UICollectionView主要用于瀑布流，由于一直接触较少，每次需要使用的时候都从网上翻阅资料，此次自己总结整理，以备不时之需。
collectionView和tableView最大的不同之处就是需要自定义cell,所以第一步自定义collectionViewCell
.h文件
#import
@interface MyCollectionViewCell:UICollectionViewCell
@property(strong,nonatomic)UIImageView *topImage;
@property(strong,nonatomic)UILabel *botlabel;
@end
.m文件
#import"MyCollectionViewCell.h"
@implementationMyCollectionViewCell
- (id)initWithFrame:(CGRect)frame{
self= [superinitWithFrame:frame];
if(self) {
_topImage = [[UIImageViewalloc] initWithFrame:CGRectMake(10,0,70,70)];
_topImage.backgroundColor = [UIColorredColor];
[self.contentView addSubview:_topImage];
_botlabel = [[UILabelalloc] initWithFrame:CGRectMake(10,80,70,30)];
_botlabel.textAlignment =NSTextAlignmentCenter;
_botlabel.textColor = [UIColorblueColor];
_botlabel.font = [UIFontsystemFontOfSize:15];
_botlabel.backgroundColor = [UIColorpurpleColor];
[self.contentView addSubview:_botlabel];
}
returnself;
}
@end
在viewController中实现collectionView的三个协议
UICollectionViewDataSource,UICollectionViewDelegate,UICollectionViewDelegateFlowLayout
具体实例化步骤均在代码中有注释，如下
#import"CollectionViewController.h"
#import"MyCollectionViewCell.h"
@interfaceCollectionViewController(){
UICollectionView*mainCollectionView;
}
@end
@implementationCollectionViewController
- (void)viewDidLoad {
[superviewDidLoad];// Do any additional setup after loading the view.
self.view.backgroundColor = [UIColorwhiteColor];//1.初始化layoutUICollectionViewFlowLayout*layout = [[UICollectionViewFlowLayoutalloc] init];//设置collectionView滚动方向//
[layout setScrollDirection:UICollectionViewScrollDirectionHorizontal];
//设置headerView的尺寸大小
layout.headerReferenceSize =CGSizeMake(self.view.frame.size.width,100);
//该方法也可以设置itemSize
layout.itemSize =CGSizeMake(110,150);
//2.初始化
collectionViewmainCollectionView = [[UICollectionView alloc] initWithFrame:self.view.bounds collectionViewLayout:layout];
[self.view addSubview:mainCollectionView];
mainCollectionView.backgroundColor = [UIColorclearColor];
//3.注册collectionViewCell//注意，此处的ReuseIdentifier 必须和 cellForItemAtIndexPath 方法中 一致 均为 cellId
[mainCollectionView registerClass:[MyCollectionViewCellclass] forCellWithReuseIdentifier:@"cellId"];
//注册headerView 此处的ReuseIdentifier 必须和 cellForItemAtIndexPath 方法中 一致 均为reusableView
[mainCollectionView registerClass:[UICollectionReusableViewclass] forSupplementaryViewOfKind:UICollectionElementKindSectionHeaderwithReuseIdentifier:@"reusableView"];
//4.设置代理mainCollectionView.delegate =self;
mainCollectionView.dataSource =self;
}
#pragma mark collectionView代理方法//返回section个数
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView*)collectionView{
return3;
}
//每个section的item个数
- (NSInteger)collectionView:(UICollectionView*)collectionView numberOfItemsInSection:(NSInteger)section{
return9;
}
- (UICollectionViewCell*)collectionView:(UICollectionView*)collectionView cellForItemAtIndexPath:(NSIndexPath*)indexPath{
MyCollectionViewCell *cell = (MyCollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"cellId"forIndexPath:indexPath];
cell.botlabel.text = [NSStringstringWithFormat:@"{%ld,%ld}",(long)indexPath.section,(long)indexPath.row];
cell.backgroundColor = [UIColoryellowColor];
return cell;
}
//设置每个item的尺寸
- (CGSize)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath*)indexPath{
returnCGSizeMake(90,130);
}
//footer的size//
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section
//{
// return CGSizeMake(10, 10);
//}
//header的size
//- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section
//{
// return CGSizeMake(10, 10);
//}
//设置每个item的UIEdgeInsets
- (UIEdgeInsets)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{
returnUIEdgeInsetsMake(10,10,10,10);
}//设置每个item水平间距
- (CGFloat)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{
return10;
}//设置每个item垂直间距
- (CGFloat)collectionView:(UICollectionView*)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{
return15;
}
//通过设置SupplementaryViewOfKind 来设置头部或者底部的view，其中 ReuseIdentifier 的值必须和 注册是填写的一致，本例都为 “reusableView”- (UICollectionReusableView*)collectionView:(UICollectionView*)collectionView viewForSupplementaryElementOfKind:(NSString*)kind atIndexPath:(NSIndexPath*)indexPath{
UICollectionReusableView*headerView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeaderwithReuseIdentifier:@"reusableView"forIndexPath:indexPath]; headerView.backgroundColor =[UIColorgrayColor];UILabel*label = [[UILabelalloc] initWithFrame:headerView.bounds];
label.text =@"这是collectionView的头部";
label.font = [UIFontsystemFontOfSize:20];
[headerView addSubview:label];
return headerView;
}//点击item方法
- (void)collectionView:(UICollectionView*)collectionView didSelectItemAtIndexPath:(NSIndexPath*)indexPath{
MyCollectionViewCell *cell = (MyCollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
NSString*msg = cell.botlabel.text;NSLog(@"%@",msg);
}
- (void)didReceiveMemoryWarning {
[superdidReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/@end
完成以上两步，效果图如下：
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