一、从React Native中调用原生方法(原生模块)
原生模块是JS中也可以使用的Objective-C类。一般来说这样的每一个模块的实例都是在每一次通过JS bridge通信时创建的。他们可以导出任意的函数和常量给React Native。相关细节可以参阅这篇文章。
在React Native中,一个“原生模块”就是一个实现了“RCTBridgeModule”协议的Objective-C类,其中RCT是ReaCT的缩写。
// CalendarManager.h
#import <React/RCTBridgeModule.h>
#import <React/RCTLog.h>
@interface CalendarManager : NSObject <RCTBridgeModule>
@end
为了实现RCTBridgeModule
协议,你的类需要包含RCT_EXPORT_MODULE()
宏。这个宏也可以添加一个参数用来指定在Javascript中访问这个模块的名字。如果你不指定,默认就会使用这个Objective-C类的名字。
// CalendarManager.m
@implementation CalendarManager
RCT_EXPORT_MODULE();
@end
//支付宝支付
RCT_EXPORT_METHOD(onAliPay:(NSString *)orderString resolver:(RCTPromiseResolveBlock)resolve rejecter:(RCTPromiseRejectBlock)reject) {
//模块代码
}
现在从Javascript里可以这样调用这个方法:
import {
NativeModules
} from 'react-native';
var pay = NativeModules.ReactNativePay;
Pay.onAliPay(payStr) .then((message)=>{
console.log("message" + message); if(message !== "")
//支付成功的处理
this.refs.toast.show(message, DURATION.LENGTH_SHORT);
}) .catch(e=>{
console.log("e.message" + e.message);
if(e.message !== "") this.refs.toast.show(e.message, DURATION.LENGTH_SHORT);
if(e.code === '-1' || e.message === '支付失败') {
//支付失败
}
})
注意: 导出到Javascript的方法名是Objective-C的方法名的第一个部分。React Native还定义了一个RCT_REMAP_METHOD()宏,它可以指定Javascript方法名。当许多方法的第一部分相同的时候用它来避免在Javascript端的名字冲突。
二、参数类型
RCT_EXPORT_METHOD
支持所有标准JSON类型,包括:
- string (
NSString
) - number (
NSInteger
,float
,double
,CGFloat
,NSNumber
) - boolean (
BOOL
,NSNumber
) - array (
NSArray
) 包含本列表中任意类型 - object (
NSDictionary
) 包含string类型的键和本列表中任意类型的值 - function (
RCTResponseSenderBlock
)
除此以外,任何RCTConvert
类支持的的类型也都可以使用(参见RCTConvert了解更多信息)。RCTConvert
还提供了一系列辅助函数,用来接收一个JSON值并转换到原生Objective-C类型或类。如下:
RCT_EXPORT_METHOD(addEvent:(NSString *)name location:(NSString *)location date:(nonnull NSNumber *)secondsSinceUnixEpoch)
{
NSDate *date = [RCTConvert NSDate:secondsSinceUnixEpoch];
}
或
RCT_EXPORT_METHOD(addEvent:(NSString *)name location:(NSString *)location date:(NSString *)ISO8601DateString)
{
NSDate *date = [RCTConvert NSDate:ISO8601DateString];
}
三、回调函数
原生模块还支持一种特殊的参数——回调函数。它提供了一个函数来把返回值传回给JavaScript。如下:
typedef void (^RCTResponseSenderBlock)(NSArray *response);
typedef void (^RCTResponseErrorBlock)(NSError *error);
typedef void (^RCTPromiseResolveBlock)(id result);
typedef void (^RCTPromiseRejectBlock)(NSString *code, NSString *message, NSError *error);
四、实例代码(一)
(1)原生代码
//.h文件
#import <React/RCTBridgeModule.h>
#import <React/RCTLog.h>
@interface RNMethodTool : NSObject <RCTBridgeModule>
@end
//.m文件
#import "RNMethodTool.h"
#import "AppDelegate.h"
@implementation RNMethodTool
//这个宏必须要写的,否则RN找不到该类
RCT_EXPORT_MODULE()
RCT_EXPORT_METHOD(doSomething:(NSString *)string){
//这也是暴露给RN的方法,弹出系统框,stirng是RN传过来的参数
dispatch_async(dispatch_get_main_queue(), ^{
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"我是iOS系统框 RN 调用 原生方法" message:string preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:nil];
[alertController addAction:cancelAction];
[alertController addAction:okAction];
AppDelegate *delegate = (AppDelegate *)([UIApplication sharedApplication].delegate);
[delegate.window.rootViewController presentViewController:alertController animated:YES completion:nil];
});
}
@end
(2)在JS端的应用
import React, {Component} from 'react';
import {Platform, StyleSheet, Text, View,NativeModules,TouchableHighlight} from 'react-native';
const methodTool = NativeModules.RNMethodTool;
type Props = {};
export default class App extends Component<Props> {
render() {
return (
<View style={styles.container}>
<TouchableHighlight onPress={()=>methodTool.doSomething("我是rn传过来的数据")}>
<Text style={styles.welcome}>Welcome to React Native!</Text>
</TouchableHighlight>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
},
});
五、实例代码(二)
原生端
//.h文件
#import <Foundation/Foundation.h>
#import <React/RCTBridgeModule.h>
@interface NativeInteraction : NSObject <RCTBridgeModule>
@end
//.m实现文件
#import "NativeInteraction.h"
#define TestNativeJsonData @"{\"callback1\":\"123\",\"callback2\":\"asd\"}"
@implementation NativeInteraction
{
RCTPromiseResolveBlock _resolveBlock;
RCTPromiseRejectBlock _rejectBlock;
}
RCT_EXPORT_MODULE();
RCT_EXPORT_METHOD(RNTransferIOS) {
NSLog(@"RN调用iOS");
}
RCT_EXPORT_METHOD(RNTransferIOSWithParameter:(NSString *)logString) {
NSLog(@"来自RN的数据:%@",logString);
}
RCT_EXPORT_METHOD(RNTransferIOSWithCallBack:(RCTResponseSenderBlock)callback) {
callback(@[[NSString stringWithFormat:@"来自iOS Native的数据:%@",TestNativeJsonData]]);
}
RCT_REMAP_METHOD(RNTransferIOSWithParameterAndCallBack, para1:(NSString *)para1 para2:(NSString *)para2 resolver:(RCTPromiseResolveBlock)resolver rejecter:(RCTPromiseRejectBlock)reject) {
NSLog(@"来自RN的数据:para1——%@, para2——%@",para1, para2);
_resolveBlock=resolver;
_rejectBlock=reject;
NSString *jsonString = TestNativeJsonData;
_resolveBlock(@[jsonString]);
}
@end
在JS端的应用
import React, {Component} from 'react';
import {Platform, StyleSheet, Text, View, DeviceEventEmitter, Alert, Button, NativeModules} from 'react-native';
const NativeInteraction = NativeModules.NativeInteraction;
type Props = {};
export default class App extends Component<Props> {
constructor(props) {
super(props);
this.state = {
notice: '默认值',
};
}
componentWillMount() {
DeviceEventEmitter.addListener('EventInit', (msg) => {
let receive = "EventInit: " + msg;
console.log(receive);
this.setState({notice: receive});
});
DeviceEventEmitter.addListener('EventLogin', (msg) => {
let receive = "EventLogin: " + msg;
console.log(receive);
this.setState({notice: receive});
});
}
transferIOS = () => {
NativeInteraction.RNTransferIOS();
}
transferIOS1 = () => {
NativeInteraction.RNTransferIOSWithParameter('{\'para1\':\'rndata1\',\'para2\':\'rndata2\'}');
}
transferIOS2 = () => {
NativeInteraction.RNTransferIOSWithCallBack((data) => {
this.setState({notice: data});
});
}
transferIOS3 = () => {
NativeInteraction.RNTransferIOSWithParameterAndCallBack('rndata1','rndata2').then(result =>{
let jsonString = JSON.stringify(result);
this.setState({notice: jsonString});
}).catch(error=>{
});
}
render() {
return (
<View style={styles.container}>
<Text style={styles.welcome}>第一个React Native页面</Text>
<Text style={styles.instructions}>{this.state.notice}</Text>
<Button
onPress={this.transferIOS}
title="RN调用iOS(无回调无参数)"
color="#841584"
/>
<Button
onPress={this.transferIOS1}
title="RN调用iOS(有参数)"
color="#841584"
/>
<Button
onPress={this.transferIOS2}
title="RN调用iOS(有回调)"
color="#841584"
/>
<Button
onPress={this.transferIOS3}
title="RN调用iOS(有参数有回调)"
color="#841584"
/>
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
},
instructions: {
textAlign: 'center',
color: '#333333',
marginBottom: 5,
},
});