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

Posted 2023-03-16

【中文标题】在键盘演示中点击 UITextView 或 UITextField 时出现 UIScrollView 问题

【英文标题】：UIScrollView issue on tapping UITextView or UITextField on keyboard presentation

【发布时间】：2013-04-02 06:26:44

【问题描述】：

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，会触发确实更改框架通知操作，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;
            ];
        
    

应用程序仅支持横向。 我在这里面临的问题是

点击 textView 会显示键盘，如果 textview 被键盘隐藏，则会滚动到顶部。现在，改变方向（从左到右）会使 textView 滚动到顶部，因此不可见。 TextView 的滚动有时适用于横向左侧，但不适用于横向右侧，反之亦然。这是因为我使用了 keyboardEndFrame 值。我不应该使用 keyboardEndFrame 原始值吗？如果没有，还有什么替代方案？ 有时它适用于 textField 但不适用于 textView。

【参考方案1】：

您可以尝试使用this，而不是使用如此复杂的解决方案。 还可以找到一种更简单的解决方案here。

此外，不建议像您那样对帧进行硬编码。详情请参阅apple documentation。

【讨论】：

非常感谢。有效。我用这个链接中的代码替换了我的代码 - github.com/michaeltyson/TPKeyboardAvoiding。谢谢。