When developing an iOS app in Objective-C, it is important to handle the keyboard properly, especially when dealing with text input fields. One common task is to dynamically adjust the layout when the keyboard appears and disappears. In this article, we will discuss how to programmatically calculate and get the height of the keyboard in Objective-C.

Step 1: Notification Observing

First, you need to observe the keyboard notifications to detect when the keyboard appears and disappears. You can add observers for the following notifications: UIKeyboardWillShowNotification and UIKeyboardWillHideNotification.

Step 2: Notification Handling

When the keyboard notification is received, you can obtain the keyboard height from the notification's userInfo dictionary. The key UIKeyboardFrameEndUserInfoKey provides the frame of the keyboard when it appears, and you can calculate the keyboard height from this frame.

Step 3: Converting Coordinates

It is important to convert the keyboard frame to the appropriate coordinate system, especially if your app supports different orientations. You can use the convertRect:toView: method to convert the keyboard frame to the coordinate system of your view or window.

Step 4: Handling the Keyboard Height

Once you have obtained the keyboard height, you can use it to adjust the layout of your UI elements accordingly. For example, you can move up the text input fields to ensure they are not obstructed by the keyboard.

Sample Code

Here is a sample Objective-C code snippet demonstrating how to get the keyboard height:

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

CGRect keyboardFrame = [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];

keyboardFrame = [self.view convertRect:keyboardFrame fromView:nil];

CGFloat keyboardHeight = keyboardFrame.size.height;

// Use keyboardHeight to update UI layout

}

By following these steps and using the appropriate notifications and methods, you can accurately get the height of the keyboard in Objective-C. This will allow you to dynamically adapt your app's UI to provide a seamless user experience when the keyboard appears and disappears.