工具-生命周期管理

监听app切换前后台

ActivityLifecycleCallbacks使用要求API 14+ （Android 4.0+）。

public class ForegroundCallbacks implements Application.ActivityLifecycleCallbacks {
    public static final long CHECK_DELAY = 500;
    public static final String TAG = ForegroundCallbacks.class.getName();
    public interface Listener {
        public void onBecameForeground();
        public void onBecameBackground();
    }
    private static ForegroundCallbacks instance;
    private boolean foreground = false, paused = true;
    private Handler handler = new Handler();
    private List<Listener> listeners = new CopyOnWriteArrayList<Listener>();
    private Runnable check;
    public static ForegroundCallbacks init(Application application){
        if (instance == null) {
            instance = new ForegroundCallbacks();
            application.registerActivityLifecycleCallbacks(instance);
        }
        return instance;
    }
    public static ForegroundCallbacks get(Application application){
        if (instance == null) {
            init(application);
        }
        return instance;
    }
    public static ForegroundCallbacks get(Context ctx){
        if (instance == null) {
            Context appCtx = ctx.getApplicationContext();
            if (appCtx instanceof Application) {
                init((Application)appCtx);
            }
            throw new IllegalStateException(
                    "Foreground is not initialised and " +
                            "cannot obtain the Application object");
        }
        return instance;
    }
    public static ForegroundCallbacks get(){
        if (instance == null) {
            throw new IllegalStateException(
                    "Foreground is not initialised - invoke " +
                            "at least once with parameterised init/get");
        }
        return instance;
    }
    public boolean isForeground(){
        return foreground;
    }
    public boolean isBackground(){
        return !foreground;
    }
    public void addListener(Listener listener){
        listeners.add(listener);
    }
    public void removeListener(Listener listener){
        listeners.remove(listener);
    }
    @Override
    public void onActivityResumed(Activity activity) {
        paused = false;
        boolean wasBackground = !foreground;
        foreground = true;
        if (check != null)
            handler.removeCallbacks(check);
        if (wasBackground){
           L.d ("went foreground");

            for (Listener l : listeners) {
                try {
                    l.onBecameForeground();


                } catch (Exception exc) {
                    L.d ("Listener threw exception!:"+exc.toString());
                }
            }
        } else {
            L.d ("still foreground");
        }
    }
    @Override
    public void onActivityPaused(Activity activity) {
        paused = true;
        if (check != null)
            handler.removeCallbacks(check);
        handler.postDelayed(check = new Runnable(){
            @Override
            public void run() {
                if (foreground && paused) {
                    foreground = false;
                    L.d ("went background");
                    for (Listener l : listeners) {
                        try {
                            l.onBecameBackground();
                        } catch (Exception exc) {
                            L.d ("Listener threw exception!:"+exc.toString());
                        }
                    }
                } else {
                    L.d ("still foreground");
                }
            }
        }, CHECK_DELAY);
    }
    @Override
    public void onActivityCreated(Activity activity, Bundle savedInstanceState) {}
    @Override
    public void onActivityStarted(Activity activity) {}
    @Override
    public void onActivityStopped(Activity activity) {}
    @Override
    public void onActivitySaveInstanceState(Activity activity, Bundle outState) {}
    @Override
    public void onActivityDestroyed(Activity activity) {}
}

Application 中使用

MyApplication 结合Application.ActivityLifecycleCallbacks

public class MyApplication extends Application{

    @Override
    public void onCreate() {
        super.onCreate();
        ForegroundCallbacks.init(this);

        ForegroundCallbacks.get().addListener(new ForegroundCallbacks.Listener() {
            @Override
            public void onBecameForeground() {
                L.d("当前程序切换到前台");
                if(CacheUtils.getBoolean(getApplicationContext(), MyConst.GESTRUE_IS_LIVE)){
                    L.d("已经开启手势锁");
                    Intent intent = new Intent(getApplicationContext(), CheckGesPwdActivity.class);
                    intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_NEW_TASK);
                    startActivity(intent);
                }else{

                }

            }

            @Override
            public void onBecameBackground() {
                L.d("当前程序切换到后台");
            }
        });

    }
}

单个Activity单独使用

public class TestLifeAc extends AppCompatActivity implements ForegroundCallbacks.Listener {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_city_list);
        // 注册监听
        ForegroundCallbacks.get(this).addListener(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // 移除监听
        ForegroundCallbacks.get(this).removeListener(this);
    }

    @Override
    public void onBecameForeground(Activity activity) {
        // 切换为前台
    }

    @Override
    public void onBecameBackground(Activity activity) {
        //切换为后台
    }
}