Creating a delegate and dataSource for UIPickerView

Question

I am trying to create a delegate and a dataSource for a UIPickerView in a separate file. In the ViewController i have:

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIPickerView *myPickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 200, 320, 200)];

    MonthPicker *monthPicker = [[MonthPicker alloc] init];
    myPickerView.delegate = monthPicker;
    myPickerView.dataSource = monthPicker;
    myPickerView.showsSelectionIndicator = YES;
    [self.view addSubview:myPickerView];
}

MonthPicker.h

#import <UIKit/UIKit.h>

@interface MonthPicker : NSObject<UIPickerViewDelegate,UIPickerViewDataSource>

@end

MonthPicker.m

#import "MonthPicker.h"

@implementation MonthPicker


- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    return 7;
}

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

- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
    return @"yyy";
}

@end

At the moment i am using just placeholder values to get the delegate to work. Everyting compiles ok, but when i run the app and go to the view that has the picker in it, it crashes with 0 error messages in the console.

The only message i get is: Thread 1:EXC_BAD_ACCESS (code=2,address=0x0) but this does not help me at all.

I also tried overriding the dealloc method in the delegate with an NSLog, and it appears that before the crash occurs, it gets deallocated, which i find very wierd.

What am i missing?

Thank you.

Answer 1

the problem may be that at the end of the viewDidLoad method, the monthPicker object gets deallocated.

try to make monthPicker be a property instead, see if that works