在遊戲的開發中，一般要用到顯示道具或者是籌碼的價格，爲了顯示優惠幅度和吸引玩家付費，一般會強調原價與現價的優惠幅度，原價上面畫上一條刪除線。下面是在iOS開發時用到的代碼，可以作爲參考實現。
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下面是UILabelStrikeThrough.h文件
/*
* 用於在UILabel上畫刪除線
*/
#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}; //紅色
//CGFloat black[4] = {0.0f, 0.0f, 0.0f, 0.5f};//黑色
CGContextSetStrokeColor(c, red);
CGContextSetLineWidth(c, 2);
CGContextBeginPath(c);
//畫直線
//CGFloat halfWayUp = rect.size.height/2 + rect.origin.y;
//CGContextMoveToPoint(c, rect.origin.x, halfWayUp );//開始點
//CGContextAddLineToPoint(c, rect.origin.x + rect.size.width, halfWayUp);//結束點
//畫斜線
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); //斜線
CGContextStrokePath(c);
}
[superdrawRect:rect];
}
- (void)dealloc
{
[superdealloc];
}
@end
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調用代碼：
UILabelStrikeThrough *originalPrice=[[[UILabelStrikeThroughalloc] initWithFrame:CGRectMake(coinPic.frame.origin.x+coinPic.frame.size.width+5,0, 120,15)]autorelease];
originalPrice.isWithStrikeThrough=TRUE;
