首页 \ 问答 \ Android NDK暂停/恢复的hello-gl2示例是否正确？(Is hello-gl2 example from Android NDK pause/resume correct?)

Android NDK暂停/恢复的hello-gl2示例是否正确？(Is hello-gl2 example from Android NDK pause/resume correct?)

 题：  
 考虑到Android NDK r6b的hello-gl2示例，当用户反复调用GLSurfaceView的暂停/恢复操作时，此示例是否正确？ 我问，因为每次调用GL2JNIView.Renderer.onSurfaceChanged（）时，它都会创建所有OpenGL资源（着色器，纹理）但它永远不会破坏它们。  
 背景：  
 我正在尝试调试一些使用C ++和JNI实现的OpenGL ES 2.0游戏，这些游戏在暂停/恢复期间表现不正确。 我试图找到一些参考示例，但我没有找到任何除了NDK提到的hello2-gl示例，可能恕我直言创建内存泄漏， 这个更复杂的版本，我目前正在使用，但是在GLSurfaceView完成其onPause（）方法之前，似乎OpenGL上下文被破坏了，我正在销毁绑定到上下文的所有OpengGL着色器和纹理。 您能否指点我使用NDK在Android上使用OpenGL ES 2.0的一些真正正确的例子，关于暂停/恢复OpenGL资源处理的正确方法？  
 感谢您的帮助。 

Question: 
Considering the hello-gl2 example from Android NDK r6b, is this example correct when user repeatedly invokes pause/resume actions of the GLSurfaceView? I'm asking because each time a GL2JNIView.Renderer.onSurfaceChanged() is called, it creates all OpenGL resources (shaders, textures) but it never destroys them. 
Background: 
I'm trying to debug some OpenGL ES 2.0 game implemented using C++ and JNI which behaves incorrectly during pause/resume. I was trying to find some reference example for this but I haven't found any except of the mentioned hello2-gl example from NDK, which may IMHO create memory leaks, and this more complex version of it, which I'm currently using, but where it seems like OpenGL context is destroyed before GLSurfaceView finishes with its onPause() method where I'm destroying all the OpengGL shaders and textures bound to the context. Could you point me to some truly correct example of OpenGL ES 2.0 on Android using NDK concerning the correct way of pause/resume OpenGL resource handling? 
Thank you for your help.

原文：https://stackoverflow.com/questions/8040149

更新时间：2021-12-02 20:12

最满意答案

 您需要使用SqlDataReader ，然后启动循环以读取返回的值 
 假设ReceiptNO是文本字段，此示例将起作用  
cn.Open()
Dim reader = da2.SelectCommand.ExecuteReader()
while reader.Read()
    textBox1.Text = reader("ReceiptNO").ToString()
End While
 
 或者，如果您确定您的查询返回零或只有一条记录而您只对ReceiptNO字段感兴趣，那么您可以使用ExecuteScalar  
Dim cmd = New SqlCommand("SELECT RecepitNO FROM Receipt WHERE (PaidFor=@PaidFor AND RegNO=@RegNO)")
cmd.Connection = cn
cmd.Parameters.Add("@paidFor", SqlDbType.VarChar).Value = cbMonth.Text
cmd.Parameters.Add("@RegNO", SqlDbType.Int).Value = lblRegNO.Text
cn.Open()
Dim result = cmd.ExecuteScalar()
if result IsNot Nothing Then
    textBox1.Text = result.ToString()
End If
 
 这里有关于ExecuteScalar的MSDN文档 

You need to use a SqlDataReader, and then start a loop to read the values returned
 This example will work assuming the ReceiptNO is a text field  
cn.Open()
Dim reader = da2.SelectCommand.ExecuteReader()
while reader.Read()
    textBox1.Text = reader("ReceiptNO").ToString()
End While
 
In alternative, if you are sure that your query returns zero or just one record and you are interested only in the ReceiptNO field, then you can use ExecuteScalar 
Dim cmd = New SqlCommand("SELECT RecepitNO FROM Receipt WHERE (PaidFor=@PaidFor AND RegNO=@RegNO)")
cmd.Connection = cn
cmd.Parameters.Add("@paidFor", SqlDbType.VarChar).Value = cbMonth.Text
cmd.Parameters.Add("@RegNO", SqlDbType.Int).Value = lblRegNO.Text
cn.Open()
Dim result = cmd.ExecuteScalar()
if result IsNot Nothing Then
    textBox1.Text = result.ToString()
End If
 
Here the MSDN docs on ExecuteScalar

Android NDK暂停/恢复的hello-gl2示例是否正确？(Is hello-gl2 example from Android NDK pause/resume correct?)

最满意答案

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