Javascript React Native:功能组件到类组件
我正在使用 我正在尝试将以下示例转换为类组件: 下面是我提供的代码片段:Javascript React Native:功能组件到类组件,javascript,react-native,react-functional-component,react-native-gifted-chat,react-class-based-component,Javascript,React Native,React Functional Component,React Native Gifted Chat,React Class Based Component,我正在使用 我正在尝试将以下示例转换为类组件: 下面是我提供的代码片段: constructor(props) { super(props); this.state = { message: [{ _id: 1, text: 'Hello developer', createdAt: new Date(), user: { _id: 2
constructor(props) {
super(props);
this.state = {
message: [{
_id: 1,
text: 'Hello developer',
createdAt: new Date(),
user: {
_id: 2,
name: 'React Native',
avatar: 'https://placeimg.com/140/140/any',
},
}],
}
}
componentDidMount() { }
onSend(messageSend = []) {
this.setState(
previousMessages => ({
message: GiftedChat.append(previousMessages, messageSend)
})
);
}
render() {
const chat = <GiftedChat
messages={this.state.message}
onSend={(messageSend) => this.onSend(messageSend)}
user={{
_id: 1,
}}
/>;
if (Platform.OS === 'android') {
return (
<KeyboardAvoidingView
style={{ flex: 1 }}
behaviour="padding"
keyboardVerticalOffset={30}
enabled
>
{chat}
</KeyboardAvoidingView>
);
}
}
//send message will no longer overlap/replace 'hello developer'
onSend(messageSend = []) {
this.setState(
previousMessages => ({
message: GiftedChat.append(previousMessages.messsage, messageSend)
})
);
}
构造函数(道具){
超级(道具);
此.state={
信息:[{
_id:1,
文本:“你好,开发者”,
createdAt:新日期(),
用户:{
_id:2,
名称:“反应本机”,
阿凡达:'https://placeimg.com/140/140/any',
},
}],
}
}
componentDidMount(){}
onSend(messageSend=[]){
这是我的国家(
以前的消息=>({
消息:GiftedChat.append(以前的消息,messageSend)
})
);
}
render(){
const chat=this.onSend(messageSend)}
使用者={{
_id:1,
}}
/>;
如果(Platform.OS==='android'){
返回(
{chat}
);
}
}
然而,在转换成类组件之后,我并没有得到期望的结果。
()
问题是,当发送新邮件时,它正在“替换”发件人的邮件
我的最新消息
下面是基于您的代码的类组件的完整代码
import React from 'react';
import {KeyboardAvoidingView, Platform} from 'react-native';
import { GiftedChat } from 'react-native-gifted-chat';
export default class Example extends React.Component {
constructor(props) {
super(props);
this.state = {
message: [{
_id: 1,
text: 'Hello developer',
createdAt: new Date(),
user: {
_id: 2,
name: 'React Native',
avatar: 'https://placeimg.com/140/140/any',
},
}],
}
}
//send message will no longer overlap/replace 'hello developer'
onSend(messageSend = []) {
this.setState(
previousMessages => ({
message: GiftedChat.append(previousMessages.messsage, messageSend)
})
);
}
render() {
const chat = <GiftedChat
messages={this.state.message}
onSend={(messageSend) => this.onSend(messageSend)}
user={{
_id: 1,
}}
/>;
if (Platform.OS === 'android') {
return (
<KeyboardAvoidingView
style={{ flex: 1 }}
behaviour="padding"
keyboardVerticalOffset={30}
enabled
>
{chat}
</KeyboardAvoidingView>
);
} else {
return chat
}
}
}
从“React”导入React;
从“react native”导入{KeyboardAvoidingView,Platform};
从“react native gifted chat”导入{GiftedChat};
导出默认类示例扩展了React.Component{
建造师(道具){
超级(道具);
此.state={
信息:[{
_id:1,
文本:“你好,开发者”,
createdAt:新日期(),
用户:{
_id:2,
名称:“反应本机”,
阿凡达:'https://placeimg.com/140/140/any',
},
}],
}
}
//发送消息将不再重叠/替换“hello developer”
onSend(messageSend=[]){
这是我的国家(
以前的消息=>({
消息:giftechat.append(previousMessages.message,messageSend)
})
);
}
render(){
const chat=this.onSend(messageSend)}
使用者={{
_id:1,
}}
/>;
如果(Platform.OS==='android'){
返回(
{chat}
);
}否则{
回话
}
}
}
您也可以将样本签入
上述代码的输出:
constructor(props) {
super(props);
this.state = {
message: [{
_id: 1,
text: 'Hello developer',
createdAt: new Date(),
user: {
_id: 2,
name: 'React Native',
avatar: 'https://placeimg.com/140/140/any',
},
}],
}
}
componentDidMount() { }
onSend(messageSend = []) {
this.setState(
previousMessages => ({
message: GiftedChat.append(previousMessages, messageSend)
})
);
}
render() {
const chat = <GiftedChat
messages={this.state.message}
onSend={(messageSend) => this.onSend(messageSend)}
user={{
_id: 1,
}}
/>;
if (Platform.OS === 'android') {
return (
<KeyboardAvoidingView
style={{ flex: 1 }}
behaviour="padding"
keyboardVerticalOffset={30}
enabled
>
{chat}
</KeyboardAvoidingView>
);
}
}
//send message will no longer overlap/replace 'hello developer'
onSend(messageSend = []) {
this.setState(
previousMessages => ({
message: GiftedChat.append(previousMessages.messsage, messageSend)
})
);
}
显然,我不得不添加
以前的消息。消息
而不是以前的消息
解决方案:
constructor(props) {
super(props);
this.state = {
message: [{
_id: 1,
text: 'Hello developer',
createdAt: new Date(),
user: {
_id: 2,
name: 'React Native',
avatar: 'https://placeimg.com/140/140/any',
},
}],
}
}
componentDidMount() { }
onSend(messageSend = []) {
this.setState(
previousMessages => ({
message: GiftedChat.append(previousMessages, messageSend)
})
);
}
render() {
const chat = <GiftedChat
messages={this.state.message}
onSend={(messageSend) => this.onSend(messageSend)}
user={{
_id: 1,
}}
/>;
if (Platform.OS === 'android') {
return (
<KeyboardAvoidingView
style={{ flex: 1 }}
behaviour="padding"
keyboardVerticalOffset={30}
enabled
>
{chat}
</KeyboardAvoidingView>
);
}
}
//send message will no longer overlap/replace 'hello developer'
onSend(messageSend = []) {
this.setState(
previousMessages => ({
message: GiftedChat.append(previousMessages.messsage, messageSend)
})
);
}
嗨,谢谢你的建议。然而,我已经设法解决了这个问题。似乎我在
onSend
函数上犯了一个小错误,特别是previousMessages
参数。