iOSのUILabel設定は上揃え、中揃え、下揃え

2645 ワード

iOSでデフォルトのUILabelの文字は縦方向に中央揃えしかできません.ブロガーは海外のサイトを参考に、UILabelから新しいクラスを継承し、中央揃え、中央揃え、下揃えを実現しました.具体的には以下の通りです.
//
//  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

使用時:
    lbl_mylabel = [[myUILabel alloc] initWithFrame:CGRectMake(20, 50, 150, 600)];
    UIColor *color = [UIColor colorWithPatternImage:[UIImage imageNamed:@"halfTransparent.png"]];//         label    
    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];