How to give this picker view a datasource - iphone

Question

Here I am adding a pickerview programaticly
- (void)viewDidLoad {
[super viewDidLoad];
CGRect pickerFrame = CGRectMake(0,280,321,200);
UIPickerView *myPickerView = [[UIPickerView alloc] init]; //Not sure if this is the proper allocation/initialization procedure
//Set up the picker view as you need it
//Set up the display frame
myPickerView.frame = pickerFrame; //I recommend using IB just to get the proper width/height dimensions
//Add the picker to the view
[self.view addSubview:myPickerView];
}
But now I need to actually have it display content and somehow find out when it changes and what value it has changed to. How do I do this?

Answer 1

in .h file place this code
#interface RootVC : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource>
assign the datasource and delegate to the picker
// this view controller is the data source and delegate
myPickerView.delegate = self;
myPickerView.dataSource = self;
use the following delegate and datasouce methods
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
}
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
{
return 200;
}
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{
return 50;
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
NSString *returnStr = #"";
if (pickerView == myPickerView)
{
returnStr = [[levelPickerViewArray objectAtIndex:row] objectForKey:#"nodeContent"];
}
return returnStr;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if (pickerView == myPickerView)
{
return [levelPickerViewArray count];
}
}
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 1;
}

Answer 2

You need to create a class that implements the UIPickerViewDataSource protocol and assign an instance of it to myPickerView.dataSource.