Android感知当前App应用处于前台(可见)或后台(不可见)简洁规范的解决方案

判断当前App是否处于前台（可见）或后台（不可见）附录1是一种解决方案。然而不够简洁，也是在过去一段时间比较稳定的解决方案。现在谷歌官方推出了LifecycleObserver和与Android生命周期相关的Lifecycle维护和管理方案，那么现在判断App处于前台和后台的解决就简洁多了，如代码：

package zhangphil.test;

import android.app.Application;
import android.arch.lifecycle.Lifecycle;
import android.arch.lifecycle.LifecycleObserver;
import android.arch.lifecycle.OnLifecycleEvent;
import android.arch.lifecycle.ProcessLifecycleOwner;

import com.orhanobut.logger.AndroidLogAdapter;
import com.orhanobut.logger.Logger;

public class MyApp extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        //Logger初始化。
        Logger.addLogAdapter(new AndroidLogAdapter());


        ProcessLifecycleOwner.get().getLifecycle().addObserver(new MyLifecycleObserver());
    }

    public class MyLifecycleObserver implements LifecycleObserver {

        //App处于前台可见状态。

        @OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
        public void create() {
            System.out.println("create");
        }

        @OnLifecycleEvent(Lifecycle.Event.ON_START)
        public void start() {
            System.out.println("start");
        }

        @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
        public void resume() {
            System.out.println("resume");
        }


        //此后App进入不可见状态/后台

        @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
        public void pause() {
            System.out.println("pause");
        }

        @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
        public void stop() {
            System.out.println("stop");
        }
    }
}

    compile "android.arch.lifecycle:extensions:1.1.1"
    annotationProcessor "android.arch.lifecycle:compiler:1.1.1"