iphone notes.app 喜欢下划线

Question

我已经搜索了很多类似的问题，我决定在这里问这个问题，如果已经问过，我找不到它，抱歉。

我发现：UITextView like iPhone Notes application 重定向到这里：http://www.cocoanetics.com/2010/03/stuff-you-learn-from-reverse-engineering-notes-app/ 但在逆向工程中没有完整的代码示例！？

我正在为 iphone 创建一个应用程序，该应用程序存储并允许人们在 iphone 中输入他们的文本，如 notes.app。据我所知，我需要在文本下划线，我需要在 uitextview 中进行，这是 uiscrollview 的子类 ..

如果有人有任何建议，我会很高兴..

谢谢..

Answer 1

当我需要使用 UILabel 执行此操作时，我创建了 UIView 的子类并自己实现了自定义绘图。它非常详细，但并不那么复杂。我最终传递了处理粗体（ 和）和换行符（
）格式的类似HTML 的语法。我认为您可以使用 ( 和 u >) 对下划线做同样的事情。

基本上，我的技术是使用类似 HTML 的标记（首先在“br”标签上，然后在“b”标签上）拆分字符串，然后将每个子字符串拆分为“单词”，然后处理测量和单独绘制每个单词。如果一个单词不适合当前行，我会换行到下一行。它并不完美，它不能处理很多场景（例如，新的行标签不能放在粗体标签内），但它符合我的意图。

不幸的是，我不知道为什么某些（大多数/全部？）iOS 基本文本显示控件没有更好地支持文本格式。

---

编辑/更新：
我将继续添加我编写的 UIView 子类（UILabel 的替换）。使用风险自负！ :-)

MMFormattedTextView.h

#import <UIKit/UIKit.h><br>
@interface MMFormattedTextView : UIView {
    int InsetLeft;
    int InsetTop;
    NSString *LabelText;
    UIFont *LabelFont;
}
@property (assign, nonatomic) int InsetLeft;
@property (assign, nonatomic) int InsetTop;
@property (strong, nonatomic) NSString *LabelText;
@property (strong, nonatomic) UIFont *LabelFont;
- (NSInteger)numberOfLinesForRect:(CGRect)rect;
@end

MMFormattedTextView.m

#import "MMFormattedTextView.h"
@implementation MMFormattedTextView
@synthesize InsetLeft;
@synthesize InsetTop;
@synthesize LabelFont;
@synthesize LabelText;
// LIMITATION: Each bolded section must reside IN BETWEEN <br> tags; it MAY NOT span <br> tags!!!!
- (void)drawRect:(CGRect)rect {
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGContextClearRect(ctx, rect);
    // Sets up the first position, which is 1 line "off the top", 
    // adjusted so that the text will be centered when it's all drawn
    CGFloat howManyLinesWouldFit = rect.size.height / [[self LabelFont] lineHeight];
    NSInteger howManyLinesDoWeHave = [self numberOfLinesForRect:rect];
    CGFloat lineOffset = (howManyLinesWouldFit - howManyLinesDoWeHave) / 2.0;
    CGPoint topLeft = CGPointMake([self InsetLeft], [self InsetTop] - [[self LabelFont] lineHeight] + (lineOffset * [[self LabelFont] lineHeight]));
    // Split the text into hard-split lines (actual <br> tags in the text)
    NSArray *lines = [[self LabelText] componentsSeparatedByString:@"<br>"];
    // Iterate through each hard-coded line
    for (NSString *line in lines) {
        // Iterate to the next line
        topLeft = CGPointMake([self InsetLeft], topLeft.y + [[self LabelFont] lineHeight]);
        NSArray *pieces = [line componentsSeparatedByString:@"<b>"];
        BOOL bold = YES;
        for (NSString *piece in pieces) {
            bold = !bold;
            UIFont *fontToUse;
            if (bold) {
                fontToUse = [UIFont boldSystemFontOfSize:[[self LabelFont] pointSize]];
            } else {
                fontToUse = [UIFont systemFontOfSize:[[self LabelFont] pointSize]];
            }
            NSArray *words = [piece componentsSeparatedByString:@" "];
            for (NSString *word in words) {
                if ([word isEqualToString:@""]) continue;
                NSString *wordWithSpace = [NSString stringWithFormat:@"%@ ", word];
                CGSize wordSize = [wordWithSpace sizeWithFont:fontToUse];
                if ((topLeft.x + wordSize.width) > (rect.size.width - [self InsetLeft])) {
                    // This runs off this line, so go to the next line
                    topLeft = CGPointMake([self InsetLeft], topLeft.y + [[self LabelFont] lineHeight]);
                }
                [wordWithSpace drawAtPoint:topLeft withFont:fontToUse];
                topLeft = CGPointMake(topLeft.x + wordSize.width, topLeft.y);
            }
        }
    }
}
- (NSInteger)numberOfLinesForRect:(CGRect)rect {
    int retVal = 0;
    int left = [self InsetLeft];
    NSArray *lines = [[self LabelText] componentsSeparatedByString:@"<br>"];
    // Iterate through each hard-coded line
    for (NSString *line in lines) {
        // Iterate to the next line
        retVal = retVal + 1;
        left = [self InsetLeft];
        NSArray *pieces = [line componentsSeparatedByString:@"<b>"];
        BOOL bold = YES;
        for (NSString *piece in pieces) {
            bold = !bold;
            UIFont *fontToUse;
            if (bold) {
                fontToUse = [UIFont boldSystemFontOfSize:[[self LabelFont] pointSize]];
            } else {
                fontToUse = [UIFont systemFontOfSize:[[self LabelFont] pointSize]];
            }
            NSArray *words = [piece componentsSeparatedByString:@" "];
            for (NSString *word in words) {
                if ([word isEqualToString:@""]) continue;
                NSString *wordWithSpace = [NSString stringWithFormat:@"%@ ", word];
                CGSize wordSize = [wordWithSpace sizeWithFont:fontToUse];
                if ((left + wordSize.width) > (rect.size.width - [self InsetLeft])) {
                    // This runs off this line, so go to the next line
                    retVal = retVal + 1;
                    left = [self InsetLeft];
                }
                left = left + wordSize.width;
            }
        }
    }
    return retVal;
}
@end