iOS - 版面实现记录三

最新推荐文章于 2025-05-17 09:49:09 发布

原创最新推荐文章于 2025-05-17 09:49:09 发布 · 1k 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#ios

Mac OS X 专栏收录该内容

50 篇文章

订阅专栏

本文详细阐述了如何通过实现UICollectionViewDelegateFlowLayout代理方法来动态调整UICollectionView中item的大小，以及如何通过注册不同类型的UICollectionViewCell来实现高效的数据展示。同时，文章还介绍了如何避免数据过少导致的下拉刷新问题，并提供了优化内存消耗的解决方案。

版面三

实现该界面花了点功夫。
基本思路是通过实现 UICollectionViewDelegateFlowLayout 的代理方法

- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath;

以10个一循环返回 item 大小。另外通过代理方法

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath;

同样以10个一循环返回 item 的可供服用的样式。

配置 UICollectionView

- (void)initContentCollectionView {
//    self.adScrollView.frame.origin.y + self.adScrollView.frame.size.height
    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];

    //（cell宽高）
    layout.itemSize = CGSizeMake(CELLWEIGHT, CELLHEIGHT);
    layout.minimumLineSpacing = CELLLINESPACING;
    layout.minimumInteritemSpacing = CELLINTERITEMSPACING;
    //广告图宽高－下面还有
    layout.headerReferenceSize = CGSizeMake(IOS_SCREEN_WIDTH, HEADADVIEWHEIGHT);
    //section（上、左、下、右）
    layout.sectionInset = SECTIONBORDER;
    self.contentCollectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0 ,64.f , IOS_SCREEN_WIDTH, IOS_SCREEN_CONTENT_HEIGHT - BOTTOM_MENU_BAR_HEIGHT) collectionViewLayout:layout];
    self.contentCollectionView.backgroundColor = LIGHT_GRAY;
    self.contentCollectionView.delegate = self;
    self.contentCollectionView.dataSource = self;
    self.contentCollectionView.showsVerticalScrollIndicator = NO;
    self.contentCollectionView.alwaysBounceVertical = YES;
    //collectionView（上、左、下、右）
    self.contentCollectionView.contentInset = COLLECTIONCONTENTINSET;
    [self.contentCollectionView registerClass:[ViewHomeMenuCollectionCell class] forCellWithReuseIdentifier:@"cell"];
    [self.contentCollectionView registerClass:[ViewHomeMenuCollectionCellText class] forCellWithReuseIdentifier:@"cellText"];
    [self.contentCollectionView registerClass:[ViewHomeMenuCollectionCellImage class] forCellWithReuseIdentifier:@"cellImage"];
    [self.contentCollectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"headAdView"];
    [self addSubview:self.contentCollectionView];
}

其中self.contentCollectionView.alwaysBounceVertical = YES;是为了避免数据过少导致无法下拉刷新。

    [self.contentCollectionView registerClass:[ViewHomeMenuCollectionCell class] forCellWithReuseIdentifier:@"cell"];
    [self.contentCollectionView registerClass:[ViewHomeMenuCollectionCellText class] forCellWithReuseIdentifier:@"cellText"];
    [self.contentCollectionView registerClass:[ViewHomeMenuCollectionCellImage class] forCellWithReuseIdentifier:@"cellImage"];
    [self.contentCollectionView registerClass:[UICollectionReusableView class] forSupplementaryViewOfKind:UICollectionElementKindSectionHeader withReuseIdentifier:@"headAdView"];

注册三个 Cell 及作为 headView 的UICollectionReusableView

UICollectionView 的 content 布局抽象成为一个 UICollectionViewLayout 对象。 UICollectionViewFlowLayout 则是 UICollectionViewLayout 的一个子类。
layout.itemSize = CGSizeMake(CELLWEIGHT, CELLHEIGHT);可以实现设定 Cell 的大小。另外还有一个属性 estimatedItemSize 则是 iOS 8.0 之后实现动态修改 cell 高宽的关键。
minimumLineSpacing最小行距
minimumInteritemSpacing最小间距
headerReferenceSizeheader大小
sectionInsetsection 的上左下右边距，不包括 UICollectionReusableView
self.contentCollectionView.contentInset = COLLECTIONCONTENTINSET;设置 collectionView content边距。

#pragma mark - UICollectionViewDelegateFlowLayout
-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    switch (indexPath.row%10) {
        case 0:
            return CGSizeMake((IOS_SCREEN_WIDTH-24)*0.333333333, (IOS_SCREEN_WIDTH-26)*0.3*1.2);
            break;
        case 1:
            return CGSizeMake((IOS_SCREEN_WIDTH-20)*0.666666667, (IOS_SCREEN_WIDTH-21)*0.3*1.2);
            break;
        case 5:
            return CGSizeMake((IOS_SCREEN_WIDTH-20)*0.666666667, (IOS_SCREEN_WIDTH-21)*0.3*1.2);
            break;
        case 6:
            return CGSizeMake((IOS_SCREEN_WIDTH-24)*0.333333333, (IOS_SCREEN_WIDTH-26)*0.3*1.2);
            break;
        default:
            return CGSizeMake((IOS_SCREEN_WIDTH-24)*0.333333333, ((IOS_SCREEN_WIDTH-26)/3)*0.37);
            break;
            }
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    NSDictionary *dct =  self.menuResult[indexPath.row];
    switch (indexPath.row%10) {
        case 0: {
             ViewHomeMenuCollectionCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
            cell.titleLabel.text = dct[@"name"];
            cell.backgroundColor = self.cellColorArray[indexPath.row % self.cellColorArray.count];
            [cell.titleLabel sizeToFit];
            return cell;
            break;
        }
        case 1: {
            ViewHomeMenuCollectionCellImage * cellImage = [collectionView dequeueReusableCellWithReuseIdentifier:@"cellImage" forIndexPath:indexPath];
            [cellImage.imageView setImageURL:[NSURL URLWithString:[self createPhoto:dct[@"photo"] width:cellImage.imageView.frame.size.width height:cellImage.imageView.frame.size.height]]];
            return cellImage;
            break;
        }
        case 5: {
            ViewHomeMenuCollectionCellImage * cellImage = [collectionView dequeueReusableCellWithReuseIdentifier:@"cellImage" forIndexPath:indexPath];
            [cellImage.imageView setImageURL:[NSURL URLWithString:[self createPhoto:dct[@"photo"] width:cellImage.imageView.frame.size.width height:cellImage.imageView.frame.size.height]]];
            return cellImage;
            break;
        }
        case 6: {
            ViewHomeMenuCollectionCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
            cell.titleLabel.text = dct[@"name"];
            cell.backgroundColor = self.cellColorArray[indexPath.row % self.cellColorArray.count];
            [cell.titleLabel sizeToFit];
            return cell;
            break;
        }
        default: {
             ViewHomeMenuCollectionCellText * cellText = [collectionView dequeueReusableCellWithReuseIdentifier:@"cellText" forIndexPath:indexPath];
            cellText.titleLabel.text = dct[@"name"];
            return cellText;
            break;
        }
    }
    //
  /*  ViewHomeMenuCollectionCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
    ViewHomeMenuCollectionCellText * cellText = [collectionView dequeueReusableCellWithReuseIdentifier:@"cellText" forIndexPath:indexPath];
    ViewHomeMenuCollectionCellImage * cellImage = [collectionView dequeueReusableCellWithReuseIdentifier:@"cellImage" forIndexPath:indexPath];
    NSDictionary *dct =  self.menuResult[indexPath.row];
    NSLog(@"%ld",indexPath.row%10);
    switch (indexPath.row%10) {
        case 0:
            cell.titleLabel.text = dct[@"name"];
            cell.backgroundColor = self.cellColorArray[indexPath.row % self.cellColorArray.count];
            return cell;
            break;
        case 1:
            [cellImage.imageView setImageURL:[NSURL URLWithString:[self createPhoto:dct[@"photo"] width:cellImage.imageView.frame.size.width height:cellImage.imageView.frame.size.height]]];
            return cellImage;
            break;
        case 5:
            [cellImage.imageView setImageURL:[NSURL URLWithString:[self createPhoto:dct[@"photo"] width:cellImage.imageView.frame.size.width height:cellImage.imageView.frame.size.height]]];
            return cellImage;
            break;
        case 6:
            cell.titleLabel.text = dct[@"name"];
            cell.backgroundColor = self.cellColorArray[indexPath.row % self.cellColorArray.count];
            return cell;
            break;
        default:
            cellText.titleLabel.text = dct[@"name"];
            return cellText;
            break;
    }*/
}