从互联网加载20张图片时Listview运行如此滞后

Question

因此，我一直在尝试让它异步下载images.my应用程序，运行缓慢、滞后和延迟

​

public override View GetView(int position, View convertView,ViewGroup parent)
    			{
    				View view = convertView ?? _inflater.Inflate (Resource.Layout.textViewItems, parent, false);

    				
    				if (track.artwork_url != null) {


    					var imageBitmap = GetImageBitmapFromUrl(track.artwork_url);
    					if (imageBitmap != null && imageBitmap.Length > 0) {
    						var converterImage = BitmapFactory.DecodeByteArray (imageBitmap, 0, imageBitmap.Length);
    						viewHolder.Image.SetImageBitmap(converterImage);
    					}

    				} else {
    					viewHolder.Image.SetImageResource(Resource.Drawable.img1);
    				}


    				return view;
    			}

public static byte[] GetImageBitmapFromUrl(string url)
		{
			byte [] imageBitmap = null;

			using (var webClient = new WebClient())
			{
				var imageBytes = webClient.DownloadData(url);

				imageBitmap = imageBytes;
			}


			return imageBitmap;
	}

​

所有图像都加载到列表视图中(100px的高度和宽度)。我也设置了ImageView.layout_width=70dp和height。但我不能在列表视图中上下滚动。因为listview变得如此滞后和非常糟糕

我认为问题出在GetImageBitmapFromUrl上。如何修复。

Answer 1

您可以使用MonoDroid.UrlImageViewHelper异步加载镜像。

    if (track.artwork_url != null) {
            viewHolder.Image.SetUrlDrawable(track.artwork_url, Resource.Drawable.img1);
    }

您可以在Xamarin论坛上查看更多详细信息：ListView - Asynchronous Image Loading (from URL)