React native 无法在React本机默认项目中将类作为函数调用

我刚刚安装了react本机默认项目，并在默认类中添加了一个函数，但它并没有得到执行

 import React, {Component} from 'react';
    import {Platform, StyleSheet, Text, View, Alert,TouchableOpacity} from 'react-native';

    const instructions = Platform.select({
      ios: 'Press Cmd+R to reload,\n' + 'Cmd+D or shake for dev menu',
      android:
        'Double tap R on your keyboard to reload,\n' +
        'Shake or press menu button for dev menu',
    });

    type Props = {};
    export default class App extends Component {
    //the function i added      
    clickMe() {
        Alert("started");
      }
      render() {
        return (
          <View>
            <Text >Welcome to  Native!</Text>
            <Text >To get started, edit App.js</Text>
            <TouchableOpacity onPress={() => this.clickMe()}>
            <Text>{instructions}</Text>
            </TouchableOpacity>
          </View>
        );
      }
    }

---

React Native中警报的正确方式是：

Alert.alert(
  'Alert Title',
  'My Alert Msg',
  [        
    {text: 'Cancel', onPress: () => console.log('Cancel Pressed'), style: 'cancel'},
    {text: 'OK', onPress: () => console.log('OK Pressed')},
  ],
  { cancelable: false }
)

谢谢你

~z~普拉斯