tag：C++，彈出菜單，列表框，wxWidgets
/* Create by zyzx
* Created 2008-06-24
* Modified 2008-07-17
*/
???????? VS系列IDE在管理工程文件的列表框中右擊不同類型對象會彈出不同的操作菜單，這是個(gè)不錯(cuò)的用戶體驗(yàn)方式，那么他是如何實(shí)現(xiàn)的呢？
???????? 目標(biāo)：在自定義的列表框（繼承標(biāo)準(zhǔn)列表框）右擊不同對象，會彈出不同操作菜單。
???????? 分析：列表框一般只會保存每一個(gè)項(xiàng)目的顯示字串和圖標(biāo)，我們能跟據(jù)用戶操作（左擊，右擊等）得到當(dāng)前的ItemID（這個(gè)ID是唯一的）。那么我們將這個(gè)ID與實(shí)際對應(yīng)的對象做一個(gè)關(guān)聯(lián)，當(dāng)用戶右擊時(shí)，檢索關(guān)聯(lián)列表取得對象類型，根據(jù)這個(gè)類型彈出適應(yīng)于此類型的菜單。如下實(shí)現(xiàn)是基于wxWidgets的wxTreeCtrl類。
一、先定義我們要處理對象
class StrObjProject;??????????????????????????????? ?? //對應(yīng)VS工程
class StrObjFolder;??????????????????????????????????? //對應(yīng)VS的文件夾
class StrOjbFile;????????????????????????????????????? ?? //對應(yīng)VS的cpp,h等文件
typedef std::map<long, StrObjProject*>??????????????????????????????? MapProject;???????????????????? //存儲工程對象結(jié)構(gòu)
typedef std::map<long, StrObjProject*>::iterator ???????????? ??? MapProjectIt;
typedef std::map<long, StrObjFolder*>???????????????????????????? ??? MapFolder;???????????????????? //存儲文件夾對象結(jié)構(gòu)
typedef std::map<long, StrObjFolder*>::iterator ???????????? ???? MapFolderIt;
typedef std::map<long, StrOjbFile*>?????????????????????????????????? ?? MapFile;????????????????????????? //存儲文件對象結(jié)構(gòu)
typedef std::map<long, StrOjbFile*>::iterator ????????????? ???????? MapFileIt;
typedef std::map<int, wxMenu*>???????????????????????????????????????????? MapMenu;
typedef std::map<int, wxMenu*>::iterator MapMenuIt;
enum{VS_UNKNOWN = 0, VS_PROJECT, VS_FOLDER, VS_FILE}???????? //對象樣式，分別對應(yīng)不同菜單
class VsObj?????????????????????????????????????????????????????? // 此基類的作用在于包裝統(tǒng)一的結(jié)構(gòu)
{
public:
??????? virtual ~VsObj(){}
??????? virtual int GetType(){ }
??????? ......
}
class VsProject : public VsObj?????????????????????? // VS_PROJECT類，存儲工程結(jié)構(gòu)
{
public:
?????? virtual ~VsProject (){}
?????? virtual int GetType() { return VS_PROJECT;}
?????? virtual MapProject* GetMap(){ return m_MapProject;}
?????? ......
protected:
?????? MapProject*?? m_MapProject;
}
class VsFolder : public VsObj???????????????????? // VS_FOLDER類，存儲文件夾結(jié)構(gòu)
{
public:
?????? virtual ~VsFoldert (){}
?????? virtual int GetType() { return VS_FOLDER;}
?????? virtual MapFolder* GetMap(){ return m_MapFolder;}
?????? ......
protected:
?????? MapFolder*?? m_MapFolder;
}
class VsFile : public VsObj???????????????????????? // VS_FILE類，存儲文件（.cpp,.h）之結(jié)構(gòu)
{
public:
?????? virtual ~VsFile (){}
?????? virtual int GetType() { return VS_FILE;}
?????? virtual MapFile* GetMap(){ return m_MapFile;}
?????? ......
protected:
?????? MapFile*?? m_MapFile;
}
typedef std::map<long, VsObj*>?????????????????????????????????? ?????????????? MapVsObj;
typedef std::map<long, VsObj*>::iterator ????????????? ???????????????????? MapVsObjIt;??
二、將這些對象集成到自定義的控件中去
class VsTreeCtrl : public wxTreeCtrl
{
??????? DECLARE_DYNAMIC_CLASS( VsTreeCtrl )
??????? DECLARE_EVENT_TABLE()
public:
??????? ......
protected:
??????? //* 創(chuàng)建彈出菜單
??????? wxMenu* CreatePopupMenuUnknown( const wxString& title );
??????? wxMenu* CreatePopupMenuProject( const wxString& title );
??????? wxMenu* CreatePopupMenuFolder( const wxString& title );
??????? wxMenu* CreatePopupMenuFile( const wxString& title );
?????
??????? void InitPoupMenu(){
??????????????? m_Menu.insert( std::make_pair( VS_UNKNOWN,?? CreatePopupMenuUnknown( ... ) ) );
??????????????? m_Menu.insert( std::make_pair( VS_PROJECT,??? CreatePopupMenuProject( ... ) ) );
??????????????? m_Menu.insert( std::make_pair( VS_FOLDER,????? CreatePopupMenuFolder( ... ) ) );
??????????????? m_Menu.insert( std::make_pair( VS_ VS_FILE, ??? CreatePopupMenuFile( ... ) ) );
???????? }
??????? void PopUpMenuFromType( int type, wxPoint pt ) {?????????????????? // 根據(jù)類型彈出對應(yīng)的菜單
???????????????? MapMenuIt* it= m_Menu.find( type );
???????????????? if ( it != m_Menu.end() ){
???????????????????????? this->PopupMenu( it->second, pt);
???????????????? }
??????? }
protected:
?????? void InitData(){
??????????????? m_VsObj.insert( std::make_pair( VS_PROJECT,??? new VsProject () ) );
??????????????? m_VsObj.insert( std::make_pair( VS_FOLDER,????? new VsFolder () ) );
??????????????? m_VsObj.insert( std::make_pair( VS_FILE,????????????? new VsFile () ) );
?????? }
?????? int GetDataType( long ID ){
????????????? // 遍歷整個(gè)m_VsObj中存儲的數(shù)據(jù)
?????????????? //返回VS_PROJECT，VS_FOLDER,，VS_FILE等。
?????? }
protected:
?????? virtual bool DoAdd( long ID, StrObjProject* obj);
?????? virtual bool DoAdd( long ID, StrObjFolder*obj);
?????? virtual bool DoAdd( long ID, StrOjbFile* obj){
??????????????? MapVsObjIt it = m_VsObj.find( VS_FILE );
??????????????? if ( it != m_VsObj.end() ){
???????????????????????? VsObj* obj = it->second;
???????????????????????? VsFile* vsFile = wxDynamicCast( obj , VsFile );????????????? //類型轉(zhuǎn)換，還要檢查。
???????????????????????? vsFile->GetMap()->insert( std::make_paer( ID, obj ) );
??????????????? }
??????? }
protected:
??????? //* 事件處理-- Sys Mouse Event
???? ?? void OnLMouseDown(wxMouseEvent& event);
???? ?? void OnRMouseDown(wxMouseEvent& event){
??????????????? wxTreeItemId id = HitTest( event.GetPosition() );
????????????????? if( id )
????????????????? {
???????????????????????? //wxPtrToUInt函數(shù)將一個(gè)void*轉(zhuǎn)換成Int類型，這里將列表框創(chuàng)建的wxTreeItemId::m_pItem指針的值作為標(biāo)示對象的唯一ID。
???????????????????????? PopUpMenuFromType( GetDataType( (long)wxPtrToUInt( id.m_pItem) ), event.GetPosition() );
????????????????? }else{
???????????????????????? PopUpMenuFromType( TYPE_MU_UNKNOWN, event.GetPosition() );
????????????????? }
????????????????? event.Skip();
???????? }
?? ???? void OnRMouseUp(wxMouseEvent& event);
?? ???? void OnRMouseDClick(wxMouseEvent& event);
protected:
??????? MapMenu????????? m_Menu;??????????????? // <= 存儲全部的菜單
???? ?? MapVsObj???????? m_VsObj;????????????? // <= 存儲全部的對象
};
?????????? 上面的類只寫了關(guān)鍵的部分。基本思想還是先取得列表框?qū)ο驣D編號（即列表框生成GDI對象指針地址），然后查詢這個(gè)ID得到其類型，根據(jù)此類型做出相應(yīng)的反饋（此處為彈出不同的菜單）。
擴(kuò)展：可以將 m_Menu和 m_VsObj “外包”給專門的管理類來統(tǒng)一協(xié)調(diào)，做到我們的TreeCtrl列表框與實(shí)際的數(shù)據(jù)對象無關(guān)。
????????? 也可以擴(kuò)展此類思想，比如Windows桌面右鍵菜單等等，跳出列表框的限制。
????????? 還可以考慮列表框?qū)ο筝^多時(shí)，如何加速查找。
????????? 這里只是提供一個(gè)思路，其實(shí)對于列表框而言，實(shí)現(xiàn)類似的效果還有更好的處理手法。一般而言，它會提供一個(gè)指針，用戶只需要訪問此指針的信息即可做出判斷。。