Question

我想绘制一个段落（所以我想使用CTFrameDraw或ctlinedraw）但我还需要截断文本，如果它不适合定义的区域（rect）。通常我们通过附加省略号来修剪最后一行（即字符'...'）如何做到这一点？如何使用像'... [+]'

这样的特殊字符来完成此操作

此外，我想知道如何为第一行指定缩进（以像素为单位），如果可以定义自定义 linespacing

并且要完成，我需要知道完全适合整个段落的确切最终矩形（它可能低于定义的区域）

Answer 1

将以下代码复制到测试项目中的viewDidLoad。

// Set the size of the area the paragraph will be drawn in.
CGSize sizeOfTextArea = CGSizeMake(200.0f, 100.0f);

// Sample text and views.
NSString *text = @"Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.";
UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, sizeOfTextArea.width, sizeOfTextArea.height)];
imageView.backgroundColor = [UIColor whiteColor];
[self.view addSubview:imageView];
self.view.backgroundColor = [UIColor blackColor];
CGRect textRect = imageView.frame;
UIButton *moreBtn = [UIButton buttonWithType:UIButtonTypeCustom];
moreBtn.frame = CGRectMake(CGRectGetMaxX(textRect)-45, CGRectGetMaxY(textRect), 45, 20);
[moreBtn setTitle:@"more" forState:UIControlStateNormal];
[self.view addSubview:moreBtn];

// Create a paragraph style and add it to attributed text options.
NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
style.firstLineHeadIndent = 10.0f;  // <- CHANGE THIS TO ADJUST INDENT
style.lineSpacing = 10.0f;          // <- CHANGE THIS TO ADJUST LINE SPACING
NSDictionary *attributes = @{NSParagraphStyleAttributeName : style};

// Render the text
// The options set the text to word-wrap and to add an ellipsis if needed.
UIGraphicsBeginImageContext(sizeOfTextArea);
NSAttributedString *attributedText = [[NSAttributedString alloc] initWithString:text attributes:attributes];
[attributedText drawWithRect:CGRectMake(0, 0, sizeOfTextArea.width, sizeOfTextArea.height)
                     options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingTruncatesLastVisibleLine
                     context:nil];
UIImage *renderedText = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

// Display the rendered text.
imageView.image = renderedText;

// Calculate the rect for the full text.  We fix the width and let iOS calculate the height.
CGRect fullTextRect = [attributedText boundingRectWithSize:CGSizeMake(sizeOfTextArea.width, CGFLOAT_MAX)
                                                   options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading
                                                   context:nil];
NSLog(@"full rect: %@", NSStringFromCGRect(fullTextRect));

// Show/hide more button depending on whether there's more text to show
moreBtn.hidden = CGRectGetHeight(fullTextRect) <= sizeOfTextArea.height;

对于省略号之后的[+]，在显示或隐藏的文本之后添加“更多”按钮，具体取决于是否有更多要显示的文本（请参阅上面的代码以了解我的意思）。

Answer 2

[month,number of sales]

使用上面的代码和你的NSMutableParagraphStyle *paragraph = [[NSMutableParagraphStyle alloc] init]; paragraph.lineBreakMode = NSLineBreakByTruncatingTail; [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraph range:NSMakeRange(0, [attributedString length])]; descriptionLabel.attributedText = attributedString;标签或按钮.U将在最后一行得到省略号。我也尝试在结束时附加字符串，但我没有。因为在有限的区域内，标签显示只有剩余隐藏的合适信息。在该行上表示除了椭圆之外我尝试了一些文本。请提供更少的信息。

IOS如何用省略号截断段落的最后一行？

2 个答案: