Setup
MainActivity
Create an activity that inherits from MvxCachingFragmentCompatActivity or MvxCachingFragmentActivity.
[Activity]
public class MainActivity : BaseFragmentActivity<MainContainerViewModel>
{
}
MainContainerViewModel
Create a Viewmodel to associate to the Activity. You will never navigate directly using this Viewmodel. Instead you will navigate to this Viewmodel via the fragments that specifies MainContainerViewModel as their parent's Viewmodel.
public class MainContainerViewModel : MvxViewModel
{
}
XML layout example
Add a layout to your MainActivity. Make sure to include a FrameLayout that has an id. In this case content_frame. This id is important as this is how you will identify the frame where to place your fragment. You specify multiple FrameLayout's if you want more that one fragment for the same view.
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/coordinator_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary">
<TextView
android:id="@+id/textview_toolbar_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="@android:color/white"
android:layout_gravity="left"
style="@style/TextAppearance.AppCompat.Widget.ActionBar.Title" />
</android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>
<FrameLayout
android:id="@+id/content_frame"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
</android.support.design.widget.CoordinatorLayout>
HomeFragment
In terms of fragments you need to include the MvxFragment attribute, which needs the type of Viewmodel associate to the Activity you want to place your fragment in. Additionally, you need to specify the id for the FrameLayout that is found on the activities layout, where you want to place the fragment.
[MvxFragment(typeof(MainContainerViewModel), Resource.Id.content_frame)]
[Register(nameof(HomeFragment))]
public class HomeFragment : BaseFragment<HomeViewModel>
{
}
Usage
When navigating your can now use ShowViewModel<HomeViewModel>() which will navigate to the home fragment. But, importantly it will first start up the required Activity MainActivity before doing the fragment navigation. This allows for better shared navigation with other platforms which do not require these container Viewmodels, i.e. they get handled automatically via convention.
Notes
You can specify multiple MvxFragment attributes. Is is usefully if you want the same fragment shared under multiple Activities. The Top MvxFragment attribute will be used as the default. If you are currently in the context of any of the other matching MvxFragment attributes then navigation will take place under that activity.
If your Setup.cs is not inheriting from MvxAppCompatSetup or you are using a custom presenter, you need to make sure that you also registering your presenter against IMvxAndroidViewPresenter. This is important as MvxCachingFragmentCompatActivity or MvxCachingFragmentActivity resolve IMvxAndroidViewPresenter in order to navigate to the required fragment.
protected override IMvxAndroidViewPresenter CreateViewPresenter()
{
var mvxFragmentsPresenter = new MvxFragmentsPresenter(AndroidViewAssemblies);
Mvx.RegisterSingleton<IMvxAndroidViewPresenter>(mvxFragmentsPresenter);
return mvxFragmentsPresenter;
}
You can also check out the Sample Repo for an example of this in use.
