拦截Android应用程序状态背景前景

Question

Android是否具有应用程序状态，如后台或前台（前台）？基本上，每当我的应用程序转到后台（主页按钮被按下），如果我然后重新打开它（使它前景）我想做一个asyc电话给我的网络服务器，就像p​​ing我的网络服务器。它不应该在哪些活动im进来。

我不能用活动生命周期方法做它，因为它们只能用于活动。我想要在整个应用程序级别上工作/行动的东西。谢谢

Answer 1

我不确定你的问题，但我认为你可以有一个BaseActivity并从那个派生，然后onResume（）将永远被称为是正确的？

Answer 2

简单的回答是不，android不提供这样的状态。

了大量的研究后，我发现了一个可靠的和简单的解决方案：

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

我写在这里简单的答案找到，如果应用程序是在前台或后台。没有得到任务，也没有这样的检查。但结果是非常明确的，并根据需要。

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) { 

} 

}