textFieldが隠れない！NSNotificationCenterの使い方その１

最近つかっているNSNotificationCenterがかなり便利だったのでまとめてみた。

おすすめの使い方はいくつかあるが、その一つを紹介する
今回NSNotificationCenterで主に使うメソッドは以下の2つ

NSNotificationCenter

[[NSNotificationCenter defaultCenter] addObserver: selector: name:object:]
 [[NSNotificationCenter defaultCenter] removeObserver: name: object:]

これを使って、キーボートと一緒にせりあがるtextFieldを作れる
実装は以下のとおり。

Keyboard.h

@interface Keyboard : UIViewController
@property (strong, nonatomic) UITextField * textField;
@end

Keyboard.m

@implementation Keyboard
-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];

//キーボード表示・非表示の通知を開始
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];    
}

-(void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    //キーボード表示・非表示の通知を終了
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}


#pragma mark - Keyboard animation method

- (void)keyboardWillShow:(NSNotification *)aNotification {
    //キーボードの高さをとる
    CGRect keyboardRect = [[aNotification userInfo][UIKeyboardFrameEndUserInfoKey] CGRectValue];
    keyboardRect = [[self.view superview] convertRect:keyboardRect fromView:nil];
    NSNumber *duration = [aNotification.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    
    //アニメーションでtextFieldを動かす
    [UIView animateWithDuration:[duration doubleValue]
                     animations:^{
                         CGRect rect = self.textField.frame;
                         rect.origin.y = keyboardRect.origin.y - self.textField.frame.size.height;
                         self.textField.frame = rect
                     } ];
}

- (void)keyboardWillHide:(NSNotification *)aNotification {
    NSNumber *duration = [aNotification.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey];

    //アニメーションでtextFieldを動かす
    [UIView animateWithDuration:[duration doubleValue]
                     animations:^{
                         CGRect rect = self.textField.frame;
                         rect.origin.y = self.view.frame.size.height- self.textField.frame.size.height;
                         self.textField.frame = rect
                     }];
}

#pragma mark - textField

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    // エンターをおしたら、キーボードを閉じる
    [textField resignFirstResponder];

    return YES;
}
@end

次 : delegateいらず！NSNotificationCenterの使い方その2