Swift语言开发：仿Clear手势操作(拖拽、划动、捏合)UITableView

这是一个完全依靠手势的操作TodoList的演示，功能上左划删除，右划完成任务，拖拽调整顺序，捏合张开插入。

项目源码: https://github.com/luan-ma/ClearStyleDemo.Swift

初始化

TDCTodoItem.swift 定义模型对象

TDCTodoListController.swift 继承自UITableViewController， 演示UITableView操作

varitems=[
TDCTodoItem(text:"Feedthecat"),TDCTodoItem(text:"Buyeggs"),TDCTodoItem(text:"PackbagsforWWDC"),TDCTodoItem(text:"Ruletheweb"),TDCTodoItem(text:"BuyanewiPhone"),TDCTodoItem(text:"Findmissingsocks"),TDCTodoItem(text:"Writeanewtutorial"),TDCTodoItem(text:"MasterObjective-C"),TDCTodoItem(text:"Rememberyourweddinganniversary!"),TDCTodoItem(text:"Drinklessbeer"),TDCTodoItem(text:"Learntodraw"),TDCTodoItem(text:"Takethecartothegarage"),TDCTodoItem(text:"SellthingsoneBay"),TDCTodoItem(text:"Learntojuggle"),TDCTodoItem(text:"Giveup")
]

overridefuncviewDidLoad(){
super.viewDidLoad()

//捏合手势
letpinch=UIPinchGestureRecognizer(target:self,action:"handlePinch:")
//长按拖拽
letlongPress=UILongPressGestureRecognizer(target:self,action:"handleLongPress:")

tableView.addGestureRecognizer(pinch)
tableView.addGestureRecognizer(longPress)
}

左划删除、右划完成

在每一个Cell添加滑动手势(Pan)。处理划动距离，超过宽度1/3就为有效操作，左划为删除操作，右划为完成操作。

布局使用AutoLayout，中间内容区的限制条件是宽度等于容器宽度、高度等于容器高度、垂直中对齐、水平中对齐，而平移操作实际上就是操作水平中对齐的距离值。

TDCTodoItemCell.swift关键代码如下

手势判断

//如果是划动手势，仅支持左右划动；如果是其它手势，则有父类负责
overridefuncgestureRecognizerShouldBegin(gestureRecognizer:UIGestureRecognizer)->Bool{
ifletpanGesture=gestureRecognizeras?UIPanGestureRecognizer{
lettranslation=panGesture.translationInView(self.superview)
returnfabs(translation.x)>fabs(translation.y)
}else{
returnsuper.gestureRecognizerShouldBegin(gestureRecognizer)
}
}

手势操作

varonDelete:((TDCTodoItemCell)->Void)?
varonComplete:((TDCTodoItemCell)->Void)?

privatevardeleteOnDragrelease:Bool=false
privatevarcompleteOnDragrelease:Bool=false

//划动平移的实际AutoLayout中的水平中对齐的距离
@IBOutletweakvarcenterConstraint:NSLayoutConstraint!
privatevaroriginConstant:CGFloat=0

funchandlePan(panGesture:UIPanGestureRecognizer){
switchpanGesture.state{
case.Began:
originConstant=centerConstraint.constant
case.Changed:
lettranslation=panGesture.translationInView(self)
centerConstraint.constant=translation.x

//划动移动1/3宽度为有效划动
letfinished=fabs(translation.x)>CGRectGetWidth(bounds)/3
iftranslation.x<originConstant{//右划
iffinished{
deleteOnDragrelease=true
rightLabel.textColor=UIColor.redColor()
}else{
deleteOnDragrelease=false
rightLabel.textColor=UIColor.whiteColor()
}
}else{//左划
iffinished{
completeOnDragrelease=true
leftLabel.textColor=UIColor.greenColor()
}else{
completeOnDragrelease=false
leftLabel.textColor=UIColor.whiteColor()
}
}
case.Ended:
centerConstraint.constant=originConstant

ifdeleteOnDragrelease{
deleteOnDragrelease=false
ifletonDelete=onDelete{
onDelete(self)
}
}

ifcompleteOnDragrelease{
completeOnDragrelease=false
ifletonComplete=onComplete{
onComplete(self)
}
}
default:
break
}
}

在TDCTodoListController.swift中执行删除操作

/*
//简单删除
funcdeletetoDoItem(indexPath:NSIndexPath){
tableView.beginUpdates()
items.removeAtIndex(indexPath.row)
tableView.deleteRowsAtIndexPaths([indexPath],withRowAnimation:.Automatic)
tableView.endUpdates()
}
*/

//视觉效果更漂亮的删除
funcdeletetoDoItem(indexPath:NSIndexPath){
letitem=items.removeAtIndex(indexPath.row)
varanimationEnabled=false
letlastCell=tableView.visibleCells.last
vardelay:NSTimeInterval=0
forcellintableView.visibleCells{
letcell=cellas!TDCTodoItemCell
ifanimationEnabled{
UIView.animateWithDuration(0.25,delay:delay,options:.CurveEaseInOut,animations:{()->Voidin
cell.frame=CGRectOffset(cell.frame,-CGRectGetHeight(cell.frame))
},completion:{(completed)->Voidin
ifcell==lastCell{
self.tableView.reloadData()
}
})
delay+=0.03
}

ifcell.todoItem==item{
animationEnabled=true
cell.hidden=true
}
}
}

拖拽排序

长按选中某Cell，截图此Cell生成UIImageView，然后隐藏此Cell（hidden=true），随手指移动拖拽UIImageView，每次拖拽到一个Cell上的时候，交换当前Cell和隐藏Cell位置。效果如下

截图UIView生成一个新的UIImageVIew

funcsnapView(view:UIView)->UIImageView{
UIGraphicsBeginImageContextWithOptions(view.bounds.size,false,0)
view.layer.renderInContext(UIGraphicsGetCurrentContext()!)
letimage=UIGraphicsGetimageFromCurrentimageContext()
UIGraphicsEndImageContext()

letsnapShot=UIImageView(image:image)
snapShot.layer.masksToBounds=false;
snapShot.layer.cornerRadius=0;
snapShot.layer.shadowOffset=CGSizeMake(-5.0,0.0);
snapShot.layer.shadowOpacity=0.4;
snapShot.layer.shadowRadius=5;
snapShot.frame=view.frame
returnsnapShot
}

拖拽操作代码，详细操作参考注释

privatevarsourceIndexPath:NSIndexPath?
privatevarsnapView:UIView?

funchandleLongPress(longPress:UILongPressGestureRecognizer){
letpoint=longPress.locationInView(tableView)

ifletindexPath=tableView.indexPathForRowAtPoint(point){
switchlongPress.state{
case.Began:
ifletcell=tableView.cellForRowAtIndexPath(indexPath){
sourceIndexPath=indexPath
letsnapView=self.snapView(cell)
snapView.alpha=0

self.snapView=snapView

tableView.addSubview(snapView)

UIView.animateWithDuration(0.25,animations:{
//选中Cell跳出放大效果
snapView.alpha=0.95
snapView.center=CGPointMake(cell.center.x,point.y)
snapView.transform=CGAffineTransformMakeScale(1.05,1.05)

cell.alpha=0
},completion:{(completed)->Voidin
cell.hidden=true
cell.alpha=1
})
}else{
sourceIndexPath=nil
snapView=nil
break
}
case.Changed:
ifletsnapView=snapView{
//截图随手指上下移动
snapView.center=CGPointMake(snapView.center.x,point.y)
}

//如果手指移动到一个新的Cell上面，隐藏Cell跟此Cell交换位置
ifletfromIndexPath=sourceIndexPath{
iffromIndexPath!=indexPath{
tableView.beginUpdates()
lettemp=items[indexPath.row]
items[indexPath.row]=items[fromIndexPath.row]
items[fromIndexPath.row]=temp
tableView.moveRowAtIndexPath(fromIndexPath,toIndexPath:indexPath)
tableView.endUpdates()
sourceIndexPath=indexPath
}
}

//手指移动到屏幕顶端或底部，UITableView自动滚动
letstep:CGFloat=64
ifletparentView=tableView.superview{
letparentPos=tableView.convertPoint(point,toView:parentView)
ifparentPos.y>parentView.bounds.height-step{
varoffset=tableView.contentOffset
offset.y+=(parentPos.y-parentView.bounds.height+step)
ifoffset.y>tableView.contentSize.height-tableView.bounds.height{
offset.y=tableView.contentSize.height-tableView.bounds.height
}
tableView.setContentOffset(offset,animated:false)
}elseifparentPos.y<=step{
varoffset=tableView.contentOffset
offset.y-=(step-parentPos.y)
ifoffset.y<0{
offset.y=0
}
tableView.setContentOffset(offset,animated:false)
}
}
default:
ifletsnapView=snapView,letfromIndexPath=sourceIndexPath,letcell=tableView.cellForRowAtIndexPath(fromIndexPath){
cell.alpha=0
cell.hidden=false

//长按移动结束，隐藏的Cell恢复显示，删除截图
UIView.animateWithDuration(0.25,animations:{()->Voidin
snapView.center=cell.center
snapView.alpha=0

cell.alpha=1
},completion:{[uNownedself](completed)->Voidin
snapView.removeFromSuperview()
self.snapView=nil
self.sourceIndexPath=nil

self.tableView.performSelector("reloadData",withObject:nil,afterDelay:0.5)
})
}
}
}
}

捏合张开插入

通过捏合手势中两个触点获取两个相邻的Cell，通过修改UIView.transform属性移动屏幕上的Cell位置。

获取Pinch两个手指坐标的工具方法

funcpointsOfPinch(pinch:UIPinchGestureRecognizer)->(CGPoint,CGPoint){
ifpinch.numberOftouches()>1{
letpoint1=pinch.locationOfTouch(0,inView:tableView)
letpoint2=pinch.locationOfTouch(1,inView:tableView)
ifpoint1.y<=point2.y{
return(point1,point2)
}else{
return(point2,point1)
}
}else{
letpoint=pinch.locationOfTouch(0,inView:tableView)
return(point,point)
}
}

捏合张开操作代码，详情请参考代码和注释

//插入点
privatevarpinchIndexPath:NSIndexPath?
//临时代理视图
privatevarplacheHolderCell:TDCPlaceHolderView?
//两触点的起始位置
privatevarsourcePoints:(upperPoint:CGPoint,downPoint:CGPoint)?
//可以插入操作的标志
privatevarpinchInsertEnabled=false

funchandlePinch(pinch:UIPinchGestureRecognizer){
switchpinch.state{
case.Began:
pinchBegan(pinch)
case.Changed:
pinchChanged(pinch)
default:
pinchEnd(pinch)
}
}

funcpinchBegan(pinch:UIPinchGestureRecognizer){
pinchIndexPath=nil
sourcePoints=nil
pinchInsertEnabled=false

let(upperPoint,downPoint)=pointsOfPinch(pinch)
ifletupperIndexPath=tableView.indexPathForRowAtPoint(upperPoint),letdownIndexPath=tableView.indexPathForRowAtPoint(downPoint){
ifdownIndexPath.row-upperIndexPath.row==1{
letupperCell=tableView.cellForRowAtIndexPath(upperIndexPath)!
letplacheHolder=NSBundle.mainBundle().loadNibNamed("TDCPlaceHolderView",owner:tableView,options:nil).firstas!TDCPlaceHolderView
placheHolder.frame=CGRectOffset(upperCell.frame,CGRectGetHeight(upperCell.frame)/2)
tableView.insertSubview(placheHolder,atIndex:0)

sourcePoints=(upperPoint,downPoint)
pinchIndexPath=upperIndexPath
placheHolderCell=placheHolder
}
}
}

funcpinchChanged(pinch:UIPinchGestureRecognizer){
ifletpinchIndexPath=pinchIndexPath,letoriginPoints=sourcePoints,letplacheHolderCell=placheHolderCell{
letpoints=pointsOfPinch(pinch)

letupperdistance=points.0.y-originPoints.upperPoint.y
letdowndistance=originPoints.downPoint.y-points.1.y
letdistance=-min(0,min(upperdistance,downdistance))
NSLog("distance=\(distance)")

//移动两边的Cell
forcellintableView.visibleCells{
letindexPath=tableView.indexPathForCell(cell)!
ifindexPath.row<=pinchIndexPath.row{
cell.transform=CGAffineTransformMakeTranslation(0,-distance)
}else{
cell.transform=CGAffineTransformMakeTranslation(0,distance)
}
}

//插入的Cell变形
letscaleY=min(64,fabs(distance)*2)/CGFloat(64)
placheHolderCell.transform=CGAffineTransformMakeScale(1,scaleY)

placheHolderCell.lblTitle.text=scaleY<=0.5?"张开双指插入新项目":"松手可以插入新项目"

//张开超过一个Cell高度时，执行插入操作
pinchInsertEnabled=scaleY>=1
}
}

funcpinchEnd(pinch:UIPinchGestureRecognizer){
ifletpinchIndexPath=pinchIndexPath,letplacheHolderCell=placheHolderCell{
placheHolderCell.transform=CGAffineTransformIdentity
placheHolderCell.removeFromSuperview()
self.placheHolderCell=nil

ifpinchInsertEnabled{
//恢复各Cell的transform
forcellinself.tableView.visibleCells{
cell.transform=CGAffineTransformIdentity
}

//插入操作
letindex=pinchIndexPath.row+1
items.insert(TDCTodoItem(text:""),atIndex:index)
tableView.reloadData()

//弹出键盘
letcell=tableView.cellForRowAtIndexPath(NSIndexPath(forRow:index,inSection:0))as!TDCTodoItemCell
cell.txtField.becomeFirstResponder()
}else{
//放弃插入，恢复原位置
UIView.animateWithDuration(0.25,delay:0,animations:{[uNownedself]()->Voidin
forcellinself.tableView.visibleCells{
cell.transform=CGAffineTransformIdentity
}
},completion:{[uNownedself](completed)->Voidin
self.tableView.reloadData()
})
}
}

sourcePoints=nil
pinchIndexPath=nil
pinchInsertEnabled=false
}

参考

1. https://github.com/ColinEberhardt/iOS-ClearStyle

2. http://blog.csdn.net/u013604612/article/details/43884039