本文实例为大家分享了iOS自定义滑杆的具体代码，供大家参考，具体内容如下
先让我们看看效果：
主要实现的代码：
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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
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- (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
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[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]; |
对于不同的状态来进行不同的操作，让滑杆的用户体验度更加的完整
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/ChasingDreamsCoder/article/details/53074677
