我正在从子元素的props(mytextfield.js)设置父状态(login.js)。从儿童元素中,道具的状态表示已设置(即用户名),但从父母的角度(login.js)设置,未设置状态。我很困惑。从myTextfield,以下是在change_text(text)函数
中定义的this.props.parent.state
但是从login.js的登录()函数中,以下内容不确定:
this.state
他们应该指向同一件事。
mytextfield.js
export default class MyTextField extends Component
{
constructor(props)
{
super(props);
this.state = {text: props.text, style:styles.unfocused};
this.state[this.props.name] = '';
}
change_text(text)
{
this.setState({text:text});
if(this.props.parent && this.props.name)
{
this.props.parent.state[this.props.name] = text;
}
else
console.log('no parent or name');
}
render()
{
return (
<TextInput style={this.state.style} multiline={false} maxLength={100} onFocus={() => this.setState({style:styles.focused}) } onBlur={() => this.setState({style:styles.unfocused}) } onChangeText={(text) => this.change_text(text)} value={this.state.text} placeholder={this.props.placeholder}
/>)
}
}
MyTextField.propTypes =
{
text: React.PropTypes.string,
parent: React.PropTypes.object,
name: React.PropTypes.string
};
login.js
import React, { Component, PropTypes } from 'react';
import { View, Text, Button, TextInput,TouchableHighlight,StatusBar,StyleSheet } from 'react-native';
import MyButton from './MyButton';
import MyTextField from './MyTextField';
export default class Login extends Component
{
constructor(props)
{
super(props);
this.state =
{
username:'',
password:'',
};
}
login()
{
console.log('login',JSON.stringify(this.state,null,2));
}
render()
{
return (
<View style={{flex: 1,flexDirection: 'column',justifyContent: 'space-between',margin:10}}>
<View style={{backgroundColor: 'powderblue'}} />
<MyTextField name='username' placeholder="User Name" parent={this} />
<MyTextField name='password' placeholder="Password" parent={this} />
<MyButton onPress={this.login} title='Login'/>
</View>
);
}
}
这个原因是可以从孩子(mytextinput.js)而不是login.js访问父母的状态(login.js),是因为我需要 bind 录。JS的登录函数本身(为什么我不知道),因为我从未在孩子(mytextinput.js)上打电话 bind ,孩子的工作正常。
this.login = this.login.bind(this);