UIPicker 选择行
我正在尝试选择第一行作为默认值.. 在这里，我尝试了
-(void)pickerViewLoaded{
[pickerView setShowSelectionIndicator:YES];
pickerView.delegate = self;
[pickerView reloadAllComponents];
[pickerView selectRow:1 inComponent:0 animated:YES]
}
当我在 viewDidLoad() 上调用此方法（它调用 didSelectRow 方法）时效果很好，但它选择的是该组件的第二行而不是第一行。 当我使用 [pickerView selectRow:0 inComponent:0animated:YES] 调用时，它永远不会调用 didSelectRow 方法。
另一个问题是当我在选择分段控件时调用 pickerViewLoaded 方法时，它不会调用 didSelectRow 方法。我仍然不知道什么时候它可以使用viewDidLoad调用，那么为什么不使用segmentedControl呢？
谢谢大家，
I am trying to select the first row as default..
Here i tried
-(void)pickerViewLoaded{
[pickerView setShowSelectionIndicator:YES];
pickerView.delegate = self;
[pickerView reloadAllComponents];
[pickerView selectRow:1 inComponent:0 animated:YES]
}
It works fine when i call this method on viewDidLoad() which call didSelectRow method but it is selecting the second row of that component not first one.
when i call with [pickerView selectRow:0 inComponent:0 animated:YES] then it never call didSelectRow method.
another problem is when i call pickerViewLoaded method on selection of segmented control it does not call the didSelectRow method. i still could not figure when it may call with viewDidLoad then why not with segmentedControl.
Thanks all,
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似乎是一个老线程，无论如何我想分享我的经验。
我遇到了同样的问题，并
。
仅在使用通知返回最后一行调用的 titleForRow 后才将其移至我调用 selectRow:inComponent:animated
seems to be a old thread, anyway I thought of sharing my experience.
I had the same issue and moved the
to
I call the selectRow:inComponent:animated only after returning the titleForRow called for last-row using a notification.
现在问题已经从死里复活了...
我认为 selectRow 使用从 0 开始的索引，而不是 1。所以 0 是第一行，1 是第二行。
Now that the question has been raised from the dead...
I think selectRow uses an index that starts at 0 - not 1. So 0 is the first row, and 1 is the second row.
我刚刚遇到了同样的问题并解决了这个问题：如果所选行没有更改，则不会调用委托。此外，默认情况下会选择第 0 行，因此在
viewDidLoad中重新选择第 0 行不会触发委托。就我而言，我能够直接调用委托方法，也许这也是您的情况的解决方案。I just ran into the same problem and figured it out: The delegate doesn't get called, if the selected row doesn't change. Also, row 0 is selected by default, so re-selecting row 0 in
viewDidLoaddoesn't trigger the delegate. In my case I was able to call the delegate method directly, maybe that's the solution in your case, too.