向上移动UITextField而不向上移动整个视图

Question

I have a UITableView inside a UIScrollView. The tableView does not span the length of the view as I have a UITextView at the bottom of the view (to enter messages) so the table ends at the textview. However, The scrollView does span the entire length of the view. When the keyboard comes up, I move the entire view up with it,(so nothing is hidden) but that makes the top cells of the table inaccessible (as in, I don't need to see the cells, but when i try to scroll to them I can't get to them) as it is pushing the whole view up. I am wondering if instead, I can push the scrollview underneath up, in turn having it push the keyboard up with it, and then have the tableview stay in place and scroll to the proper cell (for me in this case it is the most recent message, or last cell in the table). Having the tableview stay in place will allow scrolling access to all the cells in the table. Am I going about this the right way or is there an easier and better way to accomplish this? I'm working on a messaging app, and I want the UI to behave in a similar way to the native messages app. When the keyboard comes up, it brings the last message up above the top of the keyboard, but when the keyboard is visible you can still scroll to the top of the table. I will post my code for the movement of the view.

//call move view method and scroll to last cell in table
-(void) keyboardWasShown:(NSNotification*)aNotification
{
NSLog(@"Keyboard was shown");

[self moveView:[aNotification userInfo] up:YES];


[self.chatTable scrollRectToVisible:CGRectMake(0, self.chatTable.contentSize.height - self.chatTable.bounds.size.height, self.chatTable.bounds.size.width, self.chatTable.bounds.size.height) animated:YES];

}

-(void) keyboardWillHide:(NSNotification*)aNotification
{
      NSLog(@"Keyboard will hide");
     [self moveView:[aNotification userInfo] up:NO];
}

- (void)moveView:(NSDictionary*)userInfo up:(BOOL)up
{
     CGRect keyboardEndFrame;
    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey]getValue:&keyboardEndFrame];

    UIViewAnimationCurve animationCurve;
   [[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey]
 getValue:&animationCurve];

  NSTimeInterval animationDuration;
    [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey]
 getValue:&animationDuration];

// Get the correct keyboard size to we slide the right amount.
   [UIView beginAnimations:nil context:nil];
   [UIView setAnimationBeginsFromCurrentState:YES];
   [UIView setAnimationDuration:animationDuration];
   [UIView setAnimationCurve:animationCurve];

   CGRect keyboardFrame = [self.view convertRect:keyboardEndFrame toView:nil];
   int y = keyboardFrame.size.height * (up ? -1 : 1);
   self.view.frame = CGRectOffset(self.view.frame, 0, y);

   [UIView commitAnimations];




}

Answer 1

What I would do is NOT move the whole view up, but just shrink the scrollView's height by y amount.

So instead of

self.view.frame = CGRectOffset(self.view.frame, 0, y);

you could

CGRect scrlRect = self.myScrollView.frame;
self.myScrollView.frame = CGMakeRect(scrlRect.origin.x, scrlRect.origin.y, scrlRect.size.width, scrlRect.size.height+y);

Answer 2

The first step in dealing with this is modify the insets on the table. This gist would help you ensure that the tableView (or scrollview) scrollable area is no longer covered by the keyboard: https://gist.github.com/TimMedcalf/9505416

It may reveal further issues, but that's always my first port of call.

Answer 3

In your keyboarWasShown method wright below code:

- (void)keyboardWillShow:(NSNotification *)notification
{
    NSDictionary *info = [notification userInfo];

    CGSize kbSize = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
    float kbHeight = kbSize.width > kbSize.height ? kbSize.height : kbSize.width;

    self.keyboardHeight.constant = kbHeight+5;
}

Now in your textFieldShouldBeginEditing delegate method of UITextField write below code:

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
    CGPoint point = [textField.superview convertPoint:textField.frame.origin toView:yourTableViewHere];
    NSIndexPath *indexPath = [tblAsset indexPathForRowAtPoint:point];

    CGRect tableViewVisibleRect = [tblAsset rectForRowAtIndexPath:indexPath];

    if (point.y > (tableViewVisibleRect.size.height - self.keyboardHeight.constant))
    {
        CGPoint contentOffsetPoint = tblAsset.contentOffset;
        contentOffsetPoint.y -= self.keyboardHeight.constant;
        CGSize contectSize = tblAsset.contentSize;
        contectSize.height += self.keyboardHeight.constant;
        [tblAsset setContentSize:contectSize];
        [tblAsset setContentOffset:contentOffsetPoint animated:NO];
    }
}

Above is from my current project and its working somewhat like what you want. Using this way may help you achive your task.