Question

我正在摆弄MonoDroid（又名Mono for Android），尝试构建一个简单的播客下载应用程序，目前只是测试RSS提要内容的检索。

我的简单应用是：

输入RSS Feed的网址的编辑文本
“下载”rss的按钮
下载操作输出的文本显示

当用户点击下载时，我会获取当前使用XDocument的RSS内容（我也尝试使用just WebRequest / Streams etc.），这是简短版本：

void button_Click(object sender, EventArgs e)
{
    output.Text += "user input: " + rssUriInput.Text + "\n";

    try
    {
        output.Text += "### document ###";
        output.Text += XDocument.Load(rssUriInput.Text).ToString();
        output.Text += "### document ###";
    }
    catch (Exception ex)
    {
        output.Text += "OOOPS something went wrong:\n" + ex.ToString();
    }
}

我尝试了多种方法，但在ObjectDisposedException

时继续XDocument.Load(/*my uri here*/);

我的AssemblyInfo.cs包含

[assembly: UsesPermission(Android.Manifest.Permission.Internet)]

现在，免责声明，在获得hello world running后，我有点自行了，所以我可能会错过一些MonoDroid基础知识，但这段代码适用于普通的C＃应用程序（我测试过）但是 为什么我在这里做错了？我是否必须在MonoDroid中使用xml / linq / network访问权限？

这是完整的活动代码：

using System;

using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;
using System.Xml.Linq;

namespace RssDownlowd
{
    [Activity(Label = "RssDownlowd", MainLauncher = true, Icon = "@drawable/icon")]
    public class Activity1 : Activity
    {
        EditText rssUriInput;
        Button button;
        TextView output;

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            SetContentView(Resource.Layout.RssDownload);

            rssUriInput = FindViewById<EditText>(Resource.Id.rssUriText);
            button = FindViewById<Button>(Resource.Id.downloadButton);
            output = FindViewById<TextView>(Resource.Id.outputTextView);

            button.Click += new EventHandler(button_Click);
        }

        void button_Click(object sender, EventArgs e)
        {
            output.Text += "user input: " + rssUriInput.Text + "\n";

            try
            {
                output.Text += "### document ###";
                output.Text += XDocument.Load(rssUriInput.Text).ToString();
                output.Text += "### document ###";
            }
            catch (Exception ex)
            {
                output.Text += "OOOPS something went wrong:\n" + ex.ToString();
            }
        }

    }
}

以下是完整的例外情况：

"System.ObjectDisposedException: The object was used after being disposed.

  at System.Net.WebConnection.BeginRead (System.Net.HttpWebRequest request, System.Byte[] buffer, Int32 offset, Int32 size, System.AsyncCallback cb, System.Object state) [0x00000] in <filename unknown>:0 

  at System.Net.WebConnectionStream.BeginRead (System.Byte[] buffer, Int32 offset, Int32 size, System.AsyncCallback cb, System.Object state) [0x00000] in <filename unknown>:0 

  at System.Net.WebConnectionStream.Read (System.Byte[] buffer, Int32 offset, Int32 size) [0x00000] in <filename unknown>:0 

  at System.Xml.XmlInputStream.Read (System.Byte[] buffer, Int32 offset, Int32 count) [0x00000] in <filename unknown>:0 

  at System.Xml.NonBlockingStreamReader.ReadBuffer () [0x00000] in <filename unknown>:0 

  at System.Xml.NonBlockingStreamReader.Read (System.Char[] dest_buffer, Int32 index, Int32 count) [0x00000] in <filename unknown>:0 

  at System.Xml.XmlStreamReader.Read (System.Char[] dest_buffer, Int32 index, Int32 count) [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.ReadTextReader (Int32 remained) [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.PeekChar () [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.ReadChar () [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.Expect (Int32 expected) [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.ReadEntityReference (Boolean ignoreEntityReferences) [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.ReadReference (Boolean ignoreEntityReferences) [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.ReadText (Boolean notWhitespace) [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.ReadContent () [0x00000] in <filename unknown>:0 

  at Mono.Xml2.XmlTextReader.Read () [0x00000] in <filename unknown>:0 

  at System.Xml.XmlTextReader.Read () [0x00000] in <filename unknown>:0 

  at Mono.Xml.XmlFilterReader.Read () [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XElement.LoadCore (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XNode.ReadFrom (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XContainer.ReadContentFrom (System.Xml.XmlReader reader, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XElement.LoadCore (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XNode.ReadFrom (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XContainer.ReadContentFrom (System.Xml.XmlReader reader, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XElement.LoadCore (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XNode.ReadFrom (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XContainer.ReadContentFrom (System.Xml.XmlReader reader, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XElement.LoadCore (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XNode.ReadFrom (System.Xml.XmlReader r, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XContainer.ReadContentFrom (System.Xml.XmlReader reader, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XDocument.ReadContent (System.Xml.XmlReader reader, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XDocument.LoadCore (System.Xml.XmlReader reader, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XDocument.Load (System.String uri, LoadOptions options) [0x00000] in <filename unknown>:0 

  at System.Xml.Linq.XDocument.Load (System.String uri) [0x00000] in <filename unknown>:0 

  at RssDownlowd.Activity1.button_Click (System.Object sender, System.EventArgs e) [0x0004a] in C:\\Users\\khd483\\code\\HelloMonoDroid\\RssDownlowd\\Activity1.cs:47 "

Answer 1

奇怪的是，当我尝试你的代码时，它工作得很好：

Screen shot

您是否在Mono for Android选项中启用了项目中的链接？

同时考虑对RSS进行异步下载，因为它会阻止UI线程直到完成，从而使应用程序无响应。

加载XDocument for RSS时的MonoDroid ObjectDisposedException

1 个答案: