提示用户启用蓝牙 Xamarin Forms

Question

Are there any workaround which I can use to prompt a user to enable bluetooth in Xamarin Forms / C#?

Like a Display Alert with 'Yes' or 'No' for prompting the user to switch on the bluetooth in case its not enabled.

If the user selects, 'Yes', the bluetooth is enabled.

Please help me to achieve this in both Android and iOS. Thanks in advance.

Answer 1

iOS

On iOS you can not change bluetooth programmatically without using private API's (which Apple does not allow in the App Store), the most you can do is redirect the user to the Bluetooth Settings with this code (note that it only works on a real device):

// Is bluetooth enabled?
var bluetoothManager = new CoreBluetooth.CBCentralManager();
if (bluetoothManager.State == CBCentralManagerState.PoweredOff) {
    // Does not go directly to bluetooth on every OS version though, but opens the Settings on most
    UIApplication.SharedApplication.OpenUrl(new NSUrl("App-Prefs:root=Bluetooth")); 
}

Be aware that this method will prevent your app from getting App Store approval, since 'App-Prefs:root' is also considered a private API with this explanation: (thanks to @chucky for mentioning that)

Your app uses the "prefs:root=" non-public URL scheme, which is a private entity. The use of non-public APIs is not permitted on the App Store because it can lead to a poor user experience should these APIs change.

So for iOS there is no possibility without risk for app rejection.

Android

Android.Bluetooth.BluetoothAdapter bluetoothAdapter = BluetoothAdapter.DefaultAdapter;
// is bluetooth enabled?
bluetoothAdapter.IsEnabled;

bluetoothAdapter.Disable();
// or
bluetoothAdapter.Enable();

The BLUETOOTH and BLUETOOTH_ADMIN permission are required for this method to work.

Answer 2

In Xamarin Forms

if(await DisplayAlert(null,"Enable Bluetooth","Yes", "No"))
{
    // Enablebluetooth here via custom service
}

For bluetooth implementation download Xamarin.BluetoothLE in nugget or you can implement your own

In PCL

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Test.App
{
    public interface IBluetoothService
    {
        void OpenBluetooth();
        
    }
}

In Android

using System;
using BluetoothLE.Core;
using Android.Bluetooth;
using Java.Util;
using System.Collections.Generic;
using BluetoothLE.Core.Events;

namespace Test.App.Droid.Services
{
    public class BluetoothService : IBluetoothService
    {
    
        public void OpenBluetooth()
        {
        //native code here to open bluetooth
        }
    
    }
    
}

// register it on MainActivity


// do the same in ios

Answer 3

I dont know about iOS,

If you are looking for navigating to Bluetooth settings in Android from your app in the click of a button. Here is the code:

    private void OpenBluetoothSettings()
    {
        Intent intentOpenBluetoothSettings = new Intent();
        intentOpenBluetoothSettings.SetAction(Android.Provider.Settings.ActionBluetoothSettings);
        intentOpenBluetoothSettings.AddFlags(ActivityFlags.NewTask);
        Android.App.Application.Context.StartActivity(intentOpenBluetoothSettings);
    }