Question

android有应用程序状态，如背景还是前（前景）？

基本上每当我的应用程序进入后台（按下主页按钮）时，如果我重新打开它（使其进入前台）我想对我的网络服务器进行asyc调用，就像ping到我的网络服务器一样。它应该在哪个活动中存在。

我不能使用Activity生命周期方法，因为它们只适用于活动。我想要在整个应用程序级别上工作/行为的东西。感谢

Answer 1

我不确定你的问题，但我认为你可以拥有一个BaseActivity并从那个派生出来然后onResume（）将永远被调用吗？

Answer 2

简单的答案是不，android没有提供这样的状态。

经过大量研究后，我找到了一个可靠而简单的解决方案：

public class ApplicationLifecycleHandler implements Application.ActivityLifecycleCallbacks, ComponentCallbacks2 {

    private static final String TAG = ApplicationLifecycleHandler.class.getSimpleName();
    private static boolean isInBackground = false;

    @Override
    public void onActivityCreated(Activity activity, Bundle bundle) {
    }

    @Override
    public void onActivityStarted(Activity activity) {
    }

    @Override
    public void onActivityResumed(Activity activity) {
        Adjust.onResume();
        if(isInBackground){
            Log.d(TAG, "app went to foreground");
            isInBackground = false;
        }
    }

    @Override
    public void onActivityPaused(Activity activity) {
        Adjust.onPause();
    }

    @Override
    public void onActivityStopped(Activity activity) {
    }

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

    @Override
    public void onActivityDestroyed(Activity activity) {
    }

    @Override
    public void onConfigurationChanged(Configuration configuration) {
    }

    @Override
    public void onLowMemory() {
    }

    @Override
    public void onTrimMemory(int i) {
        if(i == ComponentCallbacks2.TRIM_MEMORY_UI_HIDDEN){
            Log.d(TAG, "app went to background");
            isInBackground = true;
        }
    }
}

Answer 3

我在这里写的最简单的答案是找到app是在前景还是后台。没有得到任务，没有这样的检查。但结果非常明确，并且根据需要。

public class MainApplication extends Application implements Application.ActivityLifecycleCallbacks {
private static boolean background = false;
private static int count = 0;
@Override
public void onCreate() {
    super.onCreate();
    registerActivityLifecycleCallbacks(this);
}

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

}

@Override
public void onActivityStarted(Activity activity) {
   if(background){
       background = false;
       Log.v("activityFocus", "Activity came in foreground ");
       Toast.makeText(getApplicationContext(), "Foreground", Toast.LENGTH_SHORT).show();
   }
}

@Override
public void onActivityResumed(Activity activity) {
    count++;
}

@Override
public void onActivityPaused(Activity activity) {
    count--;

}

@Override
public void onActivityStopped(Activity activity) {
 if(count==0){
     Log.v("activityFocus", "Activity is in background ");
     Toast.makeText(getApplicationContext(), "Background", Toast.LENGTH_SHORT).show();
     background=true;
 }
}

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

}

@Override
public void onActivityDestroyed(Activity activity) {

}

}

拦截android应用程序状态背景前景

3 个答案: