我目前正在研究ZebraLink打印机库的端口，以便在MonoTouch项目中使用。存在这些库以及为iOS创建的库，因此我获得了.a文件和使用Objective-C开发的一堆头文件。一旦我取得了一些成功，我很乐意上传它与任何有兴趣的人分享，但首先我要解决几个问题，我请求你的帮助：
我目前有3个班级 - ＆gt; Main.cs，enums.cs和helpers.cs
在Main.cs中，我遵循Binding Objective-C教程中提到的基本结构
using System;
using MonoTouch.Foundation;
namespace btouchtest
{
[BaseType (typeof (NSObject))]
[Model]
interface ZebraPrinterConnection
{
/**
* Returns the maximum time, in milliseconds, to wait for any data to be received.
*/
//- (NSInteger) getMaxTimeoutForRead;
[Export ("getMaxTimeoutForRead")]
int getMaxTimeoutForRead();
/**
* Returns the maximum time, in milliseconds, to wait between reads after the initial read.
*/
//- (NSInteger) getTimeToWaitForMoreData;
[Export ("getTimeToWaitForMoreData")]
int getTimeToWaitForMoreData();
/**
* Returns <c>YES</c> if the connection is open.
*
* @return <c>YES</c> if this connection is open.
*/
//- (BOOL) isConnected;
[Export ("isConnected")]
bool isConnected();
/**
* Opens the connection to a device. If the ZebraPrinterConnection::open method is called on an open connection
* this call is ignored. When a handle to the connection is no longer needed, call ZebraPrinterConnection::close
* to free up system resources.
*
* @return <c>NO</c> if the connection cannot be established.
*/
//- (BOOL) open;
[Export ("open")]
bool open();
/**
* Closes this connection and releases any system resources associated with the connection. If the connection is
* already closed then invoking this method has no effect.
*/
//- (void) close;
[Export ("close")]
void close();
/**
* Writes the number of bytes from <c>data</c> to the connection. The connection must be
* open before this method is called. If ZebraPrinterConnection::write:error: is called when a connection is closed, -1 is returned.
*
* @param data The data.
* @param error Will be set to the error that occured.
* @return The number of bytes written or -1 if an error occurred.
*/
//- (NSInteger) write:(NSData *)data error:(NSError **)error;
[Internal, Export ("write:error:")]
int _write(NSData data, IntPtr error);
/**
* Reads all the available data from the connection. This call is non-blocking.
*
* @param error Will be set to the error that occured.
* @return The bytes read from the connection or <c>nil</c> if an error occurred.
*/
//- (NSData *)read: (NSError**)error;
[Internal, Export ("read:")]
NSData _read(IntPtr error);
/**
* Returns <c>YES</c> if at least one byte is available for reading from this connection.
*
* @return <c>YES</c> if there is data available.
*/
//- (BOOL) hasBytesAvailable;
[Export ("hasBytesAvailable")]
bool hasBytesAvailable();
/**
* Causes the currently executing thread to sleep until <c>hasBytesAvailable</c> equals <c>YES</c>, or for a maximum of
* <c>maxTimeout</c> milliseconds.
*
* @param maxTimeout Maximum time in milliseconds to wait for an initial response from the printer.
*/
//- (void) waitForData: (NSInteger)maxTimeout;
[Export ("waitForData:")]
void waitForData(int maxTimeout);
}
}
在enums.cs中，我只列出枚举，没有命名空间，我使用空c＃文件的模板：
public enum PrinterLanguage
{
/**
* Printer control language ZPL
*/
PRINTER_LANGUAGE_ZPL,
/**
* Printer control language CPCL
*/
PRINTER_LANGUAGE_CPCL
}
此时我对构建没有任何问题，我可以使用bash获得.dll
/Developer/MonoTouch/usr/bin/btouch Main.cs -s:enums.cs -out:btouchtest.dll
当我尝试使用“帮助程序类”导出需要处理某些指针的方法时，问题就开始了。教程很清楚，方法与参数（NSError **）的绑定，所以我创建了helper.cs文件
using System;
using MonoTouch.Foundation;
namespace btouchtest
{
partial class ZebraPrinterConnection
{
int write (NSData data, out NSError error)
{
unsafe
{
IntPtr error;
IntPtr ptr_to_error = (IntPtr) (&error);
_write(data, ptr_to_error);
if (error != IntPtr.Zero)
error = (NSError) Runtime.GetNSObject (error);
else
error = null;
}
}
NSData read (out NSError error)
{
unsafe
{
IntPtr error;
IntPtr ptr_to_error = (IntPtr) (&error);
_read(ptr_to_error);
if (error != IntPtr.Zero)
error = (NSError) Runtime.GetNSObject (error);
else
error = null;
}
}
}
}
这次的构建是这样的：
/Developer/MonoTouch/usr/bin/btouch -unsafe -out:btouchtest.dll Main.cs helper.c
和宾果！而不是一个漂亮的.dll，btouch吐出各种错误：
Main.cs(8,19): error CS0260: Missing partial modifier on declaration of type `btouchtest.ZebraPrinterConnection'. Another partial declaration of this type exists
helper.cs(7,23): (Location of the symbol related to previous error)
helper.cs(7,23): error CS0261: Partial declarations of `btouchtest.ZebraPrinterConnection' must be all classes, all structs or all interfaces
Main.cs(8,19): (Location of the symbol related to previous error)
helper.cs(13,25): error CS0136: A local variable named `error' cannot be declared in this scope because it would give a different meaning to `error', which is already used in a `parent or current' scope to denote something else
helper.cs(10,21): error CS0531: `btouchtest.ZebraPrinterConnection.write(NSData, out NSError)': interface members cannot have a definition
helper.cs(27,25): error CS0136: A local variable named `error' cannot be declared in this scope because it would give a different meaning to `error', which is already used in a `parent or current' scope to denote something else
helper.cs(24,24): error CS0531: `btouchtest.ZebraPrinterConnection.read(out NSError)': interface members cannot have a definition
Compilation failed: 6 error(s), 0 warnings
btouch: API binding contains errors.
我得到的是，在同一个命名空间中，我得到了一个名为“ZebraPrinterConnection”的接口，还有一个名为“ZebraPrinterConnection”的部分类。我不知道如何处理这个因为我只是遵循指南。
另一个问题来自于使用下一个代码片段来处理（NSError **），它是Binding Objective-C教程中显示的示例，所以出了点问题。
我声明了我导出的方法：
[Internal, Export ("write:error:")]
int _write(NSData data, IntPtr error);
[Internal, Export ("read:")]
NSData _read(IntPtr error);
因为它的Objective-C签名是：
(NSInteger) write:(NSData *)data error:(NSError **)error;
(NSData *)read: (NSError**)error;
我需要实现辅助类，根据教程，处理错误的方式类似于之前在帮助类的源代码中显示的内容（这对我来说非常合理，因为我需要处理指针指针）：
int write (NSData data, out NSError error)
{
unsafe
{
IntPtr error;
IntPtr ptr_to_error = (IntPtr) (&error);
_write(data, ptr_to_error);
if (error != IntPtr.Zero)
error = (NSError) Runtime.GetNSObject (error);
else
error = null;
}
}
NSData read (out NSError error)
{
unsafe
{
IntPtr error;
IntPtr ptr_to_error = (IntPtr) (&error);
_read(ptr_to_error);
if (error != IntPtr.Zero)
error = (NSError) Runtime.GetNSObject (error);
else
error = null;
}
}
但是btouch讨厌这个!!!当试图建立它时大喊：
helper.cs(27,25): error CS0136: A local variable named `error' cannot be declared in this scope because it would give a different meaning to `error', which is already used in a `parent or current' scope to denote something else
在提到的所有内容之后......我从http://mtcocos2d.googlecode.com/svn/trunk下载了一个绑定源示例，它是Cocos2D到Monotouch的“几乎工作”端口，除了源代码之外，还可以找到lib.a和.dll可用，所以我想绑定源代码可以是“btouch”-ed并根据提供的源代码生成我自己的lib ...
/Developer/MonoTouch/usr/bin/btouch -unsafe -out:cocos2d.dll -s:cocos2d.cs enums.cs extensions.cs structs.cs
不要!!!!! Btouch吐出的36个错误与我的相同......所以我注定要失败......
我一直在比较这个绑定演示中的源文件，我发现一般结构，相同类型的文件，相同类型的接口，相同类型的类没有太大的区别......所有括号都关闭...... < / p>
我真的很感谢你的帮助，我不是C＃的专家，但我有很多iOS开发经验......但是在这个新工作中我们必须在MonoTouch下工作，所以我还在学习。
请帮助!!!!还有很多提前!!
答案 0 :(得分：0)
如果您将片段（和链接）发布到objective-c标头，那将非常有用。也许ZebraPrinter不能用[Model]来定义。在您的描述中包含您正在使用的MT的版本总是有用的。