iOS UITextField最大字符数和字节数的限制详解

2.解决uitableview中键盘遮挡问题

/*
 * 键盘要显示的时候
 */
- (void)showKeyboardWithRect:(CGRect)keyboardRect
    withDuration:(CGFloat)animationDuration{
 
 CGSize kbSize = keyboardRect.size;
 
 UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);
 _baseTableView.contentInset = contentInsets;
 _baseTableView.scrollIndicatorInsets = contentInsets;
 
 // If active text field is hidden by keyboard, scroll it so it's visible
 // Your app might not need or want this behavior.
 CGRect aRect = self.view.frame;
 aRect.size.height -= kbSize.height;
 
 if (!CGRectContainsPoint(aRect, _activeCell.frame.origin) ) {
  [_baseTableView scrollRectToVisible:_activeCell.frame animated:YES];
 }
}

/*
 * 键盘要消失的时候
 */
- (void)hiddenKeyboardWithRect:(CGRect)keyboardRect
     withDuration:(CGFloat)animationDuration{
 _baseTableView.contentInset = UIEdgeInsetsZero;
 _baseTableView.scrollIndicatorInsets = UIEdgeInsetsZero;
}