我正在尝试在我的视图控制器中设置UICollectionView
以编程方式扩展UIViewController
。出于某种原因,我的集合视图根本没有出现。以下是我所拥有的。
为什么不出现?我将它连接到委托和数据源,并将其作为子视图添加到self.view
。我的代码中缺少什么?
在我的.h
文件中
@interface MainViewController : UIViewController
{
@private
UICollectionView *_collectionView;
NSMutableArray *_results; // data source array
}
@end
在我的.m
文件中
@interface MainViewController () <UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>
@property (nonatomic, retain) UICollectionView *collectionView;
@property (nonatomic, retain) NSMutableArray *results;
@end
@implementation MainViewController
@synthesize collectionView = _collectionView;
@synthesize results = _results;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// some init stuff - nothing to do with collection view.
}
return self;
}
- (void)loadView
{
self.results = [NSMutableArray array];
UIImage *image1 = [UIImage imageNamed:@"img1.jpg"];
UIImage *image2 = [UIImage imageNamed:@"img2.jpg"];
[self.results addObject:image1];
[self.results addObject:image2];
self.collectionView.dataSource = self;
self.collectionView.delegate = self;
UICollectionViewFlowLayout *flowLayout = [[UICollectionViewFlowLayout alloc] init];
UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height) collectionViewLayout:flowLayout];
self.collectionView = collectionView;
[self.view addSubview:self.collectionView];
[self.collectionView registerClass:[UICollectionViewCell class] forCellWithReuseIdentifier:@"Cell"];
[self.collectionView reloadData];
}
- (NSInteger)collectionView:(UICollectionView *)view numberOfItemsInSection:(NSInteger)section
{
return [self.results count];
}
- (NSInteger)numberOfSectionsInCollectionView: (UICollectionView *)collectionView
{
return 1;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
cell.backgroundColor = [UIColor colorWithPatternImage:[self.results objectAtIndex:indexPath.row]];
return cell;
}
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
UIImage *image = [self.results objectAtIndex:indexPath.row];
return CGSizeMake(image.size.width, image.size.height);
}
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
return UIEdgeInsetsMake(50, 20, 50, 20);
}
答案 0 :(得分:3)
我尝试运行代码时遇到错误,除非我将loadView方法更改为viewDidLoad - 根据您不应该直接调用loadView的文档。要获取要运行的数据源和委托方法,我将设置委托和数据源的行移动到您设置self.collectionView = collectionView
的下方的self。 self.collectionView = collectionView;
self.collectionView.dataSource = self;
self.collectionView.delegate = self;
答案 1 :(得分:0)
您的numberOfSectionsInCollectionView:
返回0
。对于包含一个部分的集合视图,您应该返回1
或者不执行此方法。
此外,我无法看到你在哪里分配/初始化self.collectionView
。
答案 2 :(得分:0)
我最终继承了UICollectionViewController而不是UIViewController
,并将init方法更改为:
- (id)initWithCollectionViewLayout:(UICollectionViewLayout *)layout
并且有效。
答案 3 :(得分:0)
您只需要将您的CollectionView委托和dataSource绑定到StoryBoard中的ViewController。enter image description here