测试键盘在显示时是否隐藏文本字段

Question

I try to move up the form when the keyboard is shown, my approach is to test whether the frame of the keyboard and the frame of the text field intersects.

- (void)keyboardDidShow:(NSNotification *)notification
{


    // Get the size of the keyboard.
    CGRect keyboardFrame = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];

    //Test whether the current frame of the text field is hidden by the keyboard

    if (!CGRectIsNull(CGRectIntersection(keyboardFrame,self.activeField.frame))) {
        NSLog(@"Key board frame intersects with the text field frame");
    }


}

In the code above, CGRectIsNull always return null.

A debugging statements return me these info about the keyboard and the active text field being selected in the form:

Keyboard size = (width=352, height=1024) keyboard origin = (x=-352, y=0)

key board frame = (-352,0,352,1024) Text field frame = (200, 15, 300, 30)

Every text field has the same frame values, which means something is wrong. So how can I test whether the keyboard is hiding the text field so that I move my form up and down. Thanx.

Answer 1

I'd put the entire thing in a fullscreen UIScrollView and then resize it when needed...

// This in your init somewhere
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];

-(void) keyboardWillChange:(NSNotification*)notify {

    CGRect endFrame;
    float duration = [[[notify userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
    [[[notify userInfo] valueForKey:UIKeyboardFrameEndUserInfoKey] getValue:&endFrame];
    endFrame = [self.view convertRect:endFrame fromView:nil];
    float y = (endFrame.origin.y > self.view.bounds.size.height ? self.view.bounds.size.height : endFrame.origin.y);

    [UIView animateWithDuration:duration animations:^{
        scrollView.frame = CGRectMake(0, 0, self.view.bounds.size.width, y);
    }];

}

Answer 2

Try this:

 [[NSNotificationCenter defaultCenter] addObserverForName:UIKeyboardWillShowNotification object:nil queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {}];

And use info from [note userInfo];