在用UILabel
和text
初始化之后,如何找到font
的实际行数?我已将其numberOfLines
属性设置为0
,因此它将扩展到需要许多行。但是,在设置text
之后,我怎么能找到最终得到的线数?
我发现了类似的问题,但似乎没有一个提供简洁的答案,在我看来,在没有任何开销与boundingRectWithSize
或sizeWithFont
杂耍的情况下获得它一定非常容易,...
第一选择:
首先根据字体计算文本的高度:
NSInteger lineCount = 0;
CGSize labelSize = (CGSize){yourLabel.frame.size.width, MAXFLOAT};
CGRect requiredSize = [self boundingRectWithSize:labelSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName: yourLabel.font} context:nil];
现在计算行数:
int charSize = lroundf(yourLabel.font.lineHeight);
int rHeight = lroundf(requiredSize.height);
lineCount = rHeight/charSize;
NSLog(@"No of lines: %i",lineCount);
第二种选择:
NSInteger lineCount = 0;
CGSize textSize = CGSizeMake(yourLabel.frame.size.width, MAXFLOAT);
int rHeight = lroundf([yourLabel sizeThatFits:textSize].height);
int charSize = lroundf(yourLabel.font.lineHeight);
lineCount = rHeight/charSize;
NSLog(@"No of lines: %i",lineCount);
let l = UILabel()
l.numberOfLines = 0
l.layer.frame.size.width = self.view.frame.width - 40 /*padding(20 + 20)*/
l.font = UIFont(name: "BwModelica-Bold", size: 16.0)
l.text = "Random Any length Text!!"
let noOfLines = ceil(l.intrinsicContentSize.width) / l.frame.width)
let lbl_height = noOfLines * l.intrinsicContentSize.height
这将是您的精确标签和行数的动态高度。快乐的编码!
请注意,@ kurt-j的答案并不总是有效。在某些情况下,您必须手动提供标签的宽度。由于存在这些情况,因此最好有一个可选的宽度参数,即使您最终没有使用它也是如此。
Swift 4.2:
extension UILabel {
func calculateMaxLines(actualWidth: CGFloat?) -> Int {
var width = frame.size.width
if let actualWidth = actualWidth {
width = actualWidth
}
let maxSize = CGSize(width: width, height: CGFloat(Float.infinity))
let charSize = font.lineHeight
let text = (self.text ?? "") as NSString
let textSize = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: font], context: nil)
let linesRoundedUp = Int(ceil(textSize.height/charSize))
return linesRoundedUp
}
}
似乎官方开发者网站在Objc中提到了一个解决方案Counting Lines of Text。但是,它假定您具有对使用布局管理器,文本存储和文本容器配置的文本视图的引用。不幸的是,UILabel没有向我们公开这些,所以我们需要使用与UILabel相同的配置创建它们。
我把Objc代码翻译成swift,如下所示。这似乎对我有用。
extension UILabel {
var actualNumberOfLines: Int {
let textStorage = NSTextStorage(attributedString: self.attributedText!)
let layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)
let textContainer = NSTextContainer(size: self.bounds.size)
textContainer.lineFragmentPadding = 0
textContainer.lineBreakMode = self.lineBreakMode
layoutManager.addTextContainer(textContainer)
let numberOfGlyphs = layoutManager.numberOfGlyphs
var numberOfLines = 0, index = 0, lineRange = NSMakeRange(0, 1)
while index < numberOfGlyphs {
layoutManager.lineFragmentRect(forGlyphAt: index, effectiveRange: &lineRange)
index = NSMaxRange(lineRange)
numberOfLines += 1
}
return numberOfLines
}
}
Xamarin iOS
label.Text = text;
var lineCount = 0;
var textSize = new CGSize(label.Frame.Size.Width, float.MaxValue);
var height = label.SizeThatFits(textSize).Height;
var fontHeight = label.Font.LineHeight;
lineCount = Convert.ToInt32(height / fontHeight);
这些都不适合我。下面做了一个,
Swift 4.2:
extension UILabel {
func calculateMaxLines() -> Int {
let maxSize = CGSize(width: frame.size.width, height: CGFloat(Float.infinity))
let charSize = font.lineHeight
let text = (self.text ?? "") as NSString
let textSize = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [NSAttributedString.Key.font: font], context: nil)
let linesRoundedUp = Int(ceil(textSize.height/charSize))
return linesRoundedUp
}
}
Swift 4 / 4.1:
extension UILabel {
func calculateMaxLines() -> Int {
let maxSize = CGSize(width: frame.size.width, height: CGFloat(Float.infinity))
let charSize = font.lineHeight
let text = (self.text ?? "") as NSString
let textSize = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [.font: font], context: nil)
let linesRoundedUp = Int(ceil(textSize.height/charSize))
return linesRoundedUp
}
}
斯威夫特3:
extension UILabel {
func calculateMaxLines() -> Int {
let maxSize = CGSize(width: frame.size.width, height: CGFloat(Float.infinity))
let charSize = font.lineHeight
let text = (self.text ?? "") as NSString
let textSize = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
let linesRoundedUp = Int(ceil(textSize.height/charSize))
return linesRoundedUp
}
}
Swift 5(IOS 12.2)
获取标签在不截断的情况下呈现文本所需的最大行数。
extension UILabel {
var maxNumberOfLines: Int {
let maxSize = CGSize(width: frame.size.width, height: CGFloat(MAXFLOAT))
let text = (self.text ?? "") as NSString
let textHeight = text.boundingRect(with: maxSize, options: .usesLineFragmentOrigin, attributes: [.font: font], context: nil).height
let lineHeight = font.lineHeight
return Int(ceil(textHeight / lineHeight))
}
}
获取最大行数可以显示在具有约束边界的标签中。将文本分配给标签后使用此属性。
extension UILabel {
var numberOfVisibleLines: Int {
let maxSize = CGSize(width: frame.size.width, height: CGFloat(MAXFLOAT))
let textHeight = sizeThatFits(maxSize).height
let lineHeight = font.lineHeight
return Int(ceil(textHeight / lineHeight))
}
}
用法
print(yourLabel.maxNumberOfLines)
print(yourLabel.numberOfVisibleLines)
这是@Paresh解决方案的快速版本:
func lines(label: UILabel) -> Int {
let textSize = CGSize(width: label.frame.size.width, height: CGFloat(Float.infinity))
let rHeight = lroundf(Float(label.sizeThatFits(textSize).height))
let charSize = lroundf(Float(label.font.lineHeight))
let lineCount = rHeight/charSize
return lineCount
}
编辑:我不知道为什么,但代码返回的行多于实际行数,对于我的解决方案,我只是在返回lineCount之前减去它们。
这里的其他答案不尊重numberOfLines
的UILabel
属性,当它设置为0以外的其他值时。
这是您可以添加到类别或子类的另一个选项:
- (NSUInteger)lineCount
{
CGSize size = [self sizeThatFits:CGSizeMake(self.frame.size.width, CGFLOAT_MAX)];
return MAX((int)(size.height / self.font.lineHeight), 0);
}
一些说明:
font
属性,并且它工作正常。如果您在attributedText
中使用多种字体,显然会遇到问题。UILabel
子类化为自定义边缘插入(例如通过重写drawTextInRect:
,这是一个巧妙的技巧,我发现here),那么你必须记住在计算上面的size
时考虑这些插入。例如:CGSizeMake(self.frame.size.width - (self.insets.left + self.insets.right), CGFLOAT_MAX)
这里是Swift3代码,您可以通过使用(MAXFLOAT)定义Int值并获取文本大小的高度,使用该高度可以获得UILabel的总高度,并通过字符大小来计算总高度,您可以获得实际行UILabel的数量。
var lineCount: Int = 0
var textSize = CGSize(width: CGFloat(yourLabel.frame.size.width), height: CGFloat(MAXFLOAT))
var rHeight: Int = lroundf(yourLabel.sizeThatFits(textSize).height)
var charSize: Int = lroundf(yourLabel.font.leading)
lineCount = rHeight / charSize
print("No of lines: \(lineCount)")
关注@Prince的回答,我现在在UILabel
上实现了一个类别,如下所示(注意我在他的回答中纠正了一些不会让代码编译的语法错误):
#import <UIKit/UIKit.h>
@interface UILabel (Util)
- (NSInteger)lineCount;
@end
#import "UILabel+Util.h"
@implementation UILabel (Util)
- (NSInteger)lineCount
{
// Calculate height text according to font
NSInteger lineCount = 0;
CGSize labelSize = (CGSize){self.frame.size.width, FLT_MAX};
CGRect requiredSize = [self.text boundingRectWithSize:labelSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName: self.font} context:nil];
// Calculate number of lines
int charSize = self.font.leading;
int rHeight = requiredSize.size.height;
lineCount = rHeight/charSize;
return lineCount;
}
@end
您可以在自定义标签中找到可用的总行数请检查此代码...
NSInteger numberOfLines = [self lineCountForText:@"YOUR TEXT"];
- (int)lineCountForText:(NSString *) text
{
UIFont *font = [UIFont systemFontOfSize: 15.0];
int width=Your_LabelWidht;
CGRect rect = [text boundingRectWithSize:CGSizeMake(width, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : font} context:nil];
return ceil(rect.size.height / font.lineHeight);
}
Xamarin.iOS
感谢上面提供的每个人的答案。
这会获得可见行数。
public static int VisibleLineCount(this UILabel label)
{
var textSize = new CGSize(label.Frame.Size.Width, nfloat.MaxValue);
nfloat rHeight = label.SizeThatFits(textSize).Height;
nfloat charSize = label.Font.LineHeight;
return Convert.ToInt32(rHeight / charSize);
}
这将获得文本在屏幕上占用的实际行数。
public static int LineCount(this UILabel label)
{
var maxSize = new CGSize(label.Frame.Size.Width, nfloat.MaxValue);
var charSize = label.Font.LineHeight;
var text = (label.Text ?? "").ToNSString();
var textSize = text.GetBoundingRect(maxSize, NSStringDrawingOptions.UsesLineFragmentOrigin, new UIStringAttributes() { Font = label.Font }, null);
return Convert.ToInt32(textSize.Height / charSize);
}
我认为对我的用例有用的辅助方法。
public static bool IsTextTruncated(this UILabel label)
{
if (label.Lines == 0)
{
return false;
}
return (label.LineCount() > label.Lines);
}
要获得更准确的行数:
font.lineHeight
而不是font.pointSize