ios - collectionView的使用
2016-06-28 本文已影响9609人
fjytqiu
－. 布局
UICollectionViewFlowLayout流水布局
- 通过UICollectionViewFlowLayout对象进行布局( 如果布局的尺寸是固定的，例如：item的尺寸大小都是固定，可以使用全局属性，即设置下文中layout )
UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
// 1.设置列间距
layout.minimumInteritemSpacing = 1;
// 2.设置行间距
layout.minimumLineSpacing = 1;
// 3.设置每个item的大小
layout.itemSize = CGSizeMake(50, 50);
// 4.设置Item的估计大小,用于动态设置item的大小，结合自动布局（self-sizing-cell）
layout.estimatedItemSize = CGSizeMake(320, 60);
// 5.设置布局方向
layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
// 6.设置头视图尺寸大小
layout.headerReferenceSize = CGSizeMake(50, 50);
// 7.设置尾视图尺寸大小
layout.footerReferenceSize = CGSizeMake(50, 50);
// 8.设置分区(组)的EdgeInset（四边距）
layout.sectionInset = UIEdgeInsetsMake(10, 20, 30, 40);
// 9.10.设置分区的头视图和尾视图是否始终固定在屏幕上边和下边
layout.sectionFootersPinToVisibleBounds = YES;
layout.sectionHeadersPinToVisibleBounds = YES;
- 通过遵守UICollectionViewDelegateFlowLayout实现代理方法来布局（非固定情况则需要通过数据源方法）
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath;
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section;
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section;
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section;
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section;
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section;
二. 数据源方法
//设置分区数（必须实现）
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 1;
}
//设置每个分区的item个数
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return 5;
}
//设置返回每个item的属性必须实现）
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
UICollectionViewCell *cell = [self.collection dequeueReusableCellWithReuseIdentifier:ID forIndexPath:indexPath];
return cell;
}
//对头视图或者尾视图进行设置
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath {
NSString *identifier;
if ([kind isEqualToString:UICollectionElementKindSectionHeader]) {
identifier = @"headerView";
} else {
identifier = @"footerView";
}
UICollectionReusableView *view = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:identifier forIndexPath:indexPath];
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 10, 120, 30)];
[view addSubview:label];
if (indexPath.section == 0) {
label.text = @"section1";
}else {
label.text = @"section2";
}
if ([kind isEqualToString:UICollectionElementKindSectionHeader]) {
view.backgroundColor = [UIColor redColor];
} else {
view.backgroundColor = [UIColor purpleColor];
}
return view;
}
//是否允许移动Item
- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath NS_AVAILABLE_IOS(9_0){
return YES;
}
//移动Item时触发的方法
- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath*)destinationIndexPath NS_AVAILABLE_IOS(9_0); {
}
三. 常用到的代理方法
//是否允许某个Item的高亮，返回NO，则不能进入高亮状态
- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath; {
return YES;
}
//当item高亮时触发的方法
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath; {
}
//结束高亮状态时触发的方法
- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath; {
}
//是否可以选中某个Item，返回NO，则不能选中
- (BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath; {
return YES;
}
//是否可以取消选中某个Item
- (BOOL)collectionView:(UICollectionView *)collectionView shouldDeselectItemAtIndexPath:(NSIndexPath *)indexPath; {
return YES;
}
//已经选中某个item时触发的方法
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath; {
}
//取消选中某个Item时触发的方法
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath; {
}
//将要加载某个Item时调用的方法
- (void)collectionView:(UICollectionView *)collectionView willDisplayCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath NS_AVAILABLE_IOS(8_0); {
}
//将要加载头尾视图时调用的方法
- (void)collectionView:(UICollectionView *)collectionView willDisplaySupplementaryView:(UICollectionReusableView *)view forElementKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath NS_AVAILABLE_IOS(8_0); {
}
//已经展示某个Item时触发的方法
- (void)collectionView:(UICollectionView *)collectionView didEndDisplayingCell:(UICollectionViewCell *)cell forItemAtIndexPath:(NSIndexPath *)indexPath; {
}
//已经展示某个头尾视图时触发的方法
- (void)collectionView:(UICollectionView *)collectionView didEndDisplayingSupplementaryView:(UICollectionReusableView *)view forElementOfKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath; {
}
//这个方法设置是否展示长按菜单
- (BOOL)collectionView:(UICollectionView *)collectionView shouldShowMenuForItemAtIndexPath:(NSIndexPath *)indexPath; {
return YES;
}
//这个方法用于设置要展示的菜单选项
- (BOOL)collectionView:(UICollectionView *)collectionView canPerformAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(nullable id)sender; {
return YES;
}
//这个方法用于实现点击菜单按钮后的触发方法,通过测试，只有copy，cut和paste三个方法可以使用
- (void)collectionView:(UICollectionView *)collectionView performAction:(SEL)action forItemAtIndexPath:(NSIndexPath *)indexPath withSender:(nullable id)sender; {
//通过下面的方式可以将点击按钮的方法名打印出来：
NSLog(@"%@",NSStringFromSelector(action));
}
//collectionView进行重新布局时调用的方法
//- (nonnull UICollectionViewTransitionLayout *)collectionView:(UICollectionView *)collectionView transitionLayoutForOldLayout:(UICollectionViewLayout *)fromLayout newLayout:(UICollectionViewLayout *)toLayout; {
//
//}
四. collectionView的属性和相关方法
//通过一个布局策略初识化CollectionView
- (instancetype)initWithFrame:(CGRect)frame collectionViewLayout:(UICollectionViewLayout *)layout;
//获取和设置collection的layout
@property (nonatomic, strong) UICollectionViewLayout *collectionViewLayout;
//数据源和代理
@property (nonatomic, weak, nullable) id <UICollectionViewDelegate> delegate;
@property (nonatomic, weak, nullable) id <UICollectionViewDataSource> dataSource;
//从一个class或者xib文件进行cell(item)的注册
- (void)registerClass:(nullable Class)cellClass forCellWithReuseIdentifier:(NSString *)identifier;
- (void)registerNib:(nullable UINib *)nib forCellWithReuseIdentifier:(NSString *)identifier;
//下面两个方法与上面相似，这里注册的是头视图或者尾视图的类
//其中第二个参数是设置 头视图或者尾视图 系统为我们定义好了这两个字符串
//UIKIT_EXTERN NSString *const UICollectionElementKindSectionHeader NS_AVAILABLE_IOS(6_0);
//UIKIT_EXTERN NSString *const UICollectionElementKindSectionFooter NS_AVAILABLE_IOS(6_0);
- (void)registerClass:(nullable Class)viewClass forSupplementaryViewOfKind:(NSString *)elementKind withReuseIdentifier:(NSString *)identifier;
- (void)registerNib:(nullable UINib *)nib forSupplementaryViewOfKind:(NSString *)kind withReuseIdentifier:(NSString *)identifier;
//这两个方法是从复用池中取出cell或者头尾视图
- (__kindof UICollectionViewCell *)dequeueReusableCellWithReuseIdentifier:(NSString *)identifier forIndexPath:(NSIndexPath *)indexPath;
- (__kindof UICollectionReusableView *)dequeueReusableSupplementaryViewOfKind:(NSString *)elementKind withReuseIdentifier:(NSString *)identifier forIndexPath:(NSIndexPath *)indexPath;
//设置是否允许选中 默认yes
@property (nonatomic) BOOL allowsSelection;
//设置是否允许多选 默认no
@property (nonatomic) BOOL allowsMultipleSelection;
//获取所有选中的item的位置信息
- (nullable NSArray<NSIndexPath *> *)indexPathsForSelectedItems;
//设置选中某一item，并使视图滑动到相应位置，scrollPosition是滑动位置的相关参数，如下：
/*
typedef NS_OPTIONS(NSUInteger, UICollectionViewScrollPosition) {
//无
UICollectionViewScrollPositionNone = 0,
//垂直布局时使用的 对应上中下
UICollectionViewScrollPositionTop = 1 << 0,
UICollectionViewScrollPositionCenteredVertically = 1 << 1,
UICollectionViewScrollPositionBottom = 1 << 2,
//水平布局时使用的 对应左中右
UICollectionViewScrollPositionLeft = 1 << 3,
UICollectionViewScrollPositionCenteredHorizontally = 1 << 4,
UICollectionViewScrollPositionRight = 1 << 5
};
*/
- (void)selectItemAtIndexPath:(nullable NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UICollectionViewScrollPosition)scrollPosition;
//将某一item取消选中
- (void)deselectItemAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated;
//重新加载数据
- (void)reloadData;
//下面这两个方法，可以重新设置collection的布局，后面的方法多了一个布局完成后的回调，iOS7后可以用
//使用这两个方法可以产生非常炫酷的动画效果
- (void)setCollectionViewLayout:(UICollectionViewLayout *)layout animated:(BOOL)animated;
- (void)setCollectionViewLayout:(UICollectionViewLayout *)layout animated:(BOOL)animated completion:(void (^ __nullable)(BOOL finished))completion NS_AVAILABLE_IOS(7_0);
//下面这些方法更加强大，我们可以对布局更改后的动画进行设置
//这个方法传入一个布局策略layout，系统会开始进行布局渲染，返回一个UICollectionViewTransitionLayout对象
//这个UICollectionViewTransitionLayout对象管理动画的相关属性，我们可以进行设置
- (UICollectionViewTransitionLayout *)startInteractiveTransitionToCollectionViewLayout:(UICollectionViewLayout *)layout completion:(nullable UICollectionViewLayoutInteractiveTransitionCompletion)completion NS_AVAILABLE_IOS(7_0);
//准备好动画设置后，我们需要调用下面的方法进行布局动画的展示，之后会调用上面方法的block回调
- (void)finishInteractiveTransition NS_AVAILABLE_IOS(7_0);
//调用这个方法取消上面的布局动画设置，之后也会进行上面方法的block回调
- (void)cancelInteractiveTransition NS_AVAILABLE_IOS(7_0);
//获取分区数
- (NSInteger)numberOfSections;
//获取某一分区的item数
- (NSInteger)numberOfItemsInSection:(NSInteger)section;
//下面两个方法获取item或者头尾视图的layout属性，这个UICollectionViewLayoutAttributes对象
//存放着布局的相关数据，可以用来做完全自定义布局，后面博客会介绍
- (nullable UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath;
- (nullable UICollectionViewLayoutAttributes *)layoutAttributesForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath;
//获取某一点所在的indexpath位置
- (nullable NSIndexPath *)indexPathForItemAtPoint:(CGPoint)point;
//获取某个cell所在的indexPath
- (nullable NSIndexPath *)indexPathForCell:(UICollectionViewCell *)cell;
//根据indexPath获取cell
- (nullable UICollectionViewCell *)cellForItemAtIndexPath:(NSIndexPath *)indexPath;
//获取所有可见cell的数组
- (NSArray<__kindof UICollectionViewCell *> *)visibleCells;
//获取所有可见cell的位置数组
- (NSArray<NSIndexPath *> *)indexPathsForVisibleItems;
//下面三个方法是iOS9中新添加的方法，用于获取头尾视图
- (UICollectionReusableView *)supplementaryViewForElementKind:(NSString *)elementKind atIndexPath:(NSIndexPath *)indexPath NS_AVAILABLE_IOS(9_0);
- (NSArray<UICollectionReusableView *> *)visibleSupplementaryViewsOfKind:(NSString *)elementKind NS_AVAILABLE_IOS(9_0);
- (NSArray<NSIndexPath *> *)indexPathsForVisibleSupplementaryElementsOfKind:(NSString *)elementKind NS_AVAILABLE_IOS(9_0);
//使视图滑动到某一位置，可以带动画效果
- (void)scrollToItemAtIndexPath:(NSIndexPath *)indexPath atScrollPosition:(UICollectionViewScrollPosition)scrollPosition animated:(BOOL)animated;
//下面这些方法用于动态添加，删除，移动某些分区获取items
- (void)insertSections:(NSIndexSet *)sections;
- (void)deleteSections:(NSIndexSet *)sections;
- (void)reloadSections:(NSIndexSet *)sections;
- (void)moveSection:(NSInteger)section toSection:(NSInteger)newSection;
- (void)insertItemsAtIndexPaths:(NSArray<NSIndexPath *> *)indexPaths;
- (void)deleteItemsAtIndexPaths:(NSArray<NSIndexPath *> *)indexPaths;
- (void)reloadItemsAtIndexPaths:(NSArray<NSIndexPath *> *)indexPaths;
- (void)moveItemAtIndexPath:(NSIndexPath *)indexPath toIndexPath:(NSIndexPath *)newIndexPath;
五，自定义布局
UICollectionViewDelegateFlowLayout可以继承这个自定义
自定义UICollectionViewLayout(抽象类):
- (void)prepareLayout
{
[super prepareLayout];
}
-(UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
NSMutableDictionary *dict;
dict[@"0"] = @1;
dict[@"1"] = @2;
UICollectionViewLayoutAttributes *attrs = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
attrs.transform3D = CATransform3DMakeRotation(arc4random_uniform(M_1_PI), 1, 1, 1);
// zIndex越大，就越在上面
attrs.zIndex = [self.collectionView numberOfItemsInSection:indexPath.section]-indexPath.item;
@property (nonatomic) CGRect frame;
@property (nonatomic) CGPoint center;
@property (nonatomic) CGSize size;
@property (nonatomic) CATransform3D transform3D;
@property (nonatomic) CGRect bounds NS_AVAILABLE_IOS(7_0);
@property (nonatomic) CGAffineTransform transform NS_AVAILABLE_IOS(7_0);
@property (nonatomic) CGFloat alpha;
@property (nonatomic) NSInteger zIndex; // default is 0
@property (nonatomic, getter=isHidden) BOOL hidden; // As an optimization, UICollectionView might not create a view for items whose hidden attribute is YES
@property (nonatomic, strong) NSIndexPath *indexPath; return attrs;
// ABS(1-2);绝对值 CGRectIntersectsRect(<#CGRect rect1#>, <#CGRect rect2#>) 这要和rect1相交就都算；
}
- (NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect
{
NSMutableArray *array = [NSMutableArray array];
NSInteger count = [self.collectionView numberOfItemsInSection:0];
for (int i=0; i<count; i++) {
UICollectionViewLayoutAttributes *attrs = [self layoutAttributesForItemAtIndexPath:[NSIndexPath indexPathForItem:i inSection:0]];
[array addObject:attrs];
}
return array;
}
- (BOOL)shouldInvalidateLayoutForBoundsChange:(CGRect)newBounds
{
return YES;
}
从写方法计算contentsize
