iOS~ UICollectionView 無(wú)縫緊密排列

1、先上圖：
一般排列的間隔會(huì)出現(xiàn)不準(zhǔn)確的情況：（間隔10） 而我們想要實(shí)現(xiàn)每個(gè)cell以最小間距緊密排列:
IMG_0024.PNG
IMG_0023.PNG
2、原理：

1、（swift）UICollectionView Cell大小自適應(yīng) 并靠左對(duì)齊最簡(jiǎn)單的實(shí)現(xiàn)
2、（OC）UICollectionView的無(wú)縫排序

  • 1、重寫(xiě)一個(gè)繼承自UICollectionViewFlowLayout類(lèi)的子類(lèi)：
    復(fù)雜的方法是自己寫(xiě)一個(gè)UICollectionViewLayout，這里我選擇了一種更簡(jiǎn)單的方法，根據(jù)系統(tǒng)的布局來(lái)進(jìn)行調(diào)整，創(chuàng)建一個(gè)UICollectionViewLeftFlowLayout類(lèi)繼承UICollectionViewFlowLayout，重寫(xiě)layoutAttributesForElements(in rect:CGRect)方法

UICollectionViewFlowLayout.h文件：

@interface New_DictionUICollectionViewLeftFlowLayout : UICollectionViewFlowLayout

@end

UICollectionViewFlowLayout.m文件：

#import "New_DictionUICollectionViewLeftFlowLayout.h"

@implementation New_DictionUICollectionViewLeftFlowLayout


- (NSArray *)layoutAttributesForElementsInRect:(CGRect) rect {
    NSMutableArray *attributes = [[super layoutAttributesForElementsInRect:rect] mutableCopy];
    
    for (UICollectionViewLayoutAttributes *attr in attributes) {
        
        // 每個(gè)cell的frame
        NSLog(@"???? = %@", NSStringFromCGRect([attr frame]));
        /*
         數(shù)組后發(fā)現(xiàn)數(shù)據(jù)還是有間隔，
         然后確定思路，將里面的數(shù)據(jù)進(jìn)行更改就實(shí)現(xiàn)了緊密排版
         貼上代碼：
         
        2021-10-14 17:42:17.788922+0800 km[6277:377641] ???? = {{15, 5}, {115, 32}}
        2021-10-14 17:42:26.627243+0800 km[6277:377641] ???? = {{197, 5}, {163, 32}}
        2021-10-14 17:42:26.627660+0800 km[6277:377641] ???? = {{15, 47}, {138, 32}}
        2021-10-14 17:42:26.627932+0800 km[6277:377641] ???? = {{189.5, 47}, {86, 32}}
        2021-10-14 17:42:26.628892+0800 km[6277:377641] ???? = {{312, 47}, {48, 32}}
        2021-10-14 17:42:26.629597+0800 km[6277:377641] ???? = {{15, 89}, {92, 32}}
        2021-10-14 17:42:26.630260+0800 km[6277:377641] ???? = {{117, 89}, {90, 32}}
         */
    }
    
    
    for (UICollectionViewLayoutAttributes *attr in attributes) {
        NSLog(@"%@", NSStringFromCGRect([attr frame]));
    }
    
    /// 下面代碼，設(shè)置后，就會(huì)實(shí)現(xiàn)自己想要的結(jié)果了：
    //從第二個(gè)循環(huán)到最后一個(gè)
    for(int i = 1; i < [attributes count]; ++i) {
        //當(dāng)前attributes
        UICollectionViewLayoutAttributes *currentLayoutAttributes = attributes[i];
        //上一個(gè)attributes
        UICollectionViewLayoutAttributes *prevLayoutAttributes = attributes[i - 1];
        //我們想設(shè)置的最大間距，可根據(jù)需要改
        NSInteger maximumSpacing = [UIScreen mainScreen].bounds.size.width/375*10;
        //前一個(gè)cell的最右邊
        NSInteger origin = CGRectGetMaxX(prevLayoutAttributes.frame);
        //如果當(dāng)前一個(gè)cell的最右邊加上我們想要的間距加上當(dāng)前cell的寬度依然在contentSize中，我們改變當(dāng)前cell的原點(diǎn)位置
        //不加這個(gè)判斷的后果是，UICollectionView只顯示一行，原因是下面所有cell的x值都被加到第一行最后一個(gè)元素的后面了
        if(origin + maximumSpacing + currentLayoutAttributes.frame.size.width < self.collectionViewContentSize.width) {
            CGRect frame = currentLayoutAttributes.frame;
            frame.origin.x = origin + maximumSpacing;
            currentLayoutAttributes.frame = frame;
        }
        /*
        /// 注意：（當(dāng)前的cell寬度要加上當(dāng)前這個(gè)cell右邊的間隔后，再判斷是否一行是否能放開(kāi)，+ [UIScreen mainScreen].bounds.size.width/375*10）
        //如果當(dāng)前一個(gè)cell的最右邊加上我們想要的間距加上當(dāng)前cell的寬度依然在contentSize中，我們改變當(dāng)前cell的原點(diǎn)位置（當(dāng)前的cell寬度要加上當(dāng)前這個(gè)cell右邊的間隔）
        //不加這個(gè)判斷的后果是，UICollectionView只顯示一行，原因是下面所有cell的x值都被加到第一行最后一個(gè)元素的后面了
        if(origin + maximumSpacing + currentLayoutAttributes.frame.size.width + [UIScreen mainScreen].bounds.size.width/375*10 < self.collectionViewContentSize.width) {
            CGRect frame = currentLayoutAttributes.frame;
            frame.origin.x = origin + maximumSpacing;
            currentLayoutAttributes.frame = frame;
        }
        */
    }

    return attributes;

    
    
    return [attributes copy];
}


@end
  • 2、使用：
- (void)setupUI {
    
//    UICollectionViewFlowLayout *layout = [[UICollectionViewFlowLayout alloc] init];
    /// 重寫(xiě)一個(gè)繼承自UICollectionViewFlowLayout類(lèi)的子類(lèi)：
    New_DictionUICollectionViewLeftFlowLayout *layout = [[New_DictionUICollectionViewLeftFlowLayout alloc] init];
    
    layout.scrollDirection = UICollectionViewScrollDirectionVertical;
    layout.sectionHeadersPinToVisibleBounds = NO;
    layout.sectionFootersPinToVisibleBounds = NO;
    
    UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:layout];
    collectionView.backgroundColor = [UIColor whiteColor];
    collectionView.delegate = self;
    collectionView.dataSource = self;
    collectionView.showsVerticalScrollIndicator = NO;
    collectionView.scrollEnabled = NO;
    [self addSubview:collectionView];
    [collectionView makeConstraints:^(MASConstraintMaker *make) {
        //make.edges.equalTo(self);
        make.top.bottom.equalTo(self);
        make.left.mas_equalTo(self.mas_left).offset([UIScreen mainScreen].bounds.size.width/375*15);
        make.right.mas_equalTo(self.mas_right).offset(-[UIScreen mainScreen].bounds.size.width/375*14);
    }];
    [collectionView registerClass:[N_DictionaryPanelRecordCell class] forCellWithReuseIdentifier:NSStringFromClass([N_DictionaryPanelRecordCell class])];
    self.collectionView = collectionView;
    
}

- (void)refreshCollectionView {
    [self.collectionView reloadData];
}

#pragma mark -- <UICollectionViewDelegate>
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {
    return 1;
}

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

-(CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
    
    CGFloat width = 0;
    CGFloat height = 0;
    
    if (self.searchArray.count > 0) {
        // 根據(jù)字符串的長(zhǎng)度，來(lái)設(shè)置寬度
        NSString *itemString = [NSString stringWithFormat:@"%@", self.searchArray[indexPath.row][@"word"]];
        if (itemString.length > 0 && ![itemString isEqualToString:@"(null)"] && ![itemString isEqualToString:@"<null>"]) {
            //（單行文本）
            CGSize size = [itemString sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:[UIScreen mainScreen].bounds.size.width/375*15 weight:UIFontWeightRegular]}];
            
            width = ceil(size.width) + [UIScreen mainScreen].bounds.size.width/375*(10 + 5 + 13 + 10); // ceil 如果參數(shù)是小數(shù)，則求最小的證書(shū)但不小于本身
            height = ceil(size.height);
        }
        
        if (width > [UIScreen mainScreen].bounds.size.width/375*335) {
            width = [UIScreen mainScreen].bounds.size.width/375*335;
        }
    }
        
    return CGSizeMake(width, [UIScreen mainScreen].bounds.size.width/375*32);
    
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section {
    // 水平上下
    return [UIScreen mainScreen].bounds.size.width/375*10;
}

- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section {
    // 垂直左右
    return [UIScreen mainScreen].bounds.size.width/375*10;
}

- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout insetForSectionAtIndex:(NSInteger)section {
    // section 邊界
    return UIEdgeInsetsMake([UIScreen mainScreen].bounds.size.width/375*5, [UIScreen mainScreen].bounds.size.width/375*15, [UIScreen mainScreen].bounds.size.width/375*5, [UIScreen mainScreen].bounds.size.width/375*15);
}

- (nonnull __kindof UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
    N_DictionaryPanelRecordCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:NSStringFromClass([N_DictionaryPanelRecordCell class]) forIndexPath:indexPath];
    if (self.searchArray.count > 0) {
        cell.itemDic = self.searchArray[indexPath.row];
    }
    __weak typeof(self) weakSelf = self;
    cell.deleteAloneWordRecordBlock = ^(BOOL isDeleteWordRecord) {
        if (isDeleteWordRecord) {
            NSMutableArray *recordArr = [NSMutableArray arrayWithCapacity:0];
            recordArr = [weakSelf.searchArray mutableCopy];
            
            [recordArr removeObject:[NSString stringWithFormat:@"%@", weakSelf.searchArray[indexPath.row]]];
            weakSelf.searchArray = [recordArr copy];
            
            [[NSUserDefaults standardUserDefaults] setObject:weakSelf.searchArray forKey:@"dictionary"];
            [[NSUserDefaults standardUserDefaults] synchronize];
            
            [weakSelf.collectionView reloadData];
        }
    };
    
    return cell;
}

- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
    N_DictionaryPanelRecordCell *cell = (N_DictionaryPanelRecordCell *)[collectionView cellForItemAtIndexPath:indexPath];
    
    NSDictionary *dic = [self.searchArray objectAtIndex:indexPath.row];
    NSString *word = [NSString stringWithFormat:@"%@",[dic valueForKey:@"word"]];
    
    if ([word isChinese])
    {
        
    }
    else
    {

    }
}
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