Question

我有UITableView UITableViewCell s，我以函数heightForRowAtIndexPath设置每个单元格的高度：

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
    UITableViewCell *cell = [self tableView:tableView cellForRowAtIndexPath:indexPath];
    NSStringDrawingOptions opts = (NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading);
    CGSize boundingRect = CGSizeMake(450.f, CGFLOAT_MAX);
    CGSize size = [cell.detailTextLabel.text boundingRectWithSize:boundingRect
                                                      options:opts
                                                   attributes:[cell.detailTextLabel.attributedText attributesAtIndex:0 effectiveRange:nil]
                                                      context:nil].size;
    CGFloat height = size.height;
    size = [cell.textLabel.text boundingRectWithSize:boundingRect
                                         options:opts
                                      attributes:[cell.textLabel.attributedText attributesAtIndex:0 effectiveRange:nil]
                                         context:nil].size;
    height += size.height;
    return height;
}

但是我获得的单元格对于文本而言太小，而较长的文本不适合：

在单元格中写入的文本按以下方式设置：

NSString *nickName = @"some nickname"; // gets the nickname
NSString title = [NSString stringWithFormat:@"%@ wrote:", nickName];
NSString *detail = @"some text"; // gets the content of the message

[cell.textLabel setText: title];
[cell.detailTextLabel setText: detail];
cell.detailTextLabel.numberOfLines = 0;
cell.detailTextLabel.lineBreakMode = NSLineBreakByWordWrapping;

为什么细胞的高度太短？

Answer 1

从方法boundingRectWithSize:options:attributes:context:

https://developer.apple.com/reference/foundation/nsstring/1524729-boundingrectwithsize：

＆＃34;此方法返回字符串中字形的实际边界＆＃34;

缺少的是单元格的边距，可以使用cell.layoutMargins访问：

height += cell.layoutMargins.top + cell.layoutMargins.bottom;

Answer 2

尝试使用NSAttributedString（Swift 3）

的boundingRect方法

//change this value with the width of your UITableViewCell
let availableWidth:CGFloat = 355 

let stringBoundingRect = NSAttributedString(string: "your string").boundingRect(with: CGSize(width: availableWidth, height: CGFloat.greatestFiniteMagnitude), options: [.usesDeviceMetrics, .usesLineFragmentOrigin], context: nil)

let height = stringBoundingRect.height

在Objective-C中：

// change this value with the width of your UITableViewCell
CGFloat availableWidth = 355;

NSAttributedString *attrStr = [[NSAttributedString alloc] initWithString:@"your string"];
CGRect stringBoundingRect = [attrStr boundingRectWithSize:CGSizeMake(availableWidth, CGFLOAT_MAX) options: NSStringDrawingUsesLineFragmentOrigin| NSStringDrawingUsesDeviceMetrics context:nil];

CGFloat height = stringBoundingRect.size.height;

为什么UITableViewCell的高度小于其文本的高度？

2 个答案: