在有条件的情况下禁用UIPickerView / UITableView的委托方法

Question

I want to disable below delegate method for some condition

-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view

let say if(x==YES) then only above delegate method hit else it won't respond.

Please let me know your suggestion.

Answer 1

Override respondsToSelector: and return NO in case of You does not want to call this method:

- (BOOL)respondsToSelector:(SEL)selector
{
    if (selector == @selector(pickerView:viewForRow:forComponent:reusingView:))
    {
        if(your_Condition)
        {
           return YES;
        }
        eles
        {
           return NO;
        }
    }  
    return [super respondsToSelector:selector];
}

So you're implementing the delegate method as normally. When the picker view is asking your delegate if it understands the message you're simply lying to it.

Answer 2

There are two ways you can do it.

1) Make Delegate Null

Set a condition when you do not want to call the method and at that place make delegate = nill .

And again Reset it delegate =self when needs to call the method.

The second method which I must say Better one

2) Use flag inside the Delegate method

Try to implement if-condition (Flag) inside the method and set its TRUE and FALSE values as per requirement.

for ex.

-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
     if(x == YES) {
                // Only this code need to implement
     } else {
     return;
     }

}