标签文本增加时如何以编程方式增加集合视图单元格高度？

Posted 2023-02-23

【中文标题】标签文本增加时如何以编程方式增加集合视图单元格高度？

【英文标题】：How to programmatically increase collection view cell height when label text increases?

【发布时间】：2018-08-13 10:14:41

【问题描述】：

如何增加 UICollectionViewCell 的高度？我在我的项目中实现了 2 个功能：

- (NSArray *)cellSizes 

/** Here we mentioned the code for size of collection view cells  **/
_cellSizes = [NSMutableArray array];

if ([homePageArray count] != 0 )

    _cellSizes = [NSMutableArray array];
    [_cellSizes removeAllObjects];

    for (NSInteger i = 0; i < [homePageArray count]; i++)
    
        CGSize size;
        UIImageView *sampleImage = [[[UIImageView alloc]init]autorelease];
        [sampleImage setFrame:CGRectMake(0,0,(delegate.windowWidth-30),150)];
        CGSize size1 = [self aspectScaledImageSizeForImageView:sampleImage width:150 height:150];
        //        [productTitleLbl setFont:[UIFont fontWithName:appFontRegular size:14]]; //78 //60
        CGFloat heightOfStr = [self heightForString:[[homePageArray objectAtIndex:i]objectForKey:@"item_title"] font:[UIFont fontWithName:appFontRegular size:14] maxWidth:(delegate.windowWidth-35)];

        size=CGSizeMake(size1.width, size1.height+((heightOfStr>30)?heightOfStr+55:85));
        _cellSizes[i] =[NSValue valueWithCGSize:size];
    

return _cellSizes;

对于我使用的图像

- (CGSize) aspectScaledImageSizeForImageView:(UIImageView *)iv width:(float)wid height:(float)hgth


float x,y;
float a,b;
x = iv.frame.size.width;
y = iv.frame.size.height;
a = wid;
b = hgth;

if ( x == a && y == b )            // image fits exactly, no scaling required
    // return iv.frame.size;

else if ( x > a && y > b )          // image fits completely within the imageview frame
    if ( x-a > y-b )               // image height is limiting factor, scale by height
        a = y/b * a;
        b = y;
     else 
        b = x/a * b;                // image width is limiting factor, scale by width
        a = x;
    

else if ( x < a && y < b )         // image is wider and taller than image view
    if ( a - x > b - y )           // height is limiting factor, scale by height
        a = y/b * a;
        b = y;
     else                         // width is limiting factor, scale by width
        b = x/a * b;
        a = x;
    

else if ( x < a && y > b )         // image is wider than view, scale by width
    b = x/a * b;
    a = x;

else if ( x > a && y < b )         // image is taller than view, scale by height
    a = y/b * a;
    b = y;

else if ( x == a ) 
    a = y/b * a;
    b = y;
 else if ( y == b ) 
    b = x/a * b;
    a = x;



return CGSizeMake(a,b);

对于我使用的字符串

- (CGFloat)heightForString:(NSString *)text font:(UIFont *)font maxWidth:(CGFloat)maxWidth 
if (![text isKindOfClass:[NSString class]] || !text.length) 
    // no text means no height
    return 0;


NSStringDrawingOptions options = NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading;
NSDictionary *attributes = @ NSFontAttributeName : font ;
CGSize size = [text boundingRectWithSize:CGSizeMake(maxWidth, CGFLOAT_MAX) options:options attributes:attributes context:nil].size;
CGFloat height = ceilf(size.height) + 1; // add 1 point as padding

return height;

在集合视图布局中

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


if([homePageArray count]!=0)
    return [self.cellSizes[indexPath.item] CGSizeValue];
else
    return CGSizeMake(0, 0);

我在

中计算了标签函数

CGFloat HeightForString = [self heightForString:[[homePageArray objectAtIndex:indexPath.row]objectForKey:@"item_title"] font:[UIFont fontWithName:appFontRegular size:14] maxWidth:cell.frame.size.width];
        [cell.productTitleLbl setFrame:CGRectMake(10, cell.frame.size.height-60, cell.frame.size.width,(HeightForString>30)?HeightForString:30)];

但如果标签的名称很长，则单元格不会调整大小。你能帮帮我吗？

【问题讨论】：

告诉集合视图重新加载数据，以便再次调用sizeForItem。

***.com/questions/18897896/…

【参考方案1】：

试试这个或浏览我发表评论的链接。

 itemTitleText =[[self.jsonData 
 objectAtIndex:indexPath.row]objectForKey:@"item_title"];


 NSAttributedString * attrStr = [[NSAttributedString alloc] initWithData:[itemTitleText 
 dataUsingEncoding:NSUTF8StringEncoding] options:@NSDocumentTypeDocumentAttribute: 
 NShtmlTextDocumentType, NSCharacterEncodingDocumentAttribute: [NSNumber 
 numberWithInt:NSUTF8StringEncoding] documentAttributes:nil error:nil];


    CGRect labelRect = [itemTitleText
                        boundingRectWithSize:CGSizeMake(270, CGFLOAT_MAX)
                        options:NSStringDrawingUsesLineFragmentOrigin
                        attributes:@
                         NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue- 
   Medium" size:14.0]
                                     
                        context:nil];
    cell.itemTitleText.frame=CGRectMake(cell.itemTitleText.frame.origin.x, 
     cell.itemTitleText.frame.origin.y, cell.itemTitleText.frame.size.width, 
    labelRect.size.height);