iphone - 自定义 UISegmentControl 无法正常工作

Question

我想自定义我的应用程序的 UISegmentControl，我使用了以下代码：

UIImage *segmentSelected = [UIImage imageNamed:@"segcontrol_sel.png"];
UIImage *segmentUnselected = [UIImage imageNamed:@"segcontrol_uns.png"];
UIImage *segmentSelectedUnselected = [UIImage imageNamed:@"segcontrol_sel-uns.png"];
UIImage *segUnselectedSelected = [UIImage imageNamed:@"segcontrol_uns-sel.png"];
UIImage *segmentUnselectedUnselected = [UIImage imageNamed:@"segcontrol_uns-uns.png"];

[[UISegmentedControl appearance] setBackgroundImage:segmentUnselected
                                               forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setBackgroundImage:segmentSelected
                                               forState:UIControlStateSelected barMetrics:UIBarMetricsDefault];

[[UISegmentedControl appearance] setDividerImage:segmentUnselectedUnselected
                                 forLeftSegmentState:UIControlStateNormal
                                   rightSegmentState:UIControlStateNormal
                                          barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setDividerImage:segmentSelectedUnselected
                                 forLeftSegmentState:UIControlStateSelected
                                   rightSegmentState:UIControlStateNormal
                                          barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance]
     setDividerImage:segUnselectedSelected
     forLeftSegmentState:UIControlStateNormal
     rightSegmentState:UIControlStateSelected
     barMetrics:UIBarMetricsDefault];

我从我的应用程序中获得了以下图片

第一张图片