Incorrect handling of android:name for FragmentContainerView

[Bip901]

Android application type

Classic Xamarin.Android (MonoAndroid12.0, etc.), Android for .NET (net6.0-android, etc.)

Affected platform version

.NET 7, Visual Studio 2022 17.5.0

Description

Defining a FragmentContainerView with the android:name or class attributes throws at runtime (during inflation).

Steps to Reproduce

• Create a new Xamarin.Android project named "com.example.myapp".
• Create a new MyFragment class that inherits from AndroidX.Fragment.App.Fragment.
• Insert the following XML inside the root tag in the main activity's layout file:

<androidx.fragment.app.FragmentContainerView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:name="myapp.MyFragment"
            android:id="@+id/my_fragment"/>

• Run the app - an InflateException is thrown (whereas a pure Java app would find the fragment class and inflate it).
• Note that replacing the <androidx.fragment.app.FragmentContainerView> tag with <fragment> does work as expected.

Did you find any workaround?

Use the old <fragment> tag instead of <FragmentContainerView>.

Relevant log output

Android.Views.InflateException: 'Binary XML file line #1 in com.example.myapp:layout/activity_main: Binary XML file line #1 in com.example.myapp:layout/activity_main: Error inflating class androidx.fragment.app.FragmentContainerView'

[moljac]

@Bip901

Can you create minimal repro sample so I can take a look, please?

Hi @Bip901. We have added the "need-info" label to this issue, which indicates that we have an open question for you before we can take further action. This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[Bip901]

Sure,

test_app.zip

[gmck]

@Bip901

FragmentContainerView is usually used with a navigation graph - part of Google's recommendation for modern android development, Singe Activity/multiple fragments. In other words it is the container that will hold each of the fragments that the app will use. Before they released FragmentContainerView they just used Fragment which probably explains why it works with <fragment in your example.

There is a series of tutorials at https://github.com/gmck and from memory the only one that uses fragment was their original NavigationCodeLab. All the rest NavigationGraph1 through NavigationGraph7 use the FragmentContainerView. The projects ending with Net7 are already converted projects. My email is available from github, if you have any questions.