[Android] Unhandled exception at application startup

Bug

Version Number of Plugin: 2.6.2 Compile using Android version: Use Latest Platform (Android 7.1 (Nougat)) Target Android version: Use Compile using SDK version Device Tested On: Moto G4, Android 7.0 (build NPJ25.93-14) Simulator Tested On: None

Expected Behavior

The application should start properly without errors when the plugin is installed and set up as per the instructions.

Actual Behavior

Upon starting the application, an unhandled Exception is raised when calling base.OnCreate(bundle) within MainActivity.OnCreate override:

Java.Lang.NullPointerException: Attempt to invoke virtual method ‘void android.view.View.setId(int)’ on a null object reference

Steps to reproduce the Behavior

• I added the plugin to a Xamarin.Forms (PCL) application along with the corresponding Android device application.
• I updated the AndroidManifest.xml as per the “readme.txt”
• I added the xml folder to the Resources folder
• I added the file file_paths.xml to the xml folder
• I ran the application on the device

I am also using Prism.Forms with Unity within the application if that makes any difference, though the application does not get as far as creating the App class.

MainActivity.OnCreate()

protected override void OnCreate(Android.OS.Bundle bundle) {

	TabLayoutResource = Resource.Layout.Tabbar;
	ToolbarResource = Resource.Layout.Toolbar;

	base.SetTheme(Resource.Style.MainTheme);

	base.OnCreate(bundle);
	//base.SetStatusBarColor(Color.Orange);

	global::Xamarin.Forms.Forms.Init(this, bundle);
	Acr.UserDialogs.UserDialogs.Init(this);
	LoadApplication(new App(new AndroidInitializer()));
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:installLocation="auto" package="com.mydomain.myapp">
	<application android:label="My application" android:icon="@drawable/icon">
		<provider android:name="android.support.v4.content.FileProvider" android:authorities="com.mydomain.myapp.fileprovider" android:exported="false" android:grantUriPermissions="true">
			<meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths"></meta-data>
		</provider>
	</application>
	<uses-feature android:name="android.hardware.camera" android:required="true" />
	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
	<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
	<uses-sdk android:minSdkVersion="15" />
</manifest>

file_paths.xml

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
	<external-path name="my_images" path="Android/data/com.mydomain.myapp/files/Pictures" />
	<external-path name="my_movies" path="Android/data/com.mydomain.myapp/files/Movies" />
</paths>

I have found an article in the Xamarin forums indicating that the error is caused by the presence of any file within the Resources/xml folder. If I exclude this folder from the project then the application starts without issue leading me to believe that this is in fact the cause of the problem but there has been no reply within that forum post as to any workaround.

[pbielinski]

delete bin and obj folders on Android project and rebuild it

[angelieri]

I think it’s mandatory as a xamarin developer to have a ‘nuke’ script which deletes all the solutions bin and obj folders 😃

I recomend https://github.com/madskristensen/CloseAllTabs