iOS - Label文字竖排

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前言:

有的需求会给出文字竖排的方式,下面给出两种思路来实现这种效果.一是为UILabel添加分类,添加一个文字竖排的属性;而是为NSString添加分类,添加一个文字竖排的方法- (NSString *)VerticalString

方法一(UILabel添加分类):

#import <UIKit/UIKit.h>

@interface UILabel (Extension)
@property (nonatomic) NSString *verticalText;
@end

#import "UILabel+Extension.h"
#import "objc/Runtime.h"

@implementation UILabel (Extension)
- (NSString *)verticalText{
    // 利用runtime添加属性
    return objc_getAssociatedObject(self, @selector(verticalText));
}

- (void)setVerticalText:(NSString *)verticalText{
    objc_setAssociatedObject(self, &verticalText, verticalText, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    NSMutableString *str = [[NSMutableString alloc] initWithString:verticalText];
    NSInteger count = str.length;
    for (int i = 1; i < count; i ++) {
        [str insertString:@"\n" atIndex:i*2-1];
    }
    self.text = str;
    self.numberOfLines = 0;
}
@end

具体用法如下:

   NSString *string = @"北冥有鱼，其名为鲲。";
    UILabel *label = [[UILabel alloc] initWithFrame:(CGRectMake(self.view.bounds.size.width * 0.5, 100, 300, 600))];
    label.textColor = [UIColor redColor];
    label.verticalText = string;
    [label sizeToFit];//顶部显示
    [self.view addSubview:label];

方法二(为NSSring添加分类):

#import <Foundation/Foundation.h>

@interface NSString (Extension)

- (NSString *)VerticalString;

@end

#import "NSString+Extension.h"

@implementation NSString (Extension)
- (NSString *)VerticalString{
    NSMutableString * str = [[NSMutableString alloc] initWithString:self];
    NSInteger count = str.length;
    for (int i = 1; i < count; i ++) {
        [str insertString:@"\n" atIndex:i*2 - 1];
    }
    return str;
}

@end

具体用法如下:

NSString *verText = [@"北冥有鱼，其名为鲲。" VerticalString];
    UILabel *label = [[UILabel alloc] initWithFrame:(CGRectMake(self.view.bounds.size.width * 0.5, 100, 300, 600))];
    label.text = verText;
    label.numberOfLines = 0;
    label.textColor = [UIColor redColor];
    [label sizeToFit];//顶部显示
    [self.view addSubview:label];