从UITextView和NSLayoutManager获取行信息 [英] Get line information from UITextView and NSLayoutManager

问题描述

为了支持 UIAccessibilityReadingContent 协议，我需要我的UITextView来回答有关其行的问题。这些是我需要实现的协议的方法：

In order to support the UIAccessibilityReadingContent protocol, I need my UITextView to answer me questions about its lines. These are the methods of the protocol that I need to implement:

• accessibilityLineNumberForPoint： < - 提供坐标，返回行号


• accessibilityContentForLineNumber：< - 返回给定行的文本


• accessibilityFrameForLineNumber：< - 给定行号，返回其框架


• accessibilityPageContent < - 整个文本内容。我有。 ：）

• accessibilityLineNumberForPoint: <- Provided a coordinate, return a line number
• accessibilityContentForLineNumber: <- Return the text of a given line
• accessibilityFrameForLineNumber: <- Given a line number, return its frame
• accessibilityPageContent <- The entire text content. That I have. :)

我认为NSLayoutManager可以帮助我，但我对它没有经验。我已经想到了一些（我认为），但仍需要一些帮助。

I figure that NSLayoutManager can help me, but I'm not that experienced with it. I've figured some of it out (I think), but still need some help.

Apple有一些示例代码（这里）可以获取文本视图中的行数：

Apple has some sample code (here) that can get me the number of lines in the text view:

NSLayoutManager *layoutManager = [textView layoutManager];
unsigned numberOfLines, index, numberOfGlyphs =
        [layoutManager numberOfGlyphs];
NSRange lineRange;
for (numberOfLines = 0, index = 0; index < numberOfGlyphs; numberOfLines++){
    (void) [layoutManager lineFragmentRectForGlyphAtIndex:index
            effectiveRange:&lineRange];
    index = NSMaxRange(lineRange);
}

我认为 lineRange 上面，我可以在 NSLayoutManager 上使用此方法计算行数：

I figure that with lineRangeabove, I can calculate the line rects using this method on NSLayoutManager:

- (NSRect)boundingRectForGlyphRange:(NSRange)glyphRange inTextContainer:(NSTextContainer *)container

给出 lineRanges 我应该能够计算一个点的行号（通过找到包含字形的 lineRange index：

And given lineRanges I should be able to calculate the line number for a point using (by finding the lineRange that contains the glyph index:

- (NSUInteger)glyphIndexForPoint:(CGPoint)point inTextContainer:(NSTextContainer *)container fractionOfDistanceThroughGlyph:(CGFloat *)partialFraction

剩下的就是，如何获取一行的内容（ NSString ），给定一个行号？

So what remains is, how do I get the content of a line (as an NSString), given a line number?

推荐答案

思考一个简单的解决方案，这里是一个重现你需要的小代码

thinking in an easy solution, here is a small code that reproduce what you need

- (void)analyse:(UITextView *)textView
{
    NSLayoutManager *layoutManager = [textView layoutManager];
    NSString *string = textView.text;
    unsigned numberOfLines, index, stringLength = [string length];

    NSMutableArray *ranges = [NSMutableArray new];
    NSMutableArray *frames = [NSMutableArray new];
    for (index = 0, numberOfLines = 0; index < stringLength; numberOfLines++)
    {
        NSRange tmprange;
        NSRange range = [string lineRangeForRange:NSMakeRange(index, 0)];
        CGRect rect = [layoutManager lineFragmentRectForGlyphAtIndex:index
                                           effectiveRange:&tmprange];

        [ranges addObject:[NSValue valueWithRange:range]];

        [frames addObject:[NSValue valueWithCGRect:rect]];
        index = NSMaxRange(range);
    }
    self.ranges = ranges;
    self.frames = frames;
    self.numberOfLines = numberOfLines;
}

请查看房产：

self.ranges = ranges;
self.frames = frames;
self.numberOfLines = numberOfLines;

您可以在班级中使用以下内容来创建此属性：

You can have the following in your class to create this properties:

@property (nonatomic) NSInteger numberOfLines;
@property (strong, nonatomic) NSArray *ranges;
@property (strong, nonatomic) NSArray *frames;

我建议您在以下代理中添加分析调用：

I suggest you to add the analyse call inside the following delegate:

- (void)textViewDidChange:(UITextView *)textView

例如，你可以在分析后得到第二行的框架： self.frames [1]

There you can for example after analyse get the frame of the 2nd line just doing: self.frames[1]

或者获取第二行的文本： [textView.text substringWithRange：[self.ranges [1] rangeValue]]

Or getting the text of the second line doing: [textView.text substringWithRange:[self.ranges[1] rangeValue]]

For像这样的例子：

For example like this:

if (self.numberOfLines > 1)
{
    NSRange range = [self.ranges[1] rangeValue];
    NSLog(@"2nd line = %@", [textView.text substringWithRange:range]);
    NSLog(@"2nd line frame = %@", self.frames[1]);
}

拥有 self.frames 中的所有帧认为你可以轻松做另一件事，用坐标猜测行号。

Having all the frames in self.frames I think you can easily do the other thing, guess the line number using a coordinate.

这篇关于从UITextView和NSLayoutManager获取行信息的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！