通用UITableView键盘调整大小算法 [英] Generic UITableView keyboard resizing algorithm

问题描述

我搜索了很多代码来调整表格视图的大小以适应键盘显示和隐藏，但我遇到的几乎所有帖子都假设表格视图占据了其视图控制器的整个视图。我有一个iPad应用程序，其中表视图只占用屏幕的一部分。在这种情况下，调整表格视图的正确方法是什么？ （我上面提到的帖子中的所有代码都失败了）

I've searched a lot for code that resizes the table view to accomodate for keyboard showing and hiding, but almost every single post i came across assumes that the table view is taking the entire view of its view controller. I have an iPad application where the table view is only taking part of the screen. What's the correct way to resize the table view in this case? (all the code in the posts i've mentioned above fails)

推荐答案

以下代码可以满足您的需要并且可以使用任何代码设备和任何布局。该代码由 Sensible TableView框架（具有复制和使用权限）提供。

The following code does what you want and works with any device and any layout. The code is courtesy of the Sensible TableView framework (with permission to copy and use).

- (void)keyboardWillShow:(NSNotification *)aNotification
{
if(keyboardShown) 
    return;

keyboardShown = YES;

// Get the keyboard size
UIScrollView *tableView;
if([self.tableView.superview isKindOfClass:[UIScrollView class]])
    tableView = (UIScrollView *)self.tableView.superview;
else
    tableView = self.tableView;
NSDictionary *userInfo = [aNotification userInfo];
NSValue *aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
CGRect keyboardRect = [tableView.superview convertRect:[aValue CGRectValue] fromView:nil];

// Get the keyboard's animation details
NSTimeInterval animationDuration;
[[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
UIViewAnimationCurve animationCurve;
[[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];

// Determine how much overlap exists between tableView and the keyboard
CGRect tableFrame = tableView.frame;
CGFloat tableLowerYCoord = tableFrame.origin.y + tableFrame.size.height;
keyboardOverlap = tableLowerYCoord - keyboardRect.origin.y;
if(self.inputAccessoryView && keyboardOverlap>0)
{
    CGFloat accessoryHeight = self.inputAccessoryView.frame.size.height;
    keyboardOverlap -= accessoryHeight;

    tableView.contentInset = UIEdgeInsetsMake(0, 0, accessoryHeight, 0);
    tableView.scrollIndicatorInsets = UIEdgeInsetsMake(0, 0, accessoryHeight, 0);
}

if(keyboardOverlap < 0)
    keyboardOverlap = 0;

if(keyboardOverlap != 0)
{
    tableFrame.size.height -= keyboardOverlap;

    NSTimeInterval delay = 0;
    if(keyboardRect.size.height)
    {
        delay = (1 - keyboardOverlap/keyboardRect.size.height)*animationDuration;
        animationDuration = animationDuration * keyboardOverlap/keyboardRect.size.height;
    }

    [UIView animateWithDuration:animationDuration delay:delay 
                        options:UIViewAnimationOptionBeginFromCurrentState 
                     animations:^{ tableView.frame = tableFrame; } 
                     completion:^(BOOL finished){ [self tableAnimationEnded:nil finished:nil contextInfo:nil]; }];
}
}

- (void)keyboardWillHide:(NSNotification *)aNotification
{
if(!keyboardShown)
    return;

keyboardShown = NO;

UIScrollView *tableView;
if([self.tableView.superview isKindOfClass:[UIScrollView class]])
    tableView = (UIScrollView *)self.tableView.superview;
else
    tableView = self.tableView;
if(self.inputAccessoryView)
{
    tableView.contentInset = UIEdgeInsetsZero;
    tableView.scrollIndicatorInsets = UIEdgeInsetsZero;
}

if(keyboardOverlap == 0)
    return;

// Get the size & animation details of the keyboard
NSDictionary *userInfo = [aNotification userInfo];
NSValue *aValue = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];
CGRect keyboardRect = [tableView.superview convertRect:[aValue CGRectValue] fromView:nil];

NSTimeInterval animationDuration;
[[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
UIViewAnimationCurve animationCurve;
[[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve];

CGRect tableFrame = tableView.frame; 
tableFrame.size.height += keyboardOverlap;

if(keyboardRect.size.height)
    animationDuration = animationDuration * keyboardOverlap/keyboardRect.size.height;

[UIView animateWithDuration:animationDuration delay:0 
                    options:UIViewAnimationOptionBeginFromCurrentState 
                 animations:^{ tableView.frame = tableFrame; } 
                 completion:nil];
}

- (void) tableAnimationEnded:(NSString*)animationID finished:(NSNumber *)finished contextInfo:(void *)context
{
// Scroll to the active cell
if(self.activeCellIndexPath)
{
    [self.tableView scrollToRowAtIndexPath:self.activeCellIndexPath atScrollPosition:UITableViewScrollPositionNone animated:YES];
    [self.tableView selectRowAtIndexPath:self.activeCellIndexPath animated:NO scrollPosition:UITableViewScrollPositionNone];
}
}

注意：

a。使用以下代码将上述两种方法添加到通知中心：

a. The above two methods have been added to the notification center using the following code:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

b。上面使用的ivars已经声明如下：

b. The ivars used above has been declared like this:

BOOL keyboardShown;
CGFloat keyboardOverlap;

c。 'self.activeCellIndexPath'始终设置为拥有当前活动的UITextField / UITextView的单元格的indexPath。

c. 'self.activeCellIndexPath' is always set to the indexPath of the cell owning the currently active UITextField/UITextView.

享受！ ：）

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