访问模板类时出现“不完整类型”错误

Question

我有一个“ SignalProcessingBlock”类，其中包含“ Buffer”模板类。 它们是这样的：

SignalProcessingBlock.h:

class SignalProcessingBlock{

public:

Buffer <class BufferClass>  *InputBuffer;

Buffer <class BufferClass>  *OutputBuffer;

SignalProcessingBlock   *FrontSignalProcessingBlock;

    void Process();
};

SignalProcessingBlock.cpp:
#include "SignalProcessingBlock.h"
void SignalProcessingBlock::Process()

{
    double tmp;

    for (int i=0;i<(this->InputBuffer->BufferSize/2);i++)

    {

        this->OutputBuffer->buffer[i] = this->InputBuffer->buffer[i*2];

        tmp=this->OutputBuffer->buffer[i];

    }

}

Buffer.h:

template <class BufferClass> class Buffer
{
public:

int         BufferSize;

BufferClass buffer[];

Buffer (BufferClass *buffer,int BufferSize);
};

Buffer.cpp:
#include "Buffer.h"

template <class BufferClass> 

Buffer <BufferClass>::Buffer(BufferClass *buffer,int BufferSize)
{

this->buffer=buffer;

this->BufferSize=BufferSize;
}

甚至在尝试执行操作之前，我都会出现以下错误行：

jni/SignalProcessingBlock.cpp:34:47: error: definition of implicitly-declared 'SignalProcessingBlock::~SignalProcessingBlock()'
In file included from jni/SignalProcessingBlock.h:4:0,
                 from jni/SignalProcessingBlock.cpp:1:
jni/Buffer.h: In instantiation of 'Buffer<BufferClass>':
jni/SignalProcessingBlock.cpp:42:35:   instantiated from here
jni/Buffer.h:9:21: error: 'Buffer<BufferClass>::buffer' has incomplete type
jni/SignalProcessingBlock.h:11:16: error: forward declaration of 'struct BufferClass'
jni/SignalProcessingBlock.cpp: In member function 'void SignalProcessingBlock::Process()':
jni/SignalProcessingBlock.cpp:44:23: error: 'class Buffer<BufferClass>' has no member named 'buffer'
jni/SignalProcessingBlock.cpp:44:54: error: 'class Buffer<BufferClass>' has no member named 'buffer'
jni/SignalProcessingBlock.cpp:45:27: error: 'class Buffer<BufferClass>' has no member named 'buffer'
/cygdrive/d/Development/NDK/android-ndk-r9/build/core/build-binary.mk:348: recipe for target 'obj/local/armeabi-v7a/objs-debug/com_talkitt_beta_NativeWrapper/SignalProcessingBlock.o' failed
make: *** [obj/local/armeabi-v7a/objs-debug/com_talkitt_beta_NativeWrapper/SignalProcessingBlock.o] Error 1

我正在用C ++编写并使用Eclipse Juno，调试和构建使用ndk-build（“ make”命令包装器）执行。

我正在做本书中的所有事情，并且不了解错误，我确实有“ buffer”成员，并且语法似乎是正确的。

非常感谢您的帮助！

顺便说一句，堆栈溢出告诉我由于某种原因我需要添加更多信息，所以我只写东西

Answer 1

在模板类Buffer的定义中，标记BufferClass是模板的参数。 稍后，在声明要使用的Buffer对象的类型时，需要专门化模板，或者换句话说，指定要用作模板参数的实际类型。

在您的特定情况下，如果您需要一个包含double值数组的Buffer实例，则可以执行以下操作：

#include "Buffer.h"
class SignalProcessingBlock{

public:
  Buffer <double>  *InputBuffer;
  ...

另一方面，如果您希望推迟模板专业化，则必须使SignalProcessingBlock成为模板类：

#include "Buffer.h"
template <class BufferClass> class SignalProcessingBlock{

public:
  Buffer <typename BufferClass>  *InputBuffer;
  ...