[Android]判断当前界面是否是桌面

1.获取ActivityManager

/**
 * Return PackageManager.
 *
 * @param context A Context of the application package implementing this class.
 * @return a PackageManager instance.
 */
public static ActivityManager getActivityManager(Context context){
    return (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);

}

/**
 * Returns a list of launcher that are running on the device.
 *
 * @param context A Context of the application package implementing this class.
 * @return A list which contains all the launcher package name.If there are no launcher, an empty
 *         list is returned.
 */
public static List<String> getLaunchers(Context context){
    List<String> packageNames = new ArrayList<String>();
    PackageManager packageManager = context.getPackageManager();
    Intent intent = new Intent(Intent.ACTION_MAIN);
    intent.addCategory(Intent.CATEGORY_HOME);

    List<ResolveInfo> resolveInfos = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);

    for(ResolveInfo resolveInfo:resolveInfos){
        ActivityInfo activityInfo = resolveInfo.activityInfo;
        if(activityInfo != null) {
            packageNames.add(resolveInfo.activityInfo.processName);
            packageNames.add(resolveInfo.activityInfo.packageName);
        }
    }
    return packageNames;
}

/**
 * Returns whether the launcher which running on the device is importance foreground.
 *
 * @param context A Context of the application package implementing this class.
 * @return True if the importance of the launcher process is {@link android.app.ActivityManager.RunningAppProcessInfo#IMPORTANCE_FOREGROUND}.
 *
 *
 */
public static boolean isLauncherForeground(Context context){
    boolean isLauncherForeground = false;
    ActivityManager activityManager = getActivityManager(context);
    List<String> lanuchers = getLaunchers(context);
    List<RunningTaskInfo> runningTaskInfos =  activityManager.getRunningTasks(1);

    if(lanuchers.contains(runningTaskInfos.get(0).baseActivity.getPackageName())) {
        isLauncherForeground = true;
    }

    return isLauncherForeground;
}