iOS keyboard ทับ textfield เวลาจะพิมพ์ข้อมความใน textfield ที่อยู่ด้านล่าง แป้นพิมพ์จะทับทำให้มองไม่เห็นข้อความที่เราพิมพ์อยู่ มีรูป

- (void) animateTextField: (UITextField*) textField up: (BOOL) up{
    int txtPosition = (textField.frame.origin.y - 620);
    const int movementDistance = (txtPosition < 0 ? 0 : txtPosition); // tweak as needed
    const float movementDuration = 0.3f; // tweak as needed
    
    int movement = (up ? -movementDistance : movementDistance);
    
    [UIView beginAnimations: @"anim" context: nil];
    [UIView setAnimationBeginsFromCurrentState: YES];
    [UIView setAnimationDuration: movementDuration];
    self.view.frame = CGRectOffset(self.view.frame, 0, movement);
    [UIView commitAnimations];
}


- (void)textFieldDidEndEditing:(UITextField *)textField{
    [self animateTextField: textField up: NO];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    
    
    // Tap Gesture for Hide Keyboard
    UITapGestureRecognizer *oneTapGesture = [[UITapGestureRecognizer alloc]
                                             initWithTarget: self
                                             action: @selector(hideKeyboard:)];
    [oneTapGesture setNumberOfTouchesRequired:1];
    [[self view] addGestureRecognizer:oneTapGesture];
    
}

// Event Gesture for Hide Keyboard
- (void)hideKeyboard:(UITapGestureRecognizer *)sender {
    [txtPassword resignFirstResponder];
    [txtPassword resignFirstResponder];
    [txtName resignFirstResponder];
    [txtEmail resignFirstResponder];
    [txtTel resignFirstResponder];
}