Question

我在我的应用程序中使用了几个三元运算符，但我无法弄清楚如何在点击事件中使用三元运算符。

我正在制作的是弹出式菜单。一旦选择了该菜单项，其中一个菜单项将不可点击。只能点击另一个菜单项。

图片

我尝试了以下代码，但它没有用。我们不能在React中使用三元运算符进行点击事件吗？

<p id="menuItem" {!this.sate.priceBar? onClick={this.clickHandle} : "" } style={!this.state.priceBar? { color:'white'} : {color : '#BBBBBB'} }>{!this.state.priceBar? "Spent Last 14 Days" : "Spent Last 14 Days"}</p>

完整代码

class Home extends React.Component{

constructor(props){
    super(props);
    this.state = {
        slideOpen : false,
        priceBar: false,
        open: false,
    }
this.handleClick = this.handleClick.bind(this);
this.clickHandle = this.clickHandle.bind(this);
}


 handleClick() {
    this.setState({
        slideOpen : !this.state.slideOpen
    })
 console.log("slideOpen" + !this.state.slideOpen)
 }

 clickHandle() {

 this.setState({ 
          priceBar : !this.state.priceBar,
          open: false
  })
 console.log(!this.state.priceBar)
 }

 handleTouchTap = (event) => {
 // This prevents ghost click.
 event.preventDefault();

 this.setState({
  open: true,
  anchorEl: event.currentTarget,
 });
};

handleRequestClose = () => {
this.setState({
  open: false,
});
};

render(){
  const PaymentPanel = this.state.slideOpen? "slideOpen" : "";
  const Dropdown = this.state.open? "show" : "";

return(
<div>
<div id="PaymentPanel" className={PaymentPanel} >
<div id="PaymentTitle" >{!this.state.priceBar? "Spent Last 14 Days" : "Spent Last 30 Days"}<img src={PaymentArrow} className="PaymentArrow PaymentToggle" onClick={this.handleTouchTap}/></div>
<div id="Dropdown" className={Dropdown}  open={this.state.open}>
<p className="popoverToggle" onClick={this.handleRequestClose}> </p>
<p id="menuItem" onClick={this.clickHandle} style={!this.state.priceBar? { color:'white'} : {color : '#BBBBBB'} }>{!this.state.priceBar? "Spent Last 14 Days" : "Spent Last 14 Days"}</p>
<p id="menuItem" onClick={this.clickHandle} style={this.state.priceBar? { color:'white'} : {color : '#BBBBBB'} }>{this.state.priceBar? "Spent Last 30 Days" : "Spent Last 30 Days"}</p>
</div>


<h2 id="paymentSum" className={!this.state.open? "" : "close"}>{!this.state.priceBar? "$9,964.55" : "$19,929.1"}</h2>


<ul className="paymentTool">
<li>
<div onClick={this.handleTouchTap} className="tool">VISA <br />  {!this.state.priceBar? "$9,504.13" : "$19,008.26"}</div></li>
<li><div className="tool">MasterCard <br />   {!this.state.priceBar? "$490.64" : "$981.28"}</div></li>
<li><div className="tool">PayPal  <br /> {!this.state.priceBar? "$824.52" : "$1,649.04"}</div></li>
</ul>
<div className="paymentSlide" onClick={this.handleClick}>{this.state.slideOpen? <img src={Arrowup} alt="arrowup" className="arrowup" /> : <img src={Arrowdown} alt="arrowdown" className="arrowdown"/>}</div>
</div>

 <div className="PaymentTable" >
 <PaymentTable />
<ul>
</ul>
</div>
</div>
    )
}
}

Answer 1

当然，三元运算不能用于返回dom的属性，因为表达式的返回值是一个字符串，浏览器和react.js引擎不会将字符串视为属性。

相反：

public class SpinnerAdapter extends BaseAdapter{
private LayoutInflater layoutInflater;
private List<GetBalance> listData;
private Context context;
public SpinnerAdapter(Context context, List<GetBalance> listData) {
    this.context = context;
    layoutInflater =(LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    this.listData = listData;
}
@Override
public int getCount() {
    return listData.size();
}
@Override
public Object getItem(int position) {
    return (GetBalance)listData.get(position);
}
@Override
public long getItemId(int position) {
    return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder spinnerHolder;
    if(convertView == null){
        spinnerHolder = new ViewHolder();
        convertView = layoutInflater.inflate(R.layout.spinner_list, parent, false);
        spinnerHolder.spinnerItemList = (TextView)convertView.findViewById(R.id.spinner_list_item);
        convertView.setTag(spinnerHolder);
    }else{
        spinnerHolder = (ViewHolder)convertView.getTag();
    }
    spinnerHolder.spinnerItemList.setText(listData.get(position).getUsers());
    return convertView;
}
class ViewHolder{
    TextView spinnerItemList;
}

修改您的代码：

onClick={!this.state.priceBar ? this.clickHandle : ''}

＆＃13;

handleTouchTap(event){

}

handleRequestClose() {
}

＆＃13;

class Home extends React.Component{
constructor(props){
    super(props);
    this.state = {
        slideOpen : false,
        priceBar: false,
        open: false,
    }
   
this.handleClick = this.handleClick.bind(this);
this.clickHandle = this.clickHandle.bind(this);
}


 handleClick() {
    this.setState({
        slideOpen : !this.state.slideOpen
    })
 console.log("slideOpen" + !this.state.slideOpen)
 }

 clickHandle() {

 this.setState({ 
          priceBar : !this.state.priceBar,
          open: false
  })
 console.log(!this.state.priceBar)
 }

 handleTouchTap (event) {
 // This prevents ghost click.
 event.preventDefault();

 this.setState({
  open: true,
  anchorEl: event.currentTarget,
 });
}

handleRequestClose () {
this.setState({
  open: false,
});
}

render(){
  const PaymentPanel = this.state.slideOpen? "slideOpen" : "";
  const Dropdown = this.state.open? "show" : "";

return(
<div>
<div id="PaymentPanel" className={PaymentPanel} >
<div id="PaymentTitle" >{!this.state.priceBar? "Spent Last 14 Days" : "Spent Last 30 Days"}</div>
<p id="menuItem" onClick={this.clickHandle} style={!this.state.priceBar? { color:'white'} : {color : '#BBBBBB'} }>{!this.state.priceBar? "Spent Last 14 Days" : "Spent Last 14 Days"} (Click me!)</p>

click top line


</div>
</div>

    )
}
}
ReactDOM.render(<Home />, document.querySelector('.app'))

＆＃13;

Answer 2

如果您在React中使用函数而非类：

onClick={() => condition ?  functionToClick() : null}

Answer 3

<p id="menuItem" onClick={!this.state.priceBar ? this.clickHandle : null}>

如何在React.js中使用write三元运算符进行click事件

3 个答案: