I am implementing an APK installer for my Android app. The workflow on Android 7 executes flawlessly. However, Android 8+ is running into permission issues. Expecting this, the app is set up to detect this and asks the user for permission (REQUEST_INSTALL_PACKAGES).

Here's where I ran into my issue; even though I am granting the permission, my app does not seem to think so. This is how I handle when the user comes back from the permission settings:

ActivityResultLauncher<Intent> activityResultLauncher = registerForActivityResult(
    new ActivityResultContracts.StartActivityForResult(),
    new ActivityResultCallback<>() {
        @Override
        public void onActivityResult(ActivityResult result) {
            runOnUiThread(() -> {
                if (appHasInstallPackagePermission()) {
                    showInstallationStep();
                } else {
                    manuallyRecheckedInstallPermission = true;
                    showPermissionRequiredPage();
                }
            });
        }
    }
);

It does not matter if I turn on the permission, it is always the else branch that executes, so I am back to the permissions page of my app... More of the relevant code:

if (appHasInstallPackagePermission()) {
    showInstallationStep();
} else {
    showPermissionRequiredPage();
} 

private void showPermissionRequiredPage() {
    String appName = launcherPackageInfo.getAppName();

    titleTextView.setText(getString(R.string.permission_required_title));
    if (manuallyRecheckedInstallPermission) {
        descriptionTextView.setText("...");
    } else {
        descriptionTextView.setText("...");
    }

    permissionButton.setOnClickListener(new View.OnClickListener() {
        @Override
        @RequiresApi(api = Build.VERSION_CODES.O)
        public void onClick(View v) {
            requestInstallPackagesPermission();
            permissionButton.setText("...");
        }
    });

    permissionButton.setText(getString(R.string.grant_permission_button_text));
    permissionButton.setVisibility(View.VISIBLE);
    permissionButton.requestFocus();
}

@RequiresApi(api = Build.VERSION_CODES.O)
private void requestInstallPackagesPermission() {
    Intent settingsIntent = new Intent(
            Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES,
            Uri.parse("package:" + getPackageName())
    );
    activityResultLauncher.launch(settingsIntent);
}