in your amountTextField controller you need to write the following code in .h file
create property of your textfield
@property(nonatomic,retain)UiTextField *txt; //whatever your textfield name
Now in .m file write the following
@synthesize txt;
write following statement where you create object of amountKeyboardViewController
amountKeyboardViewController *amountKeyboard = [[amountKeyboardViewController alloc] initWithNibName:@"amountKeyboardViewController" bundle:nil]
amountKeyboard.objamountTextField = self;
Now in amountKeyboardViewController controller write the following code
@class amountTextField; //forward declaration
then create object of this class
amountTextField *objamountTextField;
then create property of
@property(nonatomic,retain)amountTextField *objamountTextField;
Now on click of button
-(IBAction)clickof1
{
if([amountTextField.text length] <= 0)
objamountTextField.txt.text = @"1";
else
objamountTextField.txt.text=[objamountTextField.txt.text stringByAppendingString:@"1"];
}