ios - 使用 drawInRect:withAttributes 对齐文本：

Question

在我的应用程序的 iOS 5 版本中，我有：

[self.text drawInRect: stringRect
             withFont: [UIFont fontWithName: @"Courier" size: kCellFontSize]
        lineBreakMode: NSLineBreakByTruncatingTail
            alignment: NSTextAlignmentRight];

我正在升级 iOS 7。不推荐使用上述方法。我现在正在使用drawInRect:withAttributes:。attributes参数是一个 NSDictionary 对象。我可以让drawInRect:withAttributes:使用这个来处理前一个字体参数：

      UIFont *font = [UIFont fontWithName: @"Courier" size: kCellFontSize];

      NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys: font, NSFontAttributeName,
                                  nil];

      [self.text drawInRect: stringRect
             withAttributes: dictionary];

我将哪些键值对添加到字典以获取NSLineBreakByTruncatingTail和NSTextAlignmentRight？

Answer 1

一键设置文本的段落样式（包括换行模式、文​​本对齐方式等）。

来自文档：

NSParagraphStyleAttributeName

该属性的值是一个NSParagraphStyle对象。使用此属性可将多个属性应用于一系列文本。如果不指定此属性，则字符串使用默认的段落属性，由 的defaultParagraphStyle方法返回NSParagraphStyle。

因此，您可以尝试以下方法：

UIFont *font = [UIFont fontWithName:@"Courier" size:kCellFontSize];

/// Make a copy of the default paragraph style
NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
/// Set line break mode
paragraphStyle.lineBreakMode = NSLineBreakByTruncatingTail;
/// Set text alignment
paragraphStyle.alignment = NSTextAlignmentRight;

NSDictionary *attributes = @{ NSFontAttributeName: font,
                    NSParagraphStyleAttributeName: paragraphStyle };

[text drawInRect:rect withAttributes:attributes];

Answer 2

代码是这样的：

CGRect textRect = CGRectMake(x, y, length-x, maxFontSize);
UIFont *font = [UIFont fontWithName:@"Courier" size:maxFontSize];
NSMutableParagraphStyle *paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
    paragraphStyle.lineBreakMode = NSLineBreakByTruncatingTail;


   paragraphStyle.alignment = NSTextAlignmentRight;
    NSDictionary *attributes = @{ NSFontAttributeName: font,
                                  NSParagraphStyleAttributeName: paragraphStyle,
                                  NSForegroundColorAttributeName: [UIColor whiteColor]};
[text drawInRect:textRect withAttributes:attributes];