UICollectionView未显示 [英] UICollectionView Not Appearing
问题描述
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。
I am trying to set up UICollectionView
programatically in my view controller which extends UIViewController
. For some reason, my collection view is not showing up at all. Below is what I have.
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?
Why is it not appearing? I am hooking it up to the delegate and data source and adding it as a subview to self.view
. What's missing in my code?
在我的 .h
文件中:
In my .h
file:
@interface MainViewController : UIViewController
{
@private
UICollectionView *_collectionView;
NSMutableArray *_results; // data source array
}
@end
在我的 .m
file:
In my .m
file:
@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);
}
推荐答案
我在尝试运行时遇到错误你的代码,除非我将loadView方法更改为viewDidLoad - 根据你不应该直接调用loadView的文档。为了运行数据源和委托方法,我将设置委托和数据源的行移动到你设置self.collectionView = collectionView
I got errors trying to run your code unless I changed the loadView method to viewDidLoad -- according to the docs you're not supposed to directly call loadView. To get the data source and delegate methods to run, I moved the lines setting the delegate and data source to self below where you set self.collectionView = collectionView
self.collectionView = collectionView;
self.collectionView.dataSource = self;
self.collectionView.delegate = self;
这篇关于UICollectionView未显示的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!