warning at the end of UIPickerViewDelegate method - iphone

Question

I use pickerview in my application and in .h file i have written code as follows
#interface tweetViewController : UIViewController<UIPickerViewDataSource,UIPickerViewDelegate> {
NSArray* activities;
NSArray* feelings;
}
#property (nonatomic,retain) NSArray *activities;
#property (nonatomic,retain)NSArray *fellings;
and i have written code in my.h file for UIPickerviewDatasource as follows which works fine
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 2;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if(component==0)
{
return [activities count];
}
else
{
return [feelings count];
}
}
but the following code of UIPickerViewDelegate shows me warning msg at the closing brace of the method
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
switch (component) {
case 0:
return [activities objectAtIndex:row];
case 1:
return [feelings objectAtIndex:row];
}
}
plz suggest me how i can solve the problem...

Answer 1

This is because the compiler is not sure you're going to return something.
Your method does the following:
if case == 0: return [activities objectAtIndex:row];
if case == 1: return [activities objectAtIndex:row];
In praxis, this will always return a value. However, the compiler checks your code fully theoretically and finds out that if case would be any other integer than 0 and 1, your method doesn't return.
Bottom line is that you need to add return nil; after your switch-block =), so your method will always return (nil will be interpreted as #"" in this case).