关于C#：如何在设备平放时将UIScrollView移动到活动的UITextField？

How to move UIScrollView to the active UITextField while the device is laying flat?

好的，所以我对这个很难过。我正在使用键盘通知和UIScrollView在点击时滚动到当前活动文本字段。当设备平放时，它在纵向和横向上的工作方式与预期完全相同。

在横向方向，如果设备保持在空中，它会按预期滚动，但当设备平放在桌子上并轻敲文本字段时，视图将完全滚出屏幕。

是什么导致这个？

我正在使用iOS7在iPad Mini和iPhone 5上进行测试。

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- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.

// Register for keyboard notifications
[self registerForKeyboardNotifications];

// keep track of scrollview insets for later
scollViewIndicatorInsets = self.scrollView.scrollIndicatorInsets;
}

- (IBAction)editingEnded:(id)sender {
[sender resignFirstResponder];
}

- (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;

if (UIInterfaceOrientationIsLandscape([UIDevice currentDevice].orientation)) {
kbSize = CGSizeMake(kbSize.height, kbSize.width);
}

UIEdgeInsets contentInsets = UIEdgeInsetsMake(65.0, 0.0, kbSize.height, 0.0);
self.scrollView.contentInset = contentInsets;
self.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;
UIEdgeInsets contentInsets = UIEdgeInsetsMake(65.0, 0.0, 0.0, 0.0);
self.scrollView.contentInset = contentInsets;
self.scrollView.scrollIndicatorInsets = contentInsets;
}

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
activeField = textField;
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
activeField = nil;
}

键盘大小的计算比它应该复杂得多。让API为您完成工作：

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- (void)keyboardWasShown:(NSNotification*)aNotification
{
NSDictionary* info = [aNotification userInfo];
CGRect kbFrame = [info[UIKeyboardFrameBeginUserInfoKey] CGRectValue];
// Convert the keyboard frame from the window to the scrollview
kbFrame = [self.scrollView convertRect:kbFrame fromView:nil];
CGSize kbSize = kbFrame.size;

UIEdgeInsets contentInsets = UIEdgeInsetsMake(65.0, 0.0, kbSize.height, 0.0);
self.scrollView.contentInset = contentInsets;
self.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];
}
}