出现键盘时如何滚动 UIScrollView? [英] How do I scroll the UIScrollView when the keyboard appears?
问题描述
我的代码有问题.当我编辑应该被键盘弹出窗口隐藏的 UITextField
时,我试图移动 UIScrollView
.
I'm having trouble with my code. I'm trying to move the UIScrollView
when I'm editing an UITextField
that should be hidden by the keyboard pop.
我现在正在移动主框架,因为我不知道如何在代码中向上滚动".所以,我编写了一些代码,它工作正常,但是当我编辑一个 UItextfield 并切换到另一个 UITextField
而不按返回"按钮时,主视图会变得很远.
I'm moving the main frame right now because I don't know how to 'scroll up' in the code.
So, I did a little bit of code, it's working fine but when I edit an UItextfield and I switch to another UITextField
without pressing on the 'return' button the main view goes waaayyyyy to far up.
我用我的变量 size、distance 和 textFieldRect.origin.y 做了一个 NSLog()
,如下所示.当我将两个 UITextField
放在同一个位置(y 原点)并执行此特定开关"(不按回车键)时,我得到相同的数字,而我的代码在第一个 UITextField
编辑但不用于第二次编辑.
I did an NSLog()
with my variables size, distance and textFieldRect.origin.y as you can see below. When I put two UITextField
at the same place (y origin) and I do this particular 'switch' (wihtout pressing return) , I get the same numbers, whereas my code worked fine for the first UITextField
editing but not for the second editing.
看看这个:
- (void)textFieldDidBeginEditing:(UITextField *)textField {
{
int size;
CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
size = textFieldRect.origin.y + textFieldRect.size.height;
if (change == FALSE)
{
size = size - distance;
}
if (size < PORTRAIT_KEYBOARD_HEIGHT)
{
distance = 0;
}
else if (size > PORTRAIT_KEYBOARD_HEIGHT)
{
distance = size - PORTRAIT_KEYBOARD_HEIGHT + 5; // +5 px for more visibility
}
NSLog(@"origin %f", textFieldRect.origin.y);
NSLog(@"size %d", size);
NSLog(@"distance %d", distance);
CGRect viewFrame = self.view.frame;
viewFrame.origin.y -= distance;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
[self.view setFrame:viewFrame];
[UIView commitAnimations];
change = FALSE;
}
- (void)textFieldDidEndEditing:(UITextField *)textField
{
change = TRUE;
CGRect viewFrame = self.view.frame;
viewFrame.origin.y += distance;
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationBeginsFromCurrentState:YES];
[UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
[self.view setFrame:viewFrame];
[UIView commitAnimations];
}
有什么想法吗?
推荐答案
Apple 推荐的方法是更改 UIScrollView
的 contentInset
.这是一个非常优雅的解决方案,因为您不必弄乱 contentSize
.以下代码是从键盘编程指南,其中解释了此问题的处理方式.你应该去看看.
The recommended way from Apple is to change the contentInset
of the UIScrollView
. It is a very elegant solution, because you do not have to mess with the contentSize
.
Following code is copied from the Keyboard Programming Guide, where the handling of this issue is explained. You should have a look into it.
// 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 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];
}
}
// Called when the UIKeyboardWillHideNotification is sent
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
scrollView.contentInset = contentInsets;
scrollView.scrollIndicatorInsets = contentInsets;
}
Swift 版本:
func registerForKeyboardNotifications() {
NotificationCenter.default.addObserver(self, selector: #selector(onKeyboardAppear(_:)), name: NSNotification.Name.UIKeyboardDidShow, object: nil)
NotificationCenter.default.addObserver(self, selector: #selector(onKeyboardDisappear(_:)), name: NSNotification.Name.UIKeyboardDidHide, object: nil)
}
// Don't forget to unregister when done
deinit {
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardDidShow, object: nil)
NotificationCenter.default.removeObserver(self, name: NSNotification.Name.UIKeyboardDidHide, object: nil)
}
@objc func onKeyboardAppear(_ notification: NSNotification) {
let info = notification.userInfo!
let rect: CGRect = info[UIKeyboardFrameBeginUserInfoKey] as! CGRect
let kbSize = rect.size
let insets = UIEdgeInsetsMake(0, 0, kbSize.height, 0)
scrollView.contentInset = insets
scrollView.scrollIndicatorInsets = insets
// If active text field is hidden by keyboard, scroll it so it's visible
// Your application might not need or want this behavior.
var aRect = self.view.frame;
aRect.size.height -= kbSize.height;
let activeField: UITextField? = [addressTextView, servicePathTextView, usernameTextView, passwordTextView].first { $0.isFirstResponder }
if let activeField = activeField {
if !aRect.contains(activeField.frame.origin) {
let scrollPoint = CGPoint(x: 0, y: activeField.frame.origin.y-kbSize.height)
scrollView.setContentOffset(scrollPoint, animated: true)
}
}
}
@objc func onKeyboardDisappear(_ notification: NSNotification) {
scrollView.contentInset = UIEdgeInsets.zero
scrollView.scrollIndicatorInsets = UIEdgeInsets.zero
}
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