如何创建一个完全适合键盘上方的 UITextView？

Question

我想创建一个视图，例如 Facebook 或 Twitter 应用程序的共享对话框，其中只有一个 UITextView 和一个永久键盘。我可以看到如何从this answer 可见的键盘开始，但我不确定如何调整 UITextView 的大小以恰好适合键盘上方。如果我不这样做，文本可能会隐藏在键盘下，这很尴尬。

Answer 1

我发现这个页面总是很有帮助 - 它显示了所有重要的尺寸，所以很容易计算出你需要的尺寸：

http://www.idev101.com/code/User_Interface/sizes.html

Answer 2

您可以订阅UIKeyboardWillShowNotification。通知包括键盘框架，因此您可以调整视图大小以适应剩余空间。

Answer 3

你可以像这样得到键盘尺寸：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardIsUp:) name:UIKeyboardDidShowNotification object:nil];

- (void)keyboardIsUp:(NSNotification *)notification{

    CGSize keyboardSize = [self.view convertRect:[[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue] toView:nil].size;
    NSLog(@"%f", keyboardSize.height);
}

[编辑]横向模式

我在 iPas Simulator 上尝试过，它在纵向模式下为 QWERTY 键盘返回 264，但是当您启动应用程序或旋转到横向模式时，它返回 1024。所以您可能需要询问宽度而不是高度横向模式...

[编辑]

感谢 rob mayoff 的评论，横向模式已经没有问题了

[编辑]

这不是最好的方法，但它提供了一个想法。我稍后再看一遍

- (void)viewDidLoad
{
    [super viewDidLoad];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardDidShowNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

    CGSize size = [self.view convertRect:self.view.frame toView:nil].size;
    CGFloat width =  size.width;
    CGFloat height = 40;
    CGFloat x =  0;
    CGFloat y =  size.height+40;

    aboveKBView = [[[UIView alloc] initWithFrame:CGRectMake(x, y, width, height)] autorelease];
    [aboveKBView setBackgroundColor:[UIColor greenColor]];
    [self.view addSubview:aboveKBView];
}

- (void)keyboardWillHide:(NSNotification *)notification{
    [aboveKBView setHidden:YES];
}

- (void)keyboardWillShow:(NSNotification *)notification{
    NSLog(@"keyboardIsUp");

    CGSize keyboardSize = [self.view convertRect:[[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue] toView:nil].size;

    CGSize size = [self.view convertRect:self.view.frame toView:nil].size;
    CGFloat width =  size.width;
    CGFloat height = 40;
    CGFloat x =  0;
    CGFloat y =  size.height-(keyboardSize.height+height);

    [aboveKBView setFrame:CGRectMake(x, y, width, height)];
    [aboveKBView setHidden:NO];    
}

Answer 4

试试这个

在 viewDidLoad 中：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil];

并添加这些方法。

- (void) keyboardWillShow: (NSNotification*) aNotification;
{   

    [UIView beginAnimations:nil context:NULL];

    [UIView setAnimationDuration:0.3];

    CGRect rect = [[self view] frame];

    rect.origin.y -= 60; 

    [[self view] setFrame: rect];

    [UIView commitAnimations];

}

- (void) keyboardWillHide: (NSNotification*) aNotification;
{

    [UIView beginAnimations:nil context:NULL];

    [UIView setAnimationDuration:0.3];

    CGRect rect = [[self view] frame];

    rect.origin.y += 60; 

    [[self view] setFrame: rect];

    [UIView commitAnimations];
}

Answer 5

我在 Apple 文档中找到了一个有用的代码示例：https://developer.apple.com/library/ios/#samplecode/KeyboardAccessory/Introduction/Intro.html

这是我最终得到的代码。我不担心键盘隐藏，因为在我看来，键盘永远不应该隐藏。

- (void)viewWillAppear:(BOOL)flag
{
    [super viewWillAppear:flag];

    // Listen for the keyboard to show up so we can get its height
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil];

    // Set focus on the text view to display the keyboard immediately
    [self.textView becomeFirstResponder];
}
- (void)keyboardWillShow:(NSNotification *)notification
{
    /*
     Reduce the size of the text view so that it's not obscured by the keyboard.
     */

    NSDictionary *userInfo = [notification userInfo];

    // Get the origin of the keyboard when it's displayed.
    NSValue* keyboardFrame = [userInfo objectForKey:UIKeyboardFrameEndUserInfoKey];

    // Get the top of the keyboard as the y coordinate of its origin in self's view's
    // coordinate system. The bottom of the text view's frame should align with the
    // top of the keyboard's final position.
    CGRect keyboardRect = [keyboardFrame CGRectValue];
    keyboardRect = [self.view convertRect:keyboardRect fromView:nil];

    // Set the text view's frame height as the distance from the top of the view bounds
    // to the top of the keyboard
    CGFloat keyboardTop = keyboardRect.origin.y;
    CGRect newTextViewFrame = self.view.bounds;
    newTextViewFrame.size.height = keyboardTop - self.view.bounds.origin.y;
    self.textView.frame = newTextViewFrame;
}