绑定MvvmCross TextColor不适用于Android

Posted 2021-04-19

我收到以下警告：

• [WARN]（MvxBind）无法为MvxValueConverterValueCombiner组合器操作创建绑定TextColor的目标绑定

绑定代码：

<TextView 
            android:id="@+id/text_view_header"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="4dp"
            style="@style/text_group_header"
            app:MvxBind="Text DisplayHeader; TextColor AppointmentFeedHeaderGroupColor(StartTime)"
        />

AppointmentFeedHeaderGroupColorValueConverter.cs

public class AppointmentFeedHeaderGroupColorValueConverter: MvxValueConverter<DateTime, Color>
    {
        private static readonly IDateTimeService DateTimeService = Mvx.Resolve<IDateTimeService>();
        private static readonly Color HeaderGroupBlack = GetColor(Resource.Color.black);
        private static readonly Color HeaderGroupRedLight = GetColor(Resource.Color.red_light);

        protected override Color Convert(DateTime value, Type targetType, object parameter, CultureInfo culture)
        {
            if (value != DateTimeService.Now.Date)
            {
                return HeaderGroupRedLight;
            }

            return HeaderGroupBlack;
        }

        private static Color GetColor(int resourceColorId)
        {
            var context = Mvx.Resolve<IMvxAndroidCurrentTopActivity>().Activity;

            return new Color(ContextCompat.GetColor(context, resourceColorId));
        }
    }

我在文件LinkerPleaseInclude.cs中添加了以下代码。

public void Include(TextView text)
{
    text.AfterTextChanged += (sender, args) => text.Text = "" + text.Text;
    text.Hint = "" + text.Hint;

    text.SetTextColor(Color.Black);
    var tc = text.TextColors;
    text.SetTextColor(tc);
} 

它没有帮助

答案

首先，检查你的MvvmCross.Plugin.Color项目和Android项目中是否安装了PCL/NetStandard。

那么你的转换器应该在你的PCL / NetStandard项目中并继承MvxColorValueConverter<DateTime>，这样你的颜色就不依赖于你的平台了：

public class AppointmentFeedHeaderGroupColorValueConverter: MvxColorValueConverter<DateTime>
{
    private static readonly IDateTimeService DateTimeService = Mvx.Resolve<IDateTimeService>();
    private static readonly MvxColor HeaderGroupBlack = new MvxColor(0,0,0);
    private static readonly MvxColor HeaderGroupRedLight = new MvxColor(255,0,0); // red_light, should see how to convert this to RGB values

    protected override MvxColor Convert(DateTime value, object parameter, CultureInfo culture)
    {
        if (value != DateTimeService.Now.Date)
        {
            return HeaderGroupRedLight;
        }

        return HeaderGroupBlack;
    }
}

最后，使用当前正在执行的颜色转换器：

TextColor AppointmentFeedHeaderGroupColor(StartTime)

更多信息：

MvvmCross Color docs

MvvmCross.Plugin.Color.MvxColorValueConverter.cs

在这里，您有MvvmCross提供的完整LinkerPleaseInclude文件。

HIH