在 Android 6.0 Marshmallow 中，我使用以下代码查询前台应用程序，但传入通知出现问题，因为它向发送通知的应用程序显示前台应用程序。该问题仅存在于 Marshmallow 中(5.X 可以正常工作)。

// API 21 and above
    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public static String getProcessNew(UsageStatsManager mUsageStatsManager, Context c) throws Exception {
        String st = null;
        try {
            long endTime = System.currentTimeMillis();
            long beginTime = endTime - 1000 * 10;

            // We get usage stats for the last minute
            List<UsageStats> stats = mUsageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_DAILY, beginTime,
                    endTime);
            // Sort the stats by the last time used
            if (stats != null) {
                SortedMap<Long, UsageStats> mySortedMap = new TreeMap<Long, UsageStats>();
                for (UsageStats usageStats : stats) {
                    mySortedMap.put(usageStats.getLastTimeUsed(), usageStats);
                }
                if (mySortedMap != null && !mySortedMap.isEmpty()) {
                    st = mySortedMap.get(mySortedMap.lastKey()).getPackageName();
                }
            }

        } catch (Exception e) {
            Log.d("main", "Wxxxxexx " + e);

        }
        return st;
    }

然后使用此答案 UsageEvents 中的解决方案解决通知问题.

作为答案的解决方案，我将代码及其工作用于获取前台应用程序，但延迟了 3 秒。我的服务正在检查前台应用程序，并且每 500 毫秒重复一次，但 whatsapp 包在启动 whatsapp 3 秒后检测到。这是我在上述解决方案中使用的 UsageEvents 代码。

                                if (BuildV >= 23) {
                                    long endTime = System.currentTimeMillis();
                                    long beginTime = endTime - 1000 * 10;
                                    UsageEvents usageEvents = mUsageStatsManager.queryEvents(beginTime, endTime);
                                    UsageEvents.Event event = new UsageEvents.Event();
                                    while (usageEvents.hasNextEvent()) {
                                        usageEvents.getNextEvent(event);
                                    }
                                    if (st.equals(event.getPackageName())
                                            && event.getEventType() == UsageEvents.Event.MOVE_TO_FOREGROUND) {
                                        pack = st;

                                    }
                                }

最佳答案

尝试此代码并确保代码在用户授予运行时权限后应用

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;
}

关于android - 在棉花糖中获取前台应用程序包名称延迟 3 秒，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38712416/