IOS，UICollectionview

Question

IOS和目標C的新手，一直在做幾個教程，添加按鈕，textfields等在stackoverflow上看起來很有幫助:)現在我試圖在一個框架內創建一個collectionview，然後在它下面放一個按鈕。我可以得到一個按鈕來顯示，並且我已經定義集合的屏幕的上半部分變成黑色，而其餘的部分變成白色，如預期的那樣。目前收集應該拿出一個標籤告訴我細胞的數量，所以非常基本。不知道我是否設置了錯誤的視圖，或者我的CellView有什麼問題。 我創建了一個MAINVIEW控制器，在那裏我有我的定義按鈕，集合視圖，就像這樣： MainViewController.h：

@interface MainViewController : UIViewController <UICollectionViewDataSource, UICollectionViewDelegateFlowLayout> 

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

- (id)init; 

我的.m看起來是這樣的：

@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外觀像這樣：

@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; 
} 

任何幫助將不勝感激。

Answer 1

我不知道爲什麼你的集合沒有顯示任何內容，但是你缺少來自UICollectionViewDataSource的numberOfSectionsInCollectionView：方法。該集合視圖可能會假設部分的數量爲0。

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

另外，你設定的數據源和委託自我爲您UICollectionView？