DeviceEventEmitter on iOS

manpreet Best Answer 2 years ago

I'm working on a react-native app. I'm trying to emit events from native code to my react native code. This works in Android, but struggling with iOS.

I'm successfully listening to events being sent from my native Android code. The same events are however not being "picker up" by my react native app when running on iOS, and trying to figure out why.

I have code which connects to an MQTT broker. The code is written natively for iOS and Android. During the connection process, I'm sending the connection status from my native code to react-native. This is working well on Android. The event being sent from my Android code using the reactContext.getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class).emit(eventName, eventString) method reaches my react native code as expected. However, in my iOS code, messages transmitted using the sendEvent() method are being sent, but I'm not picking them up in my react-native code. I even get a yellow warning in my iOS emulator stating that "Sending Statuswith no listeners registered. My Swift class which is sending the event extends the RCTEventEmitter class.

Hope this is all the details people need to help. I've not much experience using DeviceEventEmitter and very little experience with Swift and iOS. Mainly an Android guy, so this has been a little confusing. I'm guessing its actually super simple, but I'm a little lost.

this.handleMqttStatusChange = this.handleMqttStatusChange.bind(this);
DeviceEventEmitter.addListener("Status", this.handleMqttStatusChange);

The following Swift code sends the event.

self.sendEvent(withName: "Status", body: ["status":"Connecting"]);

The Swift class sending the event extends the RCTEventEmitter.

class AwsIotModule: RCTEventEmitter {

My Android Java file extends the ReactContextBaseJavaModule.

public class AwsIotModule extends ReactContextBaseJavaModule {

And the following java method is used to send the events.

private void sendEvent(ReactContext reactContext,
                           String eventName,
                           @Nullable WritableMap params) {
        reactContext.getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
                .emit(eventName, params);
    }