IOS开发之----让UILabel 垂直方向顶端对齐的代码

VerticalAlignment.h文件

#import <UIKit/UIKit.h>

typedef enum VerticalAlignment {

    VerticalAlignmentTop,

    VerticalAlignmentMiddle,

    VerticalAlignmentBottom,

} VerticalAlignment;

@interface VerticallyAlignedLabel : UILabel

{

@private VerticalAlignment verticalAlignment_;

}

@property (nonatomic, assign) VerticalAlignment verticalAlignment;

@end

VerticalAlignment.m文件

 

#import "VerticallyAlignedLabel.h"

@implementation VerticallyAlignedLabel

@synthesize verticalAlignment = verticalAlignment_;

- (id)initWithFrame:(CGRect)frame

{

    self = [super initWithFrame:frame];

    if (self) {

        // Initialization code

    }

    return self;

}

- (void)setVerticalAlignment:(VerticalAlignment)verticalAlignment {

    verticalAlignment_ = verticalAlignment;

    [self setNeedsDisplay];

}

- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines {

    CGRect textRect = [super textRectForBounds:boundslimitedToNumberOfLines: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:requestedRectlimitedToNumberOfLines:self.numberOfLines];

    [super drawTextInRect:actualRect];

}

@end