我正在尝试创建一个与iOS跳板屏幕相似的集合视图。 这意味着我希望拥有一个包含所有项目的集合视图，并在网格下面有一个页面控制器（就像跳板屏幕一样）。我还想实现相同的编辑模式，这意味着我的一个图标处于编辑模式，我可以将它们从一个页面拖到另一个页面，这样页面就不必满了。 我试图设置一个集合视图来水平滚动，但它没有按我的意愿行事。首先，图标在另一个下面添加，而在另一个旁边添加一个。其次，我没有这种方式的页面点，用户不能在不同的页面上放置图标 我还尝试设置页面控制器，并在每个页面中放入集合视图。在这种情况下，我在编辑模式下得到它，我不能进入屏幕之间。我想这是因为我有一个更多的集合视图，并且它们不会相互交互。 我用另一种方式，使用滚动视图，并尝试将集合视图放在该滚动视图中。但对我来说这听起来像是一个非常不优雅的解决方案。
有没有人知道如何创建这样的场景？
编辑： 我认为我的问题的答案隐藏在this question中。它描述了我想要的相同情况：一个集合视图，它是水平滚动的，带有分页，并且图标的顺序不是垂直流动，而是水平流动。那里有一个部分好的答案。我说它部分好，因为答案描述了UICollectionViewFlowLayout的子类，但是在上传的示例项目中，子类是UICollectionViewLayout，我认为重点是维护UICollectionViewFlowLayout具有的功能。 这个问题是在一年前提出来的，所以我相信某人有答案，或者至少我希望如此。
答案 0 :(得分：3)
我对我的问题有部分解决方案。 我确实使用了linked question above的（波格丹）答案。这是代码：
layout.h：
#import <UIKit/UIKit.h>
@interface V9Layout : UICollectionViewLayout
@property (nonatomic, assign) NSInteger itemsInOneRow;
@property (nonatomic, assign) NSInteger itemsInOneCol;
@property (nonatomic, assign) CGSize itemSize;
@end
layout.m：
#import "V9Layout.h"
@interface V9Layout()
-(void)calculateLayoutProperties;
-(int)pagesInSection:(NSInteger)section;
@property (nonatomic, strong) NSMutableArray *frames;
@property (nonatomic, assign) CGFloat lineSpacing;
@property (nonatomic, assign) CGFloat interitemSpacing;
@property (nonatomic, assign) CGSize pageSize;
@end
@implementation V9Layout
@synthesize itemsInOneRow = _itemsInOneRow, itemsInOneCol = _itemsInOneCol, itemSize = _itemSize;
@synthesize lineSpacing = _lineSpacing, interitemSpacing = _interitemSpacing;
@synthesize frames = _frames;
- (id)init
{
self = [super init];
if (self) {
[self setup];
}
return self;
}
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super init];
if (self) {
[self setup];
}
return self;
}
- (void)setup
{
self.itemsInOneRow = 3;
self.itemsInOneCol = 4;
self.frames = [NSMutableArray array];
}
-(void)calculateLayoutProperties {
self.pageSize = self.collectionView.bounds.size;
// The width of all line spacings is equal to width of ONE item. The same for interitem spacing
CGFloat itemWidth = self.pageSize.width / (self.itemsInOneRow + 1); // +1 because we all spaces make width of one additional item
CGFloat itemHeight = self.pageSize.height / (self.itemsInOneCol + 1); // the same
NSLog(@"calculateLayoutProperties item width: %f, item height: %f", itemWidth, itemHeight);
self.itemSize = CGSizeMake(itemWidth, itemHeight);
// this part is only to make a global parameter, because I'm using this data to create the size of the UICollectionViewCell. I think I need to use a delegate method for the UICollectionViewCell to ask the UICollectionViewLayout for the calculated size of cell.
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
if (standardUserDefaults) {
[standardUserDefaults setObject:[NSNumber numberWithFloat:itemWidth] forKey:@"cellWidth"];
[standardUserDefaults setObject:[NSNumber numberWithFloat:itemHeight] forKey:@"cellHeight"];
[standardUserDefaults synchronize];
}
// spacing for x
self.lineSpacing = (self.pageSize.width - (self.itemsInOneRow * self.itemSize.width)) / (self.itemsInOneRow + 1);
// spacing for y
self.interitemSpacing = (self.pageSize.height - (self.itemsInOneCol * self.itemSize.height)) / (self.itemsInOneCol + 1);
}
-(int)pagesInSection:(NSInteger)section {
NSLog(@"v9layout: numberOfItemsInSection is %ld", (long)[self.collectionView numberOfItemsInSection:section]);
return ([self.collectionView numberOfItemsInSection:section] - 1) / (self.itemsInOneRow * self.itemsInOneCol) + 1;
}
-(CGSize)collectionViewContentSize {
// contentSize.width is equal to pages * pageSize.width
NSInteger sections = 1;
if ([self.collectionView respondsToSelector:@selector(numberOfSections)]) {
sections = [self.collectionView numberOfSections];
}
int pages = 0;
for (int section = 0; section < sections; section++) {
pages = pages + [self pagesInSection:section];
}
return CGSizeMake(pages * self.pageSize.width, self.pageSize.height);
}
-(void)prepareLayout {
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
[self calculateLayoutProperties];
});
[self.frames removeAllObjects];
NSInteger sections = 1;
if ([self.collectionView respondsToSelector:@selector(numberOfSections)]) {
sections = [self.collectionView numberOfSections];
}
int pagesOffset = 0; // Pages that are used by prevoius sections
int itemsInPage = self.itemsInOneRow * self.itemsInOneCol;
for (int section = 0; section < sections; section++) {
NSMutableArray *framesInSection = [NSMutableArray array];
int pagesInSection = [self pagesInSection:section];
int itemsInSection = [self.collectionView numberOfItemsInSection:section];
for (int page = 0; page < pagesInSection; page++) {
int itemsToAddToArray = itemsInSection - framesInSection.count;
int itemsInCurrentPage = itemsInPage;
if (itemsToAddToArray < itemsInPage) { // If there are less cells than expected (typically last page of section), we go only through existing cells.
itemsInCurrentPage = itemsToAddToArray;
}
for (int itemInPage = 0; itemInPage < itemsInCurrentPage; itemInPage++) {
CGFloat originX = (pagesOffset + page) * self.pageSize.width + self.lineSpacing + (itemInPage % self.itemsInOneRow) * (self.itemSize.width + self.lineSpacing);
CGFloat originY = self.interitemSpacing + (itemInPage / self.itemsInOneRow) * (self.itemSize.height + self.interitemSpacing);
CGRect itemFrame = CGRectMake(originX, originY, self.itemSize.width, self.itemSize.height);
[framesInSection addObject:NSStringFromCGRect(itemFrame)];
}
}
[self.frames addObject:framesInSection];
pagesOffset += pagesInSection;
}
}
-(NSArray *)layoutAttributesForElementsInRect:(CGRect)rect {
NSMutableArray *attributes = [NSMutableArray array];
NSInteger sections = 1;
if ([self.collectionView respondsToSelector:@selector(numberOfSections)]) {
sections = [self.collectionView numberOfSections];
}
int pagesOffset = 0;
int itemsInPage = self.itemsInOneRow * self.itemsInOneCol;
for (int section = 0; section < sections; section++) {
int pagesInSection = [self pagesInSection:section];
int itemsInSection = [self.collectionView numberOfItemsInSection:section];
for (int page = 0; page < pagesInSection; page++) {
CGRect pageFrame = CGRectMake((pagesOffset + page) * self.pageSize.width, 0, self.pageSize.width, self.pageSize.height);
if (CGRectIntersectsRect(rect, pageFrame)) {
int startItemIndex = page * itemsInPage;
int itemsInCurrentPage = itemsInPage;
if (itemsInSection - startItemIndex < itemsInPage) {
itemsInCurrentPage = itemsInSection - startItemIndex;
}
for (int itemInPage = 0; itemInPage < itemsInCurrentPage; itemInPage++) {
UICollectionViewLayoutAttributes *itemAttributes = [self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:startItemIndex + itemInPage inSection:section]];
if (CGRectIntersectsRect(itemAttributes.frame, rect)) {
[attributes addObject:itemAttributes];
}
}
}
}
pagesOffset += pagesInSection;
}
return attributes;
}
-(UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewLayoutAttributes *attributes = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
attributes.frame = CGRectFromString(self.frames[indexPath.section][indexPath.item]);
return attributes;
}
@end
这实现了水平分页，其中单元格的顺序彼此相邻而不是彼此之下。 我仍然想添加拖放功能，以便用户可以更改单元格的顺序。我对它提出了this question的意见。 希望我能找到答案并更新这个答案。