为键盘添加inputAccessoryView

    UIToolbar* numberToolbar = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 50)];

    numberToolbar.barStyle = UIBarStyleBlackTranslucent;

    numberToolbar.items = [NSArray arrayWithObjects:

                           [[UIBarButtonItem alloc]initWithTitle:@"取消" style:UIBarButtonItemStyleBordered target:self action:@selector(cancelNumberPad)],

                           [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil],

                           [[UIBarButtonItem alloc]initWithTitle:@"确定" style:UIBarButtonItemStyleDone target:self action:@selector(doneWithNumberPad)],

                           nil];

    [numberToolbar sizeToFit];

    textField.inputAccessoryView = numberToolbar;