UILabel 详解

UILabel 多行文字自动换行 （自动折行）

1.UIView *footerView = [[UIView alloc] initWithFrame:CGRectMake(10, 100, 300, 180)];   
2.    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(10, 100, 300, 150)];   
3.    label.text = @"where are you? where are you? where are you? where are you? where are you? where are you? where are you? where are you? where are you? where are you?";   
4.    //清空背景颜色   
5.    label.backgroundColor = [UIColor clearColor];   
6.    //设置字体颜色为白色   
7.    label.textColor = [UIColor whiteColor];   
8.    //文字居中显示   
9.    label.textAlignment = UITextAlignmentCenter;   
10.    //自动折行设置   
11.    label.lineBreakMode = UILineBreakModeWordWrap;   
12.    label.numberOfLines = 0;  

 

iOS的UILabel设置居上对齐，居中对齐，居下对齐

在iOS中默认的UILabel中的文字在竖直方向上只能居中对齐，博主参考国外网站，从UILabel继承了一个新类，实现了居上对齐，居中对齐，居下对齐。具体如下：

//
//  myUILabel.h
//
//
//  Created by yexiaozi_007 on 3/4/13.
//  Copyright (c) 2013 yexiaozi_007. All rights reserved.
//

#import <UIKit/UIKit.h>
typedef enum
{
    VerticalAlignmentTop = 0, // default
    VerticalAlignmentMiddle,
    VerticalAlignmentBottom,
} VerticalAlignment;
@interface myUILabel : UILabel
{
@private
VerticalAlignment _verticalAlignment;
}

@property (nonatomic) VerticalAlignment verticalAlignment;

@end

 

//
//  myUILabel.m
//
//
//  Created by yexiaozi_007 on 3/4/13.
//  Copyright (c) 2013 yexiaozi_007. All rights reserved.
//

#import "myUILabel.h"

@implementation myUILabel
@synthesize verticalAlignment = verticalAlignment_;

- (id)initWithFrame:(CGRect)frame {
    if (self = [super initWithFrame:frame]) {
        self.verticalAlignment = VerticalAlignmentMiddle;
    }
    return self;
}

- (void)setVerticalAlignment:(VerticalAlignment)verticalAlignment {
    verticalAlignment_ = verticalAlignment;
    [self setNeedsDisplay];
}

- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {
    CGRect textRect = [super textRectForBounds:bounds limitedToNumberOfLines:numberOfLines];
    switch (self.verticalAlignment) {
        case VerticalAlignmentTop:
            textRect.origin.y = bounds.origin.y;
            break;
        case VerticalAlignmentBottom:
            textRect.origin.y = bounds.origin.y + bounds.size.height - textRect.size.height;
            break;
        case VerticalAlignmentMiddle:
            // Fall through.
        default:
            textRect.origin.y = bounds.origin.y + (bounds.size.height - textRect.size.height) / 2.0;
    }
    return textRect;
}

-(void)drawTextInRect:(CGRect)requestedRect {
    CGRect actualRect = [self textRectForBounds:requestedRect limitedToNumberOfLines:self.numberOfLines];
    [super drawTextInRect:actualRect];
}


@end

 

在使用时：

 

lbl_mylabel = [[myUILabel alloc] initWithFrame:CGRectMake(20, 50, 150, 600)];  UIColor *color = [UIColor colorWithPatternImage:[UIImage imageNamed:@"halfTransparent.png"]];//使用半透明图片作为label的背景色  lbl_mylabel.backgroundColor = color;  lbl_mylabel.textAlignment = UITextAlignmentLeft;  lbl_mylabel.textColor = UIColor.whiteColor;  lbl_mylabel.lineBreakMode = UILineBreakModeWordWrap;  lbl_mylabel.numberOfLines = 0;  [lbl_mylabel setVerticalAlignment:VerticalAlignmentTop];  [self addSubview:lbl_mylabel];
lbl_mylabel = [[myUILabel alloc] initWithFrame:CGRectMake(20, 50, 150, 600)];
UIColor *color = [UIColor colorWithPatternImage:[UIImage imageNamed:@"halfTransparent.png"]];//使用半透明图片作为label的背景色
lbl_mylabel.backgroundColor = color;
lbl_mylabel.textAlignment = UITextAlignmentLeft;
lbl_mylabel.textColor = UIColor.whiteColor;
lbl_mylabel.lineBreakMode = UILineBreakModeWordWrap;
lbl_mylabel.numberOfLines = 0;
[lbl_mylabel setVerticalAlignment:VerticalAlignmentTop];
[self addSubview:lbl_mylabel];