Move view when so that keyboard does not hide text

问题:

In my app, when I click on a text field, the keyboard hides it. Please help me -- how can I move my view up when I click on the text field. I'm using this code in textFieldDidBeginEditing:

self.tableView.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, 216, 0);
self.tableView.contentInset = UIEdgeInsetsMake(0, 0, 216, 0);

but it doesn't work.

回答1:

You can do the following, but first make sure you've set the UITextField delegate to your self and

#define kOFFSET_FOR_KEYBOARD 350;

at the top. This is how far you want the view to be shifted

//method to move the view up/down whenever the keyboard is shown/dismissed

-(void)setViewMovedUp:(BOOL)movedUp
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3]; // if you want to slide up the view
    [UIView setAnimationBeginsFromCurrentState:YES];

    CGRect rect = self.view.frame;
    if (movedUp)
    {
        // 1. move the view's origin up so that the text field that will be hidden come above the keyboard 
        // 2. increase the size of the view so that the area behind the keyboard is covered up.

        if (rect.origin.y == 0 ) {
            rect.origin.y -= kOFFSET_FOR_KEYBOARD;
            //rect.size.height += kOFFSET_FOR_KEYBOARD;
        }

    }
    else
    {
        if (stayup == NO) {
            rect.origin.y += kOFFSET_FOR_KEYBOARD;
            //rect.size.height -= kOFFSET_FOR_KEYBOARD;
        }
    }
    self.view.frame = rect; 
    [UIView commitAnimations];
}


- (void)keyboardWillHide:(NSNotification *)notif {
    [self setViewMovedUp:NO];
}


- (void)keyboardWillShow:(NSNotification *)notif{
    [self setViewMovedUp:YES];
}


- (void)textFieldDidBeginEditing:(UITextField *)textField {
    stayup = YES;
    [self setViewMovedUp:YES];
}


- (void)textFieldDidEndEditing:(UITextField *)textField {
    stayup = NO;
    [self setViewMovedUp:NO];
}

- (void)viewWillAppear:(BOOL)animated
{
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) 
                                                 name:UIKeyboardWillShowNotification object:self.view.window];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) 
                                                 name:UIKeyboardWillHideNotification object:self.view.window];
}

- (void)viewWillDisappear:(BOOL)animated
{
    // unregister for keyboard notifications while not visible.
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}

回答2:

You should not trust textFieldDidBeginEditing: to adjust for the keyboard, since this method will be called even if the user is typing using a physical keyboard where an onscreen keyboard will not be displayed.

Instead listen to the UIKeyboardWillShowNotification, that is only triggered when the keyboard will actually be displayed. You need to do a three step process:

1. Determine actual size of keyboard from the notifications userInfo dictionary. The size will differ from landscape/portrait, and different devices.
2. Update the contentInset using the determined size. You can do it animated, the notification will even tell you the duration for the keyboard animation.
3. Scroll the textfield into view, very easy to forget this!

You find more information and sample code from here