如何获得运行 application activity 的名字 android 5.0 吗

检查此代码如下-
public class DetectCalendarLaunchRunnable implements Runnable {

@Override
public void run() {
String[] activePackages;
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.KITKAT_WATCH) {
activePackages = getActivePackages();
} else {
activePackages = getActivePackagesCompat();
}
if (activePackages != null) {
for (String activePackage : activePackages) {
if (activePackage.equals("com.google.android.calendar")) {
//Calendar app is launched, do something
}
}
}
mHandler.postDelayed(this, 1000);
}

String[] getActivePackagesCompat() {
final List taskInfo = mActivityManager.getRunningTasks(1);
final ComponentName componentName = taskInfo.get(0).topActivity;
final String[] activePackages = new String[1];
activePackages[0] = componentName.getPackageName();
return activePackages;
}

String[] getActivePackages() {
final Set activePackages = new HashSet();
final List processInfos = mActivityManager.getRunningAppProcesses();
for (ActivityManager.RunningAppProcessInfo processInfo : processInfos) {
if (processInfo.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) {
activePackages.addAll(Arrays.asList(processInfo.pkgList));
}
}
return activePackages.toArray(new String[activePackages.size()]);
}
}