MVVMCross Android 按钮绑定禁用它

Question

我正在尝试使用 MvvmCross 将简单命令绑定到 Android 的按钮。问题是，比起我绑定命令，按钮进入禁用状态。

删除绑定后 local:MvxBind="Click GotoScreen2Command" 按钮启用并可点击。

为什么会发生这种情况，我该如何解决？

MainContainerViewModel.cs:

public class MainContainerViewModel : BaseViewModel
{
    readonly IMvxNavigationService _navigationService;

    public IMvxAsyncCommand GotoScreen2Command { get; set; }

    public MainContainerViewModel(IMvxNavigationService navigationService)
    {
        _navigationService = navigationService;

        GotoScreen2Command = new MvxAsyncCommand(NavigateToScreen2Async);
    }

    private Task NavigateToScreen2Async()
    {
        return _navigationService.Navigate<Screen2ViewModel>();
    }
}

fragment_main.axml:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/btn_goToScreen2"
        android:text="Go to Screen2"
        android:gravity="center_horizontal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        local:MvxBind="Click GotoScreen2Command"/>

</android.support.constraint.ConstraintLayout>

这是我的 Android 观点。

MainFragment.cs:

[MvxFragmentPresentation(typeof(MainContainerViewModel), Resource.Id.content_frame)]
public class MainFragment : BaseFragment<MainViewModel>
{
    protected override int FragmentLayoutId => Resource.Layout.fragment_main;
}

和MainContainerActivity.cs：

[Activity(
        Theme = "@style/AppTheme",
        WindowSoftInputMode = SoftInput.AdjustResize | SoftInput.StateHidden)]
    public class MainContainerActivity : BaseActivity<MainContainerViewModel>, IDrawerActivity
    {
        protected override int ActivityLayoutId => Resource.Layout.activity_main_container;                         
    }

Answer 1

您似乎需要将命令代码移至 MainViewModel。你的 MainFragment 膨胀 Resource.Layout.Main，你的 MainFragment 绑定到你的 MainViewModel。

MVVMCross Android 按钮绑定禁用它

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android

xamarin.android

mvvmcross