我目前正致力于编写一个UICollectionViewController
以从服务器加载图像,并将图像置于UICollectionView
内的自定义UICollectionViewCells
中。为了让事情变得更简单比它已经是,我不拉从一个数据库中,我只是简单地创建存储在本地的图像阵列。它起作用,但由于某种原因,直到我开始滚动时,并非所有单元格都显示图像。开始使用UICollectionViewController以编程方式
继承人怎么回事的形象!
我已经阅读了关于几个教程,但它们都使用storyboard
...我想以编程写这个。
继承人一些代码:
AppDelegate.m
:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
JSMediaCollectionController *instagram = [[JSMediaCollectionController alloc] initWithCollectionViewLayout:[UICollectionViewFlowLayout new]];
instagram.datasource = self;
self.array = [NSMutableArray array];
for (int i = 0; i < 100; i++) {
[self.array addObject:@"instant_noodle_with_egg.jpg"];
}
UINavigationController *navCon = [[UINavigationController alloc] initWithRootViewController:instagram];
self.window.rootViewController = navCon;
[self.window makeKeyAndVisible];
return YES;
}
- (NSArray *)itemsToLoad
{
return [NSArray arrayWithArray:self.array];
}
JSMediaController.m
- (void)viewDidLoad {
[super viewDidLoad];
// Uncomment the following line to preserve selection between presentations
// self.clearsSelectionOnViewWillAppear = NO;
// Register cell classes
[self.collectionView registerClass:[JSMediaCollectionCell class] forCellWithReuseIdentifier:reuseIdentifier];
self.showOneItemPerRow = false;
// Do any additional setup after loading the view.
}
#pragma mark <UICollectionViewDataSource>
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return [[self.datasource itemsToLoad] count];
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
JSMediaCollectionCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:reuseIdentifier forIndexPath:indexPath];
[cell setImage:[UIImage imageNamed:[[self.datasource itemsToLoad] objectAtIndex:indexPath.row]]];
cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"photo-frame.png"]];
return cell;
}
...
...
JSMediaCell.m
:
@interface JSMediaCollectionCell()
@property (nonatomic) UIImageView *view;
@end
@implementation JSMediaCollectionCell
- (id)initWithFrame:(CGRect)frame
{
if (!(self = [super initWithFrame:frame])) return nil;
self.view = [[UIImageView alloc] initWithFrame:self.frame];
[self.viewForBaselineLayout addSubview:self.view];
return self;
}
- (void)setImage:(UIImage *)image
{
self.view.image = image;
}
我非常感谢任何人的帮助,让我在正确的轨道上......正如一个提醒。 ..当我开始滚动,图像被重新加载,但不是所有的细胞在subview
加载图像...只是一些。
您不应该在setImage中添加子视图。当单元格被重用时,您将为已经具有图像视图的单元添加图像视图。最好在init方法中设置子视图。 – rdelmar 2014-12-04 05:36:28
酷酷...感谢您的建议。我做了 – jsetting32 2014-12-04 05:39:07
你应该把你的观点财产.h文件更新,所以你可以cell.view访问它的cellForRowAtIndexPath。没有理由重写setImage。 – rdelmar 2014-12-04 05:40:52