在游戏的开发中，一般要用到显示道具或者是筹码的价格，为了显示优惠幅度和吸引玩家付费，一般会强调原价与现价的优惠幅度，原价上面画上一条删除线。下面是在iOS开发时用到的代码，可以作为参考实现。
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下面是UILabelStrikeThrough.h文件
/*
* 用于在UILabel上画删除线
*/
#import<Foundation/Foundation.h>
@interface UILabelStrikeThrough :UILabel
{
BOOL isWithStrikeThrough;
}
@property (nonatomic,assign) BOOL isWithStrikeThrough;
@end
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下面是UILabelStrikeThrough.m文件
#import"UILabelStrikeThrough.h"
@implementation UILabelStrikeThrough
@synthesize isWithStrikeThrough;
- (void)drawRect:(CGRect)rect
{
if (isWithStrikeThrough)
{
CGContextRef c = UIGraphicsGetCurrentContext();
CGFloat red[4] = {1.0f,0.0f, 0.0f,0.8f}; //红色
//CGFloat black[4] = {0.0f, 0.0f, 0.0f, 0.5f};//黑色
CGContextSetStrokeColor(c, red);
CGContextSetLineWidth(c, 2);
CGContextBeginPath(c);
//画直线
//CGFloat halfWayUp = rect.size.height/2 + rect.origin.y;
//CGContextMoveToPoint(c, rect.origin.x, halfWayUp );//开始点
//CGContextAddLineToPoint(c, rect.origin.x + rect.size.width, halfWayUp);//结束点
//画斜线
CGContextMoveToPoint(c, rect.origin.x, rect.origin.y+5 );
CGContextAddLineToPoint(c, (rect.origin.x + rect.size.width)*0.5, rect.origin.y+rect.size.height-5); //斜线
CGContextStrokePath(c);
}
[superdrawRect:rect];
}
- (void)dealloc
{
[superdealloc];
}
@end
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调用代码：
UILabelStrikeThrough *originalPrice=[[[UILabelStrikeThroughalloc] initWithFrame:CGRectMake(coinPic.frame.origin.x+coinPic.frame.size.width+5,0, 120,15)]autorelease];
originalPrice.isWithStrikeThrough=TRUE;
