实现文本框到处弹的效果

#include "HelloWorldScene.h"

USING_NS_CC;

Scene* HelloWorld::createScene()
{
// 'scene' is an autorelease object
auto scene = Scene::create();

// 'layer' is an autorelease object
auto layer = HelloWorld::create();

// add layer as a child to scene
scene->addChild(layer);

// return the scene
return scene;
}

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
//////////////////////////////
// 1. super init first
if ( !Layer::init() )
{
return false;
}

Size visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();

/////////////////////////////
// 2. add a menu item with "X" image, which is clicked to quit the program
//    you may modify it.

// add a "close" icon to exit the progress. it's an autorelease object
auto closeItem = MenuItemImage::create(
"CloseNormal.png",
"CloseSelected.png",
CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));

closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
origin.y + closeItem->getContentSize().height/2));

// create menu, it's an autorelease object
auto menu = Menu::create(closeItem, NULL);
menu->setPosition(Vec2::ZERO);
this->addChild(menu, 1);

/////////////////////////////
// 3. add your codes below...

// add a label shows "Hello World"
// create and initialize a label

auto label = Label::createWithTTF("Hello World", "fonts/Marker Felt.ttf", 24);

label->setTag(123);

// position the label on the center of the screen
label->setPosition(Vec2(origin.x + visibleSize.width/2,
origin.y + visibleSize.height - label->getContentSize().height));

// add the label as a child to this layer
this->addChild(label, 1);

// add "HelloWorld" splash screen"
auto sprite = Sprite::create("HelloWorld.png");

// position the sprite on the center of the screen
sprite->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));

// add the sprite as a child to this layer
this->addChild(sprite, 0);

this->scheduleUpdate();

return true;
}

void HelloWorld::menuCloseCallback(Ref* pSender)
{
unscheduleUpdate();

Director::getInstance()->end();

#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
exit(0);
#endif
}

void HelloWorld::update(float dt)
{
auto label = this->getChildByTag(123);
Size visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();

//方向，0右下，1左下，2左上，3右上

static int dir = 0;
if (0 == dir)
{
if (label->getPositionX() == visibleSize.width) dir = 1;
if (label->getPositionY() == origin.y) dir = 3;
if (label->getPositionX() == visibleSize.width &&
label->getPositionY() == origin.y) dir = 2;
}

if (1 == dir)
{
if (label->getPositionX() == origin.x) dir = 0;
if (label->getPositionY() == origin.y) dir = 2;
if (label->getPositionX() == origin.x &&
label->getPositionY() == origin.y) dir = 3;
}

if (2 == dir)
{
if (label->getPositionX() == origin.x) dir = 3;
if (label->getPositionY() == visibleSize.height) dir = 1;
if (label->getPositionX() == origin.x &&
label->getPositionY() == visibleSize.height) dir = 0;
}

if (3 == dir)
{
if (label->getPositionX() == visibleSize.width) dir = 2;
if (label->getPositionY() == visibleSize.height) dir = 0;
if (label->getPositionX() == visibleSize.width &&
label->getPositionY() == visibleSize.height) dir = 1;
}

//	CCLOG("%f %f\n", label->getPositionX(), label->getPositionY());

//右下
if (0 == dir) label->setPosition(label->getPosition() + Vec2(1, -1));
//左下
if (1 == dir) label->setPosition(label->getPosition() + Vec2(-1, -1));
//左上
if (2 == dir) label->setPosition(label->getPosition() + Vec2(-1, 1));
//右上
if (3 == dir) label->setPosition(label->getPosition() + Vec2(1, 1));
}