Android深度链接 - 恢复导航

Question

我有两项活动：MainActivity和SettingsActivity。从通知中我启动了SettingsActivity。当我按回 - ＆gt;显示MainActivity，但如果在通知到来时它是活动的，我希望不会重新创建MainActivity。现在每次重新创建MainActivity（onCreate()被调用）

private void sendNotification(HashMap<String, String> data) {
    Intent intent = new Intent(this, SettingsActivity.class);
    intent.putExtra("fcm", data);
    TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
    stackBuilder.addParentStack(SettingsActivity.class);
    stackBuilder.addNextIntent(intent);
    PendingIntent pendingIntent =  stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);
    Uri defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
            .setSmallIcon(R.mipmap.ic_launcher)
            .setColor(getResources().getColor(R.color.colorNotification))
            .setContentTitle(getResources().getString(R.string.app_name))
            .setContentText(getResources().getString(R.string.notification))
            .setAutoCancel(true)
            .setSound(defaultSoundUri)
            .setContentIntent(pendingIntent);
    NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.notify(MESSAGE_NOTIFICATION_ID, notificationBuilder.build());
} 

清单：

<activity
    android:name=".MainActivity"
    android:label="@string/app_name"
    android:configChanges="orientation|screenSize"
    android:launchMode="singleTop">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

<activity android:name=".SettingsActivity"
          android:label="@string/settings"
          android:parentActivityName=".MainActivity">
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value=".MainActivity"/>
</activity>