions: false,
rendertravelAccordions: false,
renderratesAccordions: false,
//These variables used for other components to detect which component is currently rendered ("Active")
isSummaryAccordionActive: false,
isServicesAccordionActive: false,
isTravelAccordionActive: false,
isRatesAccordionActive: false,
};
}
//The Summary Button onClick calls this function to set the state of the summaryAccordionDetector variable
setStateisSummaryAccordionsActive = () => {
this.setState({isSummaryAccordionActive: true})
this.callSummaryAccordionsLogicGate();
//WHERE THE STATE IS READING AS FALSE IN THE CONSOLE*****
console.log(this.state.isSummaryAccordionActive)
console.log("setStateisSummaryAccordionsActive Was called")
}
//Then the function above calls this function that checks if the summaryAccordionDetector variable is really true
callSummaryAccordionsLogicGate = () => {
if (this.state.isSummaryAccordionActive) {
this.summaryAccordionsLogicGate();
}
else {
// this.setState({isSummaryAccordionActive: false})
console.log("callSummaryAccordionsLogicGate found that the summary accordion wasn't active")
}
}
//If the function above verifies that the summaryAccordionDetector is really true it calls this function which renders the summary accordion
summaryAccordionsLogicGate = () => {
this.setState({rendersummaryAccordions: true});
console.log("summaryAccordionsLogicGate was called, render the summary accordion")
}
// servicesAccordionsLogicGate = () => {
// this.setState({renderservicesAccordions: true});
// console.log("servicesAccordionsLogicGate was called")
// }
// ratesAccordionsLogicGate = () => {
// this.setState({renderratesAccordions: true});
// console.log("ratesAccordionsLogicGate was called")
// }
// travelAccordionsLogicGate = () => {
// this.setState({rendertravelAccordions: true});
// console.log("travelAccordionsLogicGate was called")
// }
render() {
let summaryAccordionPlaceHolder = null
let servicesAccordionPlaceHolder = null
let ratesAccordionPlaceHolder = null
let travelAccordionPlaceHolder = null
this.state.rendersummaryAccordions ? summaryAccordionPlaceHolder = <SummaryAccordions/> : summaryAccordionPlaceHolder = null;
this.state.renderservicesAccordions ? servicesAccordionPlaceHolder = <ServicesAccordions/> : servicesAccordionPlaceHolder = null;
this.state.renderratesAccordions ? ratesAccordionPlaceHolder = <RatesAccordions/> : ratesAccordionPlaceHolder = null;
this.state.rendertravelAccordions ? travelAccordionPlaceHolder = <TravelAccordions/> : travelAccordionPlaceHolder = null;
return (
<div>
<center>
<table cellspacing="30px">
<tr>
<td>
<Button label="ITEM" icon="pi pi-home" className="TabMenuButtons" onClick={this.setStateisSummaryAccordionsActive} style={{marginRight:'.25em', borderRadius: '8%', backgroundColor: "#1c479c" }}></Button>
</td>
<td>
<Button label="ITEM" icon="pi pi-users" className="TabMenuButtons" onClick={this.servicesAccordionsLogicGate} style={{marginRight:'.25em', borderRadius: '8%', backgroundColor: "#1c479c"}}></Button>
</td>
<td>
<Button label="ITEM" icon="pi pi-cloud" className="TabMenuButtons" onClick={this.travelAccordionsLogicGate} style={{marginRight:'.25em', borderRadius: '8%', backgroundColor: "#1c479c"}}></Button>
</td>
<td>
<Button label="ITEM" icon="pi pi-money-bill" className="TabMenuButtons" onClick={this.ratesAccordionsLogicGate} style={{marginRight:'.25em', borderRadius: '8%', backgroundColor: "#1c479c"}}></Button>
</td>
</tr>
</table>
</center>
<tr>
{/* EDIT THIS to become dynamic */}
<td className="StaticTextBelowTabView"><h1> ITEM: <em>$67,000.00 </em></h1> </td>
<td className="StaticTextBelowTabView"><h1> ITEM: <em>$5,000.00</em> </h1></td>
<td className="StaticTextBelowTabView"><h1> ITEM: <em>$54,406.00</em> </h1></td>
<td className="StaticTextBelowTabView"><h1> ITEM: <em>1,000</em> </h1></td>
<td className="StaticTextBelowTabView"><h1> ITEM: <em>20.00%</em></h1></td>
</tr>
{ratesAccordionPlaceHolder}
{servicesAccordionPlaceHolder}
{travelAccordionPlaceHolder}
{summaryAccordionPlaceHolder}
</div>
);
}
}
类选项卡按钮扩展组件{
建造师(道具){
超级(道具);
此.state={
RenderSummary手风琴:false,
RenderService记录:false,
RenderTravelaccordins:false,
渲染效果:错误,
//这些变量用于其他组件,以检测当前呈现的组件(“活动”)
IssummaryAccordinactive:false,
isServicesAccordionActive:错误,
IsTravelaccordiactive:错误,
IsratesCordioActive:错误,
};
}
//Summary按钮onClick调用此函数以设置summaryAccordionDetector变量的状态
setStateisSummaryAccordionsActive=()=>{
this.setState({IssummaryAccordinactive:true})
此.callSummaryAccordationsLogicGate();
//其中,控制台中的状态读数为FALSE*****
console.log(this.state.issummaryAccordinactive)
log(“调用了setStateisSummaryAccordionsActive”)
}
//然后,上面的函数调用该函数,该函数检查summaryAccordionDetector变量是否为真
callSummaryAccordionsLogicGate=()=>{
if(this.state.issummaryAccordinactive){
这个.summaryAccordionsLogicGate();
}
否则{
//this.setState({IssummaryAccordinactive:false})
log(“CallSummaryAccordionLogicGate发现摘要手风琴未激活”)
}
}
//如果上面的函数验证summaryAccordionDetector是否真的为true,它将调用此函数来呈现SummaryAccordion
summaryAccordionsLogicGate=()=>{
this.setState({rendersummaryAccordions:true});
log(“调用SummaryAccordionLogicGate,呈现SummaryAccordion”)
}
//服务协调逻辑门=()=>{
//this.setState({renderservicesaccordins:true});
//log(“调用了ServicesAccordionLogicGate”)
// }
//速率协调逻辑门=()=>{
//this.setState({renderRateAccordions:true});
//log(“调用RatesAccordionLogicGate”)
// }
//TravelAccordionLogicGate=()=>{
//this.setState({rendertravelaccordins:true});
//log(“调用TravelAccordionLogicGate”)
// }
render(){
让summaryAccordionPlaceHolder=null
让servicesAccordionPlaceHolder=null
让ratesAccordionPlaceHolder=null
让travelAccordionPlaceHolder=null
this.state.rendersummaryAccordions?summaryAccordionPlaceHolder=:summaryAccordionPlaceHolder=null;
this.state.renderservicesAccordions?servicesAccordionPlaceHolder=:servicesAccordionPlaceHolder=null;
this.state.renderRateAccordions?ratesAccordionPlaceHolder=:ratesAccordionPlaceHolder=null;
this.state.renderTravelaccordins?travelAccordionPlaceHolder=:travelAccordionPlaceHolder=null;
返回(
{/*将其编辑为动态*/}
项目:$67000.00
项目:5000.00美元
项目:54406.00美元
项目:1000
项目:20.00%
{ratesAccordionPlaceHolder}
{servicesAccordionPlaceHolder}
{travelAccordionPlaceHolder}
{summaryAccordionPlaceHolder}
);
}
}
我是新手,我的逻辑有什么根本性的错误吗?
编辑:感谢大家的详细回复!我真的不知道这个州,直到你们都提到它。看起来我以后必须阅读API参考。您需要了解的是,
这个.setState
是一个异步操作,它在稍后的时间间隔发生在后台,因此无法预测状态何时更新。这就是为什么在调用callsummaryAccordionLogicGate
时,isSummaryAccordionActive
的值仍然是false
这是一个可能的解决方案
setStateisSummaryAccordionsActive = () => {
// Get the original value before setting the state
const isSummaryAccordionActive=this.state.isSummaryAccordionActive;
this.setState({isSummaryAccordionActive: true})
// Pass the negation of the original value to the "callSummaryAccordionsLogicGate" function
this.callSummaryAccordionsLogicGate(!isSummaryAccordionActive);
}
// Check with the parameter "isSummaryAccordionActive" which will have the correct value you expect
callSummaryAccordionsLogicGate = (isSummaryAccordionActive) => {
if (isSummaryAccordionActive) {
this.summaryAccordionsLogicGate();
}
else {
// this.setState({isSummaryAccordionActive: false})
console.log("callSummaryAccordionsLogicGate found that the summary accordion wasn't active")
}
您需要了解的是,
this.setState
是一个异步操作,它在稍后的时间间隔发生在后台,因此无法预测状态何时更新。这就是为什么在调用callsummaryAccordionLogicGate
时,isSummaryAccordionActive
的值仍然是false
这是一个可能的解决方案
setStateisSummaryAccordionsActive = () => {
// Get the original value before setting the state
const isSummaryAccordionActive=this.state.isSummaryAccordionActive;
this.setState({isSummaryAccordionActive: true})
// Pass the negation of the original value to the "callSummaryAccordionsLogicGate" function
this.callSummaryAccordionsLogicGate(!isSummaryAccordionActive);
}
// Check with the parameter "isSummaryAccordionActive" which will have the correct value you expect
callSummaryAccordionsLogicGate = (isSummaryAccordionActive) => {
if (isSummaryAccordionActive) {
this.summaryAccordionsLogicGate();
}
else {
// this.setState({isSummaryAccordionActive: false})
console.log("callSummaryAccordionsLogicGate found that the summary accordion wasn't active")
}
我认为setState是异步的,因此紧接着的日志可能无法捕获状态更新。尝试使用状态在屏幕上呈现某些内容。@Dan是对的
setState