Question

我有一个问题，我不知道如何解决。

我试图拨打onClick内的Component。但得到了这个错误：

未捕获错误：预期onClick侦听器是一个函数，而是获得object类型的值。

我的代码调用Component：

＆＃13;

import React from 'react';
import './Square.css';
import Controller from './controller.js';

class Square extends React.Component {
 render() {
    return (
    <div className="square" onClick={<Controller/>}>
        {this.props.children(<Controller/>)}
      </div>
    )
  }
}

export default Square;

＆＃13;

我的component用函数调用：

＆＃13;

import React from 'react';

class Controller extends React.Component {
    changePlayer = () => {
       alert('oi')
    }
    render(){
        return(
            <div>
                {this.props.position}
            </div>
        )
    }

}

export default Controller;

＆＃13;

该行，我想传递render的{{1}}来渲染..

Controller

但它给出了错误。有人帮帮我吗？。

Answer 1

如果你想从你的父组件中调用子组件的功能，你需要在React中使用ref，你在这里是如何做的：

import UIKit

class ViewController: UIViewController {
    var currentValue = 0
    @IBOutlet weak var slider: UISlider!
    @IBOutlet weak var targetLabel: UILabel!
    @IBOutlet weak var scoreLabel: UILabel!
    @IBOutlet weak var roundLabel: UILabel!
    var targetVal = 0
    var score = 0
    var round = 1

    override func viewDidLoad() {
        super.viewDidLoad()

        currentValue = lroundf(slider.value)
        startRound()
    }

    @IBAction func sliderMoved(_ slider: UISlider){
        print("The value is now: \(slider.value)")
        currentValue = lroundf(slider.value)
    }

    @IBAction func showAlert(){
        let diff = abs(targetVal-currentValue)
        let points = 100 - diff

        score += points
        round += 1

        let message = "You scored \(points)"

        let alert = UIAlertController(title: "Hello, world!", message: message, preferredStyle: .alert)

        let action = UIAlertAction(title: "Awesome", style: .default, handler: nil)

        alert.addAction(action)

        present(alert, animated: true, completion: nil)

        startRound()
    }

    func startRound(){
        updateLabels()
        targetVal = 1 + Int(arc4random_uniform(100))
        currentValue = 50
        slider.value = Float(currentValue)
    }

    func updateLabels(){
        targetLabel.text = String(targetVal)
        scoreLabel.text = String(score)
        roundLabel.text = String(round)
    }
}

Answer 2

您可以通过将道具传递给由onMouseDown切换到onMouseUp并由import React, { Component } from 'react'; import './square.css'; import Controller from './Controller'; class Square extends Component { state = { clicked: false }; toggleClicked = (clicked = false) => { this.setState({ clicked }); } render() { return ( <div className="square" onMouseDown={this.toggleClicked.bind(this, true)} onMouseUp={this.toggleClicked}> <Controller clicked={this.state.clicked} /> </div> ) } } export default Square;关闭的孩子来实现此目的：

<强> Square.jsx

import React, { Component } from 'react';
import './controller.css';

class Controller extends Component {
  changePlayer = () => {
    alert('oi')
  }

  componentDidUpdate(prevProps) {
    if (this.props.clicked && !prevProps.clicked) {
      this.changePlayer();
    }
  }

  render() {
    return (
      <div className='controller'>
        {this.props.position}
      </div>
    )
  }
}

export default Controller

<强> Controller.jsx

if a > 0 and b > 0:       # (a,b) = (1,1)
    a = a + 1             # a = 2
    b = b - 1             # b = 0
if a > 0 or b < 0:
    b = b - 1             # -1

未捕获的错误：期望`onClick`监听器是一个函数，而是得到一个'object`类型

2 个答案: