单击时设置动画文本框

Question

我正在尝试从iPad应用中移动屏幕底部的文本框，以便键盘不会覆盖它。

我有以下工作。

-(void) textViewDidBeginEditing:(UITextView *) observationComment
{
observationComment.frame=CGRectMake(190, 100, 700, 250);
}

但是1 - 我想动画这个动作 - 这可能吗？

2 - 我收到警告

Local declaration of 'observationComment' hides instance variable

有什么建议吗？也许这不是最好的方法。

Answer 1

我之前找到了the answer here，但我必须添加代码，以便当用户通过按下globe键（切换键盘（如国际或表情符号）时，View Controller的view.frame会进行调整）。

在YourViewController.h中，将键盘的高度（仅当它可见时）存储在实例变量中。

@interface YourViewController : UIViewController {
    CGFloat keyboardHeightIfShowing ;
}

在YourViewController.m中，实现这些方法。

- (void) keyboardWillShow:(NSNotification*)notification {
    [self moveTextViewForKeyboard:notification up:YES] ;
}

- (void) keyboardWillHide:(NSNotification*)notification {
    [self moveTextViewForKeyboard:notification up:NO] ;
}

- (void) moveTextViewForKeyboard:(NSNotification*)notification up:(BOOL)up {
    NSDictionary* userInfo = [notification userInfo] ;
    UIViewAnimationCurve animationCurve ;
    NSTimeInterval animationDuration ;
    CGRect keyboardEndFrame ;

    [[userInfo objectForKey:UIKeyboardAnimationCurveUserInfoKey] getValue:&animationCurve] ;
    [[userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration] ;
    [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame] ;

    [UIView beginAnimations:nil context:nil] ;
    [UIView setAnimationDuration:animationDuration] ;
    [UIView setAnimationCurve:animationCurve] ;

    CGRect keyboardFrame = [self.view convertRect:keyboardEndFrame toView:nil] ;
    //Since I have a UITabBar, when the keyboard appears, self.view.frame.height should shrink by slightly less than if I did not have a UITabBar.
    keyboardFrame.size.height -= self.tabBarController.tabBar.frame.size.height ;
    CGRect newViewFrame = self.view.frame ;
    //UIKeyboardWillShowNotification can be triggered even when the keyboard is already showing, such as when switching between certain international keyboards. When this happens, before shrinking newViewFrame to accommodate keyboardFrame, enlarge newViewFrame so that it is the size it was before the previous keyboard appeared.
    if ( up && keyboardHeightIfShowing ) {
        NSLog(@"hiding keyboard with height %0.1f, showing keyboard with height %0.1f",keyboardHeightIfShowing, keyboardFrame.size.height) ;
        newViewFrame.size.height += keyboardHeightIfShowing ;
    }
    newViewFrame.size.height -= keyboardFrame.size.height * (up ? 1 : -1) ;
    keyboardHeightIfShowing = ( up ? keyboardFrame.size.height : 0 ) ;
    self.view.frame = newViewFrame ;

    [UIView commitAnimations] ;
}

最后，在YourViewController.m中，建立要由UIKeyboardWillShow / Hide通知调用的keyboardWillShow和keyboardWillHide。

- (void) viewWillAppear:(BOOL)animated {
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillShow:) name:UIKeyboardWillShowNotification object:nil] ;
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillHide:) name:UIKeyboardWillHideNotification object:nil] ;
}

- (void) viewWillDisappear:(BOOL)animated {
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil] ;
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillHideNotification object:nil] ;
}

Answer 2

查看this tutorial或this stackoverflow.com question and its answers。这是一个复杂的问题，但这些应该可以让你更好地了解你需要做什么。