UITextView: move view when keyboard appears

UITextView: move view when keyboard appears

For showing the textview fields without being hidden by the keyboard, the standard way is to move up/down the view having text fields whenever the keyboard is shown.

The following simple steps is used to move up/down the UITextField in your iPhone.

Step 1: Set the UITextViewDelegate, and tag the textViewFields (in your .h file)

Step 2: Place "CGFloat animatedDistance;" in to inside the interface (in your .h file)

Step 3:  Define the following values in top of your .m file (after @implimentation)    

static const CGFloat KEYBOARD_ANIMATION_DURATION = 0.3;
static const CGFloat MINIMUM_SCROLL_FRACTION = 0.2;
static const CGFloat MAXIMUM_SCROLL_FRACTION = 0.8;
static const CGFloat PORTRAIT_KEYBOARD_HEIGHT = 216;
static const CGFloat LANDSCAPE_KEYBOARD_HEIGHT = 162;

Step 4: And finally add the following code into your .m file   

-(void) textViewDidBeginEditing:(UITextView *)textView {
    
    CGRect textFieldRect = [self.view.window convertRect:textView.bounds fromView:textView];
    CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];
    
    CGFloat midline = textFieldRect.origin.y + 0.5 * textFieldRect.size.height;
    CGFloat numerator = midline - viewRect.origin.y - MINIMUM_SCROLL_FRACTION * viewRect.size.height;
    CGFloat denominator = (MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION) * viewRect.size.height;
    CGFloat heightFraction = numerator / denominator;
    
    if(heightFraction < 0.0){
        
        heightFraction = 0.0;
        
    }else if(heightFraction > 1.0){
        
        heightFraction = 1.0;
    }
    
    UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
    
    if(orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown){
        
        animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction);
        
    }else{
        
        animatedDistance = floor(LANDSCAPE_KEYBOARD_HEIGHT * heightFraction);
    }
    
    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y -= animatedDistance;
    
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
    
    [self.view setFrame:viewFrame];
    
    [UIView commitAnimations];
}

- (void)textViewDidEndEditing:(UITextView *)textView{
    
    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y += animatedDistance;
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
    
    [self.view setFrame:viewFrame];
    [UIView commitAnimations];
}

-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
 if([text isEqualToString:@"\n"])
 {
  [textView resignFirstResponder];
  return NO;
 }
 return YES;
}

iphone - How to dismiss keyboard for UITextView with return key:
               Did you saw the last para of the above code snippets?, that is used to hide the iphone keypad when clicking return key.

-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
 if([text isEqualToString:@"\n"])
 {
  [textView resignFirstResponder];
  return NO;
 }
 return YES;
}

评论

1 楼 luzj 2012-04-05  

这个考虑不周全， 在iOS5的键盘高度就不是这个值了，这样写死不太好