Ios 选择指示器未显示在操作表内的选择器视图中

这是我的实现，我基本上是动态创建操作表和选择器视图。问题在于显示所选项目未显示的指示器

UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:title delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:nil]; 
actionSheet.actionSheetStyle = UIActionSheetStyleDefault; 

UIPickerView* picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0,100, 320, 216)]; 
picker.dataSource = self; 
picker.delegate = self; 

[actionSheet addSubview:picker]; 


[actionSheet showInView:self.view]; 

[actionSheet setBounds:CGRectMake(0,0, 320, 411)]; 

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看起来您缺少这一行：

[picker setShowsSelectionIndicator:YES];

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就是这样，我知道我错过了一些简单的东西。