title: memory leaks at showing UIKeyboard on ARC
body: <p>When <code>UIKeyboard</code> is called, memory is allocated and not freed when <code>UIKeyboard</code> is hidden. If it is the framework who is caching it, is there any way to clear it up?
  These code is what I use to create the <code>UITextField</code> and how I hide the <code>UIKeyboard</code>:</p>
  
  <pre><code>    #import &lt;UIKit/UIKit.h&gt;
  
      @interface SignInTextField : UITextField
  
      -(id)initWithIndexPath:(NSIndexPath*)indexPath;
  
      @end
  
      #import "SignInTextField.h"
  
      @implementation SignInTextField
  
      -(id)initWithIndexPath:(NSIndexPath*)indexPath{
          self = [super init];
          if (self) {
              if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
                  // iPad
                  self.frame = CGRectMake(110, 10, 600, 30);
              } else {
                  self.frame = CGRectMake(110, 11, 150, 30);
              }
  
              self.tag = [indexPath row];
              self.returnKeyType = UIReturnKeyDone;
              self.autocapitalizationType = UITextAutocapitalizationTypeNone;
          }
          return self;
      }
  
      //SettingTextField
      SignInTextField *textField = [[SignInTextField alloc]initWithIndexPath:indexPath];
      textField.delegate = self;
  
      #pragma mark - Text Field CallBack
      -(void)textFieldDidBeginEditing:(UITextField *)textField{
          activeField = textField;
      }
  
      - (void)textFieldDidEndEditing:(UITextField *)textField {
  
          if(textField.tag == 0) temp_email = [NSString         stringWithFormat:@"%@",textField.text];
          if(textField.tag == 1) temp_password = [NSString stringWithFormat:@"%@",textField.text];
      }
  
      - (BOOL)textFieldShouldReturn:(UITextField *)textField {
          [textField resignFirstResponder];
          return YES;
     }
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/3uAwD.png" alt="This is leak point."></p>