场景切换是经过导演类Director实现的,其中的相关函数以下:php
runWithScene(Scene* scene)。该函数能够运行场景。只能在启动第一个场景时候调用该函数。若是已经有一个场景运行状况下则不能调用该函数。html
replaceScene(Scene* scene)。切换到下一个场景。用一个新的场景替换当前场景,当前场景被终端释放。函数
pushScene(Scene* scene)。切换到下一个场景。将当前场景挂起放入到场景堆栈中,而后再切换到下一个场景中。网站
void popScene()。与pushScene配合使用,能够回到上一个场景。this
void popToRootScene()。与pushScene配合使用,能够回到根场景。spa
咱们须要注意replaceScene和pushScene使用的区别。replaceScene会释放和销毁场景,若是须要保持原来场景的状态,replaceScene函数不适合。pushScene并不会释放和销毁场景,原来场景的状态能够保持,可是场景不能放太多的场景对象。.net
使用replaceScene代码以下:code
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auto sc = Setting::createScene(); htm
Director::getInstance()->replaceScene(sc);
其中的Setting是下一个要切换的场景。使用pushScene代码以下:
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auto sc = Setting::createScene();
Director::getInstance()->pushScene(sc);
从Setting场景回到上一个场景使用代码以下:
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Director::getInstance()->popScene();
下面咱们经过一个实例场景切换相关函数,以下图所示有两个场景:HelloWorld和Setting(设置)。在HelloWorld场景点击“游戏设置”菜单能够切换到Setting场景,在Setting场景中点击“OK”菜单能够返回到HelloWorld场景。
咱们首先须要在工程中添加一个Setting场景(SettingScene.cpp和SettingScene.h),以下图所示,右键点击HelloWorld工程中Classes文件夹,在弹出菜单中选择“添加”→“新建项”:
弹出对话框以下图所示,在名称中输入“SettingScene.cpp”,并选择保存文件位置,而后点击“添加”按钮建立SettingScene.cpp。使用一样的方法建立SettingScene.h。
下面咱们看看代码部分,HelloWorldScene.cpp中的重要代码以下:
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bool HelloWorld::init()
{
if ( !Layer::init() )
{
return false;
}
Size visibleSize = Director::getInstance()->getVisibleSize();
Point origin = Director::getInstance()->getVisibleOrigin();
Sprite *bg = Sprite::create("background.png");
bg->setPosition(Point(origin.x + visibleSize.width/2,
origin.y +visibleSize.height /2));
this->addChild(bg);
//开始精灵
Sprite *startSpriteNormal = Sprite::create("start-up.png");
Sprite *startSpriteSelected =Sprite::create("start-down.png");
MenuItemSprite*startMenuItem = MenuItemSprite::create(startSpriteNormal,
startSpriteSelected,
CC_CALLBACK_1(HelloWorld::menuItemStartCallback,this));
startMenuItem->setPosition(Director::getInstance()->convertToGL(Point(700,170)));
//设置图片菜单
MenuItemImage *settingMenuItem = MenuItemImage::create(
"setting-up.png",
"setting-down.png",
CC_CALLBACK_1(HelloWorld::menuItemSettingCallback,this));
settingMenuItem->setPosition(Director::getInstance()->convertToGL(Point(480,400)));
//帮助图片菜单
MenuItemImage *helpMenuItem = MenuItemImage::create(
"help-up.png",
"help-down.png",
CC_CALLBACK_1(HelloWorld::menuItemHelpCallback,this));
helpMenuItem->setPosition(Director::getInstance()->convertToGL(Point(860,480)));
Menu*mu = Menu::create(startMenuItem, settingMenuItem, helpMenuItem, NULL);
mu->setPosition(Point::ZERO);
this->addChild(mu);
return true;
}
voidHelloWorld::menuItemSettingCallback(Ref* pSender) ①
{
autosc = Setting::createScene(); ②
//Director::getInstance()->replaceScene(sc); ③
Director::getInstance()->pushScene(sc); ④
}
void HelloWorld::menuItemHelpCallback(Ref*pSender)
{
MenuItem* item = (MenuItem*)pSender;
log("TouchHelp %p", item);
}
void HelloWorld::menuItemStartCallback(Ref*pSender)
{
MenuItem* item = (MenuItem*)pSender;
log("TouchStart %p", item);
}
上述代码中的第①行定义的函数menuItemSettingCallback,是在用户点击“游戏设置”菜单时候回调。第②行代码是建立设置建立对象。第③行是使用replaceScene函数进行场景切换。第④行代码是pushScene函数进行场景切换。
HelloWorldScene.cpp中的重要代码以下:
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bool Setting::init()
{
if ( !Layer::init() )
{
return false;
}
Size visibleSize = Director::getInstance()->getVisibleSize();
Point origin = Director::getInstance()->getVisibleOrigin();
Sprite *bg = Sprite::create("setting-back.png");
bg->setPosition(Point(origin.x + visibleSize.width/2,
origin.y +visibleSize.height /2));
this->addChild(bg);
//音效
auto soundOnMenuItem = MenuItemImage::create(
"on.png",
"on.png");
auto soundOffMenuItem = MenuItemImage::create(
"off.png",
"off.png");
auto soundToggleMenuItem = MenuItemToggle::createWithCallback(
CC_CALLBACK_1(Setting::menuSoundToggleCallback,this),
soundOnMenuItem,
soundOffMenuItem,
NULL);
soundToggleMenuItem->setPosition(Director::getInstance()->convertToGL(Point(818,220)));
//音乐
auto musicOnMenuItem =MenuItemImage::create(
"on.png",
"on.png");
automusicOffMenuItem =MenuItemImage::create(
"off.png",
"off.png");
auto musicToggleMenuItem = MenuItemToggle::createWithCallback(
CC_CALLBACK_1(Setting::menuMusicToggleCallback,this),
musicOnMenuItem,
musicOffMenuItem,
NULL);
musicToggleMenuItem->setPosition(Director::getInstance()->convertToGL(Point(818,362)));
//Ok按钮
autookMenuItem = MenuItemImage::create(
"ok-down.png",
"ok-up.png",
CC_CALLBACK_1(Setting::menuOkCallback, this));
okMenuItem->setPosition(Director::getInstance()->convertToGL(Point(600,510)));
Menu* mn = Menu::create(soundToggleMenuItem,
musicToggleMenuItem,okMenuItem,NULL);
mn->setPosition(Point::ZERO);
this->addChild(mn);
return true;
}
void Setting::menuOkCallback(Ref*pSender) ①
{
Director::getInstance()->popScene(); ②
}
void Setting::menuSoundToggleCallback(Ref*pSender)
{}
void Setting::menuMusicToggleCallback(Ref*pSender)
{}
上述代码中的第①行定义的函数menuOkCallback,是在用户在设置场景点击“OK”菜单时候回调。第②行代码是使用popScene函数返回HelloWorld场景。
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