xamarin.forms - 单击背景上的 Xamarin 表单选择器

Question

我有一个自定义选择器，在 PCL 和 android 中包含此代码，如下所示。

https://xamgirl.com/picker-with-right-side-icon-in-xamarin-forms/

问题是当我打开选择器并按背景时，选择器将不会再次打开。我尝试按“确定”并取消选择器将正常运行并可以再次获得焦点

有没有办法处理选择器的背景点击，以防止它弹出，除非我点击“取消”或“确定”？

PCL:

   using Xamarin.Forms;

namespace AppXamarin
{
    public class CustomPicker : Picker
    {
        public static readonly BindableProperty ImageProperty =
            BindableProperty.Create(nameof(Image), typeof(string), typeof(CustomPicker), string.Empty);
        public string Image
        {
            get { return (string)GetValue(ImageProperty); }
            set { SetValue(ImageProperty, value); }
        }
    }
}

安卓:

using Android.Content;
using Android.Graphics;
using Android.Graphics.Drawables;
using Android.Support.V4.Content;
using AppXamarin;
using AppXamarin.Droid;
using Plugin.CurrentActivity;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;

[assembly: ExportRenderer(typeof(CustomPicker), typeof(CustomPickerRenderer))]
namespace AppXamarin.Droid
{
    public class CustomPickerRenderer : PickerRenderer
    {
        CustomPicker element;
        public CustomPickerRenderer(Context context) : base(context)
        {
            AutoPackage = false;
        }

        protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
        {
            base.OnElementChanged(e);

            element = (CustomPicker)this.Element;

            if (Control != null && this.Element != null && !string.IsNullOrEmpty(element.Image))
            {
                Control.Background = AddPickerStyles(element.Image);   
            }
        }
        public LayerDrawable AddPickerStyles(string imagePath)
        {
            ShapeDrawable border = new ShapeDrawable();
            border.Paint.Color = Android.Graphics.Color.Gray;
            border.SetPadding(10, 10, 10, 10);
            border.Paint.SetStyle(Paint.Style.Stroke);

            Drawable[] layers = { border, GetDrawable(imagePath) };
            LayerDrawable layerDrawable = new LayerDrawable(layers);
            layerDrawable.SetLayerInset(0, 0, 0, 0, 0);

            return layerDrawable;
        }
        private BitmapDrawable GetDrawable(string imagePath)
        {
            //int resID = Resources.GetIdentifier(imagePath, "drawable", this.Context.PackageName);
            var drawable = Resources.GetDrawable(imagePath);
            var bitmap = ((BitmapDrawable)drawable).Bitmap;
            var result = new BitmapDrawable(Resources, Bitmap.CreateScaledBitmap(bitmap, 70, 70, true));
            result.Gravity = Android.Views.GravityFlags.CenterVertical;
            return result;
        }

    }
}

Answer 1

实际上有两个 PickerRenderer，Xamarin.Forms.Platform.Android.AppCompat.PickerRenderer 和基本的 Xamarin.Forms.Platform.Android，基本的有这个问题你实际需要做的就是你的 Android 渲染器:

using Android.Content;
using Android.Graphics;
using Android.Graphics.Drawables;
using Xamarin.Forms.Platform.Android;
using AppXamarin;
using AppXamarin.Droid;
using Plugin.CurrentActivity;
using Xamarin.Forms;


[assembly: ExportRenderer(typeof(CustomPicker), typeof(CustomPickerRenderer))]
namespace AppXamarin.Droid
{
     public class CustomPickerRenderer : Xamarin.Forms.Platform.Android.AppCompat.PickerRenderer
    {
        private CustomPicker element;
        public CustomPickerRenderer(Context context) : base(context)
        {
            AutoPackage = false;
        }
        protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
        {
            base.OnElementChanged(e);
            element = (CustomPicker)this.Element;

            if (Control != null && this.Element != null && !string.IsNullOrEmpty(element.Image))
            {
                Control.Background = AddPickerStyles(element.Image);
            }
        }
        public LayerDrawable AddPickerStyles(string imagePath)
        {
            ShapeDrawable border = new ShapeDrawable();
            border.Paint.Color = Android.Graphics.Color.Gray;
            border.SetPadding(10, 10, 10, 10);
            border.Paint.SetStyle(Paint.Style.Stroke);

            Drawable[] layers = { border, GetDrawable(imagePath) };
            LayerDrawable layerDrawable = new LayerDrawable(layers);
            layerDrawable.SetLayerInset(0, 0, 0, 0, 0);

            return layerDrawable;
        }
        private BitmapDrawable GetDrawable(string imagePath)
        {
            //int resID = Resources.GetIdentifier(imagePath, "drawable", this.Context.PackageName);
            var drawable = Resources.GetDrawable(imagePath);
            var bitmap = ((BitmapDrawable)drawable).Bitmap;
            var result = new BitmapDrawable(Resources, Bitmap.CreateScaledBitmap(bitmap, 70, 70, true));
            result.Gravity = Android.Views.GravityFlags.CenterVertical;
            return result;
        }
    }
}