UICollectionView的使用

標籤：uiviewcontroller   uicollectionviewflow   uiedgeinsetsmake   

ViewController.h

#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];        UICollectionViewFlowLayout *flowLayout=[[UICollectionViewFlowLayout alloc] init];    [flowLayout setScrollDirection:UICollectionViewScrollDirectionVertical];        self.collectionView=[[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, 320, 240) collectionViewLayout:flowLayout];    self.collectionView.dataSource=self;    self.collectionView.delegate=self;    [self.collectionView setBackgroundColor:[UIColor grayColor]];        [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"UICollectionViewCell"];    [self.view addSubview:self.collectionView];}#pragma mark -- UICollectionViewDataSource//定義展示的UICollectionViewCell的個數-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{    return 10;}//定義展示的Section的個數-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{    return 2;}//每個UICollectionView展示的內容-(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//定義每個Item 的大小- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{    return CGSizeMake(80, 80);}//定義每個UICollectionView 的 margin-(UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{    return UIEdgeInsetsMake(5, 5, 5, 5);}#pragma mark --UICollectionViewDelegate//UICollectionView被選中時調用的方法-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{    UICollectionViewCell * cell = (UICollectionViewCell *)[collectionView cellForItemAtIndexPath:indexPath];    cell.backgroundColor = [UIColor whiteColor];}//返回這個UICollectionView是否可以被選擇-(BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath{    return YES;}@end