iOS UILabel自定义位置

前言

• 系统Api提供的textAlignment位置我们一般只会用到左边、右边、中间三种显示方式，于是写个分类提供更多的显示位置，分别包含左上、右上、左下、右下、中上、中下
• 采用Category的方式处理，简单方便使用

GitHub地址：KJCategories

简单介绍 Property & API

NS_ASSUME_NONNULL_BEGIN
/// Label 文本显示样式
typedef NS_ENUM(NSUInteger, KJLabelTextAlignmentType) {
    KJLabelTextAlignmentTypeLeft = 0,
    KJLabelTextAlignmentTypeRight,
    KJLabelTextAlignmentTypeCenter,
    KJLabelTextAlignmentTypeLeftTop,
    KJLabelTextAlignmentTypeRightTop,
    KJLabelTextAlignmentTypeLeftBottom,
    KJLabelTextAlignmentTypeRightBottom,
    KJLabelTextAlignmentTypeTopCenter,
    KJLabelTextAlignmentTypeBottomCenter,
};
@interface UILabel (KJExtension)
/// 设置文字内容显示位置，外部不需要再去设置 " textAlignment " 属性
@property(nonatomic,assign)KJLabelTextAlignmentType kTextAlignmentType;
/// 获取高度
- (CGFloat)kj_calculateHeightWithWidth:(CGFloat)width;
/// 获取高度，指定行高
- (CGFloat)kj_calculateHeightWithWidth:(CGFloat)width OneLineHeight:(CGFloat)height;
/// 获取文字尺寸
+ (CGSize)kj_calculateLabelSizeWithTitle:(NSString*)title font:(UIFont*)font constrainedToSize:(CGSize)size lineBreakMode:(NSLineBreakMode)lineBreakMode;

@end

NS_ASSUME_NONNULL_END

1. kTextAlignmentType 设置文本位置，

这里需要注意的就是内部有使用到系统的textAlignment 属性，因此调用该属性的话，则不需要调用textAlignment属性

使用示例

CGFloat x,y;
CGFloat sp = kAutoW(10);
CGFloat w = (kScreenW-sp*4)/3.;
CGFloat h = w*9/16;
NSArray *names = @[@"左边",@"右边",@"中间",@"左上",@"右上",@"左下",@"右下",@"中上",@"中下"];
NSInteger types[9] = {
    KJLabelTextAlignmentTypeLeft,
    KJLabelTextAlignmentTypeRight,
    KJLabelTextAlignmentTypeCenter,
    KJLabelTextAlignmentTypeLeftTop,
    KJLabelTextAlignmentTypeRightTop,
    KJLabelTextAlignmentTypeLeftBottom,
    KJLabelTextAlignmentTypeRightBottom,
    KJLabelTextAlignmentTypeTopCenter,
    KJLabelTextAlignmentTypeBottomCenter
};
for (int k=0; k<names.count; k++) {
    x = k%3*(w+sp)+sp;
    y = k/3*(h+sp)+sp+64+sp*2;
    UILabel *label = [UILabel kj_createLabelWithText:names[k] FontSize:16 TextColor:UIColor.orangeColor];
    label.backgroundColor = [UIColor.orangeColor colorWithAlphaComponent:0.2];
    label.kTextAlignmentType = types[k];
    label.borderWidth = 1;
    label.borderColor = UIColor.orangeColor;
    label.frame = CGRectMake(x, y, w, h);
    [self.view addSubview:label];
}

Category

//
//  UILabel+KJExtension.m
//  KJEmitterView
//
//  Created by 杨科军 on 2020/9/24.
//  Copyright © 2020 杨科军. All rights reserved.
//  https://github.com/yangKJ/KJExtensionHandler

#import "UILabel+KJExtension.h"
#import <objc/runtime.h>
@implementation UILabel (KJExtension)
- (KJLabelTextAlignmentType)kTextAlignmentType{
    return (KJLabelTextAlignmentType)[objc_getAssociatedObject(self, @selector(kTextAlignmentType)) integerValue];
}
- (void)setKTextAlignmentType:(KJLabelTextAlignmentType)kTextAlignmentType{
    objc_setAssociatedObject(self, @selector(kTextAlignmentType), @(kTextAlignmentType), OBJC_ASSOCIATION_ASSIGN);
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        method_exchangeImplementations(class_getInstanceMethod(self.class, @selector(drawTextInRect:)), class_getInstanceMethod(self.class, @selector(kj_drawTextInRect:)));
    });
    switch (kTextAlignmentType) {
        case KJLabelTextAlignmentTypeRight:
        case KJLabelTextAlignmentTypeRightTop:
        case KJLabelTextAlignmentTypeRightBottom:
            self.textAlignment = NSTextAlignmentRight;
            break;
        case KJLabelTextAlignmentTypeLeft:
        case KJLabelTextAlignmentTypeLeftTop:
        case KJLabelTextAlignmentTypeLeftBottom:
            self.textAlignment = NSTextAlignmentLeft;
            break;
        case KJLabelTextAlignmentTypeCenter:
        case KJLabelTextAlignmentTypeTopCenter:
        case KJLabelTextAlignmentTypeBottomCenter:
            self.textAlignment = NSTextAlignmentCenter;
            break;
        default:
            break;
    }
}
- (void)kj_drawTextInRect:(CGRect)rect{
    switch (self.kTextAlignmentType) {
        case KJLabelTextAlignmentTypeRight:
        case KJLabelTextAlignmentTypeLeft:
        case KJLabelTextAlignmentTypeCenter:
            [self kj_drawTextInRect:rect];
            break;
        case KJLabelTextAlignmentTypeBottomCenter:
        case KJLabelTextAlignmentTypeLeftBottom:
        case KJLabelTextAlignmentTypeRightBottom:{
            CGRect textRect = [self textRectForBounds:rect limitedToNumberOfLines:self.numberOfLines];
            textRect.origin = CGPointMake(textRect.origin.x, -CGRectGetMaxY(textRect)+rect.size.height);
            [self kj_drawTextInRect:textRect];
        }
            break;
        default:{
            CGRect textRect = [self textRectForBounds:rect limitedToNumberOfLines:self.numberOfLines];
            [self kj_drawTextInRect:textRect];
        }
            break;
    }
}

/// 获取高度
- (CGFloat)kj_calculateHeightWithWidth:(CGFloat)width{
    self.numberOfLines = 0;
    self.lineBreakMode = NSLineBreakByCharWrapping;
    CGSize size = [UILabel kj_calculateLabelSizeWithTitle:self.text font:self.font constrainedToSize:CGSizeMake(width, MAXFLOAT) lineBreakMode:NSLineBreakByCharWrapping];
    size.height += 3;
    return size.height;
}
/// 获取高度，指定行高
- (CGFloat)kj_calculateHeightWithWidth:(CGFloat)width OneLineHeight:(CGFloat)height{
    self.numberOfLines = 0;
    self.lineBreakMode = NSLineBreakByCharWrapping;
    CGSize size = [UILabel kj_calculateLabelSizeWithTitle:self.text font:self.font constrainedToSize:CGSizeMake(width, MAXFLOAT) lineBreakMode:NSLineBreakByCharWrapping];
    return size.height * height / self.font.lineHeight;
}
/// 获取文字尺寸
+ (CGSize)kj_calculateLabelSizeWithTitle:(NSString*)title font:(UIFont*)font constrainedToSize:(CGSize)size lineBreakMode:(NSLineBreakMode)lineBreakMode{
    if (title.length == 0) return CGSizeZero;
    NSMutableParagraphStyle *paragraph = [[NSMutableParagraphStyle alloc] init];
    paragraph.lineBreakMode = lineBreakMode;
    CGRect frame = [title boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:font,NSParagraphStyleAttributeName:paragraph} context:nil];
    return frame.size;
}

@end

备注：本文用到的部分函数方法和Demo，均来自三方库**KJCategories**，如有需要的朋友可自行pod 'KJCategories'引入即可

自定义文本显示位置介绍就到此完毕，后面有相关再补充，写文章不容易，还请点个**小星星**传送门