注意点
【iOS|iOS - UICollectionView】1，滚动到指定位置
[_cv scrollToItemAtIndexPath:[NSIndexPath indexPathForItem:8 inSection:0] atScrollPosition:UICollectionViewScrollPositionNone animated:YES];
1，直接拖UICollectionView控件，默认是flow布局，设置代理UICollectionViewDelegateFlowLayout,UICollectionViewDataSource 2,代码创建
- (void)createCollectionView{
//关闭自适应self.automaticallyAdjustsScrollViewInsets = NO;
_collectionView = [[UICollectionView alloc]initWithFrame:CGRectMake(0, 0, screenWidth, 200) collectionViewLayout:self.flowLayout];
_collectionView.dataSource = self;
_collectionView.delegate = self;
_collectionView.backgroundColor = [UIColor colorWithRed:237/255.0 green:237/255.0 blue:237/255.0 alpha:0.8 ];
[self.headerBgView addSubview: _collectionView];
//注册cell[_collectionView registerNib:[UINib nibWithNibName:FirstCategoryCellID bundle:nil] forCellWithReuseIdentifier:FirstCategoryCellID];
}
- (UICollectionViewFlowLayout *)flowLayout {
if (!_flowLayout) {
_flowLayout = [[UICollectionViewFlowLayout alloc]init];
//设置单元格大小
_flowLayout.itemSize = CGSizeMake(60, 90);
//最小行间距(默认为10)
_flowLayout.minimumLineSpacing = 10;
//最小item间距（默认为10）
_flowLayout.minimumInteritemSpacing = 10;
//设置senction的内边距
_flowLayout.sectionInset = UIEdgeInsetsMake(10, 10, 10, 10);
//设置UICollectionView的滑动方向
_flowLayout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
}
return _flowLayout;
}2，基本的代理方法
#pragma mark UICollectionViewDelegate-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return 7;
}3,设置cell
//Item间距
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
return 5;
}
//Item行间距
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
return 10;
}
//设置cell的size
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{HotSearchModel *model = self.hotSearchArr[indexPath.row];
NSLog(@"---%f--",[self getMultiLineWithFont:14 andText:model.text].width);
return [self getMultiLineWithFont:14 andText:model.text];
}
//计算lable的size
- (CGSize)getMultiLineWithFont:(CGFloat )font andText:(NSString *)text
{
UILabel *lable = [[UILabel alloc]init];
lable.text = text;
lable.numberOfLines = 1;
//多行显示，计算高度
CGSize size= [lable.text boundingRectWithSize:CGSizeMake([UIScreen mainScreen].bounds.size.width - 20, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:font]} context:nil].size;
return CGSizeMake(size.width+20, size.height+5);
}
//cell
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
HotSearchCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:HotSearchCellID forIndexPath:indexPath];
[cell setHotSearchText:self.hotSearchArr[indexPath.row].text];
return cell;
}另一种
代理
#pragma mark - UICollectionViewDelegateFlowLayout-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
return CGSizeMake(self.myCollection.frame.size.width/2 - 5, 55);
}#pragma mark - collection delegate-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 1;
}-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
return self.dataSource.count;
}-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
NSTCollectionCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellID forIndexPath:indexPath];
[cell setUPModel:[self.dataSource objectAtIndex:indexPath.row]];
return cell;
}-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
NSTCollectionCell * cell = (NSTCollectionCell *)[collectionView cellForItemAtIndexPath:indexPath];
if(![self.lastCell isEqual:cell])
{
[self.lastCell selectModel];
self.lastCell = cell;
}
else
self.lastCell = nil;
[UIView animateWithDuration:0.2 animations:^{
[self.NextBtn setBackgroundColor:self.lastCell ? color_green : color_btn_gray];
}];
self.NextBtn.enabled = self.lastCell ? YES:NO;
[cell selectModel];
}
