设置lable内容不上下居中

转载自：http://dong-zsh.github.io/2015/10/14/%E8%AE%BE%E7%BD%AElable%E5%86%85%E5%AE%B9%E4%B8%8D%E4%B8%8A%E4%B8%8B%E5%B1%85%E4%B8%AD/

#import <UIKit/UIKit.h>
typedef enum
{
    VerticalAlignmentTop = 0, // default文字居上
    VerticalAlignmentMiddle,
    VerticalAlignmentBottom,
} VerticalAlignment;

@interface mylable : UILabel

{
@private
    VerticalAlignment _verticalAlignment;
}

@property (nonatomic) VerticalAlignment verticalAlignment;

@end

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#import "mylable.h" @implementation mylable @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]; }

###用法

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mylable *lable = [[mylable alloc] initWithFrame:CGRectMake(10, 400, 100, 200)]; lable.text = @"dajdiojajdajdjajdadakdajdiaodaiojdioajdioajidjaijdajdadadna"; lable.backgroundColor = [UIColor grayColor]; lable.numberOfLines = 0; [lable setVerticalAlignment:VerticalAlignmentTop]; [self.view addSubview:lable];