加载selectedindex时，UISegmentedControl会触发ValueChanged [英] UISegmentedControl fires ValueChanged when loading selectedindex

问题描述

我有一个 UISplitViewController 实用程序类型的应用程序，其中每个 UIViewController 处理各种计算。我有一个带有分段控件的弹出窗口，允许用户设置某些选项。我遇到的问题是保存和重新加载 UITextfields 的内容和选定的段索引，如果段控制索引已保存并且== 1则会触发valuechanged事件来自 viewdidload ，因为州设置为

I have a UISplitViewController utility type app where each UIViewController handles various calculations. I have a popover with segmented controls that allows the user to set certain options. The problem I have is when saving and reloading the contents of UITextfields and the selected segment index, if the segment control index was saved and is == 1 a valuechanged event is fired off from viewdidload as the state is set from

   NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
   theDepthSegment.selectedSegmentIndex = [[defaults objectForKey:@"updateMe"] intValue];

无论如何都要阻止valuechanged被触发，因为在视图中设置了selectedsegment吗？或者可能在某种程度上确定触摸事件与代码之间的区别

Is there anyway to prevent valuechanged being fired as the selectedsegment is set in view did load? or maybe someway to determine the difference between touch events versus code

这种情况似乎很奇怪，也许有另一种方式....

It seems strange this happens, maybe there is another way....

谢谢

推荐答案

考虑到视图只是加载，分段控件没有以前的价值，所以它会假设它确实被改变并采取相应的行动。您可能解决此问题的一种方法是在链接到分段控件的 IBAction 方法中设置 BOOL 值。在 viewDidLoad 方法的开头，比如说 wasLoaded = NO （其中 wasLoaded 需要在头文件中声明）。然后你将分配你的 selectedSegmentIndex 。然后，声明 wasLoaded = YES 。最后，在您的 IBAction 方法中，例如

Considering the view is just loading, the segmented control doesn't have a previous value, so it will assume it is indeed being changed and acts accordingly. One way you could potentially get around this is to set up a BOOL value in your IBAction method linked to the segmented control. At the beginning of your viewDidLoad method, say wasLoaded = NO (where wasLoaded will need to be declared in your header file). Then you'll assign your selectedSegmentIndex. Afterwards, declare wasLoaded = YES. Finally, in your IBAction method, say something like

if (wasLoaded) { 
    // do what you need to do since this isn't when it's being initialized 
}

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