Objective c 如何从UISegmentedControl的选定段显示UIPover

我需要从UISegmentedControl的选定段显示popover，它是UIToolBar的子视图。 这是我的密码：

// UISegemntedControl
NSArray *segments = [NSArray arrayWithObjects:@"one", @"two", @"three", nil];
_segmentedControl = [[UISegmentedControl alloc] initWithItems:segments];
_segmentedControl.frame = CGRectMake(self.frame.size.width/2-128, self.frame.size.height/2-12, 256, 24);
_segmentedControl.selectedSegmentIndex = 0;
[self addSubview:_segmentedControl];

显示流行音乐：

- (void)show
{
UIView *view = [toolBar.segmentedControl.subviews objectAtIndex:toolBar.segmentedControl.selectedSegmentIndex];

// UIPopoverController
[popover presentPopoverFromRect:view.bounds inView:view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
}

它可以工作，但每次popover从错误的片段出现时。我不知道为什么

更新： 解决方案：

float width = toolBar.segmentedControl.frame.size.width/toolBar.segmentedControl.subviews.count;
CGRect bounds = CGRectMake(toolBar.segmentedControl.frame.origin.x+width*toolBar.segmentedControl.selectedSegmentIndex, toolBar.segmentedControl.frame.origin.y, width, toolBat.segmentedControl.frame.size.height);
...
[popover presentPopoverFromRect:bounds inView:toolBar permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];

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如果线段相等，则可以将控件的宽度除以选定线段的编号

 if ((UISegmentedControl*)sender.selectedSegmentIndex == 0)
        [self.popover presentPopoverFromRect:CGRectMake(self.segmentedControl.frame.size.width/3, self.segmentedControl.frame.origin.y, aWidth, aHeight)];

参考一下

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这是一种解决方案。非常感谢。