通過singleton模式和globalstaticvariable變數做C++程式各個模組之間的資料通訊

提示：這個辦法可以用在QtC++程式和QtQML的資料交換

首次初始化：DDocumentSets::getInstance()->setModel(oa_model);

以後任何class中都可以獲得這個執行個體：DDocumentSet*oa_model=DDocumentSets::getInstance()->getModel();

並調用其方法： oa_model->xxxx();

header檔案：

#ifndefDDOCUMENTSETS_H_#defineDDOCUMENTSETS_H_#include"DDocumentSet.hpp"classDDocumentSets{private:staticDDocumentSets*_instance;DDocumentSets();DDocumentSet*model;public:staticDDocumentSets*getInstance();voidsetModel(DDocumentSet*oa_model);DDocumentSet*getModel();virtual~DDocumentSets();};#endif/*DDOCUMENTSETS_H_*/
cpp檔案：

#include"DDocumentSets.h"DDocumentSets*DDocumentSets::_instance;//JiangDDocumentSets*DDocumentSets::getInstance(){if(_instance==0){_instance=newDDocumentSets();}return_instance;}voidDDocumentSets::setModel(DDocumentSet*model){this->model=model;}DDocumentSet*DDocumentSets::getModel(){returnmodel;}DDocumentSets::DDocumentSets(){}DDocumentSets::~DDocumentSets(){}

參考：

http://stackoverflow.com/questions/8612206/linker-error-when-using-static-members

在C++程式中，needto define thestaticvariableincppfileandnotinheaderfile.

在Qt程式中，需要在cpp和header檔案中都定義相同名字的static變數。否則編譯出錯：

undefinedreferencetoxxxx(static變數)