[英]With compiled bindings (x:bind), why do I have to call Bindings.Update()?
[英]Android view states: pressed, activated, selected etc. bindings. Do I have to write custom bindings?
从视图模型将布尔值(HasLiked)绑定到Pressed会导致错误:
Failed to create target binding for from HasLiked to Pressed
这是否意味着默认情况下不支持MvxBind的android View.Pressed(和其他状态)绑定? 我需要编写自定义绑定吗?
编辑绑定:
<RelativeLayout
style="@style/ButtonExtraSocial"
android:background="@drawable/SelectorButtonExtra"
app:MvxBind="Click LikeCommand; Pressed HasLiked">
....
</RelativeLayout>
在视图模型中存在HasLiked布尔值(当我将其绑定到TextView文本时,会得到该值)。
我似乎无法在这里重现您的问题。 我创建了一个非常简单的示例,它可以满足您的要求。
FirstViewModel.cs
public class FirstViewModel
: MvxViewModel
{
public FirstViewModel()
{
IsPressed = true;
}
private string _hello = "Hello MvvmCross";
public string Hello
{
get { return _hello; }
set { _hello = value; RaisePropertyChanged(() => Hello); }
}
public bool _isPressed;
public bool IsPressed
{
get { return _isPressed; }
set { _isPressed = value; RaisePropertyChanged(() => IsPressed); }
}
}
FirstView.cs
[Activity(Label = "View for FirstViewModel")]
public class FirstView : MvxActivity
{
public new FirstViewModel ViewModel
{
get { return (FirstViewModel)base.ViewModel; }
set { base.ViewModel = value; }
}
protected override void OnCreate(Bundle bundle)
{
base.OnCreate(bundle);
SetContentView(Resource.Layout.FirstView);
var button = FindViewById<Button>(Resource.Id.button);
button.Click += (sender, args) => ViewModel.IsPressed = !ViewModel.IsPressed;
}
}
FirstView.axml
<?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="fill_parent"
android:layout_height="fill_parent">
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="40dp"
local:MvxBind="Text Hello"
/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:textSize="40dp"
local:MvxBind="Text Hello"
/>
<Button
android:id="@+id/button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
local:MvxBind="Text Hello; Pressed IsPressed"/>
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="50dp"
android:background="@drawable/bg"
local:MvxBind="Pressed IsPressed"/>
</LinearLayout>
bg.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/bg_pressed"
android:state_pressed="true"/>
<item android:drawable="@drawable/bg_normal"/>
</selector>
bg_normal.xml
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="#FF0000" />
</shape>
bg_pressed.xml
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="#FF00FF" />
</shape>
这将产生以下两种不同的视觉状态:
如您所见,它从IsPressed
为true开始,当我单击按钮时,它变为false。 我已经证实它也可以以其他方式工作。
谢谢Stuart和Cheesebaron的回答,但我发现了造成此问题的真正原因:Xamarin studio中的打包设置:必须启用“使用共享单声道运行时”(我认为默认情况下已选中它,但是我已经做到了未选中)。
您可以通过右键单击项目(不是解决方案!)>属性> Android Build>使用共享的Mono运行时来访问打包设置。
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