iOS Keyboard show event handling - ios

Question

I am working on a chat app wherein I have a textview (not textfield) and when I click on it, the keyboard should show and everything should move up.
Till now, I have managed to shift the frame of the table view and textview up and show the keyboard using the below code.
- (void)keyboardWasShown:(NSNotification *)notification {
NSDictionary* info = [notification userInfo];
keyboardSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
CGPoint contentViewOrigin = self.contentView.frame.origin;
CGFloat contentViewHeight = self.contentView.frame.size.height;
CGRect visibleRect = self.view.frame;
visibleRect.size.height -= keyboardSize.height;
BOOL up = CGRectContainsPoint(visibleRect, contentViewOrigin);
if (!up){
self.tableView.frame = CGRectMake(self.tableView.frame.origin.x,self.tableView.frame.origin.y,self.tableView.frame.size.width,280.0f);
self.contentView.frame = CGRectOffset(self.contentView.frame, 0, 0 - keyboardSize.height);
if([self.tableView numberOfRowsInSection:0]!=0)
{
NSIndexPath* ip = [NSIndexPath indexPathForRow:[self.tableView numberOfRowsInSection:0]-1 inSection:0];
[self.tableView scrollToRowAtIndexPath:ip atScrollPosition:UITableViewScrollPositionBottom animated:UITableViewRowAnimationLeft];
}
}
}
- (void)keyboardWillBeHidden:(NSNotification *)notification {
self.contentView.frame = originalContentView;
self.tableView.frame = originalTable;
}
- (void)registerForKeyboardNotifications {
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWasShown:)
name:UIKeyboardDidShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(keyboardWillBeHidden:)
name:UIKeyboardWillHideNotification
object:nil];
}
- (void)deregisterFromKeyboardNotifications {
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardDidHideNotification
object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillHideNotification
object:nil];
}
But when I saw how whatsapp does it, mine looked like a hack. Whatsapp's keyboard moves up together with all the elements while mine works like this: First the keyboard is shown, a notification is sent to the app, notification is received, the code calculates the height of keyboard and moves up the elements according to the height.
I have searched and found the solution that I have implemented.
Can someone help??

Answer 1

I use this trick a lot in my apps. You want to listen to UIKeyboardWillShowNotification and UIKeyboardWillHideNotification.
The best way to handle animation in my opinion is using autolayout. When you call [self.view layoutIfNeeded]; your views will move along with the keyboard animation. No animation block needed.
I've set up a simple project for anyone to try and see how it works!
- (void)addKeyboardNotificationsObserver {
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(handleKeyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:#selector(handleKeyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
}
- (void)handleKeyboardWillShow:(NSNotification *)paramNotification
{
NSDictionary* info = [paramNotification userInfo];
//when switching languages keyboard might change its height (emoji keyboard is higher than most keyboards).
//You can get both sizes of the previous keyboard and the new one from info dictionary.
// size of the keyb that is about to disappear
CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
// size of the keyb that is about to appear
CGSize kbSizeNew = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
//make adjustments to constraints here...
//and here where's magick happen!
[self.view layoutIfNeeded];
}
- (void)handleKeyboardWillHide:(NSNotification *)paramNotification
{
//adjust constraints
[self.view layoutIfNeeded];
}

Answer 2

You can use UIKeyboardWillShowNotification and UIKeyboardWillHideNotification
Try TPKeyboardAvoidingScrollView from here: https://github.com/michaeltyson/TPKeyboardAvoiding (my choice)