android – 如何理解React Native中“向Javascript发送事件”中的“ReactContext”

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我想使用方法sendEvent(),但是如何获取ReactContext reactContext?
private void sendEvent(ReactContext reactContext,String eventName,@Nullable WritableMap params) {reactContext
  .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
  .emit(eventName,params);}@H_502_3@

解决方法

我通过在MainActivity类上保存对ReactInstanceManager的静态引用,并添加了一个public static getContext()方法来暂时解决了这个问题.它感觉不对,但似乎有效.
public final class MainActivity extends ReactActivity {

    private static ReactInstanceManager sReactInstanceManager = null;

    /* [...] */

    @Override
    protected ReactInstanceManager createReactInstanceManager() {
        ReactInstanceManager manager = super.createReactInstanceManager();
        sReactInstanceManager = manager;
        return manager;
    }

    public static ReactContext getContext() {
        if (sReactInstanceManager == null){
            // This doesn't seem to happen ...
            throw new IllegalStateException("Instance manager not available");
        }
        final ReactContext context = sReactInstanceManager.getCurrentReactContext();
        if (context == null){
            // This really shouldn't happen ...
            throw new IllegalStateException("React context not available");
        }
        return context;
    }

    /* [...] */
}@H_502_3@ 
 

createReactInstanceManager()由ReactActivity的onCreate()方法调用,所以我认为可以安全地假设sReactInstanceManager将指向正确的实例,但不要相信我的话.

原文链接:https://www.f2er.com/android/315104.html

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