Android fails to Initiate APK Installation Despite Having Admin Permissions

Question

Hello Stack Overflow Community,

I am working on a Flutter Android plugin that is supposed to install an application on a device given the APK URL. Despite having set the app as the device admin and ensured all necessary permissions, the code fails to initiate the installation and throws an error on the line result.error("INSTALL_APPLICATION_FAILED", "App installer not available.", null). Below is the snippet of my code responsible for this functionality:

private fun installApplication(apkUrl: String?, result: Result) {
    if (!apkUrl.isNullOrEmpty()) {
        try {
            val uri = Uri.parse(apkUrl)

            // Create an Intent to start the installation process
            val installIntent = Intent(Intent.ACTION_VIEW).apply {
                setDataAndType(uri, "application/vnd.android.package-archive")
                addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)
            }

            // Check if the app installer is available
            val packageManager = context.packageManager
            val activities = packageManager.queryIntentActivities(installIntent, 0)

            if (activities.isNotEmpty()) {
                context.startActivity(installIntent)
                result.success(true) // Return success if the installation is started successfully
            } else {
                result.error("INSTALL_APPLICATION_FAILED", "App installer not available.", null)
            }
        } catch (e: Exception) {
            result.error("INSTALL_APPLICATION_FAILED", e.localizedMessage, null)
        }
    } else {
        result.error("INVALID_ARGUMENTS", "The 'apkUrl' argument is null or empty", null)
    }
}

When I execute the installApplication function, it doesn't proceed to install the app and throws the error indicating that the app installer is not available. The URI is correctly formed and the APK URL is valid.

I have made sure that the app has the necessary administrative permissions and I have also verified that the device has the capability to install apps from external sources.

Here are my questions:

1. Are there any additional permissions or configurations that I might be missing to allow the installation?
2. Is there anything wrong with the way I have structured the Intent or the conditions to check the availability of the app installer? (I checked and the device has the android installer on it)
3. Could there be any other external factors or settings on the device that might be preventing the app installation?

Any insights or suggestions would be greatly appreciated. Thank you!