本篇内容介绍了“ios怎么自定义滑杆效果”的有关知识,在实际案例的操作过程中,不少人都会遇到这样的困境,接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读,能够学有所成!
先让我们看看效果:
主要实现的代码:
UIImage *thumbWithLevel(float aLevel) { float INSET_AMT = 1.5f; CGRect baseRect = CGRectMake(0, 0, 40, 100); CGRect thumbRect = CGRectMake(0, 40, 40, 20); UIGraphicsBeginImageContext(baseRect.size); CGContextRef context = UIGraphicsGetCurrentContext(); [[UIColor darkGrayColor] setFill]; CGContextAddRect(context, CGRectInset(thumbRect, INSET_AMT, INSET_AMT)); CGContextFillPath(context); [[UIColor whiteColor] setStroke]; CGContextSetLineWidth(context, 2); CGContextAddRect(context, CGRectInset(thumbRect, 2 * INSET_AMT, 2 * INSET_AMT)); CGRect ellipseRect = CGRectMake(0, 0, 40, 40); [[UIColor colorWithWhite:aLevel alpha:1] setFill]; CGContextAddEllipseInRect(context, ellipseRect); CGContextFillPath(context); NSString *numString = [NSString stringWithFormat:@"%0.2f",aLevel]; UIColor *textColor = (aLevel > 0.5) ? [UIColor blackColor] : [UIColor whiteColor]; UIFont *font = [UIFont fontWithName:@"Georgia" size:15]; NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init]; style.lineBreakMode = NSLineBreakByCharWrapping; style.alignment = NSTextAlignmentCenter; NSDictionary *attr = @{NSFontAttributeName:font,NSParagraphStyleAttributeName:style,NSForegroundColorAttributeName:textColor}; [numString drawInRect:CGRectInset(ellipseRect, 0, 6) withAttributes:attr]; [[UIColor grayColor] setStroke]; CGContextSetLineWidth(context, 3); CGContextAddEllipseInRect(context, CGRectInset(ellipseRect, 2, 2)); CGContextStrokePath(context); UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return theImage; }
在这里我们通过context的方法将图片画出了,对于性能有点要求,但是现在应该不在乎这点性能了
- (void)updateThumb { if ((self.value < 0.98) && (ABS(self.value - previousValue) < 0.1f)) { return; } UIImage *customImg = thumbWithLevel(self.value); [self setThumbImage:customImg forState:UIControlStateHighlighted]; previousValue = self.value; }
通过滑块的值来使上面的值进行变化,更加的直观
[self setThumbImage:simpleThumb() forState:UIControlStateNormal]; [self addTarget:self action:@selector(startDrag:) forControlEvents:UIControlEventTouchDown]; [self addTarget:self action:@selector(updateThumb) forControlEvents:UIControlEventValueChanged]; [self addTarget:self action:@selector(endDrag:) forControlEvents:UIControlEventTouchUpOutside | UIControlEventTouchUpInside];
“ios怎么自定义滑杆效果”的内容就介绍到这里了,感谢大家的阅读。如果想了解更多行业相关的知识可以关注亿速云网站,小编将为大家输出更多高质量的实用文章!
免责声明:本站发布的内容(图片、视频和文字)以原创、转载和分享为主,文章观点不代表本网站立场,如果涉及侵权请联系站长邮箱:is@yisu.com进行举报,并提供相关证据,一经查实,将立刻删除涉嫌侵权内容。