警报显示消息而不按警报按钮

Question

我正在使用此代码通过按下按钮来显示我的输入值。但是，每当我输入文本时，只要我向 组件键入任何输入，它就会自动显示一个警告框。

当我按下“添加用户”按钮时，我想显示警报框。它有什么问题？

import React, { Component } from 'react';
import {View, Text, TextInput,Alert, Button} from 'react-native';


export default class myTest extends Component{
  constructor(){
    super();
    this.state = {firstName: 'your name', lastName: 'your last', email: 'enter your email'};
  }
  onPressButton(){
    let firstName = this.state.firstName;
    let lastName = this.state.lastName;

    Alert.alert("You've Entered" + firstName+"\n "+lastName+"\n");
  }

  render()
  {


      return (
          <View>
            <Text>ENTER YOUR DETAILS:</Text>
            <TextInput
          style={{height: 40}}
          placeholder="FirstName"
          onChangeText={(firstName) => this.setState({firstName})}
        />
           <TextInput
          style={{height: 40}}
          placeholder="Last Name"
          onChangeText={(lastName) => this.setState({lastName})}
        />
        <Text style={{padding: 10, fontSize: 30}}>
          firstName: {this.state.firstName}{'\n'}
          lastName: {this.state.lastName} 
        </Text>
        <Button title="Add User" onPress={this.onPressButton()}/>

          </View>
      );
  }
  }

Answer 1

在 Button 标签内，将 onPress = {this.onPressButton()} 替换为 onPress = {() => this.onPressButton()}