当焦点和键盘隐藏文本字段时滚动到文本字段
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【中文标题】当焦点和键盘隐藏文本字段时滚动到文本字段【英文标题】:Scroll to textfield when focus and keyboard hide text field 【发布时间】:2013-01-05 00:36:47 【问题描述】:我有多个文本字段,当我关注文本框时,它会自动向上滚动并且键盘隐藏文本字段。
知道单击时如何将文本字段滚动到焦点字段吗?
- (void)registerForKeyboardNotifications
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWasShown:)
name:UIKeyboardDidShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillBeHidden:)
name:UIKeyboardWillHideNotification object:nil];
- (void)textFieldDidBeginEditing:(UITextField *)textField
activeField = textField;
- (void)textFieldDidEndEditing:(UITextField *)textField
activeField = nil;
// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
scrollView.contentInset = contentInsets;
scrollView.scrollIndicatorInsets = contentInsets;
- (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 application might not need or want this behavior.
CGRect aRect = self.view.frame;
aRect.size.height -= kbSize.height;
if (!CGRectContainsPoint(aRect, activeField.frame.origin) )
CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y-kbSize.height);
[scrollView setContentOffset:scrollPoint animated:YES];
【问题讨论】:
【参考方案1】:我认为您发布的代码 sn-p 是 Apple 文档中的代码,它假定基本视图层次结构具有 UIScrollView(或其子类之一,如 UITableView)填充整个屏幕。如果您的视图布局更复杂,或者您需要支持多个方向,则文本字段将不会滚动到可见,因为矩形计算将是错误的。您需要稍微调整一下代码,我的建议是您以这种方式解决问题:
滚动视图的新 contentInsent 高度应该等于键盘和滚动视图之间相交矩形的高度。
在代码中:
- (void)keyboardWasShown:(NSNotification*)aNotification
CGRect kbRawRect = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
CGRect scrollViewFrame = [self.scrollView.window convertRect:self.scrollView.frame fromView:self.scrollView.superview];
// Calculate the area that is covered by the keyboard
CGRect coveredFrame = CGRectIntersection(scrollViewFrame, kbRawRect);
// Convert again to window coordinates to take rotations into account
coveredFrame = [self.scrollView.window convertRect:self.scrollView.frame fromView:self.scrollView.superview];
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, coveredFrame.size.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
CGRect activeFieldRect = [self.activeField convertRect:self.activeField.bounds toView:self.scrollView];
[self.scrollView scrollRectToVisible:activeFieldRect animated:YES];
请注意,我已经使用了方便的 UIScrollView 的 scrollRectToVisible 函数来尽可能抽象最终的滚动操作。
【讨论】:
KeyboardWasShown 在文本框焦点时没有被调用。 你在 viewDidLoad 方法中调用 registerForKeyboardNotifications 了吗?以上是关于当焦点和键盘隐藏文本字段时滚动到文本字段的主要内容,如果未能解决你的问题,请参考以下文章
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