如何在媒体库中查看我下载的图像？

问题描述

我有 Xamarin.forms 应用程序。一些图像来自互联网。我有“下载”按钮。当我点击按钮时，图像会保存在某个文件夹中。但不会出现在图库中。

这是代码：

public class MediaService : IMediaService
{
    Context CurrentContext => CrossCurrentActivity.Current.Activity;

    private readonly string path = Path.Combine(Android.OS.Environment.ExternalStorageDirectory.AbsolutePath,"Android","data","com.mob.drift","files","Pictures");

    public void SaveImageFromByte(byte[] imageByte,string filename)
    {
        try
        {
            Java.IO.File storagePath = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryPictures);
            string path = System.IO.Path.Combine(storagePath.ToString(),filename);
            var imagePath = path + "/Images";
            var imageFilePath = Path.Combine(imagePath,"img.jpg");



            //Check if the imageDirectory Exists
            if (!Directory.Exists(imagePath))
            {
                Directory.CreateDirectory(imagePath);
            }
            else
            {
                System.IO.File.WriteallBytes(imageFilePath,imageByte);
                MediaScannerConnection.ScanFile(Android.App.Application.Context,new string[] { imageFilePath,path },null,null);
            }

        }
        catch (Exception ex)
        {

        }
    }
}

MediaScannerConnection.ScanFile 不扫描图像。请帮忙

解决方法

根据我的测试，我认为您使用了错误的路径。你可以使用下面的代码，你可以在应用程序文件夹中找到图像。

媒体服务：

Context CurrentContext => CrossCurrentActivity.Current.Activity;
    public void SaveImageFromByte(byte[] imageByte,string filename)
    {
        try
        {
            var storagePath = Application.Context.GetExternalFilesDir(Android.OS.Environment.DirectoryPictures);
            string path = Path.Combine(storagePath.ToString(),filename);

            var imagePath = storagePath + "/Images";
            var imageFilePath = Path.Combine(imagePath,filename);

            //Check if the imageDirectory Exists
            if (!Directory.Exists(imagePath))
            {
                Directory.CreateDirectory(imagePath);
                System.IO.File.WriteAllBytes(imageFilePath,imageByte);
                MediaScannerConnection.ScanFile(Application.Context,new string[] { imageFilePath },null,null);
            }
            else
            {
                //System.IO.File.WriteAllBytes(imageFilePath,imageByte);
                //MediaScannerConnection.ScanFile(Application.Context,new string[] { "image/png","image/jpeg" },null);
            }


        }
        catch (Exception ex)
        {

        }
    }

下载图片：

 static readonly HttpClient _client = new HttpClient();

    public static Task<byte[]> DownloadImage(string imageUrl)
    {
        if (!imageUrl.Trim().StartsWith("https",StringComparison.OrdinalIgnoreCase))
            throw new Exception("iOS and Android Require Https");

        return _client.GetByteArrayAsync(imageUrl);
    }

用法：

var BY = DownloadImage("https://cdn.dribbble.com/users/3701/screenshots/5557667/xamarin-studio-1_2x_4x.png");

        var b = BY.Result;
        DependencyService.Get<IMediaService>().SaveImageFromByte(b,"img.jpg");

检查截图：

https://imgur.com/nmOmuZQ