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UICollectionView 的使用详解

sanshao 2018年06月24日 手机开发 562 0
 
 
#import <UIKit/UIKit.h> 
 
@interface ViewController : UIViewController<UICollectionViewDataSource,UICollectionViewDelegateFlowLayout>{ 
 
} 
@property (strong, nonatomic)UICollectionView *collectionView; 
 
@end 
 
ViewController.m 
 
#import "ViewController.h" 
 
@interface ViewController () 
 
@end 
 
@implementation ViewController 
 
- (void)viewDidLoad 
{ 
  [super viewDidLoad]; 
   
  //确定是水平滚动,还是垂直滚动 
  UICollectionViewFlowLayout *flowLayout=[[UICollectionViewFlowLayout alloc] init]; 
  [flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical]; 
   
  self.collectionView=[[UICollectionView alloc] initWithFrame:CGRectMake(0, 64, 320, 200) collectionViewLayout:flowLayout]; 
  self.collectionView.dataSource=self; 
  self.collectionView.delegate=self; 
  [self.collectionView setBackgroundColor:[UIColor clearColor]]; 
   
  //注册Cell,必须要有 
  [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"UICollectionViewCell"]; 
   
  [self.view addSubview:self.collectionView]; 
} 
 
 
#pragma mark -- UICollectionViewDataSource 
 
//定义展示的UICollectionViewCell的个数 
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section 
{ 
  return 10; 
} 
 
//定义展示的Section的个数 
-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView 
{ 
  return 2; 
} 
 
//每个UICollectionView展示的内容 
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath 
{ 
  static NSString * CellIdentifier = @"UICollectionViewCell"; 
  UICollectionViewCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:CellIdentifier forIndexPath:indexPath]; 
   
  cell.backgroundColor = [UIColor colorWithRed:((10 * indexPath.row) / 255.0) green:((20 * indexPath.row)/255.0) blue:((30 * indexPath.row)/255.0) alpha:1.0f]; 
  UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 20, 20)]; 
  label.textColor = [UIColor redColor]; 
  label.text = [NSString stringWithFormat:@"%d",indexPath.row]; 
  
  for (id subView in cell.contentView.subviews) { 
    [subView removeFromSuperview]; 
  } 
  [cell.contentView addSubview:label]; 
  return cell; 
} 
 
#pragma mark --UICollectionViewDelegateFlowLayout 
 
//定义每个Item 的大小 
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath 
{ 
  return CGSizeMake(60, 60); 
} 
 
//定义每个UICollectionView 的 margin 
-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section 
{ 
  return UIEdgeInsetsMake(5, 5, 5, 5); 
} 
 
#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]; 
  //临时改变个颜色,看好,只是临时改变的。如果要永久改变,可以先改数据源,然后在cellForItemAtIndexPath中控制。(和UITableView差不多吧!O(∩_∩)O~) 
  cell.backgroundColor = [UIColor greenColor]; 
  NSLog(@"item======%d",indexPath.item); 
  NSLog(@"row=======%d",indexPath.row); 
  NSLog(@"section===%d",indexPath.section); 
} 
 
//返回这个UICollectionView是否可以被选择 
-(BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath 
{ 
  return YES; 
} 
 
@end 
 

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