UIcollectionView

一、设置 UICollectionViewFlowLayout

    //  初始化flowLayout
    self.flowLayout = [UICollectionViewFlowLayout new];

    //  collectionView的item大小
    self.flowLayout.itemSize = CGSizeMake((kSCREEN_WIDTH-1)/2, kCollectionViewItemHeight); 

    //  collectionView的item行间距
    self.flowLayout.minimumLineSpacing = 1; 

    //  collectionView的item列间距
    self.flowLayout.minimumInteritemSpacing = 1; 

    //  collectionView的sectionHeaderView大小
    self.flowLayout.headerReferenceSize = CGSizeMake(kSCREEN_WIDTH, 41);

二、设置collectionView

    //  使用flowLayout初始化collectionView
    self.collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, self.sdCycleScrollView.frame.size.height, kSCREEN_WIDTH, 1200) collectionViewLayout:self.flowLayout];

    self.collectionView.backgroundColor = [UIColor orangeColor];
    self.collectionView.delegate = self;
    self.collectionView.dataSource = self;
    self.collectionView.scrollEnabled = NO;

    //  注册item
    [self.collectionView registerClass:[xCollectionViewItem class] forCellWithReuseIdentifier:kCollectionItemID];
    
    //  注册sectionHeaderView
    [self.collectionView registerClass:[XSectionHeaderView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:kCollectionSectionHeaderID];

三、collectionView代理方法

1、设置collectionView段数

//  collectionView段数
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{
    DebugLog(@"section number %lu", (unsigned long)self.functionNameArr.count);
    return self.functionNameArr.count;
}

2、设置collectionView每段的item个数

//  collectionView每段的item个数
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
    
    NSArray *itemCountArr = self.functionNameArr[section];
    DebugLog(@"item number of section %lu", (unsigned long)itemCountArr.count);
    
    return itemCountArr.count;
}

3、设置collectionView的item

//  collectionView的item
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
    DebugLog(@"set each item");

    //  获取自定义的cell
    xCollectionViewItem *cell = [collectionView dequeueReusableCellWithReuseIdentifier:kCollectionItemID forIndexPath:indexPath];

    //  设置自定义cell的图片
    NSArray *imgArr = self.functionImageArr[indexPath.section];
    NSString *imgString = (NSString *)imgArr[indexPath.row];
    cell.itemImageView.image = [UIImage imageNamed:imgString];
    
    //设置自定义cell标签文字
    NSArray *nameArr = self.functionNameArr[indexPath.section];
    NSString *nameString = (NSString *)nameArr[indexPath.row];
    cell.itemLabel.text = nameString;

    return cell;
}

4、设置collectionView的sectionHeaderView

//  collectionView的sectionHeaderView
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath{

    DebugLog(@"viewForSupplementaryElementOfKind");

    //  获取自定义的sectionHeaderView
    XSectionHeaderView *sectionHeadView = [collectionView dequeueReusableSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:kCollectionSectionHeaderID forIndexPath:indexPath];

    //  设置自定义sectionHeaderView的标签文字
    sectionHeadView.sectionHeadLabel.text = (NSString *)self.headTextArr[indexPath.section];

    return sectionHeadView;
}

5、点击collectionView的item

//  点击collectionView的item
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
    
    //  获取点击的cell
    xCollectionViewItem *cell = (xCollectionViewItem *)[collectionView cellForItemAtIndexPath:indexPath];
    DebugLog(@"cell name = %@", cell.itemLabel.text);
    
    //  判断cell标签的文字来跳转到相应的控制器
    if ([cell.itemLabel.text isEqualToString:@"实时路况"]) {

        //  初始化实时路况控制器
        RoadConditionViewController *vc = [RoadConditionViewController new];
        
        //  跳转
        [self.navigationController pushViewController:vc animated:YES];
    }
}