s60按键处理模型

做了一段时间航海桌面，被长按，短按，组合键各种按键逻辑搞的死去活来。

功能堆积的太多后，根本是一团浆糊。

 

正好开发到一个段落，重新整理了按键逻辑，把按键识别和执行功能分离。

 

识别模块负责将按键事件串对应成可以接受的按键状态。把不需要关心的噪音过滤掉。后面记作Filter

执行模块根据按键状态执行功能。

 

S60的按键事件分成3中类型：Down，Event，Up。

 

其中Event里的Repeats属性会变化，有0和1两种值。还有一个Modify属性，不过基本没用。后面把Event且Repeat(0)记作Event，Event且Repeat(1)记作Repeat

 

一个短按过程

Down Event Up

一个长按过程

Down Event (Repeat)+ Up

 

常见情况是一个键的长按，短按有不同的功能。

必须先出现一个Event事件，然后等待后面的时间出现，如果是Up则是短按，如果是Repeat则是长按。如果是长按，需要忽略后面的Repeat和Up事件。

 

理想的实现是，通过Filter，在长按的时候收到一个状态表示长按，短按的时候收到一个状态表示短按。

由于状态和之前收到是按键事件串是一一对应的，所以，状态可以用一个堆栈表示，按照接受顺序讲按键事件入栈就可以了。

 

可以用一棵树来描述按键接受逻辑。当做DFA来处理。

 

终结节点是可能的接受，在这个节点可以返回。

非终结节点是过度用的输入事件。

 

一个识别短按的DFA看起来是这样的

 

 

一个短按长按都要识别的DFA看起来是这样的

 

 

定义下这个DFA。

每个节点包含以下属性

 

1. 按键扫描码

2. 按键字符码

3. 重复标志

4. 按键类型

5. 控制位（终结，匹配字符码，匹配扫描码，匹配重复标志）

 

匹配时根据控制位进行对应判断。控制位不表明的属性不参与匹配。

 

然后把各种按键的DFA组合成一个DFA，作为Filter的控制逻辑。

 

当一个键盘几乎所有的键都有对应功能的时候，这个很管用

 

比如我现在做的这航海桌面。

每个按键的长按短按都有一种功能。

 

通过这个Filter，就可以简单的把Event和Repeat组成的时间串，分解成互相没关联的事件。否还要记录状态，这十分麻烦。

 

下面 LS表示左键，RS表示右键，其他的都是字符按键。

 

这个看起来很漂亮。很多部分都一样，都是长按短按都识别，创建代码也会很简单。只有一个左键（LS）比较特殊，因为有短按长按识别还有组合键识别。

 

 

这里有个组合键，LS再RS。

 

通过引入超时事件就很容易处理。每次收到UP事件后就引入一个超时。如果超时了，那么这个匹配路径就被强制退栈。如果这个路径上有终结点，就返回最后一个终结点作为最后结果。

 

其实这也就是一个普通了不能再普通的连续按键判断逻辑用DFA画一边。

 

 

识别成功后怎么知道到底是匹配了那个路径？把记录堆栈扫描一下就行了。

 

终于不用再为这种东西烦恼了。

 

以后考虑加入用xml描述DFA，这样就可以录下操作，描述不同的行为。

 

定义

 

/* * UiKeyFilter.h * * Created on: 2009-6-2 * Author: Slavik */#ifndef UIKEYFILTER_H_#define UIKEYFILTER_H_#include <e32base.h>#include <W32STD.H>class IUiKeyFilterCallback {public:virtual ~IUiKeyFilterCallback() {}public:virtual void ProcessKeyEventL( const TKeyEvent& aKeyEvent, TEventCode aType ) =0;};class CUiKeyFilter : public CTimer {public:enum TUiKeyFilterDFAFlag {ETerminator = 0x01,EUseKeyCode = 0x02,EUseScanCode = 0x04,EUseRepeats = 0x08};enum TPopEventReason {ENoReason,EMismatch,ETimeout};class TUiKeyFilterDFA : public CBase {public:TInt iScanCode;TInt iKeyCode;TInt iRepeats;TEventCode iType;TUint iFlag;private:TUiKeyFilterDFA** iNext;TInt iNextCount;public:TUiKeyFilterDFA();~TUiKeyFilterDFA();void AddSuccessorL( TUiKeyFilterDFA* );TUiKeyFilterDFA* Successor(TInt aIndex);TInt SuccessorCount();};struct TUiKeyFilterStatus {TKeyEvent iKeyEvent;TEventCode iType;TUiKeyFilterDFA* iDFA;};public:CUiKeyFilter( IUiKeyFilterCallback* aCallback );~CUiKeyFilter();void ConstructL();public:void FilterKeyEvent( const TKeyEvent& aKeyEvent, TEventCode aType );void LoadDFAL();void PopEventIfPossibleL( TPopEventReason aReason );const TUiKeyFilterStatus* Top();void Clear();// get status from the top// aPrevIndex = 0, return top// aPrecIndex = 1, return top-1;// and so onconst TUiKeyFilterStatus* Status( TInt aPrevIndex );TInt CombineKeyInterval();void SetCombineKeyInterval( TInt aMSec );protected:void Pop();void Push( const TKeyEvent& aKeyEvent, TEventCode& aType, TUiKeyFilterDFA* aDFA );TUiKeyFilterDFA* DefaultUiKeyFilterDFAL();TUiKeyFilterDFA* CreateEventAndRepeatDFA_ForScanCodeL( TInt aScanCode );TUiKeyFilterDFA* CreateEventAndRepeatDFA_ForKeyCodeL( TInt aCode );TUiKeyFilterDFA* CreateEventDFA_ForScanCodeL( TInt aScanCode );TUiKeyFilterDFA* CreateEventDFA_ForKeyCodeL( TInt aCode );TUiKeyFilterDFA* CreateScanCodeDFALC( TInt aScanCode, TEventCode aType, TBool aTerminator );TUiKeyFilterDFA* CreateScanCodeDFALC( TInt aScanCode, TEventCode aType, TInt aRepeats, TBool aTerminator );TUiKeyFilterDFA* CreateKeyCodeDFALC( TInt aCode, TEventCode aType, TBool aTerminator );TUiKeyFilterDFA* CreateKeyCodeDFALC( TInt aCode, TEventCode aType, TInt aRepeats, TBool aTerminator );TUiKeyFilterDFA* CreateDefaultKeyNoDFAL();TUiKeyFilterDFA* CreateDefaultKeyYesDFAL();TUiKeyFilterDFA* CreateDefaultKeyLeftDFAL();TUiKeyFilterDFA* CreateDefaultKeyMidDFAL();TUiKeyFilterDFA* CreateDefaultKeyRightDFAL();protected:void RunL();private:IUiKeyFilterCallback* iCallback;TUiKeyFilterDFA* iDFA;TUiKeyFilterStatus iStack[32];TInt iStackSp;TInt iCombineKeyInterval;};

 

实现

 

#include "UiKeyFilter.h"#include "PhoneFeatureAfx.h"#include <COEAUI.H>CUiKeyFilter::TUiKeyFilterDFA::TUiKeyFilterDFA() : iScanCode(0),iKeyCode(0),iRepeats(0),iType(EEventKey),iFlag(0),iNext( NULL ), iNextCount(0){}CUiKeyFilter::TUiKeyFilterDFA::~TUiKeyFilterDFA() {if( iNext ) {for( TInt i = 0; i < iNextCount; i++ ) {delete iNext[i];}User::Free( iNext );}}void CUiKeyFilter::TUiKeyFilterDFA::AddSuccessorL( CUiKeyFilter::TUiKeyFilterDFA* aNext ) {// new bufTInt count = iNextCount+1; TUiKeyFilterDFA** buf = (TUiKeyFilterDFA**)User::AllocZL( sizeof(TUiKeyFilterDFA*)*count ); if( iNextCount ) { // dump old data Mem::Copy( buf, iNext, sizeof(TUiKeyFilterDFA*)*iNextCount ); } buf[count-1] = aNext; if( iNext ) { // release old buf User::Free( iNext ); } iNext = buf; iNextCount = count;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::TUiKeyFilterDFA::Successor(TInt aIndex) {return iNext[aIndex];}TInt CUiKeyFilter::TUiKeyFilterDFA::SuccessorCount() {return iNextCount;}CUiKeyFilter::CUiKeyFilter( IUiKeyFilterCallback* aCallback ) : CTimer( CActive::EPriorityUserInput ),iCallback( aCallback ),iStackSp(0),iCombineKeyInterval( 500000 ) {}CUiKeyFilter::~CUiKeyFilter() {if( iDFA ) {delete iDFA;}}void CUiKeyFilter::ConstructL() {CTimer::ConstructL();CActiveScheduler::Add( this );LoadDFAL();}void CUiKeyFilter::FilterKeyEvent( const TKeyEvent& aKeyEvent, TEventCode aType ) {const TUiKeyFilterStatus* top = Top();TUiKeyFilterDFA* dfa = iDFA;if( top ) {dfa = top->iDFA;}TBool match = EFalse;// scan the successorTInt count = dfa->SuccessorCount();for( TInt i = 0; i < count; i++ ) {TUiKeyFilterDFA* n = dfa->Successor(i);if( aType != n->iType ) {// type not matchcontinue;}if( EUseKeyCode & n->iFlag ) {// check key codeif( aKeyEvent.iCode != n->iKeyCode ) {// the key code is not matchcontinue;}}if( EUseScanCode & n->iFlag ) {// check scan codeif( aKeyEvent.iScanCode != n->iScanCode ) {// the scan code is not matchcontinue;}}if( EUseRepeats & n->iFlag ) {// check repeatsif( aKeyEvent.iRepeats != n->iRepeats ) {// the repeats is not matchcontinue;}}// found matchmatch = ETrue;Push( aKeyEvent, aType, n );// write the output if there is oneif( 0 != (ETerminator & (n->iFlag)) && 0 == n->SuccessorCount() ) {PopEventIfPossibleL( ENoReason );}break;}if( !match ) {PopEventIfPossibleL( EMismatch );}if( EEventKeyUp == aType ) {if( IsActive() ) {Cancel();}// active timeoutAfter(iCombineKeyInterval);}}void CUiKeyFilter::PopEventIfPossibleL( TPopEventReason aReason ) {const TUiKeyFilterStatus* top = Top();if( top ) {if( aReason || 0 == top->iDFA->SuccessorCount() ) {// the current input is not acceptable or the DFA is terminatored by a leaf// return the topest terminator in the stack// pop topPop();while( top && 0 == ( ETerminator & (top->iDFA->iFlag) ) ) {// check nexttop = Top();Pop();}if( top ) {// found one value//aKeyEvent = top->iKeyEvent;//aType = top->iType;iCallback->ProcessKeyEventL( top->iKeyEvent, top->iType );}// clear the restClear();}}}void CUiKeyFilter::RunL() {PopEventIfPossibleL( ETimeout );}void CUiKeyFilter::LoadDFAL() {if( iDFA ) {delete iDFA;iDFA = NULL;}iDFA = DefaultUiKeyFilterDFAL();}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateEventAndRepeatDFA_ForScanCodeL( TInt aScanCode ) {// start by a event keyTUiKeyFilterDFA* s0 = CreateScanCodeDFALC( aScanCode, EEventKey, 0, ETrue );// accept the repeat eventTUiKeyFilterDFA* s1 = CreateScanCodeDFALC( aScanCode, EEventKey, 1, ETrue );s0->AddSuccessorL( s1 );CleanupStack::Pop(2,s0);return s0;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateEventAndRepeatDFA_ForKeyCodeL( TInt aCode ) {// start by a event keyTUiKeyFilterDFA* s0 = CreateKeyCodeDFALC( aCode, EEventKey, 0, ETrue );// accept the repeat eventTUiKeyFilterDFA* s1 = CreateKeyCodeDFALC( aCode, EEventKey, 1, ETrue );s0->AddSuccessorL( s1 );CleanupStack::Pop(2,s0);return s0;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateEventDFA_ForScanCodeL( TInt aScanCode ) {TUiKeyFilterDFA* s0 = CreateScanCodeDFALC( aScanCode, EEventKey, ETrue );CleanupStack::Pop( s0 );return s0;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateEventDFA_ForKeyCodeL( TInt aCode ) {TUiKeyFilterDFA* s0 = CreateKeyCodeDFALC( aCode, EEventKey, ETrue );CleanupStack::Pop( s0 );return s0;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateDefaultKeyNoDFAL() {return CreateEventAndRepeatDFA_ForScanCodeL( EStdKeyNo );//// accept the repeat event//TUiKeyFilterDFA* s0 = CreateScanCodeDFALC( EStdKeyNo, EEventKey, 0, EFalse );//TUiKeyFilterDFA* s1 = CreateScanCodeDFALC( EStdKeyNo, EEventKeyUp, ETrue );//s0->AddSuccessorL( s1 );//CleanupStack::Pop(s1);//TUiKeyFilterDFA* s2 = CreateScanCodeDFALC( EStdKeyNo, EEventKey, 1, ETrue );//s0->AddSuccessorL( s2 );//CleanupStack::Pop(s2);////CleanupStack::Pop(s0);//return s0;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateDefaultKeyYesDFAL() {// start by a event keyTUiKeyFilterDFA* s0 = CreateScanCodeDFALC( EStdKeyYes, EEventKey, ETrue );CleanupStack::Pop( s0 );return s0;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateDefaultKeyLeftDFAL() {// return CreateEventAndRepeatDFA_ForScanCodeL( EStdKeyDevice0 );// start by a event keyTUiKeyFilterDFA* s00 = CreateScanCodeDFALC( EStdKeyDevice0, EEventKey, 0, ETrue );// accept the repeat eventTUiKeyFilterDFA* s11 = CreateScanCodeDFALC( EStdKeyDevice0, EEventKey, 1, ETrue );s00->AddSuccessorL( s11 );CleanupStack::Pop( s11 );// accept the up eventTUiKeyFilterDFA* s21 = CreateScanCodeDFALC( EStdKeyDevice0, EEventKeyUp, EFalse );s00->AddSuccessorL( s21 );CleanupStack::Pop( s21 );// accept the right soft key down eventTUiKeyFilterDFA* s22 = CreateScanCodeDFALC( EStdKeyDevice1, EEventKeyDown, EFalse );s21->AddSuccessorL( s22 );CleanupStack::Pop( s22 );// accept the right soft key eventTUiKeyFilterDFA* s23 = CreateScanCodeDFALC( EStdKeyDevice1, EEventKey, 0, EFalse );s22->AddSuccessorL( s23 );CleanupStack::Pop( s23 );// accept the right soft key upTUiKeyFilterDFA* s24 = CreateScanCodeDFALC( EStdKeyDevice1, EEventKeyUp, ETrue );s23->AddSuccessorL( s24 );CleanupStack::Pop( s24 );// completedCleanupStack::Pop( s00 );return s00;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateDefaultKeyMidDFAL() {TUiKeyFilterDFA* s0 = CreateScanCodeDFALC( EStdKeyDevice3, EEventKey, ETrue );CleanupStack::Pop( s0 );return s0;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateDefaultKeyRightDFAL() {return CreateEventAndRepeatDFA_ForScanCodeL( EStdKeyDevice1 );}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::DefaultUiKeyFilterDFAL() {TBool hasQwertyKeyboard = SupportQwertyInputL();//TInt count = 5 + 12 + ( hasQwertyKeyboard ? 26*2 : 0 );//TUiKeyFilterDFA* dfa = (TUiKeyFilterDFA*)User::AllocZL( sizeof(TUiKeyFilterDFA) );//dfa->iNext = (TUiKeyFilterDFA**)User::AllocZL( count*sizeof(TUiKeyFilterDFA*) );//dfa->iNextCount = count;////TUiKeyFilterDFA** w = dfa->iNext;TUiKeyFilterDFA* dfa = new (ELeave) TUiKeyFilterDFA;CleanupStack::PushL( dfa );dfa->AddSuccessorL( CreateDefaultKeyNoDFAL() );dfa->AddSuccessorL( CreateDefaultKeyNoDFAL() );dfa->AddSuccessorL( CreateDefaultKeyYesDFAL() );dfa->AddSuccessorL( CreateDefaultKeyLeftDFAL() );dfa->AddSuccessorL( CreateDefaultKeyMidDFAL() );dfa->AddSuccessorL( CreateDefaultKeyRightDFAL() );// numbersTUint16 NUMS[] = {'1','2','3','4','5','6','7','8','9','0','*','#',0};TInt i =0;while( NUMS[i] ) {dfa->AddSuccessorL( CreateEventAndRepeatDFA_ForKeyCodeL( NUMS[i++] ) );}// charsif( hasQwertyKeyboard ) {for( TUint c = 'a'; c <= 'z'; c++ ) {//dfa->AddSuccessorL( CreateEventDFA_ForKeyCodeL( c ) );dfa->AddSuccessorL( CreateEventAndRepeatDFA_ForKeyCodeL( c ) );}for( TUint c = 'A'; c <= 'Z'; c++ ) {//dfa->AddSuccessorL( CreateEventDFA_ForKeyCodeL( c ) );dfa->AddSuccessorL( CreateEventAndRepeatDFA_ForKeyCodeL( c ) );}}CleanupStack::Pop( dfa );return dfa;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateScanCodeDFALC( TInt aScanCode, TEventCode aType, TBool aTerminator ) {TUiKeyFilterDFA* dfa = new (ELeave) TUiKeyFilterDFA;CleanupStack::PushL( dfa );dfa->iType = aType;dfa->iScanCode = aScanCode;dfa->iFlag = EUseScanCode | ( aTerminator ? ETerminator : 0 );return dfa;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateScanCodeDFALC( TInt aScanCode, TEventCode aType, TInt aRepeats, TBool aTerminator ) {TUiKeyFilterDFA* dfa = new (ELeave) TUiKeyFilterDFA;CleanupStack::PushL( dfa );dfa->iType = aType;dfa->iScanCode = aScanCode;dfa->iRepeats = aRepeats;dfa->iFlag = EUseScanCode | EUseRepeats | ( aTerminator ? ETerminator : 0 );return dfa;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateKeyCodeDFALC( TInt aCode, TEventCode aType, TBool aTerminator ) {TUiKeyFilterDFA* dfa = new (ELeave) TUiKeyFilterDFA;CleanupStack::PushL( dfa );dfa->iType = aType;dfa->iKeyCode = aCode;dfa->iFlag = EUseKeyCode | ( aTerminator ? ETerminator : 0 );return dfa;}CUiKeyFilter::TUiKeyFilterDFA* CUiKeyFilter::CreateKeyCodeDFALC( TInt aCode, TEventCode aType, TInt aRepeats, TBool aTerminator ) {TUiKeyFilterDFA* dfa = new (ELeave) TUiKeyFilterDFA;CleanupStack::PushL( dfa );dfa->iType = aType;dfa->iKeyCode = aCode;dfa->iRepeats = aRepeats;dfa->iFlag = EUseKeyCode | EUseRepeats | ( aTerminator ? ETerminator : 0 );return dfa;}const CUiKeyFilter::TUiKeyFilterStatus* CUiKeyFilter::Top() {if( iStackSp ) {return iStack + (iStackSp-1);}return NULL;}// get status from the top// aPrevIndex = 0, return top// aPrecIndex = 1, return top-1;// and so onconst CUiKeyFilter::TUiKeyFilterStatus* CUiKeyFilter::Status( TInt aPrevIndex ) {TInt offset = ( iStackSp-1-aPrevIndex );if( offset < 0 || offset >= iStackSp ) {return NULL;}return iStack + offset;}void CUiKeyFilter::Push( const TKeyEvent& aKeyEvent, TEventCode& aType, TUiKeyFilterDFA* aDFA ) {iStack[iStackSp].iKeyEvent = aKeyEvent;iStack[iStackSp].iType = aType;iStack[iStackSp].iDFA = aDFA;iStackSp++;}void CUiKeyFilter::Pop() {iStackSp--;}void CUiKeyFilter::Clear() {iStackSp = 0;}TInt CUiKeyFilter::CombineKeyInterval() {return iCombineKeyInterval;}void CUiKeyFilter::SetCombineKeyInterval( TInt aMSec ) {iCombineKeyInterval = aMSec;}

 

使用Filter

 

TKeyResponse CHDesktopAppUi::HandleKeyEventL( const TKeyEvent& aKeyEvent,TEventCode aType) {// filter is not custructed yetif( NULL == iKeyFilter ) { return EKeyWasNotConsumed; }// send system event to filterTKeyEvent e = aKeyEvent;TEventCode t = aType;iKeyFilter->FilterKeyEvent( e, t );return EKeyWasConsumed;}// receive event from filtervoid CHDesktopAppUi::ProcessKeyEventL( const TKeyEvent& aKeyEvent,TEventCode aType) {TBool repeat = ( aKeyEvent.iRepeats ? ETrue : EFalse );switch( aKeyEvent.iScanCode ) {...case EStdKeyYes:ShowLogsDialedCallL();return;case EStdKeyNo:if( repeat ) {LOG("long press red key");if( iUseRedKeyAsPowerKey ) {TurnOffPhone();} else {if( !IsKeyboardLocked() ) {LockKeyboard();}}} else {if( iTaskSwitcher ) {LOG("cycle task");iTaskSwitcher->CycleTaskL( KSelf, iEikonEnv->RootWin().WindowGroupId() );}}return;}switch( aKeyEvent.iCode ) {case '0':case 'm':case 'M':if( repeat ) {LaunchDefaultBrowserL();return;}break;case '#':case 'j':case 'J':if( repeat ) {if( IsSilentL() ) {SwitchProfileL( 0 );} else {SwitchProfileL( 1 );}return;}break;}...}