这节我们来学习Cocos2d-x的最后一节，怎样处理重力感应事件，移植到Android后加入再按一次返回键退出游戏等。我这里用的Android，IOS不会也没设备呃

效果图不好弄，由于是要移植到真机上的。

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__#include "cocos2d.h"
using namespace cocos2d;
class HelloWorld : public cocos2d::CCLayer
{
public:// Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphonevirtual bool init();  // there's no 'id' in cpp, so we recommend returning the class instance pointerstatic cocos2d::CCScene* scene();//重力感应事件virtual void didAccelerate(CCAcceleration* pAccelerationValue);//返回buttonvirtual void keyBackClicked();// implement the "static node()" method manuallyCREATE_FUNC(HelloWorld);
};#endif // __HELLOWORLD_SCENE_H__

这里重写了两个方法

我们都知道CCLayer是继承了重力感应事件和触屏事件，button事件的

#include "HelloWorldScene.h"#define FIX_POS(_pos, _min, _max) \if (_pos < _min)        \_pos = _min;        \
else if (_pos > _max)   \_pos = _max;        \USING_NS_CC;CCScene* HelloWorld::scene()
{// 'scene' is an autorelease objectCCScene *scene = CCScene::create();// 'layer' is an autorelease objectHelloWorld *layer = HelloWorld::create();// add layer as a child to scenescene->addChild(layer);// return the scenereturn scene;
}// on "init" you need to initialize your instance
bool HelloWorld::init()
{//// 1. super init firstif ( !CCLayer::init() ){return false;}this->setAccelerometerEnabled(true);this->setKeypadEnabled(true);CCSize visibleSize= CCDirector::sharedDirector()->getVisibleSize();CCLabelTTF *lable= CCLabelTTF::create("AccelerometerTest","Arial",34);lable->setPosition(ccp(visibleSize.width/2,visibleSize.height-50));this->addChild(lable,0,0);CCSprite *pSprite= CCSprite::create("ball.png");pSprite->setPosition(ccp(visibleSize.width/2,visibleSize.height/2));this->addChild(pSprite,0,1);return true;
}
void HelloWorld::didAccelerate(CCAcceleration* pAccelerationValue)
{CCObject *pObjectlable= this->getChildByTag(0);if (pObjectlable==NULL){return;}CCLabelTTF *lable=(CCLabelTTF*)pObjectlable;std::ostringstream strstream;strstream<<"X:"<<pAccelerationValue->x<<"  Y:"<<pAccelerationValue->y<<"  Z:"<<pAccelerationValue->z;std::string str=strstream.str();lable->setString(str.c_str());//改变小球位置CCObject *pObjectSprite= this->getChildByTag(1);if (pObjectSprite==NULL){return;}CCSprite *pSprite=(CCSprite*)pObjectSprite;CCSize pSpriteSize= pSprite->getContentSize();CCPoint ptNow  = pSprite->getPosition();CCPoint ptTemp=CCDirector::sharedDirector()->convertToUI(ptNow);ptTemp.x += pAccelerationValue->x * 9.81f;ptTemp.y -= pAccelerationValue->y * 9.81f;CCPoint ptNext = CCDirector::sharedDirector()->convertToGL(ptTemp);CCSize visibleSize= CCDirector::sharedDirector()->getVisibleSize();FIX_POS(ptNext.x, (pSpriteSize.width / 2.0), (visibleSize.width - pSpriteSize.width / 2.0));FIX_POS(ptNext.y, (pSpriteSize.height / 2.0), (visibleSize.height - pSpriteSize.height / 2.0));pSprite->setPosition(ptNext);}
void HelloWorld::keyBackClicked()
{
}

源文件代码如上,

init中我们创建了一个lable和小球的精灵

通过setAccelerometerEnabled启用重力感应事件

这里能够看下源代码，比触屏事件简单多了。

然后重写重力感应事件，这里我再事件中改动了CCLableTTF的文本，

改变小球的位置

改动文本就不多说了，非常easy，我们主要来看看怎样改变小球位置的

首先我们获得小球精灵

得到精灵位置

转换为UIKIT

这里*9.81f我也不知道什么意思，TestCpp这么写我也就这么写了

为了小球不超出手机屏幕。所以我们写了一个宏  FIX_POS

这里看看就懂了

OK。

我们移植到Android，看看效果，怎么移植，第一节专门介绍了的

效果不错，可是我们按返回键它没有退出游戏。没不论什么反应，

我们在src下的org.cocos2dx.lib中找到Cocos2dxGLSurfaceView.java打开

找到

@Overridepublic boolean onKeyDown(final int pKeyCode, final KeyEvent pKeyEvent) {switch (pKeyCode) {case KeyEvent.KEYCODE_BACK: return false;//这里是自己新增的， 返回falsecase KeyEvent.KEYCODE_MENU:this.queueEvent(new Runnable() {@Overridepublic void run() {Cocos2dxGLSurfaceView.this.mCocos2dxRenderer.handleKeyDown(pKeyCode);}});return true;default:return super.onKeyDown(pKeyCode, pKeyEvent);}}

然后我们在自己的java文件里重写onKeyDown，

详细代码例如以下

/****************************************************************************
Copyright (c) 2010-2011 cocos2d-x.orghttp://www.cocos2d-x.orgPermission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/
package com.huc.test;import org.cocos2dx.lib.Cocos2dxActivity;
import org.cocos2dx.lib.Cocos2dxGLSurfaceView;import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.Toast;public class test20140521 extends Cocos2dxActivity{private long mExitTime;protected void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);    }@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {// TODO Auto-generated method stubif (keyCode == KeyEvent.KEYCODE_BACK) {  if ((System.currentTimeMillis() - mExitTime) > 2000) {// 假设两次按键时间间隔大于2000毫秒。则不退出  Toast.makeText(this, "再按一次退出程序", Toast.LENGTH_SHORT).show();  mExitTime = System.currentTimeMillis();// 更新mExitTime  } else {  System.exit(0);// 否则退出程序  }  return true;  }  return super.onKeyDown(keyCode, event);}public Cocos2dxGLSurfaceView onCreateView() {Cocos2dxGLSurfaceView glSurfaceView = new Cocos2dxGLSurfaceView(this);// test20140521 should create stencil bufferglSurfaceView.setEGLConfigChooser(5, 6, 5, 0, 16, 8);return glSurfaceView;}static {System.loadLibrary("cocos2dcpp");}
}

OK，试试吧。

。。

附源代码和APK