使用 mvvmcross 的 LinearLayout 背景颜色

Question

我有一个圆形的线性布局，想用值转换器改变它的颜色。

下面是我的线性布局的样子

<LinearLayout
   android:orientation="vertical"
   android:id="@+id/linearLayoutDaysLeft"
   android:background="@drawable/RedBackground"
   local:MvxBind="BackgroundColor DateColor(EndDate)"/>

注意我已经将背景设置为@drawable/RedBackground

下面是我的@drawable/RedBackground.xml 文件的样子

<?xml version="1.0" encoding="utf-8" ?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval">
  <corners android:radius="10dip"/>
  <solid android:color="#D00E0D"/>
</shape>

下面是我的 DateColorValueConverter 代码

protected override Cirrious.CrossCore.UI.MvxColor Convert(object value, object parameter, System.Globalization.CultureInfo culture)
        {
            var date = (DateTime)value;
            int dayLeft;
            TimeSpan difference = date - DateTime.Today;
            dayLeft = (int)Math.Ceiling(difference.TotalDays);


            if (dayLeft < 0)
                return (new Cirrious.CrossCore.UI.MvxColor(208, 14, 13, 150));
            if (dayLeft >= 0 && dayLeft <= 1)
                return (new Cirrious.CrossCore.UI.MvxColor(255, 210, 0, 150));
            if (dayLeft > 1)
                return (new Cirrious.CrossCore.UI.MvxColor(93, 210, 85, 150));

            return (new Cirrious.CrossCore.UI.MvxColor(93, 210, 85, 150));
        }

注意我的 DateColor 按要求工作，但是当它返回颜色时，它会删除圆形

请帮帮我

谢谢

阿曼

Answer 1

首先感谢 Stuart 指导正确的方向

我已成功实现所需的可绘制背景更改

如果有人需要，我也想与其他人分享

下面是我对 LinearLayout 的自定义绑定

public class ShapeBackgroundBinding : MvxAndroidTargetBinding
    {        
        private readonly LinearLayout _linearLayout;
        public ShapeBackgroundBinding(LinearLayout view) : base(view)
        {
            this._linearLayout = view;
        }
        protected override void SetValueImpl(object target, object value)
        {
            // to do logic
        }

        public override void SetValue(object value)
        {
            var date = (DateTime)value;
            int dayLeft;
            TimeSpan difference = date - DateTime.Today;
            dayLeft = (int)Math.Ceiling(difference.TotalDays);


            if (dayLeft < 0)
                _linearLayout.SetBackgroundResource(Resource.Drawable.RedBackground);
            else if (dayLeft >= 0 && dayLeft <= 1)
                _linearLayout.SetBackgroundResource(Resource.Drawable.YellowBackground);
            else if (dayLeft > 1)
                _linearLayout.SetBackgroundResource(Resource.Drawable.GreenBackground); 
            else
                _linearLayout.SetBackgroundResource(Resource.Drawable.GreenBackground);
        }
        public override Type TargetType
        {
            get { return typeof(DateTime); }
        }
        public override MvxBindingMode DefaultMode
        {
            get { return MvxBindingMode.OneTime; }
        }        
    }

以下是我如何在设置文件中注册自定义绑定

 protected override void FillTargetFactories(IMvxTargetBindingFactoryRegistry registry)
        {
            base.FillTargetFactories(registry);
            registry.RegisterFactory(new MvxCustomBindingFactory<LinearLayout>("ShapeBackground", (view) => new ShapeBackgroundBinding(view)));
        }

完成上述步骤后，我们只需要像下面的sn-p那样绑定线性布局控件

<LinearLayout
    android:orientation="vertical"
    android:id="@+id/linearLayoutTest"                    
    local:MvxBind="ShapeBackground EndDate">

就是这样……

Answer 2

默认的 BackgroundColor 绑定在目标 View 上使用 SetBackgroundColor - 请参阅 https://github.com/MvvmCross/MvvmCross/blob/v3.1/Plugins/Cirrious/Color/Cirrious.MvvmCross.Plugins.Color.Droid/BindingTargets/MvxViewBackgroundColorBinding.cs

如果您只想在 Drawable 中的 Solid 上实现一些自定义效果，那么您需要为此形状编写自定义绑定并使用以下技术： - Android: Change Shape Color in runtime - How to change colors of a Drawable in Android? - Change shape solid color at runtime inside Drawable xml used as background

怀疑你可以这样写：

public class ShapeBackgroundColorBinding
    : MvxViewColorBinding
{
    public ShapeBackgroundColorBinding(View view)
        : base(view)
    {
    }

    protected override void SetValueImpl(object target, object value)
    {
        var view = (View)target;
        if (view == null)
            return;
        var background = view.Background;
        background.SetColor((Android.Graphics.Color) value);
    }
}

您可以在 Setup 期间将其注册为 ShapeBackgroundColor 的绑定 - 尽管该伪代码可能需要稍作调整才能正常工作！