测试键盘在显示文本字段时是否隐藏文本字段

Question

我尝试在显示键盘时向上移动表单，我的方法是测试键盘的框架和文本字段的框架是否相交。

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

    // Get the size of the keyboard.
    CGRect keyboardFrame = [[[notification userInfo] objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
    //Test whether the current frame of the text field is hidden by the keyboard
    if (!CGRectIsNull(CGRectIntersection(keyboardFrame,self.activeField.frame))) {
        NSLog(@"Key board frame intersects with the text field frame");
    }

}

在上面的代码中，CGRectIsNull总是返回null。

一个调试语句返回给我这些关于键盘和活动文本字段被选中的信息:

键盘大小=(宽=352，高=1024)键盘原点= (x=-352, y=0)

键盘帧= (-352,0,352,1024)文本框= (200,15,300,30)

每个文本字段都有相同的帧值，这意味着有问题。那么，我如何测试键盘是否隐藏了文本字段，以便上下移动窗体。谢谢。

Answer 1

我会把整个东西放在一个全屏的UIScrollView中，然后在需要的时候调整它的大小…

// This in your init somewhere
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];
-(void) keyboardWillChange:(NSNotification*)notify {
    CGRect endFrame;
    float duration = [[[notify userInfo] valueForKey:UIKeyboardAnimationDurationUserInfoKey] floatValue];
    [[[notify userInfo] valueForKey:UIKeyboardFrameEndUserInfoKey] getValue:&endFrame];
    endFrame = [self.view convertRect:endFrame fromView:nil];
    float y = (endFrame.origin.y > self.view.bounds.size.height ? self.view.bounds.size.height : endFrame.origin.y);
    [UIView animateWithDuration:duration animations:^{
        scrollView.frame = CGRectMake(0, 0, self.view.bounds.size.width, y);
    }];
}

Answer 2

试试这个:

 [[NSNotificationCenter defaultCenter] addObserverForName:UIKeyboardWillShowNotification object:nil queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {}];

和使用信息从[note userInfo];