Swift Simple waterfall Flow implementation _swift

1.viewcontroller Setting CollectionView layout information

Import Uikit

Import Sdwebimage

Import Mjrefresh

Class Yfwaterfallviewcontroller:uiviewcontroller,uicollectionviewdatasource,uicollectionviewdelegate, uicollectionviewdelegateflowlayout,yfwaterfalllayoutdelegate {

Let Cellid = "Waterid"

var datalists =array<yfvideoinfo> ()

var collectionview:uicollectionview!

Let header =mjrefreshnormalheader ()//Top Refresh

Let footer =mjrefreshautonormalfooter ()//Bottom Refresh

Overridefunc Viewdidload () {

Super.viewdidload ()

Self.view.backgroundColor =uicolor.whitecolor ()

Self.navigationItem.title = "Waterfall Flow"

Let Layout:yfwaterfallcollectionlayout =yfwaterfallcollectionlayout ()

Layout.delegate =self

Self.collectionview =uicollectionview (Frame:cgrectmake (0,0,screenwidth,screenheight), CollectionViewLayout: Layout

Collectionview.datasource =self

Collectionview.backgroundcolor =uicolor.lightgraycolor ()

Collectionview.registerclass (yfwaterfallcollectionviewcell.self, Forcellwithreuseidentifier:cellid)

Header.setrefreshingtarget (Self, refreshingaction: #selector (Yfwaterfallviewcontroller.headerrefresh))

Collectionview.mj_header =header

Footer.setrefreshingtarget (Self, refreshingaction: #selector (Yfwaterfallviewcontroller.footerrefresh))

Collectionview.mj_footer =footer

Self.view.addSubview (CollectionView)

Self.loaddata ()

}

Func Headerrefresh () {

Self.datalists = [Yfvideoinfo] ()

Self.loaddata ()

}

Func Footerrefresh () {

Self.loaddata ()

}

Data loading process

Func LoadData () {

var params:dictionary<string,string> = [:]

params["Sign"] =swsign

Yfhttptool.post ("http://...", Parameters:params, Success: {(operation, responseobject) in

Yfalertview.hidehud (Self.view)

If Responseobject? Objectforkey ("status") as! NSNumber ==1 {

Let Tmparray:nsarray = responseobject!. Objectforkey ("info") as! Nsarray

For Dictin Tmparray {

Let Model:yfvideoinfo =yfvideoinfo.ljbobjectwithdict (dictas! Dictionary)

Let sizedict = Dict.objectforkey ("Imgsize")

MODEL.W = sizedict!. Objectforkey ("width") as? NSNumber

Model.h = sizedict!. Objectforkey ("height") as? NSNumber

Self.dataLists.append (model)

}

Self.collectionView.reloadData ()

Self.collectionView.mj_header.endRefreshing ()

Self.collectionView.mj_footer.endRefreshing ()

} else {

Yfalertview.showerrortext ("Query failed!", View:self.view)

}

}) {(operation, error) in

Print ("Error:\ (Error)")

Yfalertview.hidehud (Self.view)

Yfalertview.showerrortext ("Network connection Exception!", View:self.view)

}

}

CollectionView Data Source Settings

Func CollectionView (Collectionview:uicollectionview, numberofitemsinsection section:int)-> Int {

Returnself.dataLists.count

}

Give the layout height, according to the proportional calculation

Func CollectionView (Collectionview:uicollectionview, Cellforitematindexpath Indexpath:nsindexpath)-> Uicollectionviewcell {

Let Cell:yfwaterfallcollectionviewcell = Collectionview.dequeuereusablecellwithreuseidentifier (Self.cellID, Forindexpath:indexpath) as! Yfwaterfallcollectionviewcell

Cell.model =self.datalists[indexpath.row]

return cell

}

Layout Agent

Func waterfalllayout (Layout:uicollectionviewflowlayout, Index:nsinteger, width:cgfloat)-> CGFloat {

Let Model:yfvideoinfo =self.datalists[index]

Return width/(cgfloat (MODEL.W?). Floatvalue)! /CGFloat (model.h?. Floatvalue))

}

Func columncountofwaterfalllayout (layout:uicollectionviewflowlayout)->nsinteger {

Return2

}

Overridefunc didreceivememorywarning () {

Super.didreceivememorywarning ()

}

}

2.cell set, layoutsubviews to prevent dislocation

Import Uikit

Class Yfwaterfallcollectionviewcell:uicollectionviewcell {

Initialize item data when data is assigned

var model:yfvideoinfo? {

Didset {

Let URL =nsurl (string: "Http://xxx.xxx.cn\" (model!). Videoimgurl) ")

Self.imageView.sd_setImageWithURL (URL)

}

}

Let Imageview:uiimageview =uiimageview ()

Overrideinit (Frame:cgrect) {

Super.init (Frame:frame)

Self.imageView.frame =cgrectmake (0,0, Frame.size.width, Frame.size.height)

Self.addsubview (Self.imageview)

}

Requiredinit? (Coder Adecoder:nscoder) {

FatalError ("Init (coder:) has not been implemented")

}

Re-layout, or two times refresh due to cell reuse causes dislocation

Overridefunc Layoutsubviews () {

Super.layoutsubviews ()

Self.imageView.frame =cgrectmake (0,0,self.frame.size.width,self.frame.size.height)

}

}

3. Custom Uicollectionviewflowlayout Class

Import Uikit

Protocol Yfwaterfalllayoutdelegate {

Returns the height of item at index position

Func waterfalllayout (layout:uicollectionviewflowlayout,index:nsinteger,width:cgfloat)->CGFloat

Returns the number of columns displayed by the waterfall stream

Func columncountofwaterfalllayout (layout:uicollectionviewflowlayout)->nsinteger

}

Class Yfwaterfallcollectionlayout:uicollectionviewflowlayout {

var delegate:yfwaterfalllayoutdelegate?

var attributesarray = [Uicollectionviewlayoutattributes]//Layout information store to prevent the Drop-down from seeing two of times, returning layout information multiple times.

var columnheights =array<float> ()//stores the height information for the column in the current row.

var columncount:int =2//default number of columns

var edgeinsets:uiedgeinsets =uiedgeinsets (Top:5, Left:5, Bottom:5, Right:5)

var columnmargin:cgfloat =5//column Spacing

var rowmargin:cgfloat =5//Line Spacing

Overridefunc Preparelayout () {

Super.preparelayout ()

Initializing the maximum height data collection

Columnheights =array<float> ()

Self.columncount = (self.delegate?) Columncountofwaterfalllayout (self))!

Ifself.columncount <=0 {

Return

}

For_in0.. <columncount {

Columnheights.append (Float (self.edgeInsets.top))

}

Initializing the layout information data source

Attributesarray = [Uicollectionviewlayoutattributes] ()

Let Cellcount =self.collectionview!. Numberofitemsinsection (0)

For Iin0.. <cellcount {

Let Indexpath = Nsindexpath (foritem:i, insection:0)

Let attributes =self.layoutattributesforitematindexpath (Indexpath)

Attributesarray.append (attributes!)

}

}

All cell Position Properties

Overridefunc Layoutattributesforelementsinrect (Rect:cgrect)

-> [Uicollectionviewlayoutattributes]? {

Returnself.attributesarray

}

This method returns the position and size of each cell

Overridefunc Layoutattributesforitematindexpath (indexpath:nsindexpath)-> uicollectionviewlayoutattributes? {

Let attribute =uicollectionviewlayoutattributes (Forcellwithindexpath:indexpath)

Let Collectionviewwidth:cgfloat =self.collectionview!. Frame.size.width

Let Width:cgfloat = (Collectionviewwidth-self.edgeinsets.left-self.edgeinsets.right-(CGFloat (Self.columnCount)-1) * self.columnmargin)/cgfloat (Self.columncount);

Calculates the current item should be placed in the first column (calculate which column height is the shortest)

var mincolumn:int =0//default is the No. 0 column

var minheight:float =maxfloat

Traverse to find the smallest height of the column, added below the smallest column.

for (Index,value) inself.columnHeights.enumerate () {

If MinHeight > value {

MinHeight = value

Mincolumn = Index

}

}

Let X:cgfloat =self.edgeinsets.left +cgfloat (mincolumn) * (width +self.columnmargin)

Let Y:cgfloat =cgfloat (minheight) +self.rowmargin

Let Height:cgfloat = (self.delegate?.) Waterfalllayout (self, Index:indexPath.row, width:width))!

Attribute.frame =cgrectmake (x, y, width, height)

Update the height of the shortest column in the array

Self.columnheights[mincolumn] =float (y + height)

return attribute

}

&nbs