Specific Cases

This section provides solutions for specific cases you could encounter

Android

Check/Start Service

If you find yourself in a situation where you are unsure if the Android service is running you can proceed as below using an instance of Capture Helper CaptureHelper capture = new CaptureHelper(). But first, don’t forget to set the App context:

#. Set Android App Context to enable the usage of Android Service methods with CaptureHelper.SetAndroidServiceContext(Android.App.Application.Context) method. No instance of Capture Helper is needed to set the context (this can be done in MainActivity.cs under OnCreate(...)).

1. Check if Companion is installed with IsAndroidServiceInstalled() method. Without Companion the service cannot exist.

2. Check if the Service is running with IsAndroidServiceRunning() method.

3. Start the service with StartAndroidService() method.

Here is an example:

private async Task AndroidService()
{
    if (Device.RuntimePlatform == Device.Android)
    {
        switch (capture.IsAndroidServiceInstalled())
        {
            case true:
                if (capture.IsAndroidServiceRunning() == false) capture.StartAndroidService();
                break;

            case false:
                // Make sure that Companion is installed
                break;

        }
    }
    // Add time to let the Service start
    await Task.Delay(1000);
}

The AndroidService() method can be used as follow making sure that the Service is running before using OpenAsync() method:

AndroidService().ContinueWith(res =>
{
    capture.OpenAsync(appId, developerId, appKey)
    .ContinueWith(result =>
    {
        // Events...
    });
});

Deep Sleep/Idle/Doze Mode

After some time of inactivity, the Android device will fall into deep sleep mode. This mode breaks all communications between the application and the Android Service. To re-enable the communication you can use the lifecycle of the application OnResume() triggering CloseAsync() and OpenAsync() methods from a Capture Helper instance CaptureHelper capture = new CaptureHelper().

Here is an example, in App.xaml.cs use OnResume():

MainPage rootPage;

public App()
{
    InitializeComponent();

    rootPage = new MainPage();
    MainPage = rootPage;
}

protected override void OnResume()
{
    rootPage.ReEnableConnection();
}

The example above in App.xaml.cs is valid for Xamarin but an extra has to be applied to Maui:

MainPage rootPage;

public App()
{
        InitializeComponent();

    MainPage = new AppShell();
    rootPage = new MainPage(true);
}

protected override void OnResume()
{
    rootPage.ReEnableConnection();
}

Note

In the provided Maui Sample App, MainPage(true) is empty. It is using static variables populated by the MainPage(). In this case, the credentials (appId, developperID, appKey), the instance of Capture Helper and the isFirstLaunch Boolean should be static to be re-used.

Note

OnResume() will be triggered when the application switches from being in the backgroud to being in the foreground. This action is also valid coming back from deep sleep mode.

Then add the following method:

public void ReEnableConnection()
{
    // List will be repopulated on OpenAsync()
    _deviceList.Clear();

    capture.CloseAsync().ContinueWith(result =>
    {
        if (SktErrors.SKTSUCCESS(result.Result))
        {
            isFirstLaunch = false;

            Open();
        }
    });
}

Note

_deviceList is the list of devices saved using the Device Arrival event. In the example provided, it is used to select and trigger a scan via a button. Make sure that _deviceList.Clear() is called before Open() and outside of CloseAsync().

The Open() method refers to the following:

public void Open()
{
    capture.OpenAsync(appId, developerId, appKey)
        .ContinueWith(result =>
        {
            System.Diagnostics.Debug.Print("Open Capture returns {0}", result.Result);
            if (SktErrors.SKTSUCCESS(result.Result))
            {
                if (isFirstLaunch)
                {
                    capture.DeviceArrival += Capture_DeviceArrival;
                    capture.DeviceRemoval += Capture_DeviceRemoval; ;
                    capture.DecodedData += Capture_DecodedData;

                    // (Android-iOS) Check if SocketCam is enabled to set the Switch
                    GetSocketCamStatusInit();
                }
            }
        });
}

Note

If you are re-using the instance of Capture Helper, already registered events should not be re-registered upon using ReEnableConnection(). This is prevented by using the Boolean isFirstLaunch.