要在AppCenter推送中为Xamarin.Forms Android应用程序添加震动功能，您可以使用以下代码示例：

首先，在Android项目的MainActivity.cs文件中添加以下代码：

using Android.OS;
using Android.Media;

namespace YourAppName.Droid
{
    [Activity(Label = "YourAppName", Icon = "@mipmap/icon", Theme = "@style/MainTheme", MainLauncher = true, ConfigurationChanges = ConfigChanges.ScreenSize | ConfigChanges.Orientation)]
    public class MainActivity : global::Xamarin.Forms.Platform.Android.FormsAppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            TabLayoutResource = Resource.Layout.Tabbar;
            ToolbarResource = Resource.Layout.Toolbar;

            base.OnCreate(savedInstanceState);

            global::Xamarin.Forms.Forms.Init(this, savedInstanceState);
            LoadApplication(new App());

            // Check if the device supports vibration
            Vibrator vibrator = (Vibrator)GetSystemService(VibratorService);
            if (vibrator.HasVibrator)
            {
                // Set the default notification channel for Android Oreo and above
                if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
                {
                    var channel = new NotificationChannel("channel_id", "channel_name", NotificationImportance.Default);
                    var notificationManager = (NotificationManager)GetSystemService(NotificationService);
                    notificationManager.CreateNotificationChannel(channel);
                }

                // Enable vibration for AppCenter push notifications
                AppCenter.Start("your_app_secret", typeof(Push));
                Push.PushNotificationReceived += (sender, e) =>
                {
                    // Vibrate when a push notification is received
                    vibrator.Vibrate(500); // Adjust the duration as per your requirement
                };
            }
        }
    }
}

上述代码检查设备是否支持振动，并在接收到AppCenter推送通知时触发振动功能。

确保将your_app_secret替换为您的实际AppCenter应用程序的密钥。

这样，当您的Xamarin.Forms Android应用程序接收到AppCenter推送通知时，它将触发设备振动。