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mvvmcross

Creating custom ExpandableListView, how to bind to "GroupTemplate" in axml

I've created a bindable version of ExpandableListView based off of https://github.com/hlogmans/MvvmCross.DeapExtensions/ and put it in my app. I want to add a GroupTemplate that I can bind to in the axml which would be similar to MvxListView's ItemTemplate.

Do I need to subclass MvxAndroidBindingResource? I'm also confused as to how the MvxBindingAttributes fits in.

Solution

  • The easiest route for this might be for you to take a read through how MvxListView and MvxAdapter work.

    The MvxBindingAttributes (https://github.com/MvvmCross/MvvmCross/blob/v3.1/nuspec/DroidContent/MvxBindingAttributes.xml) allow MvvmCross to add new xml tags to the axml files.

    The MvxAndroidBindingResource class (https://github.com/MvvmCross/MvvmCross/blob/v3.1/Cirrious/Cirrious.MvvmCross.Binding.Droid/ResourceHelpers/MvxAndroidBindingResource.cs) is the C# code to parse the values for the attribute tags defined in MvxBindingAttributes.

    You can see this in action for an MvxListView in https://github.com/MvvmCross/MvvmCross/blob/v3.1/Cirrious/Cirrious.MvvmCross.Binding.Droid/Views/MvxListView.cs#L33

        public MvxListView(Context context, IAttributeSet attrs, IMvxAdapter adapter)
        : base(context, attrs)
    {
        // Note: Any calling derived class passing a null adapter is responsible for setting
        // it's own itemTemplateId
        if (adapter == null) 
            return;

        var itemTemplateId = MvxAttributeHelpers.ReadListItemTemplateId(context, attrs);
        adapter.ItemTemplateId = itemTemplateId;
        Adapter = adapter;
    }

    In particular, the line:

     var itemTemplateId = MvxAttributeHelpers.ReadListItemTemplateId(context, attrs);

    This uses the id values parsed in MvxAndroidBindingResource to read the axml tag value for local:MvxItemTemplate