Content of a specific line in UITextView

Is it possible to extract the string content of a specific line in a 开发者_开发百科UITextView? Thanks.

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Just add a category to the UITextView. Note that is is pretty expensive, but definitely the simplest way to do it. Also it doesn't work for other kinds of newlines, like "\r", but you could add that.

// UITextView+ContentsOfLine.h
@interface UITextView (ContentsOfLine) 
- (NSString*)contentsOfLine:(NSInteger)line;
@end

// UITextView+ContentsOfLine.m
@implementation UITextView (ContentsOfLine)
- (NSString*)contentsOfLine:(NSInteger)line {
    NSArray* contents = [[self text] componentsSeparatedByString:@"\n"];
    if( [contents length] > line ) {
        return [contents objectAtIndex:line];
    }
    return nil;
}
@end

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Finding the content of a line in UITextView can only be solved through an extremely expensive process of iteration using the "sizeWithFont" methods. It could be done for a static page, but is not suitable for content that appears in a scrollview or tableview.