首先在viewcontroller 中创建collectionView;自定义一个类继承自UICollectionViewFlowLayout代码实现如下;
```Object-C
viewController .m
//
//ViewController.m
//MYCollectionView
//
//Created by dqk on 16/9/2.
//Copyright © 2016年dqk. All rights reserved.
//
#import"ViewController.h"
#import"MYLayout.h"
#import"CollectionViewCell.h"
#define kScreenWidth [UIScreen mainScreen].bounds.size.width
#define kScreenHeight [UIScreen mainScreen].bounds.size.height
@interfaceViewController()
@property(nonatomic,strong)NSMutableArray*arry;
@end
staticNSString*constcellresure =@"cell";
@implementationViewController
-(NSMutableArray*)arry
{
if(_arry==nil)
{
_arry=[[NSMutableArrayalloc]init];
}
return_arry;
}
```Object-C
- (void)viewDidLoad {
[superviewDidLoad];
//测试数据,后期可以根据服务器返回的数据自己设置
_arry=[NSMutableArrayarrayWithObjects:@"100",@"50",@"500",@"30",@"45",@"200",@"70",@"130",@"100",@"50",@"500",@"30",@"45",@"200",@"70",@"130",@"100",@"50",@"500",@"30",@"45",@"200",@"70",@"130",@"100",@"50",@"500",@"30",@"45",@"200",@"70",@"130",@"100",@"50",@"500",@"30",@"45",@"200",@"70",@"130",@"100",@"50",@"500",@"30",@"45",@"200",@"70",@"130",nil];
self.view.backgroundColor=[UIColorwhiteColor];
MYLayout*layout =[[MYLayoutalloc]init];
layout.delegate=self;
//layout.colCount=2;
//
//layout.delegate=self;
UICollectionView*collection =[[UICollectionViewalloc]initWithFrame:self.view.boundscollectionViewLayout:layout];
collection.delegate=self;
collection.dataSource=self;
collection.backgroundColor=[UIColorwhiteColor];
[collectionregisterClass:[UICollectionViewCellclass]forCellWithReuseIdentifier:cellresure];
[self.viewaddSubview:collection];
// Do any additional setup after loading the view, typically from a nib.
}
```
```Object
-C-(NSInteger)collectionView:(UICollectionView*)collectionView numberOfItemsInSection:(NSInteger)section
{
return_arry.count;
}
```
-(UICollectionViewCell*)collectionView:(UICollectionView*)collectionView cellForItemAtIndexPath:(NSIndexPath*)indexPath
{
UICollectionViewCell*cell =[collectionViewdequeueReusableCellWithReuseIdentifier:cellresureforIndexPath:indexPath];
cell.backgroundColor=[UIColorredColor];
UILabel*lal =(UILabel*)[cell.contentViewviewWithTag:100];
if(lal==nil)
{
lal =[[UILabelalloc]init];
lal.tag=100;
[cell.contentViewaddSubview:lal];
}
lal.text=[NSStringstringWithFormat:@"%ld",(long)indexPath.row];
[lalsizeToFit];
returncell;
}
- (CGFloat)waterflowLayout:(MYLayout*)waterflowLayout heightForWidth:(CGFloat)width atIndexPath:(NSIndexPath*)indexPath
{
CGFloatheight =[self.arry[indexPath.row]floatValue];
returnheight;
}
-(NSInteger)waterFlowLayoutColumnCount:(MYLayout*)layout
{
return3;
}
-(CGFloat)waterFlowLayoutColumnSpacing:(MYLayout*)layout
{
return10;
}
-(CGFloat)waterFlowLayoutRowSpacing:(MYLayout*)layout
{
return10;
}
-(UIEdgeInsets)waterFlowLayoutEdgeInsets:(MYLayout*)layout
{
returnUIEdgeInsetsMake(20,20,20,20);
}
//
- (void)didReceiveMemoryWarning {
[superdidReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
自定义的类MYLayout.h
#import
@classMYLayout;
@protocolMYLayoutDelegate
//此方法必须实现,设置每个item的高度
- (CGFloat)waterflowLayout:(MYLayout*)waterflowLayout heightForWidth:(CGFloat)width atIndexPath:(NSIndexPath*)indexPath;
@optional
//设置collectionView有几列,如果不设置默认是3列
-(NSInteger)waterFlowLayoutColumnCount:(MYLayout*)layout;
//设置每个item的列间距,如果不设置默认10
-(CGFloat)waterFlowLayoutColumnSpacing:(MYLayout*)layout;
//设置每个item的行间距,如果不设置默认10
-(CGFloat)waterFlowLayoutRowSpacing:(MYLayout*)layout;
//设置item距离屏幕上下左右的距离,默认是上下左右都是10;
-(UIEdgeInsets)waterFlowLayoutEdgeInsets:(MYLayout*)layout;
@end
@interfaceMYLayout :UICollectionViewFlowLayout
@property(assign,nonatomic)iddelegate;
@end
自定义的类MYLayout.m
#import"MYLayout.h"
staticNSIntegerconstdefaultColumnCount =3;
staticCGFloatconstdefaucolumspacesing =10;
staticCGFloatconstdedaultRowsping =10;
staticUIEdgeInsetsconstdefaultEdgeInsets = {10,10,10,10};
@interfaceMYLayout();
@property(nonatomic,strong) NSMutableArray * attrArray;
@property(nonatomic,strong) NSMutableArray *maxYArray;
-(NSInteger)columnCount;
-(CGFloat)columSpacing;
-(CGFloat)rowSpacing;
-(UIEdgeInsets)edgeInsets;
@end
@implementationMYLayout
-(NSMutableArray *)attrArray
{
if(_attrArray==nil)
{
_attrArray=[NSMutableArray array];
}
return_attrArray;
}
-(NSMutableArray *)maxYArray
{
if(_maxYArray ==nil)
{
_maxYArray =[NSMutableArray array];
}
return_maxYArray;
}
-(NSInteger)columnCount
{
if([self.delegate respondsToSelector:@selector(waterFlowLayoutColumnCount:)]) {
return[self.delegate waterFlowLayoutColumnCount:self];
}
returndefaultColumnCount;
}
-(CGFloat)columSpacing
{
{
if([self.delegate respondsToSelector:@selector(waterFlowLayoutColumnSpacing:)]) {
return[self.delegate waterFlowLayoutColumnSpacing:self];
}
returndefaucolumspacesing;
}
}
-(CGFloat)rowSpacing
{
{
if([self.delegate respondsToSelector:@selector(waterFlowLayoutRowSpacing:)]) {
return[self.delegate waterFlowLayoutRowSpacing:self];
}
returndedaultRowsping;
}
}
-(UIEdgeInsets)edgeInsets
{
{
if([self.delegate respondsToSelector:@selector(waterFlowLayoutEdgeInsets:)]) {
return[self.delegate waterFlowLayoutEdgeInsets:self];
}
returndefaultEdgeInsets;
}
}
-(void)prepareLayout
{
[superprepareLayout];
[self.attrArray removeAllObjects];
[self.maxYArray removeAllObjects];
for(inti =0; i <[selfcolumnCount]; i ++)
{
[self.maxYArray addObject:@([selfedgeInsets].top)];
}
NSInteger itemCount =[self.collectionView numberOfItemsInSection:0];
for(inti =0; i
{
NSIndexPath *indepath =[NSIndexPath indexPathForRow:i inSection:0];
[self.attrArray addObject:[selflayoutAttributesForItemAtIndexPath:indepath ]];
}
}
-(NSArray *)layoutAttributesForElementsInRect:(CGRect)rect
{
returnself.attrArray;
}
-(UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewLayoutAttributes*attabuest =[UICollectionViewLayoutAttributeslayoutAttributesForCellWithIndexPath:indexPath];
NSInteger__blockminHegihtColumn =0;
NSInteger__blockminheight = [self.maxYArray[minHegihtColumn]floatValue];
[self.maxYArrayenumerateObjectsUsingBlock:^(id_Nonnullobj,NSUIntegeridx,BOOL*_Nonnullstop) {
CGFloatcolumnHeight = [(NSNumber*)objfloatValue];
if(minheight>columnHeight)
{
minheight =columnHeight;
minHegihtColumn=idx;
}
}];
UIEdgeInsetsedgeInsets =[selfedgeInsets];
CGFloatwidth =(CGRectGetWidth(self.collectionView.frame)-edgeInsets.left-edgeInsets.right-[selfcolumSpacing]*([selfcolumnCount]-1))/[selfcolumnCount];
CGFloatheight = [self.delegatewaterflowLayout:selfheightForWidth:widthatIndexPath:indexPath];
CGFloatorginX =edgeInsets.left +minHegihtColumn *(width +[selfcolumSpacing]);
CGFloat orginY = minheight;
if(orginY != edgeInsets.top)
{
orginY +=[selfrowSpacing];
}
attabuest.frame =CGRectMake(orginX,orginY,width,height);
self.maxYArray[minHegihtColumn]=@(CGRectGetMaxY(attabuest.frame));
returnattabuest;
}
-(CGSize)collectionViewContentSize
{
NSInteger__blockmaxheight =0;
[self.maxYArray enumerateObjectsUsingBlock:^(id_Nonnullobj, NSUInteger idx,BOOL*_Nonnullstop) {
CGFloat columnHeight = [(NSNumber *)obj floatValue];
if(maxheight
{
maxheight =columnHeight;
}
}];
returnCGSizeMake(0, maxheight +[selfedgeInsets].bottom);
}
@end
```Object-C
到此瀑布流已经实现
