誆騙自己與類繼承，需要一些指導

Question

我有一個Player類......他需要訪問PlayerStateFlying和PlayerStateHit類中的組件，以便我從他們身上繼承...

class PlayerStateFlying 
{ 
    // Includes a function that sets Player::currentState = something 
} 

class PlayerStateHit 
{ 
    // Includes a function that sets Player::currentState = something 
} 

class Player : public PlayerStateFlying, 
       public PlayerStateHit 
{ 
    public: 
     STATE currentState; // Needs to be accessed by the State classes 
} 

問題是，我的國家課程需要訪問玩家的某個屬性

我該如何解決這個問題？

--------- -----------編輯

所以它應該是這樣的？ PS我不能完全得到它的工作

class IBaseStates 
{ 
    public: 
     STATE currentState; 
} 

class PlayerStateFlying : public IBaseStates 
{ 
    // Includes a function that sets IBaseStates::currentState = something 
} 

class PlayerStateHit : public IBaseStates 
{ 
    // Includes a function that sets IBaseStates::currentState = something 
} 

class Player : public IBaseStates 
{ 
    // Includes a function that checks what IBaseStates::currentState equals 
} 

這裏是我的困境的一個例子：

void Player::ChangeState(STATE state) 
{ 
    switch(state) 
    { 
    case FLYING: 
     currentState = FLYING; 
     break; 
    case HIT: 
     currentState = HIT; 
     break; 
    } 
} 

void Player::StateUpdate() 
{ 
    switch(currentState) 
    { 
    case FLYING: 
     PlayerStateFlying::Update(); 
     currentTextureIndex = PlayerStateFlying::current; 
     break; 
    case HIT: 
     PlayerStateHit::Update(); 
     currentTextureIndex = PlayerStateHit::current; 
     break; 
    } 
} 

void PlayerStateHit::Update() 
{ 
    ... 
      currentState = FLYING; 
      index = 0; 
    ...  
} 

Answer 1

玩家應該是設置當前狀態的人。不是國家本身。狀態更新函數應該如下所示：

void Player::StateUpdate() { 
    mCurrentState->update(this); 
} 

void PlayerHitState(Player * player) { 
    player->setCurrentState(player->getStateFromListOfAvailableStates(FLYING)) 
} 

一個簡單的狀態機應該存儲所有需要的狀態和轉換。就像你在水中或類似的東西時不能飛行一樣。

Answer 2

具有存儲所需要訪問和繼承國家和信息的通用類從這兩個球員狀態。

Answer 3

不要忘記多態性。你不需要執行任何switch'es。

我認爲解決的辦法應該是這樣的：

class PlayerState { 
} 

class PlayerStateFlying : public PlayerState { 
} 

class PlayerStateHit : public PlayerState { 
} 

現在你Player類（對象）應該包含（或接入）的狀態對象：

class Player { 
protected: 
    PlayerState *playerState; 
public: 
    void setPlayerState(PlayerState *newState); 
} 

setPlayerState()應該是這樣的：

Player::setPlayerState(PlayerState *newState) { 
    playerState = newState; 
} 

現在你可以簡單地重寫你的方法未來支持多種PlayerState子類：

void Player::StateUpdate() { 
    playerState->Update(); // Polymorphism! 
    currentTextureIndex = playerState->current; 
} 

在下一個方法，你仍然可以使用一個開關，如果你還真需要存儲您的currentState變量並使用它：

void Player::ChangeState(STATE state) { 
    switch(state) { 
    case FLYING: 
     currentState = FLYING; 
     playerState = new PlayerStateFlying(); 
     break; 
    case HIT: 
     currentState = HIT; 
     playerState = new PlayerStateHit(); 
     break; 
    } 
} 

...但還有另外一個 - 更方便的解決方案 - 我們已經有了它，但是如果我們仍然需要currentState enum（或int或其他）變量，我們可以簡單地用一個新字段擴展我們的PlayerState類（和子類） - label：

class PlayerState { 
public: 
    int label; 
} 

PlayerStateFlying::PlayerStateFlying() { 
    label = FLYING; 
} 

PlayerStateHit::PlayerStateHit() { 
    label = HIT; 
} 

現在可以：

Player::setPlayerState(PlayerState *newState) { 
    playerState = newState; 
    currentState = playerState->label; 
} 

您也可以嘗試用恆定的領域，那就是：

class PlayerState { 
public: 
    const int label; 
} 

PlayerStateFlying::PlayerStateFlying() : label(FLYING) {}; 

PlayerStateHit::PlayerStateHit() : label(HIT) {}; 

關心。