我有一个带有文本,文本输入(一个组件)和一个按钮(另一个组件)的主应用程序:
import { StatusBar } from 'expo-status-bar';
import React from 'react';
import { StyleSheet, Text, View, Alert } from 'react-native';
import { Tinput } from './components/Tinput.js';
import { Button } from './components/Button.js';
export default function App() {
return (
<View style={styles.container}>
<Text style={{fontSize:20, padding:20, textAlign:'center'}}>Ingrese un numero del pokémon a buscar!</Text>
<Tinput/>
<Button onPress={()=> ConsultarPokemon(/*this is where i want to insert the value from Tinput */)}>
Ingresar
</Button>
<StatusBar style="auto" />
</View>
);
}
这是我的组件Tinput,具有文本输入:
import React from 'react';
import { TextInput } from 'react-native';
const Tinput = () => {
const [numero, setNumero] = React.useState('');
return (
<TextInput
style={{ width:'90%', height: 50, borderColor: 'gray', borderWidth: 1, backgroundColor: '#fffff0', textAlign:'center', borderRadius: 20, borderWidth:5, margin:20}}
onChangeText={(value) => setNumero({numero: value})}
value={this.state.numero}
maxLength={20}
/>
);
}
export { Tinput };
我想使用onPress函数上输入的文本中的值,我尝试这样做但没有用:
<Button onPress={()=> ConsultarPokemon(Tinput.state.numero)}>
Ingresar
</Button>
此外,我的Tinput组件上有一个错误:未定义不是对象(正在评估'_this.state.numero') 所以我也可能以错误的方式使用状态
答案 0 :(得分:1)
仅当创建了类似组件类之类的类时,才使用this.state.X,这是一个示例:
class Counter extends React.Component {
constructor(props) {
super(props);
this.initialCount = props.initialCount || 0;
this.state = {
count: this.initialCount
}
}
increment() {
this.setState({ count: this.state.count + 1 })
}
reset() {
this.setState({ count: this.initialCount})
}
render() {
const { count } = this.state;
return (
<>
<button onClick={this.increment.bind(this)}>+1</button>
<button onClick={this.reset.bind(this)}>Reset</button>
<p>Count: {count}</p>
</>
);
}
}
我建议不要使事情复杂化,而只需在Tinput内处理onPress
const Tinput = () => {
const [numero, setNumero] = React.useState('');
return (
<View>
<TextInput
style={{ width:'90%', height: 50, borderColor: 'gray', borderWidth: 1, backgroundColor: '#fffff0', textAlign:'center', borderRadius: 20, borderWidth:5, margin:20}}
onChangeText={(value) => setNumero(value)}
value={numero} // no need to use this.state.numero
maxLength={20}
/>
<Button onPress={()=> ConsultarPokemon(numero)}>
Ingresar
</Button>
</View>
);
}