在键盘演示中点击UITextView或UITextField的UIScrollView问题

Question

我有一个UIScrollView，其中包含UITextFields和UITextViews。我已经注册了UIKeyboardDidChangeFrameNotification。当我点击文本字段或文本视图时，触发了更改框架通知操作，我调整滚动视图的contentOffset，如下所示

- (void)keyboardDidChangeFrame:(NSNotification *)notification
{
    CGRect keyboardEndFrame;
    [[[notification userInfo] objectForKey:UIKeyboardFrameEndUserInfoKey] getValue:&keyboardEndFrame];
    CGRect screenRect = [[UIScreen mainScreen] bounds];
    CGRect intersection;
    UIView *theFirstResponder = [[UIApplication sharedApplication].keyWindow findFirstResponder];

    if ([theFirstResponder isKindOfClass:[UITextView class]]) {
        if ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeLeft) {
            keyboardEndFrame = CGRectMake(keyboardEndFrame.origin.y, 416, keyboardEndFrame.size.height, keyboardEndFrame.size.width);
        }
        else if ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeRight)
        {
            keyboardEndFrame = CGRectMake(keyboardEndFrame.origin.y, 0, keyboardEndFrame.size.height, keyboardEndFrame.size.width);
        }
    }
    else
        keyboardEndFrame = CGRectMake(keyboardEndFrame.origin.y, keyboardEndFrame.origin.x, keyboardEndFrame.size.height, keyboardEndFrame.size.width);

    screenRect = CGRectMake(screenRect.origin.y, screenRect.origin.x, screenRect.size.height, screenRect.size.width);
    if(CGRectEqualToRect(lastKBDRect, keyboardEndFrame)) {
        return;
    }                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
    lastKBDRect = keyboardEndFrame;
    if (CGRectIntersectsRect(keyboardEndFrame, screenRect)) {
        // Keyboard is visible

        //Convert Frame of the first responder, in context of the view that needs to be shifted
        UIView *firstResponder = [[UIApplication sharedApplication].keyWindow findFirstResponder];
        CGRect theRect = [firstResponder convertRect:firstResponder.frame toView:[UIApplication sharedApplication].keyWindow];
        theRect = CGRectMake(theRect.origin.y, theRect.origin.x > 768 ? 750 : theRect.origin.x, theRect.size.height, theRect.size.width);

        intersection = CGRectIntersection(keyboardEndFrame, theRect);

        //If intersection is null, then no need to shift anything. Simply return.
        if(CGRectIsNull(intersection)) {
            return;
        }
        //Shift the view so that the first responder view is completely visible, keeping the constraint that the origin of the first responder view is also visible.


        //Remember the current offset, so when we shift the view back, we shift it to the proper position.
        if (!wasContentViewShifted) {
            lastContentOffset = contentScrollView.contentOffset;
            lastContentSize = contentScrollView.contentSize;
            wasContentViewShifted = YES;
        }

        CGFloat offset = theRect.origin.y + theRect.size.height - keyboardEndFrame.origin.y;
        if((theRect.origin.y - offset) < 40) {
            offset += 42;
        }
        [UIView animateWithDuration:0.3f animations:^{
        contentScrollView.contentOffset = CGPointMake(0, contentScrollView.contentOffset.y + offset);
            contentScrollView.contentSize = CGSizeMake(0, lastContentSize.height + (600 - theRect.size.height));
    }];

    } else {
        // Keyboard is hidden. Move the view back only if it was shifted.
        if(wasContentViewShifted) {
            wasContentViewShifted = NO;
            [UIView animateWithDuration:0.3f animations:^{
                contentScrollView.contentOffset = lastContentOffset;
               contentScrollView.contentSize = lastContentSize;
            }];
        }
    }
}

该应用程序仅支持横向。我面临的问题是

1. 点击textView会显示键盘，如果键盘隐藏了文本视图，则会将其滚动到顶部。现在，更改方向（横向左侧为横向右侧）使textView进一步滚动到顶部，因此不可见。
2. TextView的滚动有时适用于横向左方向，但不适用于横向右方向，反之亦然。这是因为我正在使用的keyboardEndFrame值。我不应该使用keyboardEndFrame原点值吗？如果没有，会有什么替代方案？
3. 有时它适用于textField但不适用于textView。

Answer 1

您可以尝试使用this而不是拥有如此复杂的解决方案。一个更简单的解决方案也可以找到here。

此外，建议您不要像现在一样对帧进行硬编码。有关更多详细信息，请参阅apple documentation。