标签：try 需要 sys art .so .net creat cat tip
初始界面：
PlayOnline：（网页错误时提示url无效）
Download：（有下载完成，下载失败，文件已存在，url无效提示）
首先应该找到在线播放文件的方法，找了使用MediaPlayer播放音频和视频，找到如下代码：
mediaPlayer = new MediaPlayer(); mediaPlayer.Source = MediaSource.CreateFromUri(new Uri("ms-appx:///Assets/example_video.mkv")); mediaPlayer.Play();
因为我用了一个Text Box来输入url，所以可以将MediaSource.CreateFromUri方法的参数稍作修改就可以了，于是我写出了如下代码：
mediaPlayer.Source = MediaSource.CreateFromUri(new Uri(source.Text)); Tips.Text = "正在播放：";
想在上面加一个判断输入网址是否为有效网址的判断，本来用的是：
if(source.Text != null)
却发现行不通，于是参考了Uri Class和uri.IsWellFormedUriString，写出了如下判断语句：
if (Uri.IsWellFormedUriString(source.Text,UriKind.Absolute)) { mediaPlayer.Source = MediaSource.CreateFromUri(new Uri(source.Text)); Tips.Text = "正在播放："; } else { Tips.Text = "Invalid url!"; }
毫不犹豫的打开Google，搜索，找到了Win10 uwp 存放网络图片到本地，找到如下代码：
Windows.Web.Http.HttpClient http = new Windows.Web.Http.HttpClient(); IBuffer buffer = await http.GetBufferAsync(uri); BitmapImage img = new BitmapImage(); using (IRandomAccessStream stream = new InMemoryRandomAccessStream()) { await stream.WriteAsync(buffer); stream.Seek(0); await img.SetSourceAsync(stream); await StorageImageFolder(stream, uri); return img; }
需要将得到的音频文件以二进制流写入，通过buffer解决。
StorageFile musicFile = await myMusic.CreateFileAsync(fileName, Windows.Storage.CreationCollisionOption.FailIfExists); if (musicFile != null) { Windows.Web.Http.HttpClient httpClient = new Windows.Web.Http.HttpClient(); IBuffer buffer; try { buffer = await httpClient.GetBufferAsync(uri); } catch (Exception ex) { Tips.Text = "download fail!"; return; } await FileIO.WriteBufferAsync(musicFile, buffer); Tips.Text = "download complete!"; mediaPlayer.Source = MediaSource.CreateFromUri(new Uri(source.Text)); }
又参考Files and folders in the Music, Pictures, and Videos libraries中找到如何找到本地缓存文件夹：
var myPictures = await Windows.Storage.StorageLibrary.GetLibraryAsync(Windows.Storage.KnownLibraryId.Pictures); Windows.Storage.StorageFolder savePicturesFolder = myPictures.SaveFolder;
写出了如下代码：
var myMusics = await StorageLibrary.GetLibraryAsync(KnownLibraryId.Music); var myMusic = myMusics.SaveFolder;
这次操作，明显比上次娴熟很多，bug少很多，但是还是有很多参数啊，方法啊不知道怎么用，一边搜索一边做作业一边进步可能才是菜鸡程序员的日常。
标签：try 需要 sys art .so .net creat cat tip
原文地址：https://www.cnblogs.com/pingyue/p/8848827.html
