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。
在(BOOL)textFieldShouldBeginEditing:(UITextField*)textField中
if (textField.frame.origin.y > self.view.frame.size.height - 216)
{
if (screenHeight>500)
scrollView.contentSize = CGSizeMake(0.0, scrollView.contentSize.height + 100);
else
scrollView.contentSize = CGSizeMake(0.0, scrollView.contentSize.height + 216);
CGPoint scrollPoint = CGPointMake(0.0,(textField.frame.origin.y - (self.view.frame.size.height - 216 - textField.frame.size.height - 20)));
[scrollView setContentOffset:scrollPoint animated:YES];
}
[scrollView setScrollEnabled:YES];
辞职时,你需要写以下代码
scrollView.contentSize = CGSizeMake(0.0, 640);
CGPoint scrollPoint = CGPointMake(0.0,0.0);
[scrollView setContentOffset:scrollPoint animated:YES];
如果你还在为这件事而挣扎,请阅读我的帖子
我今天提出了一个解决方案。我读过很多关于这个问题的帖子和“教程”,没有一篇在任何情况下都有效(大多数都是相互复制粘贴的)。甚至苹果官方提出的“解决方案”也不起作用,更重要的是,它在横向模式下完全不起作用。苹果公司没有给开发者们解决这样一个常见的基本问题的方法,真是可耻。非常不专业。如此惊人的框架(Cocoa)和如此严重的被低估的问题。
现在,我的解决方案是:让UIScrollView成为您的根视图,然后将所有内容放入其中。然后从这个KeyboardAwareController类子类化视图控制器(您可能需要重新定义scrollView和keyboardPadding方法):
////键盘AwareController.h//社会病////管理员于2014年1月13日创建。//版权所有(c)2014 kuchumovn。保留所有权利。//
#import <UIKit/UIKit.h>
@interface KeyboardAwareController : UIViewController <UITextFieldDelegate>
@end
////键盘AwareController.m//社会病////管理员于2014年1月13日创建。//版权所有(c)2014 kuchumovn。保留所有权利。//
#import "KeyboardAwareController.h"
@interface KeyboardAwareController ()
@end
@implementation KeyboardAwareController
{
CGPoint scrollPositionBeforeKeyboardAdjustments;
__weak UIScrollView* scrollView;
UITextField* activeField;
}
- (id) initWithCoder: (NSCoder*) decoder
{
if (self = [super initWithCoder:decoder])
{
scrollPositionBeforeKeyboardAdjustments = CGPointZero;
}
return self;
}
- (void) viewDidLoad
{
[super viewDidLoad];
}
- (UIScrollView*) scrollView
{
return (UIScrollView*) self.view;
}
- (CGFloat) keyboardPadding
{
return 5;
}
- (void) registerForKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillShow:)
name:UIKeyboardWillShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardDidShow:)
name:UIKeyboardDidShowNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWillBeHidden:)
name:UIKeyboardWillHideNotification object:nil];
}
- (void) deregisterFromKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardDidShowNotification
object:nil];
[[NSNotificationCenter defaultCenter] removeObserver:self
name:UIKeyboardWillHideNotification
object:nil];
}
- (void) viewWillAppear: (BOOL) animated
{
[super viewWillAppear:animated];
[self registerForKeyboardNotifications];
}
- (void) viewWillDisappear: (BOOL) animated
{
[self deregisterFromKeyboardNotifications];
[super viewWillDisappear:animated];
}
- (void) keyboardWillShow: (NSNotification*) notification
{
//NSLog(@"keyboardWillShow");
// force the animation from keyboardWillBeHidden: to end
scrollView.contentOffset = scrollPositionBeforeKeyboardAdjustments;
scrollPositionBeforeKeyboardAdjustments = CGPointZero;
}
// warning: i have no idea why this thing works and what does every line of this code mean
// (but it works and there is no other solution on the internets whatsoever)
// P.S. Shame on Apple for missing such a basic functionality from SDK (and many other basic features we have to hack and mess around with for days and nights)
- (void) keyboardDidShow: (NSNotification*) notification
{
//NSLog(@"keyboardDidShow");
UIWindow* window = [[[UIApplication sharedApplication] windows]objectAtIndex:0];
UIView* mainSubviewOfWindow = window.rootViewController.view;
CGRect keyboardFrameIncorrect = [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
CGRect keyboardFrame = [mainSubviewOfWindow convertRect:keyboardFrameIncorrect fromView:window];
CGSize keyboardSize = keyboardFrame.size;
CGRect visibleFrame = CGRectMake(0, 0, 0, 0);
visibleFrame.origin = self.scrollView.contentOffset;
visibleFrame.size = self.scrollView.bounds.size;
CGFloat paddedKeyboardHeight = keyboardSize.height + self.keyboardPadding;
//NSLog(@"visibleFrame %@", NSStringFromCGRect(visibleFrame));
visibleFrame.size.height -= paddedKeyboardHeight;
//NSLog(@"visibleFrame after keyboard height %@", NSStringFromCGRect(visibleFrame));
if (CGRectContainsPoint(visibleFrame, activeField.frame.origin))
return;
scrollPositionBeforeKeyboardAdjustments = scrollView.contentOffset;
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, activeField.frame.origin.y - visibleFrame.size.height + activeField.frame.size.height, 0);
contentInsets = UIEdgeInsetsMake(0.0, 0.0, paddedKeyboardHeight, 0);
self.scrollView.contentInset = contentInsets;
self.scrollView.scrollIndicatorInsets = contentInsets;
CGSize scrollContentSize = self.scrollView.bounds.size;
scrollContentSize.height += paddedKeyboardHeight;
self.scrollView.contentSize = scrollContentSize;
//NSLog(@"scrollView %@", NSStringFromCGRect(scrollView.frame));
//NSLog(@"activeField %@", NSStringFromCGRect(activeField.frame));
//[scrollView scrollRectToVisible:activeField.frame animated:YES];
CGPoint scrollPoint = CGPointMake(0.0, activeField.frame.origin.y - visibleFrame.size.height + activeField.frame.size.height);
//NSLog(@"scrollPoint %@", NSStringFromCGPoint(scrollPoint));
[self.scrollView setContentOffset:scrollPoint animated:YES];
}
- (void) keyboardWillBeHidden: (NSNotification*) notification
{
//NSLog(@"keyboardWillBeHidden");
UIEdgeInsets contentInsets = UIEdgeInsetsZero;
// this doesn't work when changing orientation while the keyboard is visible
// because when keyboardDidShow: will be called right after this method the contentOffset will still be equal to the old value
//[scrollView setContentOffset:scrollPositionBeforeKeyboardAdjustments animated:YES];
[UIView animateWithDuration:.25 animations:^
{
self.scrollView.contentInset = contentInsets;
self.scrollView.scrollIndicatorInsets = contentInsets;
// replacement for setContentOffset:animated:
self.scrollView.contentOffset = scrollPositionBeforeKeyboardAdjustments;
}];
}
- (void) textFieldDidBeginEditing: (UITextField*) textField
{
activeField = textField;
}
- (void) textFieldDidEndEditing: (UITextField*) textField
{
activeField = nil;
}
@end
如果您有任何问题,我的项目将在github上托管:https://github.com/kuchumovn/sociopathy.ios
为了更好地解释,我还拍了一张截图:
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;
}