iOS自定义滑杆效果
作者：ChasingDreamsCoder
这篇文章主要为大家详细介绍了iOS自定义滑杆效果，文中示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下
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：
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];
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脚本之家。