android - 检测应用程序何时打开/恢复

Question

我想在每次应用程序打开/关闭时通过服务器 checkin 和 checkout 用户，无论是从任务抽屉启动还是恢复。有没有一种方法可以做到这一点，同时避免在每个 Activity 中调用一个函数？

谢谢!

Answer 1

编辑

在this answer , matdev 让我注意到通过 ProcessLifeCycleOwner 监听应用程序生命周期事件的更现代的方法。参见 https://developer.android.com/topic/libraries/architecture/lifecycle

因此，为了更好地组织所需的 session 管理功能，应使用以下结构。在 MyApplication 的 onCreate 中注册 SessionTracker。然后将与跟踪用户 session 相关的功能隔离到 SessionTracker 类中。

首先添加到你的build.gradle

dependencies {
    implementation "android.arch.lifecycle:extensions:1.1.1"
}

然后，执行以下操作:

public class MyApplication extends Application {  

    @Override
    public void onCreate() {
        super.onCreate();
        ProcessLifecycleOwner.get().getLifecycle().addObserver(SessionTracker.getInstance());
    }
}

public class SessionTracker implements LifecycleObserver {
    private static SessionTracker sSessionTracker;
    private static final long MAX_ACTIVITY_TRANSITION_TIME_MS = 2000;  // Time allowed for transitions

    private Timer mStopDelayTimer;
    private TimerTask mActivityTransitionTimerTask;
    private boolean mWasInBackground = true;
    private AppSession mAppSession;

    public static SessionTracker getInstance() {
        if (sSessionTracker == null) {
            sSessionTracker = new SessionTracker();
        }
        return sSessionTracker;
    }

    private SessionTracker() {
        // no-op
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
    private void onLifecycleStop() {
        submitAppSession(appSession);
    }

    @OnLifecycleEvent(Lifecycle.Event.ON_START)
    private void onLifecycleStart() {
        mAppSession = new AppSession();
    }

    private void submitAppSession(AppSession appSession) {
        // TODO submit app session here
    }
}

public class AppSession {
    /* TODO */
}

上一个答案

d60402提供的答案here以及 Hanno Binder 使用 Application.registerActivityLifecycleCallbacks() 注册 Activity 回调的建议引导我找到这个解决方案。

我扩展了应用程序并将回调注册到 Activity 方法 onPause 和 onStart，如下所示。在这些方法中，一个计时器被启动/停止(一个 Activity 在调用 onPause 时退出，在调用 onStart 时进入一个新 Activity )。当应用程序确定处于后台/前台(真/假)时，标志“wasInBackground”被切换。如果运行 onStart 回调时应用程序处于后台，则调用“appEntered”。如果在 onPause 和 onStart 回调之间传递的时间大于指定时间(为 Activity 转换提供足够的时间)，则在应用 session 被视为完成时调用“appExited”。

public class MyApplication extends Application {

public static final String LOG_TAG = "MyApp";

public boolean wasInBackground = true;

private AppSession appSession;
private Timer mActivityTransitionTimer;
private TimerTask mActivityTransitionTimerTask;
private final long MAX_ACTIVITY_TRANSITION_TIME_MS = 2000;  // Time allowed for transitions

Application.ActivityLifecycleCallbacks activityCallbacks = new Application.ActivityLifecycleCallbacks() {

    @Override
    public void onActivityResumed(Activity activity) {

        if (wasInBackground) {
            //Do app-wide came-here-from-background code
            appEntered();
        }
        stopActivityTransitionTimer();
    }

    @Override
    public void onActivityPaused(Activity activity) {
        startActivityTransitionTimer();
    }

    ...

};

@Override
public void onCreate() {
    super.onCreate();
    registerActivityLifecycleCallbacks(activityCallbacks);
}

public void startActivityTransitionTimer() {
    this.mActivityTransitionTimer = new Timer();
    this.mActivityTransitionTimerTask = new TimerTask() {
        public void run() {
            // Task is run when app is exited
            wasInBackground = true;
            appExited();
        }
    };

    this.mActivityTransitionTimer.schedule(mActivityTransitionTimerTask,
            MAX_ACTIVITY_TRANSITION_TIME_MS);
}

public void stopActivityTransitionTimer() {
    if (this.mActivityTransitionTimerTask != null) {
        this.mActivityTransitionTimerTask.cancel();
    }

    if (this.mActivityTransitionTimer != null) {
        this.mActivityTransitionTimer.cancel();
    }

    this.wasInBackground = false;
}

private void appEntered() {
    Log.i(LOG_TAG, "APP ENTERED");

    appSession = new AppSession();
}

private void appExited() {
    Log.i(LOG_TAG, "APP EXITED");

    appSession.finishAppSession();

    // Submit AppSession to server
    submitAppSession(appSession);
    long sessionLength = (appSession.getT_close() - appSession.getT_open())/1000L;
    Log.i(LOG_TAG, "Session Length: " + sessionLength);
}