Question

I have been having trouble pulling up a custom UIPickerView from the textfield’s inputview property. I have been working on this for awhile, did some research, and tried to put together a separate project based on Apple’s UICatalog example.

However, whenever I tap inside the textfield all I get is a black screen that pops up in place of the picker view. Im sure I’ve overlooked something but I have been looking for days any help would be appreciated.

Keep in mind this was my test project to see if I could add this functionality to my other app and that a lot of the code I tried to copy from the UICatalog app. Sorry if anything doesn’t make sense and please feel free to ask any questions you may have. Thank you.

//  ViewController.h
//  TestPicker

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UITextFieldDelegate,UIPickerViewDelegate,UIPickerViewDataSource>{

UIPickerView *picker;
     //The picker view the textfield responds to.

IBOutlet UITextField *myText;
     //The textfield which has the input view of a picker.

NSArray *testArray;
     //The array which values are loaded into the picker.
}

@end


//  ViewController.m
//  TestPicker


#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    picker.delegate=self;
    picker.dataSource=self;
    myText.delegate=self;

    [self createPicker];

    [super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

- (void)viewDidUnload
{
    myText = nil;
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
        return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
    } 
    else {
        return YES;
    }
}

-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
    picker = [[UIPickerView alloc] initWithFrame:CGRectZero];
    myText.inputView=picker;
    return YES;
}

-(void)textFieldDidBeginEditing:(UITextField *)textField{

}


- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    NSString *returnStr = @"";

    if (pickerView == picker)
    {
        if (component == 0)
        {
            returnStr = [testArray objectAtIndex:row];
        }
        else
        {
            returnStr = [[NSNumber numberWithInt:row] stringValue];
        }
    }

    return returnStr;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return [testArray count];
}

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}


- (void)createPicker
{
    testArray = [NSArray arrayWithObjects:
                            @"John Appleseed", @"Chris Armstrong", @"Serena Auroux",
                            @"Susan Bean", @"Luis Becerra", @"Kate Bell", @"Alain Briere",
                        nil];


    picker = [[UIPickerView alloc] initWithFrame:CGRectZero];


    picker.showsSelectionIndicator = YES;   // note this is default to NO

    picker.delegate = self;
    picker.dataSource = self;

}

@end

Answer 1

The problem is in this method:

-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
    picker = [[UIPickerView alloc] initWithFrame:CGRectZero];
    myText.inputView=picker;
    return YES;
}

You already created picker in your createPicker method, called from viewDidLoad, so this creates another instance (this instance won’t have the delegate or data source set to self, since these were set on the first instance you created). If you just delete the first line of this method, it should work.

Two other comments on your code. The first 2 lines in the viewDidLoad method aren’t doing anything since you haven’t created picker yet — they should be deleted. You also need to implement the pickerView:didSelectRow:inComponent: method in order to get the selected value of your picker into the text field.