使用iOS SDK：
我有一个带UITextFields的UIView，可以启动键盘。我需要它能够：
启动键盘后，允许滚动UIScrollView的内容以查看其他文本字段自动“跳转”（通过向上滚动）或缩短
我知道我需要一个UIScrollView。我已经尝试将UIView的类更改为UIScrollView，但仍然无法上下滚动文本框。
我需要UIView和UIScrollView吗？一个在另一个里面吗？
要自动滚动到活动文本字段，需要执行哪些操作？
理想情况下，尽可能多的组件设置将在Interface Builder中完成。我只想编写需要的代码。
注意：我使用的UIView（或UIScrollView）是由一个选项卡（UITabBar）启动的，它需要正常工作。
我正在添加滚动条，只为键盘出现时使用。尽管不需要它，但我觉得它提供了一个更好的界面，例如，用户可以滚动和更改文本框。
当键盘上下移动时，我可以改变UIScrollView的框架大小。我只是在使用：
-(void)textFieldDidBeginEditing:(UITextField *)textField {
//Keyboard becomes visible
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height - 215 + 50); // Resize
}
-(void)textFieldDidEndEditing:(UITextField *)textField {
// Keyboard will hide
scrollView.frame = CGRectMake(scrollView.frame.origin.x,
scrollView.frame.origin.y,
scrollView.frame.size.width,
scrollView.frame.size.height + 215 - 50); // Resize
}
然而，这不会自动“向上移动”或将可见区域中的下部文本字段居中，这是我真正想要的。
试试这个，效果很好：
if Firstnametxt.text == "" || Passwordtxt.text == "" || emailtxt.text == ""
{
if Firstnametxt.text == ""
{
Firstnametxt!.shake(10, withDelta: 5, speed: 0.05, shakeDirection: ShakeDirection.Horizontal)
Firstnametxt.becomeFirstResponder()
}
else if Passwordtxt.text == ""
{
Passwordtxt!.shake(10, withDelta: 5, speed: 0.05, shakeDirection: ShakeDirection.Horizontal)
Passwordtxt.becomeFirstResponder()
}
else if emailtxt.text == ""
{
emailtxt!.shake(10, withDelta: 5, speed: 0.05, shakeDirection: ShakeDirection.Horizontal)
emailtxt.becomeFirstResponder()
}
}
else
{
let isValidEmail:Bool = self.isValidEmail(emailtxt.text!)
if isValidEmail == true
{
}
else
{
emailtxt!.shake(10, withDelta: 5, speed: 0.05, shakeDirection: ShakeDirection.Horizontal)
emailtxt.becomeFirstResponder()
}
}
注意：此答案假设您的textField位于scrollView中。
我更喜欢使用scrollContentInset和scrollContentOffset来处理这个问题，而不是干扰视图的框架。
首先让我们听听键盘通知
//call this from viewWillAppear
-(void)addKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillHide:)
name:UIKeyboardWillHideNotification
object:nil];
}
//call this from viewWillDisappear
-(void)removeKeyboardNotifications{
[[NSNotificationCenter default
Center] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil];
}
下一步是保留表示当前第一响应者的属性（当前具有键盘的UITextfield/UUITextVIew）。
我们使用委托方法来设置此属性。如果您正在使用另一个组件，则需要类似的组件。
请注意，对于textfield，我们在didBegginEditing中设置它，而对于textView，我们在shouldBeginEditing中将其设置。这是因为出于某种原因，在UIKeyboardWillShowNotification之后调用textViewDidBegginEditing。
-(BOOL)textViewShouldBeginEditing:(UITextView * )textView{
self.currentFirstResponder = textView;
return YES;
}
-(void)textFieldDidBeginEditing:(UITextField *)textField{
self.currentFirstResponder = textField;
}
最后，这里是魔术
- (void)keyboardWillShow:(NSNotification*)aNotification{
NSDictionary* info = [aNotification userInfo];
CGRect kbFrame = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
/*if currentFirstResponder is overlayed by the keyboard, move it so it bottom ends where the keyboard begins*/
if(self.currentFirstResponder){
//keyboard origin in currentFirstResponderFrame
CGPoint keyboardOrigin = [self.currentFirstResponder convertPoint:kbFrame.origin fromView:nil];
float spaceBetweenFirstResponderAndKeyboard = abs(self.currentFirstResponder.frame.size.height-keyboardOrigin.y);
//only scroll the scrollview if keyboard overlays the first responder
if(spaceBetweenFirstResponderAndKeyboard>0){
//if i call setContentOffset:animate:YES it behaves differently, not sure why
[UIView animateWithDuration:0.25 animations:^{
[self.scrollView setContentOffset:CGPointMake(0,self.scrollView.contentOffset.y+spaceBetweenFirstResponderAndKeyboard)];
}];
}
}
//set bottom inset to the keyboard height so you can still scroll the whole content
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, kbFrame.size.height, 0.0);
_scrollView.contentInset = contentInsets;
_scrollView.scrollIndicatorInsets = contentInsets;
}
- (void)keyboardWillHide:(NSNotification*)aNotification{
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
_scrollView.contentInset = contentInsets;
_scrollView.scrollIndicatorInsets = contentInsets;
}
这是使用Swift的解决方案。
import UIKit
class ExampleViewController: UIViewController, UITextFieldDelegate {
@IBOutlet var scrollView: UIScrollView!
@IBOutlet var textField1: UITextField!
@IBOutlet var textField2: UITextField!
@IBOutlet var textField3: UITextField!
@IBOutlet var textField4: UITextField!
@IBOutlet var textField5: UITextField!
var activeTextField: UITextField!
// MARK: - View
override func viewDidLoad() {
super.viewDidLoad()
self.textField1.delegate = self
self.textField2.delegate = self
self.textField3.delegate = self
self.textField4.delegate = self
self.textField5.delegate = self
}
override func viewWillAppear(animated: Bool) {
super.viewWillAppear(animated)
self.registerForKeyboardNotifications()
}
override func viewWillDisappear(animated: Bool) {
super.viewWillDisappear(animated)
self.unregisterFromKeyboardNotifications()
}
// MARK: - Keyboard
// Call this method somewhere in your view controller setup code.
func registerForKeyboardNotifications() {
let center: NSNotificationCenter = NSNotificationCenter.defaultCenter()
center.addObserver(self, selector: "keyboardWasShown:", name: UIKeyboardDidShowNotification, object: nil)
center.addObserver(self, selector: "keyboardWillBeHidden:", name: UIKeyboardWillHideNotification, object: nil)
}
func unregisterFromKeyboardNotifications () {
let center: NSNotificationCenter = NSNotificationCenter.defaultCenter()
center.removeObserver(self, name: UIKeyboardDidShowNotification, object: nil)
center.removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
}
// Called when the UIKeyboardDidShowNotification is sent.
func keyboardWasShown (notification: NSNotification) {
let info : NSDictionary = notification.userInfo!
let kbSize = (info.objectForKey(UIKeyboardFrameBeginUserInfoKey)?.CGRectValue() as CGRect!).size
let contentInsets: UIEdgeInsets = 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.
var aRect = self.view.frame
aRect.size.height -= kbSize.height;
if (!CGRectContainsPoint(aRect, self.activeTextField.frame.origin) ) {
self.scrollView.scrollRectToVisible(self.activeTextField.frame, animated: true)
}
}
// Called when the UIKeyboardWillHideNotification is sent
func keyboardWillBeHidden (notification: NSNotification) {
let contentInsets = UIEdgeInsetsZero;
scrollView.contentInset = contentInsets;
scrollView.scrollIndicatorInsets = contentInsets;
}
// MARK: - Text Field
func textFieldDidBeginEditing(textField: UITextField) {
self.activeTextField = textField
}
func textFieldDidEndEditing(textField: UITextField) {
self.activeTextField = nil
}
}
