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。


当前回答

在更改文本字段或编辑其内容时,我遇到了重新设置为默认主视图的问题(例如,电话文本字段和添加“-”符号,视图返回覆盖文本字段)我最终通过使用自动布局和更改约束常量(而不是通知代理函数中的帧大小或位置)来克服这一问题,如下所示:

另外,我并没有使用滚动视图,只是简单地向上移动视图,但它的工作原理应该类似

func keyboardWillShow(notification: NSNotification) {
if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
    if !keyboardIsShown{
        self.infoViewTopConstraint.constant -= keyboardSize.height
        self.infoViewBottomConstraint.constant += keyboardSize.height
        self.view.setNeedsLayout()
        self.view.layoutIfNeeded()
        keyboardIsShown = true
    }
}

func keyboardWillHide(notification: NSNotification) {
if keyboardIsShown {
    self.infoViewTopConstraint.constant += keyboardSize.height
    self.infoViewBottomConstraint.constant -= keyboardSize.height
    self.view.setNeedsLayout()
    self.view.layoutIfNeeded()
    keyboardIsShown = false
}

其他回答

我迟到了一点。您应该在viewController上添加scrollView。

您必须实现以下2种方法。

TextField委托方法。

    - (void)textFieldDidBeginEditing:(UIView *)textField {
    [self scrollViewForTextField:reEnterPINTextField];
}

然后在委托方法中调用以下方法。

 - (void)scrollViewForTextField:(UIView *)textField {
    NSInteger keyboardHeight = KEYBOARD_HEIGHT;

    if ([textField UITextField.class]) {
        keyboardHeight += ((UITextField *)textField).keyboardControl.activeField.inputAccessoryView.frame.size.height;
    } 

    CGRect screenFrame = [UIScreen mainScreen].bounds;
    CGRect aRect = (CGRect){0, 0, screenFrame.size.width, screenFrame.size.height - ([UIApplication sharedApplication].statusBarHidden ? 0 : [UIApplication sharedApplication].statusBarFrame.size.height)};
    aRect.size.height -= keyboardHeight;
    CGPoint relativeOrigin = [UIView getOriginRelativeToScreenBounds:textField];
    CGPoint bottomPointOfTextField = CGPointMake(relativeOrigin.x, relativeOrigin.y + textField.frame.size.height);

    if (!CGRectContainsPoint(aRect, bottomPointOfTextField) ) {
        CGPoint scrollPoint = CGPointMake(0.0, bottomPointOfTextField.y -aRect.size.height);
        [contentSlidingView setContentOffset:scrollPoint animated:YES];
    }
}

要恢复到原始视图状态,请添加:

-(void)textFieldDidEndEditing:(UITextField *)sender

{
    //move the main view, so that the keyboard does not hide it.
    if  (self.view.frame.origin.y < 0)
    {
        [self setViewMovedUp:NO];
    }
}

一个适用于许多UITextFields的小补丁:

#pragma mark UIKeyboard handling

#define kMin 150

-(void)textFieldDidBeginEditing:(UITextField *)sender
{
    if (currTextField) {
        [currTextField release];
    }
    currTextField = [sender retain];
    // Move the main view, so that the keyboard does not hide it.
    if (self.view.frame.origin.y + currTextField.frame.origin. y >= kMin) {
        [self setViewMovedUp:YES];
    }
}


// Method to move the view up/down whenever the keyboard is shown/dismissed
-(void)setViewMovedUp:(BOOL)movedUp
{
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:0.3]; // If you want to slide up the view

    CGRect rect = self.view.frame;
    if (movedUp)
    {
        // 1. move the view's origin up so that the text field that will be hidden come above the keyboard
        // 2. increase the size of the view so that the area behind the keyboard is covered up.
        rect.origin.y = kMin - currTextField.frame.origin.y ;
    }
    else
    {
        // Revert back to the normal state.
        rect.origin.y = 0;
    }
    self.view.frame = rect;

    [UIView commitAnimations];
}


- (void)keyboardWillShow:(NSNotification *)notif
{
    // Keyboard will be shown now. Depending on which textfield is active, move up or move down the view appropriately

    if ([currTextField isFirstResponder] && currTextField.frame.origin.y + self.view.frame.origin.y >= kMin)
    {
        [self setViewMovedUp:YES];
    }
    else if (![currTextField isFirstResponder] && currTextField.frame.origin.y + self.view.frame.origin.y < kMin)
    {
        [self setViewMovedUp:NO];
    }
}


- (void)keyboardWillHide:(NSNotification *)notif
{
    // Keyboard will be shown now. Depending on which textfield is active, move up or move down the view appropriately
    if (self.view.frame.origin.y < 0 ) {
        [self setViewMovedUp:NO];
    }
}


- (void)viewWillAppear:(BOOL)animated
{
    // Register for keyboard notifications
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:)
                                                 name:UIKeyboardWillShowNotification object:self.view.window];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:)
                                                 name:UIKeyboardWillHideNotification object:self.view.window];
}

- (void)viewWillDisappear:(BOOL)animated
{
    // Unregister for keyboard notifications while not visible.
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
}

有很多答案可以告诉我们这个方法。我采取了相同的方法,但实施效果不佳。

这是基本想法。我修改了keyboardWasShown方法。

{
// Obtain keyboard Info
NSDictionary* info = [notification userInfo];
CGRect keyboardRect = [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
keyboardRect = [self.view convertRect:keyboardRect fromView:nil];

// Obtain ScrollView Info w.r.t. top View
CGRect scrollViewRect = [self.view convertRect:self.scrollView.frame fromView:nil];

// Depending upon your screen Ui, Scroll View's bottom edge might be at some offset from screen's bottom
// Calculate the exact offset
int scrollViewBottomOffset = self.view.frame.size.height - (scrollViewRect.origin.y + scrollViewRect.size.height);
int heightToBeAdjusted = keyboardRect.size.height - scrollViewBottomOffset;


// We may also need to consider the Insets if already present with ScrollView. Let's keep it simple for now
// But we should store these, so that we can restore the Insets when Keyboard is gone
// origInsets = self.scrollView.contentInset;

// Set the new Insets for ScrollView
UIEdgeInsets contentInsets = UIEdgeInsetsMake(0.0, 0.0, heightToBeAdjusted, 0.0);
self.scrollView.contentInset = contentInsets;
self.scrollView.scrollIndicatorInsets = contentInsets;

// Visible frame (not overlapped by Keyboard)
CGRect visibleFrame = self.view.frame;
visibleFrame.size.height -= keyboardRect.size.height;

// Get the Rect for Textfield w.r.t self.view
CGRect activeFieldFrame = self.activeField.frame;
activeFieldFrame = [self.view convertRect:activeFieldFrame fromView:self.scrollView];

// Check if the TextField is Visible or not
if (!CGRectContainsRect(visibleFrame, activeFieldFrame) ) {
    // Scroll to make it visible but for scrolling use the activeField frame w.r.t. to scroll View
    [self.scrollView scrollRectToVisible:self.activeField.frame animated:YES];
}

}

并添加此方法来初始化activeField

- (IBAction)textFieldDidBeginEditing:(UITextField *)sender
{
self.activeField = sender;
}

实际上,最好只使用苹果的实现,正如文档中所提供的那样。然而,他们提供的代码是错误的。将keyboardWasShow:注释下方的部分替换为以下内容:

NSDictionary* info = [aNotification userInfo];
CGRect keyPadFrame=[[UIApplication sharedApplication].keyWindow convertRect:[[info objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue] fromView:self.view];
CGSize kbSize =keyPadFrame.size;
CGRect activeRect=[self.view convertRect:activeField.frame fromView:activeField.superview];
CGRect aRect = self.view.bounds;
aRect.size.height -= (kbSize.height);

CGPoint origin =  activeRect.origin;
origin.y -= backScrollView.contentOffset.y;
if (!CGRectContainsPoint(aRect, origin)) {
    CGPoint scrollPoint = CGPointMake(0.0,CGRectGetMaxY(activeRect)-(aRect.size.height));
    [backScrollView setContentOffset:scrollPoint animated:YES];
}

苹果代码存在以下问题:(1) 他们总是计算该点是否在视图的框架内,但它是一个ScrollView,因此它可能已经滚动,您需要考虑该偏移:

origin.y -= scrollView.contentOffset.y

(2) 他们按键盘的高度移动contentOffset,但我们希望相反(我们希望按屏幕上可见的高度而不是不可见的高度移动contentOffset):

activeField.frame.origin.y-(aRect.size.height)