Question

在我的iPhone应用程序中，我使用以下代码抬起视图以显示键盘上方的文本字段。我的应用程序支持所有四种界面方向。我使用以下代码来提升视图。这里的问题是它只适用于纵向。有没有办法在所有四个方向上实现正确的提升

static const CGFloat KEYBOARD_ANIMATION_DURATION = 0.3;
static const CGFloat MINIMUM_SCROLL_FRACTION = 0.2;
static const CGFloat MAXIMUM_SCROLL_FRACTION = 0.8;
static const CGFloat PORTRAIT_KEYBOARD_HEIGHT = 216;
static const CGFloat LANDSCAPE_KEYBOARD_HEIGHT = 162;

- (void)textFieldDidBeginEditing:(UITextField *)textField {
    UIInterfaceOrientation orientation =    [Globals getUIInterfaceOrientation];//[[UIApplication sharedApplication] statusBarOrientation];
    CGRect textFieldRect = [self.view.window convertRect:textField.bounds fromView:textField];
    CGRect viewRect = [self.view.window convertRect:self.view.bounds fromView:self.view];   

    CGFloat midline = textFieldRect.origin.y + 0.5 * textFieldRect.size.height;
    CGFloat numerator = midline - viewRect.origin.y - MINIMUM_SCROLL_FRACTION * viewRect.size.height;
    CGFloat denominator = (MAXIMUM_SCROLL_FRACTION - MINIMUM_SCROLL_FRACTION) * viewRect.size.height;   
    CGFloat heightFraction = numerator / denominator;

    if (heightFraction < 0.0) {
        heightFraction = 0.0;
    }
    else if (heightFraction > 1.0) {
        heightFraction = 1.0;
    }   
    if (orientation == UIInterfaceOrientationPortrait || orientation == UIInterfaceOrientationPortraitUpsideDown) 
        animatedDistance = floor(PORTRAIT_KEYBOARD_HEIGHT * heightFraction);
    else 
        animatedDistance = floor(LANDSCAPE_KEYBOARD_HEIGHT * heightFraction);
    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y -= animatedDistance;
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
    [self.view setFrame:viewFrame];    
    [UIView commitAnimations];  
}

- (void)textFieldDidEndEditing:(UITextField *)textField{
    CGRect viewFrame = self.view.frame;
    viewFrame.origin.y += animatedDistance;
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationBeginsFromCurrentState:YES];
    [UIView setAnimationDuration:KEYBOARD_ANIMATION_DURATION];
    [self.view setFrame:viewFrame];    
    [UIView commitAnimations];      
}

Answer 1

以下是我目前在所有应用中实现这一目标的方法。

这里的技巧是虽然视图知道方向，但键盘不是。这意味着在Landscape中，键盘宽度实际上是它的高度，反之亦然。

要修改Apples推荐的更改内容插入的方法并使其支持横向，我建议使用以下内容：

// 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
{
    UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
    CGSize keyboardSize = [[[notif userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
    if (orientation == UIDeviceOrientationLandscapeLeft || orientation == UIDeviceOrientationLandscapeRight ) {
        CGSize origKeySize = keyboardSize;
        keyboardSize.height = origKeySize.width;
        keyboardSize.width = origKeySize.height;
    }
    UIEdgeInsets contentInsets = UIEdgeInsetsMake(0, 0, keyboardSize.height, 0);
    scroller.contentInset = contentInsets;
    scroller.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 rect = scroller.frame;
    rect.size.height -= keyboardSize.height;
    NSLog(@"Rect Size Height: %f", rect.size.height);

    if (!CGRectContainsPoint(rect, activeField.frame.origin)) {
        CGPoint point = CGPointMake(0, activeField.frame.origin.y - keyboardSize.height);
        NSLog(@"Point Height: %f", point.y);
        [scroller setContentOffset:point animated:YES];
    }
}

// Called when the UIKeyboardWillHideNotification is sent    
- (void)keyboardWillBeHidden:(NSNotification*)aNotification
{
    UIEdgeInsets contentInsets = UIEdgeInsetsZero;
    scrollView.contentInset = contentInsets;
    scrollView.scrollIndicatorInsets = contentInsets;
}

这里要注意的部分如下：

UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
CGSize keyboardSize = [[[notif userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;
if (orientation == UIDeviceOrientationLandscapeLeft || orientation == UIDeviceOrientationLandscapeRight ) {
    CGSize origKeySize = keyboardSize;
    keyboardSize.height = origKeySize.width;
    keyboardSize.width = origKeySize.height;
}

做什么，是检测设备的方向。如果是横向，它将'交换'keyboardSize变量的宽度和高度值，以确保在每个方向使用正确的值。

Answer 2

您可能希望使用此Text and Web Programming Guide for the iOS文档中显示的键盘通知，请参阅清单2-1 2-2 2-3

收到通知后，您可以获得键盘大小。

如何在键盘上方显示所有界面方向的文本字段

2 个答案: