IOS，UICollectionview

Question

IOS和目标C的新手，一直在做几个教程，添加按钮，textfields等在stackoverflow上看起来很有帮助:)现在我试图在一个框架内创建一个collectionview，然后在它下面放一个按钮。我可以得到一个按钮来显示，并且我已经定义集合的屏幕的上半部分变成黑色，而其余的部分变成白色，如预期的那样。目前收集应该拿出一个标签告诉我细胞的数量，所以非常基本。不知道我是否设置了错误的视图，或者我的CellView有什么问题。 我创建了一个MAINVIEW控制器，在那里我有我的定义按钮，集合视图，就像这样： MainViewController.h：

@interface MainViewController : UIViewController <UICollectionViewDataSource, UICollectionViewDelegateFlowLayout> 

@property(nonatomic, strong) IBOutlet UICollectionView *collectionView; 
@property(nonatomic, strong) IBOutlet UIButton *diaryButton; 

- (id)init; 

我的.m看起来是这样的：

@implementation MainViewController 
@synthesize collectionView; 
@synthesize diaryButton; 

- (id) init { 

self = [super init]; 
if (self) { 

    CGRect buttonFrame = CGRectMake(10, 250, 70, 30); 
    diaryButton = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
    [diaryButton setFrame:buttonFrame]; 
    [diaryButton setTitle:@"Diary" forState:UIControlStateNormal]; 

    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init]; 
    layout.itemSize = CGSizeMake(64.0, 64.0); 
    layout.minimumInteritemSpacing = 4; 
    layout.minimumLineSpacing = 4; 
    layout.scrollDirection = UICollectionViewScrollPositionCenteredVertically; 
    layout.sectionInset = UIEdgeInsetsMake(2.0, 2.0, 2.0, 2.0); 
    CGRect collectionFrame = CGRectMake(0, 0, 320, 200); 
    collectionView = [[UICollectionView alloc] initWithFrame:collectionFrame collectionViewLayout:layout]; 


    [self.view addSubview:collectionView]; 
    [self.view addSubview:diaryButton]; 
    //[self.view setBackgroundColor:[UIColor blueColor]]; 
} 
return self; 
} 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 
    // Do any additional setup after loading the view. 
    [self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"ID"]; 
} 


- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section 
{ 
    return 30; 
} 
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath 
{ 
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"ID" forIndexPath:indexPath]; 
    UILabel *label = [[UILabel alloc] initWithFrame:cell.bounds]; 
    label.textAlignment = NSTextAlignmentCenter; 
    label.text = [NSString stringWithFormat:@"%d", indexPath.row]; 
    [cell.contentView addSubview:label]; 
    return cell; 
} 
///////////////////////////////////////////////////////////////////////////////// 
// collection view delegate methods //////////////////////////////////////// 
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath 
{ 
    NSLog(@"cell #%d was selected", indexPath.row); 
} 

我的appdelegate外观像这样：

@synthesize mainVC; 

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    self.mainVC = [[MainViewController alloc] init]; 
    [self.window addSubview:mainVC.view]; 
    //self.window.rootViewController = mainVC; 
    // Override point for customization after application launch. 
    self.window.backgroundColor = [UIColor whiteColor]; 
    [self.window makeKeyAndVisible]; 
    return YES; 
} 

任何帮助将不胜感激。

Answer 1

我不知道为什么你的集合没有显示任何内容，但是你缺少来自UICollectionViewDataSource的numberOfSectionsInCollectionView：方法。该集合视图可能会假设部分的数量为0。

http://developer.apple.com/library/ios/#documentation/uikit/reference/UICollectionViewDataSource_protocol/Reference/Reference.html

另外，你设定的数据源和委托自我为您UICollectionView？