ios uicollectionview 橫向滾動

現在使用卡片效果的app很多，之前公司讓實作一種卡片效果，就寫了一篇關于實作卡片的文章。文章最後附有demo

實作上我選擇了使用UICollectionView ；用UICollectionViewFlowLayout來定制樣式；下面看看具體實作

效果

實作上我選擇了使用UICollectionView ；用UICollectionViewFlowLayout來定制樣式；下面看看具體實作

具體實作

1、ViViewController.m 代碼實作

#import "ViewController.h"
#import "CollModel.h"
#define SCREEN_WIDTH  [UIScreen mainScreen].bounds.size.width
#define SCREEN_HEIGHT [UIScreen mainScreen].bounds.size.height
#define SCREEN_RATE   ([UIScreen mainScreen].bounds.size.width/375.0)
#import "imageCell.h"
#import "LHHorizontalPageFlowlayout.h"
static NSString * const imageC = @"imageCell";
static NSString * const moreImageC = @"imageCell";
static const NSInteger kItemCountPerRow = 5; //每行顯示5個
static const NSInteger kRowCount = 3; //每頁顯示行數
static float imageHeight = 80;//cell 高度
@interface ViewController ()<UICollectionViewDelegate,UICollectionViewDataSource>
@property (nonatomic, strong) UICollectionView * collectionView;
@property (nonatomic, strong) NSMutableArray * modelArray;
@property (nonatomic, strong) UICollectionView * moreCollectionView;
@end
@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
    NSArray *appArray = [[self getDict] objectForKey:@"dictInfo"];
    for (int i = 0; i < appArray.count; i++) {
        NSDictionary * appDic = appArray[i];
        CollModel * model = [[CollModel alloc]init];
        model.title = [appDic objectForKey:@"title"];
        model.url = [appDic objectForKey:@"url"];
        [self.modelArray addObject:model];
    }
    [self createCollectionView];
    [self createRightCollectionView];
}

- (NSDictionary *)getDict {
    NSString * string  = @"{\"dictInfo\":[{\"title\":\"你好啊\",\"url\":\"1.jpeg\"},{\"title\":\"你好啊\",\"url\":\"2.jpeg\"},{\"title\":\"你好啊\",\"url\":\"3.jpeg\"},{\"title\":\"你好啊\",\"url\":\"4.jpeg\"},{\"title\":\"你好啊\",\"url\":\"5.jpeg\"},{\"title\":\"你好啊\",\"url\":\"6.jpeg\"},{\"title\":\"是很好\",\"url\":\"7.jpeg\"},{\"title\":\"你好啊\",\"url\":\"1.jpeg\"},{\"title\":\"你好啊\",\"url\":\"2.jpeg\"},{\"title\":\"你好啊\",\"url\":\"3.jpeg\"},{\"title\":\"你好啊\",\"url\":\"4.jpeg\"},{\"title\":\"你好啊\",\"url\":\"5.jpeg\"},{\"title\":\"你好啊\",\"url\":\"6.jpeg\"},{\"title\":\"是很好\",\"url\":\"7.jpeg\"},{\"title\":\"你好啊\",\"url\":\"1.jpeg\"},{\"title\":\"你好啊\",\"url\":\"2.jpeg\"},{\"title\":\"你好啊\",\"url\":\"3.jpeg\"},{\"title\":\"你好啊\",\"url\":\"4.jpeg\"},{\"title\":\"你好啊\",\"url\":\"5.jpeg\"},{\"title\":\"你好啊\",\"url\":\"6.jpeg\"},{\"title\":\"是很好\",\"url\":\"7.jpeg\"}]}";
    NSDictionary *infoDic = [self dictionaryWithJsonString:string];
    return infoDic;
}


-(NSDictionary *)dictionaryWithJsonString:(NSString *)jsonString {
    if (jsonString == nil) {
        return nil;
    }
    NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    NSError *err;
    NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers  error:&err];
    if(err)
    {
        NSLog(@"json解析失敗：%@",err);
        return nil;
    }
    return dic;
}

- (NSMutableArray *)modelArray {
    if (!_modelArray) {
        _modelArray = [NSMutableArray array];
    }
    return _modelArray;
}

- (void)createCollectionView{
    UICollectionViewFlowLayout * layout = [[UICollectionViewFlowLayout alloc]init];
    layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
    layout.minimumLineSpacing = 0;
    layout.minimumInteritemSpacing = 0;
    _collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 100, [UIScreen mainScreen].bounds.size.width, imageHeight * SCREEN_RATE) collectionViewLayout:layout];
    _collectionView.tag = 11;
    _collectionView.backgroundColor = [UIColor colorWithRed:186 / 255.0 green:186 / 255.0 blue:186 / 255.0 alpha:0.9];
    _collectionView.dataSource = self;
    _collectionView.delegate = self;
    _collectionView.bounces = NO;
    _collectionView.alwaysBounceHorizontal = YES;
    _collectionView.alwaysBounceVertical = NO;
    _collectionView.showsHorizontalScrollIndicator = NO;
    _collectionView.showsVerticalScrollIndicator = NO;
    [self.view addSubview:_collectionView];
    [_collectionView registerClass:[imageCell class] forCellWithReuseIdentifier:imageC];
}

- (void)createRightCollectionView{
    
    LHHorizontalPageFlowlayout * layout = [[LHHorizontalPageFlowlayout alloc] initWithRowCount:kRowCount itemCountPerRow:kItemCountPerRow];
    [layout setColumnSpacing:0 rowSpacing:0 edgeInsets:UIEdgeInsetsMake(0, 0, 0, 0)];
    layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
    //    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc]init];
    //    layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
    layout.minimumLineSpacing = 0;
    layout.minimumInteritemSpacing = 0;
    _moreCollectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 300, [UIScreen mainScreen].bounds.size.width, imageHeight * SCREEN_RATE * kRowCount) collectionViewLayout:layout];
    _moreCollectionView.backgroundColor = [UIColor clearColor];
    _moreCollectionView.tag = 22;
    _moreCollectionView.dataSource = self;
    _moreCollectionView.delegate = self;
    _moreCollectionView.bounces = NO;
    _moreCollectionView.alwaysBounceHorizontal = YES;
    _moreCollectionView.alwaysBounceVertical = NO;
    _moreCollectionView.backgroundColor = [UIColor colorWithRed:186 / 255.0 green:186 / 255.0 blue:186 / 255.0 alpha:0.9];
    _moreCollectionView.showsHorizontalScrollIndicator = NO;
    _moreCollectionView.showsVerticalScrollIndicator = NO;
    [self.view addSubview:_moreCollectionView];
    [_moreCollectionView registerClass:[imageCell class] forCellWithReuseIdentifier:moreImageC];
}

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
    return self.modelArray.count;
}



- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    CollModel * model = self.modelArray[indexPath.row];
    imageCell * cell = [collectionView dequeueReusableCellWithReuseIdentifier:imageC forIndexPath:indexPath];
    cell.itemModel = model;
    return cell;
}

// 傳回每個item的大小
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    CGFloat CWidth =  imageHeight * SCREEN_RATE;
    CGFloat CHeight = imageHeight * SCREEN_RATE;
    return CGSizeMake(CWidth, CHeight);
}

#pragma mark - UICollectionViewDelegate點選事件
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{
    CollModel * model = self.modelArray[indexPath.row];
    NSLog(@"self.appModelArray----%@",model.title);
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

2、自定義UICollectionViewFlowLayout

LHHorizontalPageFlowlayout.h 實作

#import <UIKit/UIKit.h>
@interface LHHorizontalPageFlowlayout : UICollectionViewFlowLayout
/** 列間距 */
@property (nonatomic, assign) CGFloat columnSpacing;
/** 行間距 */
@property (nonatomic, assign) CGFloat rowSpacing;
/** collectionView的内邊距 */
@property (nonatomic, assign) UIEdgeInsets edgeInsets;

/** 多少行 */
@property (nonatomic, assign) NSInteger rowCount;
/** 每行展示多少個item */
@property (nonatomic, assign) NSInteger itemCountPerRow;

//固定寬度
@property (nonatomic, assign) CGFloat itemWidth; //設定完這個，就會自動計算列間距
//固定高度
@property (nonatomic, assign) CGFloat itemHight;//設定完這個，就會自動計算行間距

/** 所有item的屬性數組 */
@property (nonatomic, strong) NSMutableArray *attributesArrayM;

/** 設定行列間距及collectionView的内邊距 */
- (void)setColumnSpacing:(CGFloat)columnSpacing rowSpacing:(CGFloat)rowSpacing edgeInsets:(UIEdgeInsets)edgeInsets;
/** 設定多少行及每行展示的item個數 */
- (void)setRowCount:(NSInteger)rowCount itemCountPerRow:(NSInteger)itemCountPerRow;

#pragma mark - 構造方法
/** 設定多少行及每行展示的item個數 */
+ (instancetype)horizontalPageFlowlayoutWithRowCount:(NSInteger)rowCount itemCountPerRow:(NSInteger)itemCountPerRow;
/** 設定多少行及每行展示的item個數 */
- (instancetype)initWithRowCount:(NSInteger)rowCount itemCountPerRow:(NSInteger)itemCountPerRow;

@end

LHHorizontalPageFlowlayout.m 實作

#import "LHHorizontalPageFlowlayout.h"

@implementation LHHorizontalPageFlowlayout

#pragma mark - Public
- (void)setColumnSpacing:(CGFloat)columnSpacing rowSpacing:(CGFloat)rowSpacing edgeInsets:(UIEdgeInsets)edgeInsets
{
    self.columnSpacing = columnSpacing;
    self.rowSpacing = rowSpacing;
    self.edgeInsets = edgeInsets;
}

- (void)setRowCount:(NSInteger)rowCount itemCountPerRow:(NSInteger)itemCountPerRow
{
    self.rowCount = rowCount;
    self.itemCountPerRow = itemCountPerRow;
}

#pragma mark - 構造方法
+ (instancetype)horizontalPageFlowlayoutWithRowCount:(NSInteger)rowCount itemCountPerRow:(NSInteger)itemCountPerRow
{
    return [[self alloc] initWithRowCount:rowCount itemCountPerRow:itemCountPerRow];
}

- (instancetype)initWithRowCount:(NSInteger)rowCount itemCountPerRow:(NSInteger)itemCountPerRow
{
    self = [super init];
    if (self) {
        self.rowCount = rowCount;
        self.itemCountPerRow = itemCountPerRow;
    }
    return self;
}


#pragma mark - 重寫父類方法
- (instancetype)init
{
    self = [super init];
    if (self) {
        [self setColumnSpacing:0 rowSpacing:0 edgeInsets:UIEdgeInsetsZero];
    }
    return self;
}

/** 布局前做一些準備工作 */
- (void)prepareLayout
{
    [super prepareLayout];
    if (self.attributesArrayM && self.attributesArrayM.count > 0) {
        [self.attributesArrayM removeAllObjects];
    }
    
    // 從collectionView中擷取到有多少個item
    NSInteger itemTotalCount = [self.collectionView numberOfItemsInSection:0];
    
    // 周遊出item的attributes,把它添加到管理它的屬性數組中去
    for (int i = 0; i < itemTotalCount; i++) {
        NSIndexPath *indexpath = [NSIndexPath indexPathForItem:i inSection:0];
        UICollectionViewLayoutAttributes *attributes = [self layoutAttributesForItemAtIndexPath:indexpath];
        [self.attributesArrayM addObject:attributes];
    }
}

/** 計算collectionView的滾動範圍 */
- (CGSize)collectionViewContentSize
{
    // 計算出item的寬度
    CGFloat itemWidth = (self.collectionView.frame.size.width - self.edgeInsets.left - self.itemCountPerRow * self.columnSpacing) / self.itemCountPerRow;
    // 從collectionView中擷取到有多少個item
    NSInteger itemTotalCount = [self.collectionView numberOfItemsInSection:0];
    
    // 理論上每頁展示的item數目
    NSInteger itemCount = self.rowCount * self.itemCountPerRow;
    // 餘數（用于确定最後一頁展示的item個數）
    NSInteger remainder = itemTotalCount % itemCount;
    // 除數（用于判斷頁數）
    NSInteger pageNumber = itemTotalCount / itemCount;
    // 總個數小于self.rowCount * self.itemCountPerRow
    if (itemTotalCount <= itemCount) {
        pageNumber = 1;
    }else {
        if (remainder == 0) {
            pageNumber = pageNumber;
        }else {
            // 餘數不為0,除數加1
            pageNumber = pageNumber + 1;
        }
    }
    
    CGFloat width = 0;
    // 考慮特殊情況(當item的總個數不是self.rowCount * self.itemCountPerRow的整數倍,并且餘數小于每行展示的個數的時候)
    if (pageNumber > 1 && remainder != 0 && remainder < self.itemCountPerRow) {
        width = self.edgeInsets.left + (pageNumber - 1) * self.itemCountPerRow * (itemWidth + self.columnSpacing) + remainder * itemWidth + (remainder - 1)*self.columnSpacing + self.edgeInsets.right;
    }else {
        width = self.edgeInsets.left + pageNumber * self.itemCountPerRow * (itemWidth + self.columnSpacing) - self.columnSpacing + self.edgeInsets.right;
    }
    
    // 隻支援水準方向上的滾動
    return CGSizeMake(width, 150);
}

/** 設定每個item的屬性(主要是frame) */
- (UICollectionViewLayoutAttributes *)layoutAttributesForItemAtIndexPath:(NSIndexPath *)indexPath
{
    // item的寬高由行列間距和collectionView的内邊距決定
    CGFloat itemWidth = (self.collectionView.frame.size.width) / self.itemCountPerRow;
    CGFloat itemHeight = (self.collectionView.frame.size.height) / self.rowCount;
    
    NSInteger item = indexPath.item;
    // 目前item所在的頁
    NSInteger pageNumber = item / (self.rowCount * self.itemCountPerRow);
    NSInteger x = item % self.itemCountPerRow + pageNumber * self.itemCountPerRow;
    NSInteger y = item / self.itemCountPerRow - pageNumber * self.rowCount;
    
    // 計算出item的坐标
    CGFloat itemX = itemWidth * x;
    CGFloat itemY = itemHeight * y;
    
    UICollectionViewLayoutAttributes *attributes = [super layoutAttributesForItemAtIndexPath:indexPath];
    // 每個item的frame
    attributes.frame = CGRectMake(itemX, itemY, itemWidth, itemHeight);
    
    return attributes;
}

/** 傳回collectionView視圖中所有視圖的屬性數組 */
- (NSArray<UICollectionViewLayoutAttributes *> *)layoutAttributesForElementsInRect:(CGRect)rect
{
    return self.attributesArrayM;
}


#pragma mark - Lazy
- (NSMutableArray *)attributesArrayM
{
    if (!_attributesArrayM) {
        _attributesArrayM = [NSMutableArray array];
    }
    return _attributesArrayM;
}
@end

4、自定義cell 和model

model

#import <Foundation/Foundation.h>

@interface CollModel : NSObject
@property (nonatomic,strong)NSString *imgUrl;
@property (nonatomic,strong)NSString *title;
@property (nonatomic,strong)NSString *url;
@end

cell 自定義

#import "imageCell.h"
// 螢幕比例
#define SCREEN_RATE       ([UIScreen mainScreen].bounds.size.width/375.0)

@interface imageCell()
@property (nonatomic, strong) UIImageView *itemIcon;
@end

@implementation imageCell

@synthesize itemModel = _itemModel;

- (instancetype)initWithFrame:(CGRect)frame{
    if (self = [super initWithFrame:frame]) {
        self.contentView.backgroundColor = [UIColor clearColor];
        [self initView];
    }
    return self;
}

- (void)initView{
    _itemIcon = [[UIImageView alloc] init];
    [self.contentView addSubview:_itemIcon];
    _itemIcon.backgroundColor = [UIColor clearColor];
    CGFloat iconWidth = 80 * SCREEN_RATE;
    _itemIcon.frame = CGRectMake(0, 0, iconWidth, iconWidth);
    _itemIcon.center = self.contentView.center;
}

- (CollModel *)itemModel{
    return _itemModel;
}

- (void)setItemModel:(CollModel *)itemModel
{
    if (!itemModel) {
        return;
    }
    _itemModel = itemModel;
    
    [self setCellWithModel:_itemModel];
}

- (void)setCellWithModel:(CollModel *)itemModel{
    [[NSOperationQueue mainQueue] addOperationWithBlock:^{
        _itemIcon.image = [UIImage imageNamed:itemModel.url];
    }];
}

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