android - 如何在 Android 5.0 + 中获取 Top Activity

Question

我正在使用以下代码获取热门 Activity

private String getTopPackageName() {
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
        return activityManager.getRunningTasks(1).get(0).topActivity.getPackageName();
    } else {
        final List<ActivityManager.RunningAppProcessInfo> pis = activityManager.getRunningAppProcesses();
        for (ActivityManager.RunningAppProcessInfo pi : pis) {
            if (pi.pkgList.length == 1) return pi.pkgList[0];
        }
    }
    return "";
}

它在 API<21 上有字，但 API>=21 它返回“”:( 如何得到它？ 我会尝试:

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);

但返回 NULL :( 请帮助我!谢谢

Answer 1

getRunningTasks()在 API 级别 21(Lollipop)

中已弃用

作为替代，你可以这样做

List<ActivityManager.RunningAppProcessInfo> task = manager.getRunningAppProcesses();
ComponentName componentInfo = task.get(0).importanceReasonComponent;
String packageName = componentInfo.getPackageName()

注意:

this method is only intended for debugging and presenting task management user interfaces. This should never be used for core logic in an application, such as deciding between different behaviors based on the information found here.

Refer the doc

更新:

    ActivityManager manager = (ActivityManager) MainActivity.this.getSystemService(Context.ACTIVITY_SERVICE);
    List<ActivityManager.RunningAppProcessInfo> task = manager.getRunningAppProcesses();
    ActivityManager.RunningAppProcessInfo runningAppProcessInfo = null;

    for(ActivityManager.RunningAppProcessInfo singleTask : task){
        if(singleTask.importanceReasonComponent !=null){
            runningAppProcessInfo = singleTask;
            break;
            }
    }

    if(runningAppProcessInfo!=null) {
        ComponentName componentInfo = runningAppProcessInfo.importanceReasonComponent;
        String packageName = componentInfo.getPackageName();
        Log.d("myPackageName", packageName);
    }