UICollectionViewCell「居左显示」

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UICollectionViewCell「居左显示」

准备:

1.UICollectionView Left Aligned Layout

• 一款UICollectionView居左显示的约束
  点击下载_UICollectionView Left Aligned Layout

UICollectionView Left Aligned Layout

工程目录:

工程目录

自定义UICollectionViewCell

CollectionViewCell.h 创建UILabel属性,用来传值

#import <UIKit/UIKit.h>
@interface CollectionViewCell : UICollectionViewCell
@property (nonatomic, strong) UILabel *titleLB;;
@end

CollectionViewCell.m 创建显示文本视图

• 此处titleLB文字大小要和计算的文字大小相同

#import "CollectionViewCell.h"
@implementation CollectionViewCell- (instancetype)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if (self) {
self.backgroundColor = [UIColor colorWithRed:251/255.0 green:74/255.0 blue:71/255.0 alpha:1];
self.layer.cornerRadius = 3;
self.layer.masksToBounds = YES;
self.layer.borderColor = [UIColor lightTextColor].CGColor;
self.layer.borderWidth = 0.5; [self createSubViews];
}
return self;
}- (void)createSubViews{
_titleLB = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
//_titleLB.backgroundColor = [UIColor yellowColor];
_titleLB.textColor = [UIColor whiteColor];
_titleLB.textAlignment = NSTextAlignmentCenter;
_titleLB.font = [UIFont systemFontOfSize:14];
[self.contentView addSubview:_titleLB];
}
@end

在ViewController中创建UICollectionView

ViewController.h

#import <UIKit/UIKit.h>
@interface ViewController : UIViewController@end

ViewController.m

#import "ViewController.h"
#import "UICollectionViewLeftAlignedLayout.h"
#import "CollectionViewCell.h"
@interface ViewController ()<UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout>@end@implementation ViewController{
NSArray *_allTextArr;
}- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.view.backgroundColor = [UIColor whiteColor];
[self initailData];
[self createMianView];
}/**
* 虚拟数据
*/
- (void)initailData{
_allTextArr = @[@"19朵玫瑰礼盒", @"19朵红玫瑰礼盒+百合", @"33朵红玫瑰礼盒", @"33朵红玫瑰礼盒(三世情缘)", @"33朵香槟玫瑰礼盒(生日推荐)", @"38朵红玫瑰心连心礼盒(一见倾心)", @"19朵红玫瑰礼盒(热卖推荐)", @"19朵粉玫瑰礼盒(热卖推荐)", @"19朵混色玫瑰礼盒"];
}/**
* 创建视图
*/
- (void)createMianView{
//居左约束
UICollectionViewLeftAlignedLayout *leftAlignedLayout = [[UICollectionViewLeftAlignedLayout alloc] init];
leftAlignedLayout.minimumLineSpacing = 10; //最小行间距
leftAlignedLayout.minimumInteritemSpacing = 10; //最小列间距
leftAlignedLayout.sectionInset = UIEdgeInsetsMake(20, 20, 20, 20); //网格上左下右间距 //网格
UICollectionView *mainCollectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height) collectionViewLayout:leftAlignedLayout];
mainCollectionView.backgroundColor = [UIColor whiteColor];
mainCollectionView.dataSource = self;
mainCollectionView.delegate = self;
[self.view addSubview:mainCollectionView];
[mainCollectionView registerClass:[CollectionViewCell class] forCellWithReuseIdentifier:@"cell"];
}- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}#pragma mark -UICollectionViewDataSource
//item内容
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
CollectionViewCell *cell = (CollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
cell.titleLB.text = [NSString stringWithFormat:@"%@", [_allTextArr objectAtIndex:indexPath.row]];
return cell;
}//Section中item数量
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
return _allTextArr.count;
}#pragma mark -UICollectionViewDelegate
//点击item触发方法
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{}#pragma mark -UICollectionViewDelegateFlowLayout
//设置每个item的尺寸
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{
NSString *textString = [_allTextArr objectAtIndex:indexPath.row];
CGFloat cell_width = [self settingCollectionViewItemWidthBoundingWithText:textString];
return CGSizeMake(cell_width, 30);
}//计算文字宽度
- (CGFloat)settingCollectionViewItemWidthBoundingWithText:(NSString *)text{
//1,设置内容大小 其中高度一定要与item一致,宽度度尽量设置大值
CGSize size = CGSizeMake(MAXFLOAT, 20);
//2,设置计算方式
//3,设置字体大小属性 字体大小必须要与label设置的字体大小一致
NSDictionary *attributeDic = @{NSFontAttributeName: [UIFont systemFontOfSize:14]};
CGRect frame = [text boundingRectWithSize:size options: NSStringDrawingUsesLineFragmentOrigin attributes:attributeDic context:nil];
//4.添加左右间距
return frame.size.width + 15;
}

运行效果:

效果图