UISegmentedControl 设置背景图片时不设置段宽

Question

我有一个分段控件，我希望第一个和最后一个项目具有指定的宽度（例如，比其他项目更宽）。当我 setWidth:forSegmentAtIndex: 用于标准样式的分段控制（即 [[UISegmantedControl appearence] setBackgroundImage:forState:barMetrics:] 未设置）时，事情会按应有的方式运行。但是当我设置背景图像时，段宽度不会改变。

这是我的代码：

[[UISegmentedControl appearance] setBackgroundImage:[[UIImage imageNamed:@"btn_normal.png"] stretchableImageWithLeftCapWidth:25 topCapHeight:0] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setBackgroundImage:[[UIImage imageNamed:@"btn_selected.png"]  stretchableImageWithLeftCapWidth:25 topCapHeight:0] forState:UIControlStateSelected barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setDividerImage:[UIImage imageNamed:@"nn.png"] forLeftSegmentState:UIControlStateNormal rightSegmentState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setDividerImage:[UIImage imageNamed:@"sn.png"] forLeftSegmentState:UIControlStateSelected rightSegmentState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[[UISegmentedControl appearance] setDividerImage:[UIImage imageNamed:@"ns.png"] forLeftSegmentState:UIControlStateNormal rightSegmentState:UIControlStateSelected barMetrics:UIBarMetricsDefault];
[self.segmentedControl setContentMode:UIViewContentModeScaleToFill];
[self.segmentedControl setWidth:100.0 forSegmentAtIndex:0];
[self.segmentedControl setWidth:100.0 forSegmentAtIndex:4];

这样，我的所有段都会自动显示为相等的宽度。
当我在上面注释掉所有内容时

[self.segmentedControl setContentMode:UIViewContentModeScaleToFill];
[self.segmentedControl setWidth:100.0 forSegmentAtIndex:0];
[self.segmentedControl setWidth:100.0 forSegmentAtIndex:4];

尺寸设置正确。
这是我的问题：如何为带有背景图像的片段设置大小？
我是 cocoa-touch 和 Objective-c 的新手，所以我可能会遗漏一些东西...
你能帮忙吗？

Answer 1

我认为当您使用 [UISegmentedControl appearance] 代理时，它会覆盖 "setWidth:forSegmentAtIndex:" 方法值。所以可能的解决方案：

1)

[[UISegmentedControl appearance] setContentMode:UIViewContentModeScaleToFill];
[[UISegmentedControl appearance] setWidth:100.0 forSegmentAtIndex:0];
[[UISegmentedControl appearance] setWidth:100.0 forSegmentAtIndex:4];

我不建议使用它，因为它会为您应用中的每个分段控件设置 0 和 4 段的自定义宽度。

2)

[self.segmentedControl setBackgroundImage:[[UIImage imageNamed:@"btn_normal.png"] stretchableImageWithLeftCapWidth:25 topCapHeight:0] forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[self.segmentedControl setBackgroundImage:[[UIImage imageNamed:@"btn_selected.png"]  stretchableImageWithLeftCapWidth:25 topCapHeight:0] forState:UIControlStateSelected barMetrics:UIBarMetricsDefault];
[self.segmentedControl setDividerImage:[UIImage imageNamed:@"nn.png"] forLeftSegmentState:UIControlStateNormal rightSegmentState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[self.segmentedControl setDividerImage:[UIImage imageNamed:@"sn.png"] forLeftSegmentState:UIControlStateSelected rightSegmentState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
[self.segmentedControl setDividerImage:[UIImage imageNamed:@"ns.png"] forLeftSegmentState:UIControlStateNormal rightSegmentState:UIControlStateSelected barMetrics:UIBarMetricsDefault];

如果您需要应用程序中的所有分段控件都应具有自定义背景，那么我建议您编写自己的代理方法。像这样的：

- (UISegmentedControl *) customSegmentedControl {
    UISegmentedControl *segmentedControl = [ [ [UISegmentedControl alloc] init] autorelease];

    [segmentedControl setBackgroundImage: [ [UIImage imageNamed: @"btn_normal.png"] stretchableImageWithLeftCapWidth: 25 topCapHeight: 0] forState: UIControlStateNormal barMetrics: UIBarMetricsDefault];
    [segmentedControl setBackgroundImage: [ [UIImage imageNamed: @"btn_selected.png"] stretchableImageWithLeftCapWidth: 25 topCapHeight: 0] forState: UIControlStateSelected barMetrics: UIBarMetricsDefault];
    [segmentedControl setDividerImage: [UIImage imageNamed: @"nn.png"] forLeftSegmentState: UIControlStateNormal rightSegmentState: UIControlStateNormal barMetrics: UIBarMetricsDefault];
    [segmentedControl setDividerImage: [UIImage imageNamed: @"sn.png"] forLeftSegmentState: UIControlStateSelected rightSegmentState: UIControlStateNormal barMetrics: UIBarMetricsDefault];
    [segmentedControl setDividerImage: [UIImage imageNamed: @"ns.png"] forLeftSegmentState: UIControlStateNormal rightSegmentState: UIControlStateSelected barMetrics: UIBarMetricsDefault];

    return segmentedControl;
}

Answer 2

我通过编写自定义控件解决了这个问题，基于这个http://idevrecipes.com/2010/12/11/custom-segmented-controls/