计算从键盘高度 UITableview 向上滚动多少答案

【问题标题】：Calculating how much to scroll up from keyboard height UITableview计算从键盘高度 UITableview 向上滚动多少
【发布时间】：2014-11-20 09:37:40
【问题描述】：

我有这样的 UIScrollView 和 UITextField。我知道如何在我的 self.view 中显示键盘高度。但是，UITextField 位置不会固定在特定位置，因为用户可以滚动。

只有当它被键盘覆盖时，如何才能向上移动 uitextfield？我需要使用 CGPoint 和 convertPoint 吗？我可以知道怎么做吗？

【问题讨论】：

你知道表格中没有单元格还是未知的

标签： ios objective-c uitableview uiscrollview uitextfield

【解决方案1】：

您应该使用 UITextFieldDelegate。这是一个如何实现它的示例：

-(void)textFieldDidBeginEditing:(UITextField *)textField {
  if(!moved) {
   [self animateViewToPosition:self.view directionUP:YES];
  moved = YES; } 
}
 -(void)textFieldDidEndEditing:(UITextField *)textField {
  if(moved) {
  [self animateViewToPosition:self.view directionUP:NO];
   moved = NO;
    }
  [textField resignFirstResponder];
}

-(BOOL)textFieldShouldReturn:(UITextField *)textField {
  [textField resignFirstResponder];
  if(moved) {
   [self animateViewToPosition:self.view directionUP:NO];
  }
  moved = NO;
  return YES;
 }

-(void)animateViewToPosition:(UIView *)viewToMove directionUP:(BOOL)up {

  const int movementDistance = -260; // tweak as needed
  const float movementDuration = 0.3f; // tweak as needed

  int movement = (up ? movementDistance : -movementDistance);
  [UIView beginAnimations: @"animateTextField" context: nil];
  [UIView setAnimationBeginsFromCurrentState: YES];
  [UIView setAnimationDuration: movementDuration];
  viewToMove.frame = CGRectOffset(viewToMove.frame, 0, movement);
  [UIView commitAnimations];
}

【讨论】：

【解决方案2】：

// Call this method somewhere in your view controller setup code.

- (void)registerForKeyboardNotifications

{

    [[NSNotificationCenter defaultCenter] addObserver:self

            selector:@selector(keyboardWasShown:)

            name:UIKeyboardDidShowNotification object:nil];



   [[NSNotificationCenter defaultCenter] addObserver:self

             selector:@selector(keyboardWillBeHidden:)

             name:UIKeyboardWillHideNotification object:nil];



}



// Called when the UIKeyboardDidShowNotification is sent.

- (void)keyboardWasShown:(NSNotification*)aNotification

{

    NSDictionary* info = [aNotification userInfo];

    CGSize kbSize = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;



    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbSize.height, 0.0);

    scrollView.contentInset = contentInsets;

    scrollView.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, activeField.frame.origin) ) {

        [self.scrollView scrollRectToVisible:activeField.frame animated:YES];

    }

}



// Called when the UIKeyboardWillHideNotification is sent

- (void)keyboardWillBeHidden:(NSNotification*)aNotification

{

    UIEdgeInsets contentInsets = UIEdgeInsetsZero;

    scrollView.contentInset = contentInsets;

    scrollView.scrollIndicatorInsets = contentInsets;

}

【讨论】：

【解决方案3】：

如果有人想尝试它可能会有所帮助，但它可能不是最好的解决方案

   -(void)textFieldDidBeginEditing:(UITextField *)textField
 {
   CGRect actualframe = [textField convertRect:[textField bounds] toView:self.view];
   if ((actualframe.origin.y) >= (self.view.frame.size.height-keyboardheignt))
   {
      CGRect scrollfrm = [textField convertRect:[textField bounds] toView:tableview];
      [tableview setContentOffset:CGPointMake(0, scrollfrm.origin.y) animated:YES];//60
   }
 }

如果文本字段是表格的最后一行，则必须使用内容插入

【讨论】：