从后台任务或服务确定当前前台应用程序

Question

我希望有一个在后台运行的应用程序,它知道任何内置应用程序(消息,联系人等)何时运行.

所以我的问题是:

1. 我应该如何在后台运行我的应用程序.

2. 我的后台应用程序如何知道前台运行的应用程序是什么.

有经验的人的回应将不胜感激.

Answer 1

关于"2.我的后台应用程序如何知道当前在前台运行的应用程序是什么."

不要使用这个getRunningAppProcesses()方法,因为这会从我的经验中返回各种系统垃圾,你会得到多个结果RunningAppProcessInfo.IMPORTANCE_FOREGROUND.请getRunningTasks()改用

这是我在服务中用来识别当前前台应用程序的代码,它非常简单:

ActivityManager am = (ActivityManager) AppService.this.getSystemService(ACTIVITY_SERVICE);
// The first in the list of RunningTasks is always the foreground task.
RunningTaskInfo foregroundTaskInfo = am.getRunningTasks(1).get(0);

多数民众赞成,然后您可以轻松访问前台应用/活动的详细信息:

String foregroundTaskPackageName = foregroundTaskInfo .topActivity.getPackageName();
PackageManager pm = AppService.this.getPackageManager();
PackageInfo foregroundAppPackageInfo = pm.getPackageInfo(foregroundTaskPackageName, 0);
String foregroundTaskAppName = foregroundAppPackageInfo.applicationInfo.loadLabel(pm).toString();

这需要在活动清单中获得额外的许可,并且完美地运行.

<uses-permission android:name="android.permission.GET_TASKS" />

Answer 2

我必须以艰难的方式找出正确的解决方案.下面的代码是cyanogenmod7(平板电脑调整)的一部分,并在android 2.3.3/gingerbread上测试.

方法:

• getForegroundApp - 返回前台应用程序.
• getActivityForApp - 返回找到的应用程序的活动.
• isStillActive - 确定先前找到的应用程序是否仍然是活动应用程序.
• isRunningService - getForegroundApp的辅助函数

希望能在所有方面解决这个问题(:

private RunningAppProcessInfo getForegroundApp() {
    RunningAppProcessInfo result=null, info=null;

    if(mActivityManager==null)
        mActivityManager = (ActivityManager)mContext.getSystemService(Context.ACTIVITY_SERVICE);
    List <RunningAppProcessInfo> l = mActivityManager.getRunningAppProcesses();
    Iterator <RunningAppProcessInfo> i = l.iterator();
    while(i.hasNext()){
        info = i.next();
        if(info.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND
                && !isRunningService(info.processName)){
            result=info;
            break;
        }
    }
    return result;
}

private ComponentName getActivityForApp(RunningAppProcessInfo target){
    ComponentName result=null;
    ActivityManager.RunningTaskInfo info;

    if(target==null)
        return null;

    if(mActivityManager==null)
        mActivityManager = (ActivityManager)mContext.getSystemService(Context.ACTIVITY_SERVICE);
    List <ActivityManager.RunningTaskInfo> l = mActivityManager.getRunningTasks(9999);
    Iterator <ActivityManager.RunningTaskInfo> i = l.iterator();

    while(i.hasNext()){
        info=i.next();
        if(info.baseActivity.getPackageName().equals(target.processName)){
            result=info.topActivity;
            break;
        }
    }

    return result;
}

private boolean isStillActive(RunningAppProcessInfo process, ComponentName activity)
{
    // activity can be null in cases, where one app starts another. for example, astro
    // starting rock player when a move file was clicked. we dont have an activity then,
    // but the package exits as soon as back is hit. so we can ignore the activity
    // in this case
    if(process==null)
        return false;

    RunningAppProcessInfo currentFg=getForegroundApp();
    ComponentName currentActivity=getActivityForApp(currentFg);

    if(currentFg!=null && currentFg.processName.equals(process.processName) &&
            (activity==null || currentActivity.compareTo(activity)==0))
        return true;

    Slog.i(TAG, "isStillActive returns false - CallerProcess: " + process.processName + " CurrentProcess: "
            + (currentFg==null ? "null" : currentFg.processName) + " CallerActivity:" + (activity==null ? "null" : activity.toString())
            + " CurrentActivity: " + (currentActivity==null ? "null" : currentActivity.toString()));
    return false;
}

private boolean isRunningService(String processname){
    if(processname==null || processname.isEmpty())
        return false;

    RunningServiceInfo service;

    if(mActivityManager==null)
        mActivityManager = (ActivityManager)mContext.getSystemService(Context.ACTIVITY_SERVICE);
    List <RunningServiceInfo> l = mActivityManager.getRunningServices(9999);
    Iterator <RunningServiceInfo> i = l.iterator();
    while(i.hasNext()){
        service = i.next();
        if(service.process.equals(processname))
            return true;
    }

    return false;
}

Answer 3

请尝试以下代码:

ActivityManager activityManager = (ActivityManager) newContext.getSystemService( Context.ACTIVITY_SERVICE );
List<RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
for(RunningAppProcessInfo appProcess : appProcesses){
    if(appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND){
        Log.i("Foreground App", appProcess.processName);
    }
}

进程名称是在前台运行的应用程序的程序包名称.将其与应用程序的包名称进行比较.如果它是相同的,那么您的应用程序正在前台运行.

我希望这回答了你的问题.

Answer 4

从棒棒糖开始,这变了.请找到下面的代码,然后用户必须进入设置 - >安全 - >(向下滚动到最后)具有使用权限的应用程序 - >授予我们的应用程序权限

private void printForegroundTask() {
    String currentApp = "NULL";
    if(android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP) {
        UsageStatsManager usm = (UsageStatsManager) this.getSystemService(Context.USAGE_STATS_SERVICE);
        long time = System.currentTimeMillis();
        List<UsageStats> appList = usm.queryUsageStats(UsageStatsManager.INTERVAL_DAILY,  time - 1000*1000, time);
        if (appList != null && appList.size() > 0) {
            SortedMap<Long, UsageStats> mySortedMap = new TreeMap<Long, UsageStats>();
            for (UsageStats usageStats : appList) {
                mySortedMap.put(usageStats.getLastTimeUsed(), usageStats);
            }
            if (mySortedMap != null && !mySortedMap.isEmpty()) {
                currentApp = mySortedMap.get(mySortedMap.lastKey()).getPackageName();
            }
        }
    } else {
        ActivityManager am = (ActivityManager)this.getSystemService(Context.ACTIVITY_SERVICE);
        List<ActivityManager.RunningAppProcessInfo> tasks = am.getRunningAppProcesses();
        currentApp = tasks.get(0).processName;
    }

    Log.e(TAG, "Current App in foreground is: " + currentApp);
}

Answer 5

考虑到已getRunningTasks()被弃用getRunningAppProcesses()且不可靠,我决定结合StackOverflow中提到的两种方法:

   private boolean isAppInForeground(Context context)
    {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP)
        {
            ActivityManager am = (ActivityManager) context.getSystemService(ACTIVITY_SERVICE);
            ActivityManager.RunningTaskInfo foregroundTaskInfo = am.getRunningTasks(1).get(0);
            String foregroundTaskPackageName = foregroundTaskInfo.topActivity.getPackageName();

            return foregroundTaskPackageName.toLowerCase().equals(context.getPackageName().toLowerCase());
        }
        else
        {
            ActivityManager.RunningAppProcessInfo appProcessInfo = new ActivityManager.RunningAppProcessInfo();
            ActivityManager.getMyMemoryState(appProcessInfo);
            if (appProcessInfo.importance == IMPORTANCE_FOREGROUND || appProcessInfo.importance == IMPORTANCE_VISIBLE)
            {
                return true;
            }

            KeyguardManager km = (KeyguardManager) context.getSystemService(Context.KEYGUARD_SERVICE);
            // App is foreground, but screen is locked, so show notification
            return km.inKeyguardRestrictedInputMode();
        }
    }

Answer 6

该ActivityManager类是适当的工具,看看哪些进程正在运行.

要在后台运行,通常需要使用服务.

Answer 7

为了确定前台应用程序，可以使用来检测前台应用程序，可以使用https://github.com/ricvalerio/foregroundappchecker。根据设备的android版本，它使用不同的方法。

至于服务，存储库还提供了所需的代码。本质上，让android studio为您创建服务，然后onCreate添加使用appChecker的代码段。但是，您将需要请求许可。

Answer 8

对于需要从我们自己的服务/后台线程检查我们的应用程序是否在前台的情况。这是我实施的方式，对我来说很好用：

public class TestApplication extends Application implements Application.ActivityLifecycleCallbacks {

    public static WeakReference<Activity> foregroundActivityRef = null;

    @Override
    public void onActivityStarted(Activity activity) {
        foregroundActivityRef = new WeakReference<>(activity);
    }

    @Override
    public void onActivityStopped(Activity activity) {
        if (foregroundActivityRef != null && foregroundActivityRef.get() == activity) {
            foregroundActivityRef = null;
        }
    }

    // IMPLEMENT OTHER CALLBACK METHODS
}

现在要从其他类中检查应用是否在前台，只需调用：

if(TestApplication.foregroundActivityRef!=null){
    // APP IS IN FOREGROUND!
    // We can also get the activity that is currently visible!
}

更新（如SHS所指出）：

不要忘记在Application类的onCreate方法中注册回调。

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