最近项目中要用到带滚动条的滑块，所有自己简单的封装了一个滚动条，配合scrollView来使用,2.2版本的引擎太古老了，但是项目要用没办法，新版本引擎应该更简单

大概思路是:

1.获取到scrollView的contentSize高度以及scrollView的viewSizie高度,创建一个滚动条，通过前面两个值，计算出滚动条的背景条高度（等于viewSize高度）和滚动条高度(viewSizeHeight/(contentSizeHeight/viewSizeHeight)))

2.scrollViewDidscroll方法中，不断获取scrollView上的contentOffSize的y坐标，与scrollView的可滚动区域（即是用scrollView的contentSize高度与scrollView的viewSize作差）做比值，来校正滚动条坐标

sliderBar代码如下:

/**
* Created by dong on 2014/9/28 0011.
*
* 滑块上的滚动条，带回弹效果
*/
var SliderBar = cc.Node.extend({
_sliderFileName: null, //滚动条图片路径
_backgroundFileName: null, //滚动条背景图路径
_bgSize: null, //画条背景图显示的区域
_multiple: null, //滑块显示区域与总区域比例
_sliderSize: null, //滑条显示区域
_bgSprite: null, //背景sprite
_sliderSprite: null, //滚动条sprite
_beginPos: null, //滚动条的起始位置
_endPos: null, //滚动条的最终位置

ctor: function (sliderFileName, backgroundFileName, bgSize, multiple) {
this._super();

if(!sliderFileName || !backgroundFileName){
cc.log("wrong args,check it !");
}
this._sliderFileName = sliderFileName;
this._backgroundFileName = backgroundFileName;
this._bgSize = bgSize;
this._multiple = multiple;

if (!this.init()) {
return false;
}
},

init: function () {
this._bgSprite = cc.Scale9Sprite.create(this._backgroundFileName);
this._bgSprite.setContentSize(cc.size(this._bgSprite.getContentSize().width, this._bgSize.height));
this.addChild(this._bgSprite);

this._sliderSprite = cc.Scale9Sprite.create(this._sliderFileName);
this._sliderSprite.setContentSize(cc.size(this._sliderSprite.getContentSize().width, this._bgSize.height / this._multiple));
this.addChild(this._sliderSprite);

this._beginPos = cc.p(0, -this._bgSize.height / 2 + this._sliderSprite.getContentSize().height / 2);
this._endPos = cc.p(0, this._bgSize.height / 2 - this._sliderSprite.getContentSize().height / 2);
this._sliderSize = this._sliderSprite.getContentSize();
this._sliderSprite.setPosition(this._beginPos);

return true;
},

setValue: function (value) {

//正常范围内活动
if (value >= 0 && value <= 1) {
//重定位
//this._sliderSprite.setContentSize(this._sliderSize);
this._sliderSprite.setPosition(cc.p(0, this._beginPos.y + (this._endPos.y - this._beginPos.y) * value));
}
//滑动到最下侧
else if (value < 0 && value > -0.8) {
var conDownValue = http://www.mamicode.com/this._sliderSize.height + value * this._sliderSize.height;
if(conDownValue < 100){
return;
}
var moveBeginPosY = this._beginPos.y + value * this._sliderSize.height / 2;
moveBeginPosY = moveBeginPosY < -this._bgSize.height / 2 ? -this._bgSize.height / 2 : moveBeginPosY;
this._sliderSprite.setContentSize(cc.size(this._sliderSize.width, conDownValue));
this._sliderSprite.setPosition(cc.p(0, moveBeginPosY));
}
//滑动到最上侧
else if (value > 1 && value < 1.8) {
var conUpValue = http://www.mamicode.com/this._sliderSize.height + (1 - value) * this._sliderSize.height;
if(conUpValue < 100){
return;
}
var moveEndPosY = this._endPos.y - (1 - value) * this._sliderSize.height / 2;
moveEndPosY = moveEndPosY > this._bgSize.height / 2 ? this._bgSize.height / 2 : moveEndPosY;
this._sliderSprite.setContentSize(cc.size(this._sliderSize.width, conUpValue));
this._sliderSprite.setPosition(cc.p(0, moveEndPosY));
}
},
//刷新进度条状态
refreshSliderStatus: function (bgSize, multiple) {
this._bgSize = bgSize;
this._multiple = multiple;
this._bgSprite.setContentSize(cc.size(this._bgSprite.getContentSize().width, this._bgSize.height));
this._sliderSprite.setContentSize(cc.size(this._sliderSprite.getContentSize().width, this._bgSize.height / this._multiple));
this._beginPos = cc.p(0, -this._bgSize.height / 2 + this._sliderSprite.getContentSize().height / 2);
this._endPos = cc.p(0, this._bgSize.height / 2 - this._sliderSprite.getContentSize().height / 2);
this._sliderSize = this._sliderSprite.getContentSize();
//this._sliderSprite.setPosition(this._beginPos);//备用
},
//设置透明度
setOpacity: function (value) {
var children = this.getChildren();
for (var k = 0; k < children.length; k++) {
children[k].setOpacity(value);
}
},
//设置隐藏
setVisible: function (bVis) {
var children = this.getChildren();
for (var k = 0; k < children.length; k++) {
children[k].setVisible(bVis);
}
},
//渐变消失
runFadeoutAction: function (value) {
var children = this.getChildren();
for (var k = 0; k < children.length; k++) {
var fadeout = cc.FadeOut.create(value);
children[k].runAction(fadeout);
}
},
//渐变出现
runFadeinAction: function (value) {
var children = this.getChildren();
for (var k = 0; k < children.length; k++) {
var fadein = cc.FadeIn.create(value);
children[k].runAction(fadein);
}
},
//停止动作
stopAllActions: function () {
var children = this.getChildren();
for (var k = 0; k < children.length; k++) {
children[k].stopAllActions();
}
},
onEnter: function () {
this._super();
},
onExit: function () {
this._super();
}
});

使用方法:

创建滚动条

this._slider = new SliderBar(slider_track_png, slider_thumb_png, this._scrollView.getViewSize(),this._scrollView.getContentSize().height /this._scrollView.getViewSize().height);

this._slider.setPosition(cc.p(WinSize.width - 40, WinSize.height / 2 + 15));
this._slider.setValue(0.01); //初始化滚动条时，保证滚动条在最下方
this._bgLayer.addChild(this._slider, 20);

//然后在scrollVIewDidView方法中不断更新滚动条:

scrollViewDidScroll: function (view) {
//Y轴相对移动距离
var offPosY = this._scrollView.getContentOffset().y;
//可滚动的区域大小，计算滚动条位置和高度用
var scrollHeight = this._scrollView.getContentSize().height - this._scrollView.getViewSize().height;
var present = -(offPosY / scrollHeight);
//根据滑块移动距离不断校正滚动条位置以及高度
if (this._slider) {
this._slider.setValue(present);
}
}

由于我的需求是scrollView上面的cell数量时时刷新的,所以还做了一些其他处理，这里就不写出来了，今天的笔记到此结束

cocos2d-js-2.2 scrollView +滚动条 开发笔记