UICollectionView基本使用
学习iOS一段时间了，早听说了UICollectionView的强大一直没有机会使用，今天自己研究了一下。
UICollectonView类似UITableView 用法基本相似， UICollectionView 更灵活，更强大
UICollectonView 将其子视图的位置，大小和外观的控制权委托给一个单独的布局对象。通过提供一个自定义布局对象，你几乎可以实现任何你能想象到得布局。
下面是UICollectionView 常用的代理方法。
//定义展示的UICollectionViewCell的个数
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return ;
}
//定义展示的Section的个数
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return ;
}-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
static NSString * CellIdentifier = @"CollectionCell"; CollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];
cell.imageView.image = [UIImage imageNamed:@"1680_1050_3983.jpg"];
// [cell sizeToFit];
return cell;
}#pragma mark --UICollectionViewDelegateFlowLayout
//定义每个UICollectionView 的大小
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
return CGSizeMake(, );
}
//定义每个UICollectionView 的 margin
-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
return UIEdgeInsetsMake(, , , );
}#pragma mark --UICollectionViewDelegate
//UICollectionView被选中时调用的方法
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell * cell = (UICollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
cell.backgroundColor = [UIColor whiteColor];
}
//返回这个UICollectionView是否可以被选择
-(BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
return YES;
}
下面给出一个实例
首先自定义一个UICollectionViewCell
#import <UIKit/UIKit.h>@interface CollectionViewCell : UICollectionViewCell@property (nonatomic, strong) UIImageView *imageView;
@property (nonatomic, strong) UILabel *titleLabel;@end#import "CollectionViewCell.h"@interface CollectionViewCell()@end@implementation CollectionViewCell- (instancetype)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
self.backgroundColor = [UIColor purpleColor];
[self createView];
}
return self;
}- (UIImageView *)imageView {
if (_imageView == nil) {
CGRect frame = CGRectMake(, , , );
_imageView = [[UIImageView alloc] initWithFrame:frame];
}
return _imageView;
}- (UILabel *)titleLabel {
if (_titleLabel == nil) {
CGRect frame = CGRectMake(, , , );
_titleLabel = [[UILabel alloc] initWithFrame:frame];
_titleLabel.textAlignment = NSTextAlignmentCenter;
}
return _titleLabel;
}- (void)createView {
[self.contentView addSubview:self.imageView];
[self.contentView addSubview:self.titleLabel];
}@end
在控制器里设置代理
UICollectionView 初始化是一定要指定布局对象
#import <UIKit/UIKit.h>@interface ViewController : UIViewController@end//
// ViewController.m
// CollectionViewController
//
// Created by chao on 15/8/3.
// Copyright (c) 2015年 chao. All rights reserved.
//#import "ViewController.h"
#import "CollectionViewCell.h"@interface ViewController ()<UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout>@property (nonatomic, strong) UICollectionView *collectionView;@end@implementation ViewController- (UICollectionView *)collectionView {
if (_collectionView == nil) {
CGRect frame = CGRectMake(, , [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height);
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
_collectionView = [[UICollectionView alloc] initWithFrame:frame collectionViewLayout:flowLayout];
_collectionView.dataSource = self;
_collectionView.delegate = self;
}
return _collectionView;
}- (void)viewDidLoad {
[super viewDidLoad];
[self.collectionView registerClass:[CollectionViewCell class] forCellWithReuseIdentifier:@"CollectionCell"];
[self.view addSubview:self.collectionView];
// Do any additional setup after loading the view, typically from a nib.
}- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}//定义展示的UICollectionViewCell的个数
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return ;
}
//定义展示的Section的个数
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return ;
}
//每个UICollectionView展示的内容
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
static NSString * CellIdentifier = @"CollectionCell"; CollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath];
cell.imageView.image = [UIImage imageNamed:@"1680_1050_3983.jpg"];
cell.titleLabel.text = [NSString stringWithFormat:@"%ld", indexPath.row];
// [cell sizeToFit];
return cell;
}#pragma mark --UICollectionViewDelegateFlowLayout
//定义每个UICollectionView 的大小
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
return CGSizeMake(, );
}
//定义每个UICollectionView 的 margin
-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section
{
return UIEdgeInsetsMake(, , , );
}
#pragma mark --UICollectionViewDelegate
//UICollectionView被选中时调用的方法
-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell * cell = (UICollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
cell.backgroundColor = [UIColor whiteColor];
}
//返回这个UICollectionView是否可以被选择
-(BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
return YES;
}@end
//
// AppDelegate.h
// CollectionViewController
//
// Created by chao on 15/8/3.
// Copyright (c) 2015年 chao. All rights reserved.
//#import <UIKit/UIKit.h>@interface AppDelegate : UIResponder <UIApplicationDelegate>@property (strong, nonatomic) UIWindow *window;@end
#import "AppDelegate.h"
#import "ViewController.h"@interface AppDelegate ()@end@implementation AppDelegate- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
ViewController *vc = [[ViewController alloc] init];
self.window.rootViewController = vc;
[self.window makeKeyAndVisible];
return YES;
}@end
