Question

我正在将我的应用程序重新编写为Universal App模型，并针对Windows（手机）8.1进行了优化。

我创建了BackgroundTask（C＃），它从外部源获取一些数据，最后一步是渲染一个可以用作tile的自定义.PNG。

以前，对于Windows Phone 7.x和8.0，我使用了名为TCD.Controls.LiveTiles.Light的第三方应用，可以帮助您将XAML UserControls转换为.PNG。这完美无缺，但它似乎与Universal App模型存在一些兼容性问题。

现在我想知道 - 在BackgroundTask中创建.PNG的最佳方法是什么？

我读到了XamlRenderingBackgroundTask and RenderTargetBitmap 的C ++实现，但由于我不了解C ++，而且我当前的任务已经在C＃中，我想使用C＃。

亲切的问候，尼尔劳特

Answer 1

我遇到了同样的问题，但发现了这个用C＃渲染PNG的例子。我在https://social.msdn.microsoft.com/Forums/en-US/43295c90-43e8-4b08-8a25-958a1c3d0a0b/explanation-on-windowsuixamlmediaxamlrenderingbackgroundtask?forum=WindowsPhonePreviewSDK

上找到了这个

using System;
using System.Threading.Tasks;
using Windows.ApplicationModel.Background;
using Windows.Storage.Streams;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Markup;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Media.Imaging;
using Windows.Graphics.Imaging;
using Windows.UI.Notifications;
using Windows.Data.Xml.Dom;

namespace BackgroundTask
{
    public sealed class AppTileUpdater : XamlRenderingBackgroundTask
    {
        protected override void OnRun(Windows.ApplicationModel.Background.IBackgroundTaskInstance taskInstance)
        {
            BackgroundTaskDeferral _deferral = taskInstance.GetDeferral();
            System.Diagnostics.Debug.WriteLine("OnRun called!");
            UpdateTileAsync(_deferral);
        }

        private async Task<string> ReadFile()
        {
            var folder = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFolderAsync("Assets");
            var file = await folder.GetFileAsync("customTile.xml");
            string szCustomTileXML = await Windows.Storage.FileIO.ReadTextAsync(file);
            return szCustomTileXML;
        }
        private async void UpdateTileAsync(BackgroundTaskDeferral deferral)
        {

            var folder = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFolderAsync("Assets");
            var file = await folder.GetFileAsync("customTile.xml");
            string szCustomTileXML = await Windows.Storage.FileIO.ReadTextAsync(file);

            Border tile = XamlReader.Load(szCustomTileXML) as Border;

            if (null != tile)
            {
                tile.Background = new SolidColorBrush(Windows.UI.Colors.Orange);
                Grid grid = tile.Child as Grid;
                TextBlock text = grid.FindName("Timestamp") as TextBlock;
                text.Text = DateTime.Now.ToString("hh:mm:ss");
                text = grid.FindName("TimeZone") as TextBlock;
                text.Text = TimeZoneInfo.Local.DisplayName;

                Image logo = grid.FindName("LogoImage") as Image;
                var img = new BitmapImage() { CreateOptions = BitmapCreateOptions.None };
                img.UriSource = new Uri("ms-appx:///Assets/acorn.png");

                RenderTargetBitmap rtb = new RenderTargetBitmap();
                await rtb.RenderAsync(tile, 150, 150);
                IBuffer pixels = await rtb.GetPixelsAsync();
                DataReader dReader = Windows.Storage.Streams.DataReader.FromBuffer(pixels);
                byte[] data = new byte[pixels.Length];
                dReader.ReadBytes(data);

                var outputFile = await Windows.ApplicationModel.Package.Current.InstalledLocation.CreateFileAsync("UpdatedLiveTile.png", Windows.Storage.CreationCollisionOption.ReplaceExisting);
                var outputStream = await outputFile.OpenAsync(Windows.Storage.FileAccessMode.ReadWrite);
                BitmapEncoder enc = await BitmapEncoder.CreateAsync(BitmapEncoder.PngEncoderId, outputStream);
                enc.SetPixelData(BitmapPixelFormat.Bgra8, BitmapAlphaMode.Premultiplied, (uint)rtb.PixelWidth, (uint)rtb.PixelHeight, 96,96, data);
                await enc.FlushAsync();                
            }
            var TileMgr = TileUpdateManager.CreateTileUpdaterForApplication();
            TileMgr.Clear();
            var tileTemplate = TileUpdateManager.GetTemplateContent(TileTemplateType.TileSquare150x150Image);
            var tileImageAttributes = tileTemplate.GetElementsByTagName("image");
            XmlElement tmp = tileImageAttributes[0] as XmlElement;
            tmp.SetAttribute("src", "UpdatedLiveTile.png");
            var notification = new TileNotification(tileTemplate);
            TileMgr.Update(notification);
            deferral.Complete();
        }

        public void Run(IBackgroundTaskInstance taskInstance)
        {
            System.Diagnostics.Debug.WriteLine("Run called!");
            OnRun(taskInstance);
        }
    }
}

Answer 2

现在最有效的方法是使用Win2D Framework并逐步绘制位图。这种方法可以保证您的资源免费。

使用WP8.1 Universal应用程序在BackgroundTask（C＃）中呈现自定义动态磁贴的最佳方法？

2 个答案: