UICollectionView基础
Posted 西贝了爷
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前言
这个控件，看起来与UITableView有点像，而且基本的用法也很相像哦！！！
我们来看看API:
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#pragma mark - UICollectionViewDataSource
// 指定Section个数
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
return 3;
}
// 指定section中的collectionViewCell的个数
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
return 10;
}
// 配置section中的collectionViewCell的显示
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
CollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"CellIdentifier" forIndexPath:indexPath];
cell.backgroundColor = [UIColor redColor];
cell.textLabel.text = [NSString stringWithFormat:@"(%ld %ld)", indexPath.section, indexPath.row];
return cell;
}
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看看直线布局的API：
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#pragma mark - UICollectionViewDelegateFlowLayout
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
return CGSizeMake(self.view.frame.size.width / 3 - 10, self.view.frame.size.width / 3 - 10);
}
// 设置每个cell上下左右相距
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
return UIEdgeInsetsMake(5, 5, 5, 5);
}
// 设置最小行间距，也就是前一行与后一行的中间最小间隔
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
return 10;
}
// 设置最小列间距，也就是左行与右一行的中间最小间隔
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
return 10;
}
// 设置section头视图的参考大小，与tableheaderview类似
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section {
return CGSizeMake(self.view.frame.size.width, 40);
}
// 设置section尾视图的参考大小，与tablefooterview类似
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section {
return CGSizeMake(self.view.frame.size.width, 40);
}
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如果是固定的，可以使用全局属性：
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NS_CLASS_AVAILABLE_ios(6_0) @interface UICollectionViewFlowLayout : UICollectionViewLayout
@property (nonatomic) CGFloat minimumLineSpacing;
@property (nonatomic) CGFloat minimumInteritemSpacing;
@property (nonatomic) CGSize itemSize;
@property (nonatomic) CGSize estimatedItemSize NS_AVAILABLE_IOS(8_0); // defaults to CGSizeZero - setting a non-zero size enables cells that self-size via -perferredLayoutAttributesFittingAttributes:
@property (nonatomic) UICollectionViewScrollDirection scrollDirection; // default is UICollectionViewScrollDirectionVertical
@property (nonatomic) CGSize headerReferenceSize;
@property (nonatomic) CGSize footerReferenceSize;
@property (nonatomic) UIEdgeInsets sectionInset;
@end
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常用到的代理方法：
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#pragma mark - UICollectionViewDelegate
// 允许选中时，高亮
- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"%s", __FUNCTION__);
return YES;
}
// 高亮完成后回调
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"%s", __FUNCTION__);
}
// 由高亮转成非高亮完成时的回调
- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"%s", __FUNCTION__);
}
// 设置是否允许选中
- (BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"%s", __FUNCTION__);
return YES;
}
// 设置是否允许取消选中
- (BOOL)collectionView:(UICollectionView *)collectionView shouldDeselectItemAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"%s", __FUNCTION__);
return YES;
}
// 选中操作
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"%s", __FUNCTION__);
}
// 取消选中操作
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"%s", __FUNCTION__);
}
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