Location access on Android (ML2) #904

paulmelis · 2024-03-15T16:16:17Z

paulmelis
Mar 15, 2024

I'm trying to get a (coarse) location on a Magic Leap 2, just once at application startup is enough. As far as I can tell one way to get location information is to use a LocationManager (or here for Quest 3) object.

using Android.App;
using Android.Content;
using Android.Locations;
using Android.OS;
using Android.Runtime;

...
    // Called after SK.Initialize()
    GCHandle gch = GCHandle.FromIntPtr(SK.Settings.androidActivity);
    Context context = (Context)gch.Target;
    LocationManager location_manager = (LocationManager) context.GetSystemService(Context.LocationService);
...

This seems pretty straight-forward, but I get a crash (SIGABRT, looking at the logcat output) at the last line when launching the app on the ML2.

I'm not very familiar with Android development, so I'm probably doing some stupid things. Yet, I'm wondering if the androidActivity is indeed what I think it is and if I'm using it in the right manner? Has someone done something similar on Android already?

maluoi · 2024-03-15T16:46:27Z

maluoi
Mar 15, 2024
Maintainer

I'd probably not recommend using StereoKit's androidActivity, there's a couple different paths I use to collect the Activity, and it may not always be present. Not to mention the IntPtr thing 😅

I'd recommend using Android.App.Application.Context instead, this seems to be a pretty conveniently available global variable that's part of the official API, and it gets you straight to the Context here anyhow!

1 reply

paulmelis Mar 15, 2024
Author

Actually, I tried that initially, but same result 😢

paulmelis · 2024-03-15T21:03:53Z

paulmelis
Mar 15, 2024
Author

After a couple of hours more trying to figure out what is wrong I'm not much further, unfortunately. Deploying to a Quest 3 gives the same SIGABRT, but slightly more info in the logcat output:

--------- beginning of crash
03-15 21:46:35.242  8053  8102 F libc    : Fatal signal 6 (SIGABRT), code -1 (SI_QUEUE) in tid 8102 (StereoKit Main), pid 8053 (d_location_test)
03-15 21:46:35.168     0     0 I CAM_INFO: CAM-SENSOR: cam_sensor_driver_cmd: 1265 20:46:35.147 CAM_START_DEV Success for imx471 sensor_id:0x471,sensor_slave_addr:0x34
03-15 21:46:35.335     0     0 I msm_cvp : sess: Opening cvp instance: 0000000000000000
03-15 21:46:35.337     0     0 I synx    : info: synx_initialize: 2287: [sess :9] session created cvp-kernel-client
03-15 21:46:35.345     0     0 I synx    : info: synx_initialize: 2287: [sess :10] session created umd-client-3262
03-15 21:46:35.854  8352  8352 F DEBUG   : *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
03-15 21:46:35.854  8352  8352 F DEBUG   : Build fingerprint: 'oculus/eureka/eureka:12/SQ3A.220605.009.A1/49872870047700510:user/release-keys'
03-15 21:46:35.854  8352  8352 F DEBUG   : Revision: '0'
03-15 21:46:35.854  8352  8352 F DEBUG   : ABI: 'arm64'
03-15 21:46:35.854  8352  8352 F DEBUG   : Timestamp: 2024-03-15 21:46:35.302935736+0100
03-15 21:46:35.854  8352  8352 F DEBUG   : Process uptime: 6s
03-15 21:46:35.854  8352  8352 F DEBUG   : Diagnostic-Collection-Type: Tombstone Proto
03-15 21:46:35.854  8352  8352 F DEBUG   : Has-Diagnostic-Summary: Yes
03-15 21:46:35.854  8352  8352 F DEBUG   : APK-Location: /data/app/~~u3w_lt4Plm3RgFRoafoBsw==/com.companyname.android_location_test-0Wqm1Ycyv8sY6szmeBbb4Q==/base.apk
03-15 21:46:35.854  8352  8352 F DEBUG   : Debugging: No
03-15 21:46:35.854  8352  8352 F DEBUG   : Has-Waited-For-Debugger: No
03-15 21:46:35.854  8352  8352 F DEBUG   : Last-Activity-Time: 1081479
03-15 21:46:35.854  8352  8352 F DEBUG   : Process-Runtime: 6258
03-15 21:46:35.854  8352  8352 F DEBUG   : Waiting-To-Kill: 
03-15 21:46:35.854  8352  8352 F DEBUG   : Killed-By-AM: No
03-15 21:46:35.854  8352  8352 F DEBUG   : Removed: No
03-15 21:46:35.854  8352  8352 F DEBUG   : Wanted-ANR-Ui: No
03-15 21:46:35.854  8352  8352 F DEBUG   : Killed: No
03-15 21:46:35.854  8352  8352 F DEBUG   : OOM-Score-Adj: 900
03-15 21:46:35.854  8352  8352 F DEBUG   : Wanted-Error-Ui: No
03-15 21:46:35.854  8352  8352 F DEBUG   : Kill-Time: 0
03-15 21:46:35.854  8352  8352 F DEBUG   : State: CRE 
03-15 21:46:35.854  8352  8352 F DEBUG   : Foreground: No
03-15 21:46:35.854  8352  8352 F DEBUG   : Executable: /system/bin/app_process64
03-15 21:46:35.854  8352  8352 F DEBUG   : Cmdline: com.companyname.android_location_test
03-15 21:46:35.854  8352  8352 F DEBUG   : pid: 8053, tid: 8102, name: StereoKit Main  >>> com.companyname.android_location_test <<<
03-15 21:46:35.854  8352  8352 F DEBUG   : uid: 10008
03-15 21:46:35.854  8352  8352 F DEBUG   : tagged_addr_ctrl: 0000000000000001
03-15 21:46:35.854  8352  8352 F DEBUG   : signal 6 (SIGABRT), code -1 (SI_QUEUE), fault addr --------
03-15 21:46:35.854  8352  8352 F DEBUG   : Abort message: 'No pending exception expected: java.lang.IllegalArgumentException: Receiver not registered: com.oculus.vrapi.SystemActivitiesReceiver@25c1256
03-15 21:46:35.854  8352  8352 F DEBUG   :   at android.content.IIntentReceiver android.app.LoadedApk.forgetReceiverDispatcher(android.content.Context, android.content.BroadcastReceiver) (LoadedApk.java:1582)
03-15 21:46:35.854  8352  8352 F DEBUG   :   at void android.app.ContextImpl.unregisterReceiver(android.content.BroadcastReceiver) (ContextImpl.java:1798)
03-15 21:46:35.854  8352  8352 F DEBUG   :   at void android.content.ContextWrapper.unregisterReceiver(android.content.BroadcastReceiver) (ContextWrapper.java:771)
03-15 21:46:35.854  8352  8352 F DEBUG   :   at void com.oculus.vrapi.SystemActivitiesReceiver.stopReceiver(android.content.Context) (:9)

Apparently somewhere an illegal argument is passed, causing an (unexpected) exception, causing the abort. This is with this simple standalone test code:

using StereoKit;
#if ANDROID
using Android.App;
using Android.Content;
using Android.Locations;
using Android.OS;
using Android.Runtime;
#endif

namespace android_location_test;

class Program : Fragment, ILocationListener
{
	static void Main(string[] args)
	{
		// Initialize StereoKit
		SKSettings settings = new SKSettings
		{
			appName = "android-location-test",
			assetsFolder = "Assets",
		};

		if (!SK.Initialize(settings))
			return;

        Program app = new Program();
        app.Run();

        SK.Shutdown();
    }

    public void OnLocationChanged(Location location)
    {
        Log.Info($"LOCATION {location}");
    }

    public void OnProviderDisabled(string provider) {}
    public void OnProviderEnabled(string provider) {}
    public void OnStatusChanged(string provider, [GeneratedEnum] Availability status, Bundle extras) {}

    public void Run()
    {
#if ANDROID
                Context context = Android.App.Application.Context;
                Log.Info($"context = {context}");
                LocationManager location_manager = (LocationManager) context.GetSystemService("location");
                Log.Info($"location manager = {location_manager}");
#endif

		// Create assets used by the app
		Pose  cubePose = new Pose(0, 0, -0.5f);
		Model cube     = Model.FromMesh(
			Mesh.GenerateRoundedCube(Vec3.One*0.1f, 0.02f),
			Material.UI);

		Matrix   floorTransform = Matrix.TS(0, -1.5f, 0, new Vec3(30, 0.1f, 30));
		Material floorMaterial  = new Material("floor.hlsl");
		floorMaterial.Transparency = Transparency.Blend;

		// Core application loop
                while (SK.Step(() =>
                {		
			        if (SK.System.displayType == Display.Opaque)
				        Mesh.Cube.Draw(floorMaterial, floorTransform);
        
			        UI.Handle("Cube", ref cubePose, cube.Bounds);
			        cube.Draw(cubePose.ToMatrix());
		        }));
	        }
}

Any tips appreciated

7 replies

maluoi Mar 16, 2024
Maintainer

Ah interesting! I just deployed this code from Windows to my Quest3, and it worked fine for me. I am using .NET SDK 8.0.103, but otherwise the same.

paulmelis Mar 17, 2024
Author

So first piece of the puzzle is the cause of the SIGABRT I'm seeing. Apparently there's an obscure bug when an APK gets incrementally built, causing inclusion of the wrong DLL (xamarin/xamarin-android#7580 (comment)). Work-around is to remove the Projects/Android/obj dir before building. With this fix at least the SIGBART goes away for me, even when using dotnet on Linux

Edit: the linked bug might not be entirely the correct one, I see similar stuff in the xamarin-android issue list, but the work-around there does work

paulmelis Mar 17, 2024
Author

Regarding permissions and the manifest, I've now added this to AndroidManifest.xml:

...
        <service android:name="MyNagivationService" android:foregroundServiceType="location">
        </service>
    </application>

    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

The <service> part is apparently needed, according to https://developer.android.com/develop/sensors-and-location/location/permissions#foreground

As far as the runtime check/request for permissions, I'm using this for now:

        Context context = Android.App.Application.Context;
        if (context.CheckSelfPermission(Manifest.Permission.AccessCoarseLocation) == Android.Content.PM.Permission.Granted)
        {
            LocationManager location_manager = (LocationManager) context.GetSystemService(Context.LocationService);
            foreach (string p in location_manager.GetProviders(false))
                Log.Info($"LOCATION PROVIDER {p}");

            Location location = location_manager.GetLastKnownLocation("fused");
            if (location != null)
                Log.Info($"LAST KNOWN LOCATION (fused) = lat {location.Latitude}, lon {location.Longitude}, alt {location.Altitude}");
        }
        else
        {
            Log.Warn("NO PERMISSION FOR COARSE LOCATION ACCESS");
            // ...RequestPermissions(new string[] { Manifest.Permission.AccessCoarseLocation }, 1);
        }

The problem is I don't know on which instance to call RequestPermissions(). The SK code you linked seems to use the AppActivityCompat class from package AndroidX.AppCompat.App to bring in RequestPermissions(). But as far as I can tell on NuGet that package is only available for .NET 6.0?

paulmelis Mar 17, 2024
Author

Btw, it seems I do need Activity.RunOnUiThread for some of the next calls I need. But I don't see how I can easily get to the Activity instance? Is of the SK IntPtrs usable at all, or should I go a different route?

maluoi Mar 17, 2024
Maintainer

It's possible that SK's IntPtr might be enough, but I'm not good enough at interop with Java objects to be really confident about getting it right! I just do a really simple global static/singleton thing if I need the actual Activity:

public class MainActivity : Activity, ISurfaceHolderCallback2
{
	View surface;

	public static Activity Activity { get; private set; }

	protected override void OnCreate(Bundle savedInstanceState)
	{
		Activity = this;
		base.OnCreate(savedInstanceState);
		Run();
		SetContentView(Resource.Layout.activity_main);
	}
	// ...

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Location access on Android (ML2) #904

paulmelis Mar 15, 2024

Replies: 2 comments · 8 replies

maluoi Mar 15, 2024 Maintainer

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Mar 15, 2024

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