UIPickerView select row doesn't work ios7 - ios

Question

I have a UIPickerView that is being "pushed" to UINavigationController like this:
[self.navigationController pushViewController:vc animated:YES];
I would like to set the selected row.
I added in ViewDidAppear:
for (int i = 0; i < [countryCodes count]; i++)
{
if ([[countryCodes objectAtIndex:i] isEqualToString:selectedCountryCode]){
[_countryPicker selectRow:i inComponent:0 animated:YES];
countrySelectedRow = i;
break;
}
}
[_countryPicker reloadAllComponents];
where i is dynamic (being changed based on data that is changing in that view controller)
It works only if I restart the app.
If I go back and forth in the navigation it doesn't work
How can I make the UIPickerView choose the the correct row?
I can see in debug mode that the lines in viewDidAppear are called. Maybe the component is being created and I can't change it?
This is how I create the UIPickerView:
- (void)viewDidLoad
{
_countryPicker = [[UIPickerView alloc] init];
[self initPicker:_countryPicker textField:_countryText];
}
- (void)initPicker:(UIPickerView*)pickerView textField:(UITextField*) textField
{
CGRect pickerFrame = CGRectMake(0, 0, 200, 216);
pickerView.frame = pickerFrame;
pickerView.userInteractionEnabled = YES;
pickerView.dataSource = self;
pickerView.hidden = YES;
pickerView.delegate = self;
pickerView.showsSelectionIndicator = YES;
[self.view addSubview:pickerView];
[textField setInputView:pickerView];
textField.delegate = self;
[pickerView removeFromSuperview];
}

Answer 1

You wrote: "where i is dynamic (being changed based on data that is changing in that view controller)""
In your code i is a local variable. Did you mean selectedCountryCode here?
for (int i = 0; i < [countryCodes count]; i++)
{
if ([[countryCodes objectAtIndex:i] isEqualToString:selectedCountryCode]){
[_countryPicker selectRow:i inComponent:0 animated:YES];
countrySelectedRow = i;
break;
}
}
[_countryPicker reloadAllComponents];
I am pretty sure selectedCountryCode is not updated correctly. Add NSLog(selectedCountryCode); to check it.
UPDATE:
It seems that problem is somewhere inside a code you did not post in the question. To check your code I created and share a project. Please find it here https://github.com/Avtolic/SOHelper If you will check it you will find that everything works ok.

Answer 2

After you set the selected row you then call this...
[_countryPicker reloadAllComponents];
Thats going to wipe out your selection? I would remove that line

Answer 3

If you make the selectedCountryCode variable part of a singleton class (for example AppDelegate or preferebly some other), and then equate the value, this is surely going to work. Here I don't understand how the selectedCountryCode is expected to be retained even after the view is popped.
I tried with making the string a part of AppDelegate (which is of course not a good practice. One should put it in another singleton class).
#import "CViewController.h"
#import "AppDelegate.h"
#interface CViewController ()<UITextFieldDelegate, UIPickerViewDelegate, UIPickerViewDataSource>
#property(nonatomic, strong) UIPickerView *countryPicker;
#property (nonatomic, weak) IBOutlet UITextField *countryText;
#property (nonatomic, strong) NSArray *countryCodes;
#property (nonatomic, assign) int countrySelectedRow;
#property (nonatomic,strong) AppDelegate *delegate;
#end
#implementation CViewController
- (void)viewDidLoad
{
self.delegate = [[UIApplication sharedApplication] delegate];
_countryPicker = [[UIPickerView alloc] init];
[self initPicker:_countryPicker textField:_countryText];
self.countryCodes = #[#"A", #"B", #"C", #"D", #"E"];
}
- (void)initPicker:(UIPickerView*)pickerView textField:(UITextField*) textField
{
CGRect pickerFrame = CGRectMake(0, 0, 200, 216);
pickerView.frame = pickerFrame;
pickerView.userInteractionEnabled = YES;
pickerView.dataSource = self;
pickerView.hidden = YES;
pickerView.delegate = self;
pickerView.showsSelectionIndicator = YES;
[self.view addSubview:pickerView];
[textField setInputView:pickerView];
textField.delegate = self;
[pickerView removeFromSuperview];
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
return [self.countryCodes objectAtIndex:row];
}
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 1;
}
// returns the # of rows in each component..
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return [self.countryCodes count];
}
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
self.delegate.selectedCountryCode = [self.countryCodes objectAtIndex:row];
NSLog(#"picker was(is): %d",[_countryPicker selectedRowInComponent:0]);
}
-(void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
for (int i = 0; i < [self.countryCodes count]; i++)
{
if ([[self.countryCodes objectAtIndex:i] isEqualToString:self.delegate.selectedCountryCode]){
[_countryPicker selectRow:i inComponent:0 animated:YES];
self.countrySelectedRow = i;
break;
}
}
[_countryPicker reloadAllComponents];
}
-(void)textFieldDidBeginEditing:(UITextField *)textField
{
self.countryPicker.hidden = NO;
}