我有一个mediacontroller的问题,这部分代码在不同的设备上完美无瑕作为Acer Liquid(姜饼),Archos 43(froyo)e Archos 32(froyo)......
VideoView videoView = (VideoView) findViewById(R.id.videoView1);
MediaController mediaController = new MediaController(this);
mediaController.setAnchorView(videoView);
File filevideo = new File(Environment.getExternalStorageDirectory() + "/edizionitsm/firenze/map_" + map_n + "/",filename + "_" + language + ".mp4");
Uri video = Uri.fromFile(filevideo);
videoView.setMediaController(mediaController);
videoView.setVideoURI(video);
videoView.start();
...但是在Point of View Pro Tab2(姜饼)上,它在活动开始时崩溃了.
11-09 14:12:59.640: E/AndroidRuntime(31433): FATAL EXCEPTION: main
11-09 14:12:59.640: E/AndroidRuntime(31433): java.lang.RuntimeException: Unable to start activity ComponentInfo{edizionitsm.archeoplayer/edizionitsm.archeoplayer.Player}: java.lang.NullPointerException
11-09 14:12:59.640: E/AndroidRuntime(31433): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
11-09 14:12:59.640: E/AndroidRuntime(31433): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
11-09 14:12:59.640: E/AndroidRuntime(31433): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
11-09 14:12:59.640: E/AndroidRuntime(31433): at …我想制作win32应用和游戏.C++和Visual C++之间有什么重大差异吗？我该怎么用
简单的问题.如何更改关闭,最小化,最大化按钮的图标.我可以在Winforms和WPF中执行此操作吗？
是否有pdf或视频或某些媒体可以告诉我如何使用C++编写Winforms.显然,C++是最常用的编程语言,我已经掌握了一些先验知识.但是,当我尝试在C++中找到有关编程的媒体时,这些示例通常是控制台应用程序.我想要一些可以教会我如何用C++编写Winforms的媒体.
我的xml文件有这样的东西:
那么如何递归获取属性的所有值并将它们添加到或.也许是一个foreach循环？
...
<Keyword name = "if" />
<Keyword name = "else" />
<Keyword name = "is" />
...nameList<string>string[]
我跟着codemeit,我不断收到错误:Data at the root level is invalid. Line 1, position 1.我的xml文件是
<KeyWords>
...
<KeyWord name = "if" />
...
</KeyWord>
新问题,The '\' character, hexadecimal value 0x5C, cannot be included in a name.但相同的文件.
如何设置关键命令,如用户按Ctrl+ Shift+ N,新对话框或操作发生.我是否必须为每个键命令创建一个新事件？我怎样才能做到这一点？
我有一个带有多个 GridViewColumns（标题、开始、到期）的 ListView。那么如何将对象与字符串 Title、datetime Start 和 datetime Due 绑定在一起。在程序代码中，我已经说过：
lvwFill.ItemsSource = assignments.ListAssignments(); //Returns a List<Assignments>
所以现在我的 XAML 是：
<ListView x:Name="lvwFill">
<ListView.View>
<GridView>
<GridViewColumn x:Name="TitleColumn" Header="Title" Width="125" />
<GridViewColumn x:Name="DueColumn" Header="Due" Width="75" />
<!-- ... -->
</GridView>
</ListView.View>
</ListView>
那么我怎样才能列出每个作业并且只显示某些信息，比如 assignment.Title 或 assignment.Due？
这是内部异常:
InnerException: System.Data.UpdateException
Message=Entities in 'OrganizerDBEntities.Assignments' participate in
the 'CourseId' relationship. 0 related 'Course' were found.
1 'Course' is expected.`
我有三个表(文件夹,作业,课程).Assignment表有一个名为AssignmentId的主键和一个名为CourseId的外键,其"Allow Nulls"属性已设置为true.所以这个例外阻止我调用_entities.SaveChanges(); 从而阻止我向数据库添加数据.
更新:感谢marc,问题解决了,但另一个问题出现了:
InnerException: System.Data.UpdateException
Message=An error occurred while updating the entries. See the InnerException for details.
Source=System.Data.Entity
StackTrace:
at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)
at System.Data.Objects.ObjectContext.SaveChanges(Boolean acceptChangesDuringSave)
at System.Data.Objects.ObjectContext.SaveChanges()
at AssignmentOrganizer.App_Data.AssignmentRepository.CreateAssignment(Assignment assignmentToCreate) in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\AssignmentOrganizer\AssignmentOrganizer\App_Data\AssignmentRepository.cs:line 19
at AssignmentOrganizer.MainWindow..ctor() in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\AssignmentOrganizer\AssignmentOrganizer\MainWindow.xaml.cs:line 54
InnerException: System.Data.EntityCommandCompilationException
Message=An error occurred while preparing the command definition. See the …