每当我的广播执行时,我想显示对前景活动的警报。


当前回答

我在Kotlin中做了以下工作

Create Application Class Edit the Application Class as Follows class FTApplication: MultiDexApplication() { override fun attachBaseContext(base: Context?) { super.attachBaseContext(base) MultiDex.install(this) } init { instance = this } val mFTActivityLifecycleCallbacks = FTActivityLifecycleCallbacks() override fun onCreate() { super.onCreate() registerActivityLifecycleCallbacks(mFTActivityLifecycleCallbacks) } companion object { private var instance: FTApplication? = null fun currentActivity(): Activity? { return instance!!.mFTActivityLifecycleCallbacks.currentActivity } } } Create the ActivityLifecycleCallbacks class class FTActivityLifecycleCallbacks: Application.ActivityLifecycleCallbacks { var currentActivity: Activity? = null override fun onActivityPaused(activity: Activity?) { currentActivity = activity } override fun onActivityResumed(activity: Activity?) { currentActivity = activity } override fun onActivityStarted(activity: Activity?) { currentActivity = activity } override fun onActivityDestroyed(activity: Activity?) { } override fun onActivitySaveInstanceState(activity: Activity?, outState: Bundle?) { } override fun onActivityStopped(activity: Activity?) { } override fun onActivityCreated(activity: Activity?, savedInstanceState: Bundle?) { currentActivity = activity } } you can now use it in any class by calling the following: FTApplication.currentActivity()

其他回答

getCurrentActivity()也在ReactContextBaseJavaModule中。 (因为这个问题最初被问到,许多Android应用程序也有ReactNative组件-混合应用程序。)

ReactNative中的类ReactContext有一整套逻辑来维护在getCurrentActivity()中返回的mCurrentActivity。

注:我希望getCurrentActivity()在Android应用程序类中实现。

其他答案我都不喜欢。ActivityManager不是用来获取当前活动的。超级分类和依赖onDestroy也是脆弱的,不是最好的设计。

老实说,到目前为止,我所想到的最好的方法就是在我的应用程序中维护一个枚举,它在创建活动时得到设置。

另一个建议可能是尽量避免使用多个活动。这既可以使用片段,也可以在我喜欢的自定义视图中完成。

在你的应用程序中创建一个类名ActivityManager (java)

public class ActivityManager implements Application.ActivityLifecycleCallbacks {

    private Activity activity;


    public ActivityManager(App myApplication) {
        myApplication.registerActivityLifecycleCallbacks(this);
    }

    public Activity getActivity(){
        return activity;
    }
    @Override
    public void onActivityCreated(@NonNull Activity activity, @Nullable Bundle bundle) {
        this. activity = activity;

    }

    @Override
    public void onActivityStarted(@NonNull Activity activity) {
       this. activity = activity;
    }

    @Override
    public void onActivityResumed(@NonNull Activity activity) {
        this. activity = activity;

    }

    @Override
    public void onActivityPaused(@NonNull Activity activity) {

    }

    @Override
    public void onActivityStopped(@NonNull Activity activity) {

    }

    @Override
    public void onActivitySaveInstanceState(@NonNull Activity activity, @NonNull Bundle bundle) {

    }

    @Override
    public void onActivityDestroyed(@NonNull Activity activity) {

    }
}

然后在应用程序(kotlin)中初始化它

class App : Application() {

    override fun onCreate() {
     
        appOpenManager =  AppOpenManager(this);
    }
  companion object {
        lateinit var appOpenManager: AppOpenManager
    }
}

然后用like

App.activityManager.getActivity ()

我找不到让我们团队满意的解决方案,所以我们就自己动手了。我们使用ActivityLifecycleCallbacks来跟踪当前活动,然后通过服务公开它。更多详情请访问:https://stackoverflow.com/a/38650587/10793

如果您正在使用kotlin,那么它可以帮助您获得当前活动名称。 然而,getRecentTasks()方法在Java中已弃用。

 val am: ActivityManager = applicationContext.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager
 val activityName: String = am.getRecentTasks(1, 0).get(0).topActivity.toString()