以编程方式截取屏幕截图时，UISegmentedControl中所选段的标题消失 [英] Title for selected segment in UISegmentedControl disappears when taking a screenshot programatically

问题描述

我将 UISegmentedControl 添加到 UIToolbar ：

  UIToolbar * toolbar = [[UIToolbar alloc] initWithFrame：toolbarFrame]; 
 toolbar.barStyle = UIBarStyleBlack; 
 toolbar.translucent = YES; 
 toolbar.barTintColor = [UIColor colorWithRed：0.97绿色：0.97蓝色：0.97 alpha：1.0]; 
 [self.view addSubview：toolbar]; 
 
 UISegmentedControl * segmentedControl = [[UISegmentedControl alloc] initWithItems：@ [@上周，@上个月，@所有时间]; 
 [segmentedControl setSelectedSegmentIndex：0]; 
 [toolbar addSubview：segmentedControl]; 
  

然后将工具栏添加到视图控制器中。当我拍摄视图控制器的屏幕截图时，会发生一些奇怪的事情。所选片段的标题消失。

屏幕截图使用：

  UIGraphicsBeginImageContextWithOptions（self.view.bounds.size，YES，[[UIScreen mainScreen] scale]）; 
 [self.view.layer renderInContext：UIGraphicsGetCurrentContext（）]; 
 UIImage * image = UIGraphicsGetImageFromCurrentImageContext（）; 
 UIGraphicsEndImageContext（）; 
  

渲染视图：

屏幕截图：

任何有关从哪里开始寻找的指示都将受到赞赏。

解决方案

我已经更换了

  [self.view .layer renderInContext：UIGraphicsGetCurrentContext（）]; 
  

使用

  [self.view drawViewHierarchyInRect：self.view.bounds afterScreenUpdates：YES]; 
  

现在它按预期工作。仍然不明白为什么会发生这种情况。

请注意 drawViewHierarchyInRect：afterScreenUpdates：仅限iOS 7。 / p>

I have a UISegmentedControl added to a UIToolbar:

UIToolbar *toolbar = [[UIToolbar alloc] initWithFrame:toolbarFrame];
toolbar.barStyle = UIBarStyleBlack;
toolbar.translucent = YES;
toolbar.barTintColor = [UIColor colorWithRed:0.97 green:0.97 blue:0.97 alpha:1.0];
[self.view addSubview:toolbar];

UISegmentedControl *segmentedControl = [[UISegmentedControl alloc] initWithItems:@[@"Last week", @"Last month", @"All time"];
[segmentedControl setSelectedSegmentIndex:0];
[toolbar addSubview:segmentedControl];

The toolbar is then added to a view controller. When I take a screenshot of the view controller, something weird happens. The title of the selected segment disappears.

The screenshot is being taken using:

UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, YES, [[UIScreen mainScreen] scale]);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

Rendered view:

Screenshot:

Any pointers on where to start looking will be appreciated.

解决方案

I've replaced

[self.view.layer renderInContext:UIGraphicsGetCurrentContext()]; 

With

[self.view drawViewHierarchyInRect:self.view.bounds afterScreenUpdates:YES];

And now it works as expected. Still don't understand why that happens though.

Note that drawViewHierarchyInRect:afterScreenUpdates: is iOS 7 only.

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