我有一个带有UIView的自定义UICollectionView。
在屏幕旋转时，我试图使UICollectionView延伸到屏幕上，然后重绘其单元格。
下载数据后，我同时尝试了[grid setNeedsLayout]和[grid setNeedsDisplay]，但是那没有用。
这就是我想发生的事情：
肖像
景观
（这也是当应用在横向模式下启动时的外观，但如果更改为纵向模式，则不会更新。）
但这就是我以Portrait模式启动并切换到Landscape时得到的。
我正在以编程方式创建这些视图。我没有使用任何情节提要。
我试过了：
-(void)viewDidLayoutSubviews {
grid = [[MyThumbnailGridView alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height/2, self.view.frame.size.width, self.view.frame.size.height/2)];
}
我也尝试过玩：
- (void) viewWillLayoutSubviews {
UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];
if (UIInterfaceOrientationIsLandscape(interfaceOrientation))
{
//LANDSCAPE
if(grid){
NSLog(@"Grid Needs Landscape Layout");
grid.frame =CGRectMake(0, self.view.frame.size.height/2, self.view.frame.size.width, self.view.frame.size.height/2);
[grid refreshData];
}
}else {
//PORTRIAT
if(grid){
NSLog(@"Grid Needs Portrait Layout");
grid.frame =CGRectMake(0, self.view.frame.size.height/2, self.view.frame.size.width, self.view.frame.size.height/2);
[grid refreshData];
}
}
}
但是我无法伸展它。
有什么帮助吗？
MyThumbnailGridView
@interface ViewController () <UINavigationControllerDelegate> {
MyThumbnailGridView *grid;
NSMutableArray * arrImages;
}
- (void)viewDidLoad {
[super viewDidLoad];
arrImages = [NSMutableArray new];
grid = [[MyThumbnailGridView alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height/2, self.view.frame.size.width, self.view.frame.size.height/2)];
//grid = [[MyThumbnailGridView alloc] initWithFrame:CGRectZero];
NSLog(@"showThumbnailGrid Grid View Size: %@", NSStringFromCGRect(grid.frame));
[self.view addSubview:grid];
[self getListOfImages];
}
-(void) getListOfImages {
//Do background task to get images and fill arrImages
[self onDownloadImageDataComplete];
}
- (void) onDownloadImageDataComplete{
grid.imageDataSource = arrImages;
// [grid setNeedsLayout];
// [grid setNeedsDisplay];
}
//...
@end
* MyThumbnailGridView.h
@interface MyThumbnailGridView : UIView
-(id)initWithFrame:(CGRect)frame;
-(void) refreshData;
@property (nonatomic,strong) NSArray *imageDataSource;
@end
* MyThumbnailGridView.m
@interface MyThumbnailGridView () <UICollectionViewDelegate, UICollectionViewDataSource>{
UICollectionView *collectionView;
}
@end
@implementation MyThumbnailGridView
- (instancetype) initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if(self){
[self customInit];
}
return self;
}
- (void) customInit {
collectionView = [[UICollectionView alloc] initWithFrame:self.bounds collectionViewLayout:[[MyFlowLayout alloc] init]];
collectionView.delegate = self;
collectionView.dataSource = self;
collectionView.allowsMultipleSelection = NO;
collectionView.showsVerticalScrollIndicator = YES;
[collectionView setBackgroundColor:[UIColor darkGrayColor]];
[collectionView registerClass:[MyCollectionViewCell class] forCellWithReuseIdentifier:@"MyId"];
[self addSubview:collectionView];
}
- (void) refreshData {
NSLog(@"Refresh Grid Data");
[collectionView reloadData];
}
////other code
@end
MyFlowLayout
@interface MyFlowLayout : UICollectionViewFlowLayout
@end
@implementation MyFlowLayout
- (instancetype)init{
self = [super init];
if (self)
{
self.minimumLineSpacing = 1.0;
self.minimumInteritemSpacing = 1.0;
self.scrollDirection = UICollectionViewScrollDirectionVertical;
}
return self;
}
- (CGSize)itemSize {
NSInteger numberOfColumns = 3;
CGFloat itemWidth = (CGRectGetWidth(self.collectionView.frame) - (numberOfColumns - 1)) / numberOfColumns;
return CGSizeMake(itemWidth, itemWidth);
}
@end
MyCollectionViewCell
@interface MyCollectionViewCell : UICollectionViewCell
@property (strong, nonatomic) UIImageView *imageView;
@end
@implementation MyCollectionViewCell
- (instancetype)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.imageView = [UIImageView new];
[self.imageView setContentMode:UIViewContentModeScaleAspectFill];
[self.imageView setClipsToBounds:YES];
[self.imageView setBackgroundColor:[UIColor darkGrayColor]];
[self.contentView addSubview:self.imageView];
}
return self;
}
- (void)prepareForReuse {
[super prepareForReuse];
self.imageView.image = nil;
[self.imageView setHidden:NO];
}
- (void)layoutSubviews {
[super layoutSubviews];
[self.imageView setFrame:self.contentView.bounds];
}
@end
最佳答案
这可以用解决
您可以在方向的委托函数中更改MyThumbnailGridView视图的框架，也可以创建具有此类约束的视图
(void)viewDidLoad {
[super viewDidLoad];
arrImages = [NSMutableArray new];
grid = [[MyThumbnailGridView alloc] initWithFrame:CGRectMake(0, self.view.frame.size.height/2, self.view.frame.size.width, self.view.frame.size.height/2)];
[self.view addSubview:grid];
[self getListOfImages];
}
-(void)viewDidLayoutSubviews
{
if(Once){
Once = NO;
// adding constraints
MyThumbnailGridView.translatesAutoresizingMaskIntoConstraints = NO;
[self.MyThumbnailGridView.widthAnchor constraintEqualToConstant:self.view.frame.size.width].active = YES;
[self.MyThumbnailGridView.heightAnchor constraintEqualToConstant:self.view.frame.size.height/2].active = YES;
[self.MyThumbnailGridView.leadingAnchor constraintEqualToAnchor:self.view.leadingAnchor].active = YES;
[self.MyThumbnailGridView.topAnchor constraintEqualToAnchor:self.view.topAnchor constant:self.view.frame.size.height/2].active = YES;
}
}
也实现这个
- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
[self.view layoutIfNeeded];
[MyThumbnailGridView.collectionView invalidate];
// Do view manipulation here.
[super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];
}