title: UIPickerView doesn't appear
body: <p>In a ViewController call by <strong>push</strong>, I try to programmatically display a ComboBox. This combobox implement UIPickerView delegate protocol and add a .xib file.</p>
  
  <p>When i run the app, i can see my combobox on the screen, but when i click on it, nothing append. Normally the pickerview will be displayed.</p>
  
  <p>What i don't understand, is in another viewcontroller call <strong>modal</strong> it works fine</p>
  
  <pre><code>//
  //  ComboBox.h
  //
  
  #import &lt;UIKit/UIKit.h&gt;
  
  @interface ComboBox : UIViewController&lt;UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate&gt;
  {
      UIPickerView* pickerView;
      IBOutlet UITextField* textField;
      NSMutableArray *dataArray;
  }
  
  -(void) setComboData:(NSMutableArray*) data; //set the picker view items
  -(void) setPlaceholder:(NSString*) label;
  @property (retain, nonatomic) NSString* selectedText; //the UITextField text
  @property (retain, nonatomic) IBOutlet UITextField* textField; //the UITextField
  
  @end
  
  //
  //  ComboBox.m
  //
  
  
  #import "ComboBox.h"
  
  @implementation ComboBox
  @synthesize selectedText;
  @synthesize textField;
  
  - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
  {
      return [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  }
  
  - (void)didReceiveMemoryWarning
  {
      [super didReceiveMemoryWarning];
  }
  
  
  #pragma mark - View lifecycle
  
  - (void)viewDidLoad
  {
      [super viewDidLoad];
  }
  
  - (void)viewDidUnload
  {
      [super viewDidUnload];
  }
  
  - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
  {
      return (interfaceOrientation == UIInterfaceOrientationPortrait);
  }
  
  
  //-- UIPickerViewDelegate, UIPickerViewDataSource
  
  - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;
  {
      return 1;
  }
  
  - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
  {
      textField.text = [dataArray objectAtIndex:row];
      selectedText = textField.text;
  }
  
  - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;
  {
      return [dataArray count];
  }
  
  - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;
  {
      return [dataArray objectAtIndex:row];
  }
  
  //-- ComboBox
  
  
  -(void) setComboData:(NSMutableArray*) data
  {
      dataArray = data;    
  }
  
  -(void) setPlaceholder:(NSString *)label
  {
      textField.placeholder = label;
  }
  
  -(void)doneClicked:(id) sender
  {
      [textField resignFirstResponder]; //hides the pickerView
  }
  
  
  - (IBAction)showPicker:(id)sender {
  
      pickerView = [[UIPickerView alloc] init];
      pickerView.showsSelectionIndicator = YES;
      pickerView.dataSource = self;
      pickerView.delegate = self;
  
      UIToolbar* toolbar = [[UIToolbar alloc] init];
      toolbar.barStyle = UIBarStyleBlackTranslucent;
      [toolbar sizeToFit];
  
      //to make the done button aligned to the right
      UIBarButtonItem *flexibleSpaceLeft = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
  
  
      UIBarButtonItem* doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done"
                                                                     style:UIBarButtonItemStyleDone target:self
                                                                    action:@selector(doneClicked:)];
  
  
      [toolbar setItems:[NSArray arrayWithObjects:flexibleSpaceLeft, doneButton, nil]];
  
      //custom input view
      textField.inputView = pickerView;
      textField.inputAccessoryView = toolbar;  
  }
  
  - (BOOL)textFieldShouldBeginEditing:(UITextField *)aTextField
  {
      [self showPicker:aTextField];
      return YES;
  }
  
  @end
  </code></pre>
  
  <p>the viewdidload of my viewcontroller</p>
  
  <pre><code>- (void)viewDidLoad
  {
      [super viewDidLoad];
  
      NSMutableArray* ServeurArray = [[NSMutableArray alloc] init];
      [ServeurArray addObject:@"1"];
      [ServeurArray addObject:@"2"];
      [ServeurArray addObject:@"3"];
  
      comboServeur = [[ComboBox alloc] init];
      [comboServeur setComboData:ServeurArray];  //Assign the array to ComboBox
      comboServeur.view.frame = CGRectMake(95, 220, 130, 31);  //ComboBox location and size (x,y,width,height)
  
      [self.view addSubview:comboServeur.view];
  }
  </code></pre>
  
  <p>thx for your answers</p>