何时在刚刚加载的UIPickerView上调用selectRow :？

Question

I am trying to learn iPhone/iOS programming. I have an UIPickerView that should dispay its selected row as soon as it becomes visible (it is contained on a flippSideView).

Unfortunately, the flipSideViewController's awakeFromNib is not called. It is somewhat too late to do it in viewDidLoad . So, how can I make the pickerView display the selected row as soon it becomes visible?

Update:

Here is how I show the flipside view

- (IBAction)showInfo:(id)sender {    

    FlipsideViewController *controller = [[FlipsideViewController alloc] initWithNibName:@"FlipsideView" bundle:nil];
    controller.delegate = self;
    controller.uData = userData;

    controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;
    [self presentModalViewController:controller animated:YES];
    controller.pickerView.delegate   = userData;
    controller.pickerView.dataSource = userData;

    [controller release];
}// showInfo

In the flipside controller there is a method mySelect (to help me trace trace the calls)

-(void) mySelect:(NSString*) strMethod{
    int row = [uData getCurrentUserRow];
    [pickerView selectRow:row inComponent:0 animated:NO];        
    NSLog(@"selectRow %d called from %@  (pickerView=%d uData=%d)", row, strMethod, (int)pickerView, (int)uData); }

and when the program runs it generates the log

selectRow 3 called from viewDidLoad  (pickerView=87412720 uData=89267696) 
selectRow 3 called from viewWillAppear (pickerView=87412720 uData=89267696) 
selectRow 3 called from viewDidAppear (pickerView=87412720 uData=89267696)

Answer 1

It seems you're having the problem i had a couple days ago, i really don't think it's a bug I think the problem is when everything is called (could be wrong). Correct me if I'm wrong but you want your PickerView to display a certain value when it's first shown onscreen correct? Are you creating the PickerView in code or from a nib?

In my app, the below code snippet is right at the bottom of my viewDidLoad method

[pickerView selectRow: 100 inComponent:0 animated:YES];

This works as intended. Please post a snippet of your code so we can better understand your problem.

PS: When developing for iOS i would stay away from awakeFromNib and just use ViewDidLoad:

Answer 2

显然，在某些版本的iOS中存在一个错误，这意味着您必须先调用[super viewWillAppear:animated]或通过调用[self view]强制加载[self view] ，才能加载[self view] 。