详解React Native与IOS端之间的交互

目录

• 前置准备
• RN 传值给 iOS

• 方法 1 正常传值给原生
• 方法 2 传递回调函数
• 方法 3 获取 promise 回调
• 方法 4 获取 promise 的同步方式

• 初始的数据提供
• 添加监听事件

#import <Foundation/Foundation.h>
#import <React/RCTBridgeModule.h>
@interface nativeModule : NSObject <RCTBridgeModule>
@end

#import <Foundation/Foundation.h>
#import "nativeModule.h"
@interface nativeModule ()
@end
@implementation nativeModule
@end

// 省略上面的代码
@implementation nativeModule
// 这句代码是必须的 用来导出 module, 这样才能在 RN 中访问 nativeModule这个 module
RCT_EXPORT_MODULE();
// 接收字符串
RCT_EXPORT_METHOD(addHelloWord:(NSString *)name location:(NSString *)location)
{
  NSLog(@"%@,%@", name, location);
}
@end

import { Button, NativeModules } from 'react-native'
const { nativeModule } = NativeModules
<Button title={'传 2 个参数给 native'} onPress={() => {
    nativeModule.addHelloWord('你的名字', '位置:浙江')
}}/>

// 只接受一个参数——传递给 JavaScript 回调函数的参数数组。
RCT_EXPORT_METHOD(checkIsRoot:(RCTResponseSenderBlock)callback) {
  NSArray *array = @[@"string", @"number"];
  callback(array);
}

<Button title={'js 传一个回调给 native,回调中收到一个数组'} onPress={() => {
    nativeModule.checkIsRoot((str: string, num: string) => {
      console.log(str, num)
    })
}}/>

@interface nativeModule ()
@property (nonatomic) RCTPromiseResolveBlock normalResolve;
@property (nonatomic) RCTPromiseRejectBlock normalReject;
@property (nonatomic) NSInteger num;
@end
// 这是一个计时器
-(void)startTime: (NSArray*) data{
  NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:2 repeats:YES block:^(NSTimer * _Nonnull timer) {
    NSArray *events =@[@"Promise ",@"test ",@" array"];
    if (events) {
      self.normalResolve(events);
      [timer invalidate];
    } else {
      [timer invalidate];
      NSError *error=[NSError errorWithDomain:@"我是回调错误信息..." code:101 userInfo:nil];
      self.normalReject(@"no_events", @"There were no events", error);
    }
  }];
  [[NSRunLoop mainRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
}
// 回调给RN的参数，回调的错误信息
RCT_EXPORT_METHOD(getHBDeviceUniqueID: (RCTPromiseResolveBlock)resolve
                  rejecter:(RCTPromiseRejectBlock)reject) {
  // 要执行的任务
  self.normalResolve = resolve;
  self.normalReject = reject;
  [self performSelectorOnMainThread:@selector(startTime:) withObject: [NSArray arrayWithObjects: @"1", @"2", nil] waitUntilDone:YES];
}

<Button title={'native传一个 promise 给 JS'} onPress={() => {
    nativeModule.getHBDeviceUniqueID().then((arr: string[]) => {
      console.log('resolve', arr)
    }).catch((err: string) => {
      console.error(err)
    })
}}/>

// 这是一个计时器2
-(void)startTime2: (NSArray*) data{
  NSLog(@"data%@",data);
  NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1 repeats:YES block:^(NSTimer * _Nonnull timer) {
    NSLog(@"%d", (int)self.num);
    self.num = self.num + 1;
    NSLog(@"%d", (int)self.num);
    if (self.num > 4) {
      [timer invalidate];
      NSLog(@"end");
      self.normalResolve(data);
    }
  }];
  [[NSRunLoop mainRunLoop] addTimer:timer forMode:NSDefaultRunLoopMode];
}
// RCT_REMAP_METHOD 与RCT_EXPORT_METHOD相同，但是该方法是在JS线程上从JS同步调用的，可能会返回结果。
// 同步可能会有性能问题  建议除了 promise 以外都别使用
RCT_REMAP_METHOD(findEvents,
                 findEventsWithResolver:(RCTPromiseResolveBlock)resolve
                 rejecter:(RCTPromiseRejectBlock)reject)
{
  self.normalResolve = resolve;
  self.normalReject = reject;
  self.num = 0;
  [self performSelectorOnMainThread:@selector(startTime2:) withObject: [NSArray arrayWithObjects: @"1", @"2", nil] waitUntilDone:YES];
}

<Button title={'native传一个 promise 给 JS2'} onPress={() => {
    nativeModule.findEvents().then((arr: string[]) => {
      console.log('resolve', arr)
    }).catch((err: string) => {
      console.error(err)
    })
}}/>

NSArray *imageList = @[@"http://foo.com/bar1.png",
                @"http://foo.com/bar2.png"];
NSDictionary *props = @{@"images" : imageList};
RCTRootView *rootView = [[RCTRootView alloc] initWithBridge:bridge moduleName:@"learn" initialProperties:props];
// 这一行代码原本就有,不同点在于 initialProperties:props

// 重写 APP ,  images就是 iOS 提供的数据,这里我们通过 context 来传递数据
export default class App extends React.Component<{ images: string[] }> {
  render() {
    return <NativeProps.Provider value={this.props.images}>
      <AppContainer/>
    </NativeProps.Provider>
  }
}
// 在 hooks 里简单的使用
const images = useContext(NativeProps);
<Text>这是从 native 端传来的初始数据{JSON.stringify(images)}</Text>

// 可供监听的事件名称
- (NSArray<NSString *> *)supportedEvents
{
  return @[@"EventReminder"];
}
RCT_EXPORT_METHOD(postNotificationEvent:(NSString *)name)
{
  NSLog(@"calendarEventReminderReceived");
    [self sendEventWithName:@"EventReminder" body:@{@"name": name}];;
}
- (void)calendarEventReminderReceived:(NSNotification *)notification
{
  // 这是官网的例子
  NSLog(@"calendarEventReminderReceived");
  NSString *eventName = notification.userInfo[@"name"];
  [self sendEventWithName:@"EventReminder" body:@{@"name": eventName}];
}
RCT_EXPORT_METHOD(Send){
  NSDictionary *dict = @{@"name" : @"veuimyzi"};
  NSNotification *notification = [[NSNotification alloc] initWithName:@"EventReminder" object:nil userInfo:dict] ;
  [self calendarEventReminderReceived:notification];
}

const ManagerEmitter = new NativeEventEmitter(nativeModule)
const [msg, setMsg] = useState([])
// hooks 中的使用,类似于 componentDidMount 生命周期
useEffect(() => {
    const subscription = ManagerEmitter.addListener(
      'EventReminder',
      (reminder) => {
        setMsg(prevState => {
          return prevState.concat(reminder.name)
        })
        console.log('这是监听的EventReminder事件回复', reminder.name)
      }
    )
    return () => {
      subscription.remove()
    }
}, [])
<Button title={'js 监听事件,让 native 给 js 发通知'} onPress={() => {
    nativeModule.postNotificationEvent('test')
}}/>
<Button title={'js 监听事件,让 native 给 js 发通知 send'} onPress={() => {
    nativeModule.Send()
}}/>
{
    msg.map((item, index) => {
      return <Text key={item + index}>item:{item}</Text>
    })
}

@implementation nativeModule
{
  bool hasListeners;
  // 一个局部变量
}
-(void)startObserving {
  hasListeners = YES;
}
-(void)stopObserving {
  hasListeners = NO;
}
// 在发送监听的添加判断,如果有监听才发送,有效减少桥接代码的调用
if (hasListeners) { 
    [self sendEventWithName:@"EventReminder" body:@{@"name": name}];;
}