iphone notes.app喜欢下划线

Question

我已经搜索了很多类似的问题，我决定通过这里问这个，如果已经被问到我找不到它并抱歉。

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/但是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，它可以存储并让人们像iphone中的notes.app一样输入文本。我需要在我知道的情况下为文本加下划线，我需要在uitextview中进行操作，uitextview是uiscrollview的子类。

如果有人有任何建议让我很开心..

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，但并不复杂。我最终传递了类似HTML的语法，处理粗体（＆lt; b＆gt;和＆lt; / b＆gt;）和新行（＆lt; br＆gt;）格式。我认为你可能会对下划线使用（＆lt; u＆gt;和＆lt; / u＆gt;）做同样的事情。

基本上，我的技术是使用类似HTML的标记拆分字符串（首先在“br”标签上吐痰，然后在“b”标签上吐痰）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，我将换行到下一行。它并不完美，并且它不适用于很多场景（例如，新的行标签不能放在粗体标签内），但它适用于我的意图。

不幸的是，我不知道为什么在一些（大多数/全部？）iOS基本文本显示控件中不支持文本格式化。

---

修改/更新
我会继续添加UIView子类（替换UILabel）我写的。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