Swift环境下一行代码实现UILabel居上 居中 居下对齐
首先在Xcode中新建.h文件,将以下代码复制进去
// // 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
再新建一个.m文件,拷入以下代码
// // 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
如果这是你导入的第一个.m文件Xcode会提示你要不要创建Bridging-Header,选Ok
在新创建的Bridging-Header文件里拷入下方代码
#import "myUILabel.h"
然后右键拖动Label或者按住Command键左键拖动连线到Label所在的父View的Class中生成Outlet,如果之前已经连线好,则改完Custom Class后,将连线生成代码中的UILabel改为myUILabel,示意图如下
然后就可以调用该label的类方法
label.verticalAlignment = VerticalAlignmentBottom
按上方代码可以实现居下对其,居中 居上 分别将代码中的Bottom改为Middle和Top,默认为居上
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文章来自:http://blog.csdn.net/nsnirvana/article/details/47720073