c# – 在Xamarin Forms中获取缓存图像源的原始高度和宽度

有没有其他方法可以访问Cached Image的 ImageInformation中的OriginalHeight和OriginalWidth,除了检查成功加载如下？

CachedImage img = new CachedImage() 
{ 
    CacheType = FFImageLoading.Cache.CacheType.Memory 
};
img.Source = GetNextImage();
img.Success += (sender,e) =>
{
    h = e.ImageInformation.OriginalHeight;
    w = e.ImageInformation.OriginalWidth;
 
    if (Device.Idiom == TargetIdiom.Phone)
    {
        if (h > w)
        {
            img.HeightRequest = 400;
        }
    }
    if (Device.Idiom == TargetIdiom.Tablet)
    {
        if (h > w)
        {
            img.HeightRequest = 800;
        }
     }            
 };

解决方法

使用FFImageLoading库,你的方法是正确的w / Success,但如果你有资源文件夹下的图像,也许可以使用下面的方法/想法：

PLC /标准：

using Xamarin.Forms;
 
namespace YourProject.Utils
{
    public interface IImageResource
    {
        Size GetSize(string fileName);
    }
}

安卓：

using Android.Graphics;
using YourProject.Droid.Utils;
using YourProject.Utils;
using System;
using Xamarin.Forms;
 
[assembly: Dependency(typeof(ImageResource))]
namespace YourProject.Droid.Utils
{
    public class ImageResource : Java.Lang.Object,IImageResource
    {
        public Size GetSize(string fileName)
        {
            var options = new BitmapFactory.Options
            {
                InJustDecodeBounds = true
            };
 
            fileName = fileName.Replace('-','_').Replace(".png","").Replace(".jpg","");
            var resId = Forms.Context.Resources.GetIdentifier(fileName,"drawable",Forms.Context.PackageName);
            BitmapFactory.DecodeResource(Forms.Context.Resources,resId,options);
 
            return new Size((double)options.OutWidth,(double)options.OutHeight);
        }
    }
}

iOS版：

using YourProject.iOS.Utils;
using YourProject.Utils;
using System;
using UIKit;
using Xamarin.Forms;
 
[assembly: Dependency(typeof(ImageResource))]
namespace YourProject.iOS.Utils
{
    public class ImageResource : IImageResource
    {
        public Size GetSize(string fileName)
        {
            UIImage image = UIImage.FromFile(fileName);
            return new Size((double)image.Size.Width,(double)image.Size.Height);
        }
    }
}

使用w / Xamarin.Forms.DependencyService：

var imageSize = DependencyService.Get<IImageResource>().GetSize("ic_launcher.png");
System.Diagnostics.Debug.WriteLine(imageSize);

XAML的另一个选择：

<ContentView.Resources>
    <ResourceDictionary>
        <Style x:Key="CachedImageStyle" TargetType="{x:Type ffimageloading:CachedImage}">
           <Setter Property="HorizontalOptions" Value="Center" />
           <Setter Property="VerticalOptions" Value="Center" />
           <Setter Property="HeightRequest">
             <Setter.Value>
               <OnIdiom x:TypeArguments="x:Double" Tablet="800" Phone="400" />
             </Setter.Value>
           </Setter>
         </Style>
    </ResourceDictionary>
</ContentView.Resources>
 
<ContentView.Content>
    <!-- ... -->
    <ffimageloading:CachedImage
        x:Name="cachedImg"
        Style="{StaticResource CachedImageStyle}">
      </ffimageloading:CachedImage>
    <!-- ... -->
</ContentView.Content>

然后,您可以创建转换器以设置平板电脑/手机大小,也许是有效的.

我希望这可以帮到你.

c# – 在Xamarin Forms中获取缓存图像源的原始高度和宽度

解决方法

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