iphone - Moving UIView up when keyboard shown

Question

I know this a frequent question but ive had no luck implementing this from examples i have found. i could be doing something simple wrong..(lets hope so). i am trying to move the UIview up as a have a textfield hidden at the bottom.

A little about my app, its got a tab bar controller and implements a standard UIView. When i add the code to move the display up nothing happens. Do i need to have a scroll view for this to work, is it a conflict with tab controller or am i doing something else wrong? thanks

Dan

Answer 1

I wrote a little category on UIView that manages temporarily scrolling things around without needing to wrap the whole thing into a UIScrollView. My use of the verb "scroll" here is perhaps not ideal, because it might make you think there's a scroll view involved, and there's not--we're just animating the position of a UIView (or UIView subclass).

There are a bunch of magic numbers embedded in this that are appropriate to my form and layout that might not be appropriate to yours, so I encourage tweaking this to fit your specific needs.

UIView+FormScroll.h:

#import <Foundation/Foundation.h>

@interface UIView (FormScroll) 

-(void)scrollToY:(float)y;
-(void)scrollToView:(UIView *)view;
-(void)scrollElement:(UIView *)view toPoint:(float)y;

@end

UIView+FormScroll.m:

#import "UIView+FormScroll.h"


@implementation UIView (FormScroll)


-(void)scrollToY:(float)y
{

    [UIView beginAnimations:@"registerScroll" context:NULL];
    [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
    [UIView setAnimationDuration:0.4];
    self.transform = CGAffineTransformMakeTranslation(0, y);
    [UIView commitAnimations];

}

-(void)scrollToView:(UIView *)view
{
    CGRect theFrame = view.frame;
    float y = theFrame.origin.y - 15;
    y -= (y/1.7);
    [self scrollToY:-y];
}


-(void)scrollElement:(UIView *)view toPoint:(float)y
{
    CGRect theFrame = view.frame;
    float orig_y = theFrame.origin.y;
    float diff = y - orig_y;
    if (diff < 0) {
        [self scrollToY:diff];
    }
    else {
        [self scrollToY:0];
    }

}

@end

Import that into your UIViewController, and then you can do

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    [self.view scrollToView:textField];
}

-(void) textFieldDidEndEditing:(UITextField *)textField
{
    [self.view scrollToY:0];
    [textField resignFirstResponder];
}

...or whatever. That category gives you three pretty good ways to adjust the position of a view.