Adding the View for the Android project

Add a button to the FirstView.axml in the Resources\layout folder of the MvvmCrossDemo.Droid project, and set the command binding like this:

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
local:MvxBind="Text Greeting" />
<Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Post List"
local:MvxBind="Click NavToPostListAsyncCommand">
</LinearLayout>

It is time to bind the data to the PostListView. Add a new AXML file called PostListView.axml into the Resources/layout folder in the MvvmCrossDemo.Droid project. Replace the content with the following codes:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:local="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<MvvmCross.Platforms.Android.Binding.Views.MvxListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
local:MvxBind="ItemsSource PostList"
android:layout_weight="1">
</MvvmCross.Platforms.Android.Binding.Views.MvxListView>
</LinearLayout>

We use MvxListView which comes from MvvmCross to show the data. Find more built in binding controls here: https://www.mvvmcross.com/documentation/fundamentals/data-binding.

Then Add an AXML file called post_item.axml to show the post item, like this:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:local="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
local:MvxBind="Text Title" />
</LinearLayout>

Now set the item template of the MvxListView, as shown below:

<MvvmCross.Platforms.Android.Binding.Views.MvxListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
local:MvxBind="ItemsSource PostList"
android:layout_weight="1"
local:MvxItemTemplate="@layout/post_item">
</MvvmCross.Platforms.Android.Binding.Views.MvxListView>

You can only name the item template file to lowercase according to the convention of MvvmCross, otherwise MvvxCross cannot find the correct template layout file.

Add a new class called PostListView.cs into the Views folder, which is used to build the connection between the ViewModel and the View. Replace the content with the following codes:

using Android.App;
using Android.OS;
using MvvmCross.Platforms.Android.Presenters.Attributes;
‚Äč
namespace MvvmCrossDemo.Droid.Views
{
[MvxActivityPresentation]
[Activity(Label = "MvvmCross Demo", MainLauncher = true)]
public class PostListView : BaseView
{
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.PostListView);
}
}
}

Do not forget to enable the permission to connect to the Internet. Right-click the MvvmCrossDemo.Droid project and select properties, then select Android Manifest tab and update the Required permissions. Make sure the INTERNET option is checked.

Run the App and click the PostList button to navigate to the PostListView. Now the List should show the correct data from the API, as shown below:

Be careful, we should not call any heavy operations in the first View because it is not good for the user experience.

By the way, I encountered a strange error here. VS cannot deploy the App to my device (it is a HUAWEI Mate 10) with an error:

[INSTALL_FAILED_ALREADY_EXISTS: Attempt to re-install MvvmCrossDemo.Droid without first uninstalling.

I tried to uninstall the App in the Settings - Applications but it still showed the error. At last, I remembered that there is a second system in my phone, which is a special feature of HUAWEI Mate 10. I entered the second system environment and found that if I uninstalled the App in the default system environment, it still existed in the second system environment. So if you have a phone with the special multiple system feature, make sure to completely uninstall the App in all of these environments.