更改 WKWebview 框架高度后如何删除 WKScrollView 内的空白区域？答案

【问题标题】：How to remove blank space inside WKScrollView after change WKWebview frame height?更改 WKWebview 框架高度后如何删除 WKScrollView 内的空白区域？
【发布时间】：2021-12-30 11:27:24
【问题描述】：

改变WKWebview的框架高度后如何去除空白区域？
我想在键盘出现时更改 webview 的高度，但是在框架高度更改后，HTML 正文下方有一个额外的空间。而这个额外的空白区域的高度大约是键盘的高度。

这里是sn-p的代码：

NotificationCenter.default.rx
.notification(UIApplication.keyboardDidShowNotification)
.subscribe(onNext: { [weak self] keyboardConfig in
    if let userInfo = keyboardConfig.userInfo{
       let keyboardBounds = (userInfo["UIKeyboardFrameEndUserInfoKey"] as! NSValue).cgRectValue;
                
       self?.webView.snp.remakeConstraints({ make in
           make.left.right.top.equalToSuperview();
           /// remake from screen height to below height.
           make.height.equalTo(UIScreen.main.bounds.size.height - keyboardBounds.size.height);
       });
    }
});

【问题讨论】：

检查它被调用了多少次。
@ShreeramBhat 只有一次

标签： ios swift uiscrollview wkwebview

【解决方案1】：

最后我仍然不知道如何删除这个额外的空白区域，但我想出了一个解决方法。
由于WKScrollView 是UIScrollView 的子类，所以UIScrollView Delegate 也适用于WKScrollView;
因此 contentOffset 可以在 UIScrollView scrollViewDidScroll 委托方法中强制重置。下面提供了代码 sn-p。

/// Change webview frame when keyboard appear.
NotificationCenter.default.rx
.notification(UIApplication.keyboardDidShowNotification)
.subscribe(onNext: { [weak self] keyboardConfig in
    if let userInfo = keyboardConfig.userInfo, let this = self {
        let keyboardBounds = (userInfo["UIKeyboardFrameEndUserInfoKey"] as! NSValue).cgRectValue;
        this.webView.snp.remakeConstraints({ make in
            make.left.right.top.equalToSuperview();
            /// remake from screen height to below height.
            make.height.equalTo(UIScreen.main.bounds.size.height - keyboardBounds.size.height);
        });
        let originalOffset = this.webView.scrollView.contentOffset;
        DispatchQueue.main.asyncAfter(deadline: .now() + 0.2) {
            this.webView.scrollView.contentOffset = originalOffset;
        }
    }
});

/// Force reset contentOffset when the contentOffset is out of HTML Body
extension YourWebviewVC: UIScrollViewDelegate{
    internal func scrollViewDidScroll(_ scrollView: UIScrollView) {
        self.adjustWebviewOffsetFor(scrollView);
    }
    
    private func adjustWebviewOffsetFor(_ scrollView: UIScrollView, animated: Bool = false){
        let currentY = scrollView.contentOffset.y + scrollView.frame.height;
        if currentY > scrollView.contentSize.height{
            let maxOffset = scrollView.contentSize.height - scrollView.frame.height;
            scrollView.setContentOffset(CGPoint(x: 0, y: maxOffset), animated: animated);
        }
    }
}

/// Don't forgot set webview scroolView's delegate, for example
self.webView.scrollView.delegate = self;
self.webView.scrollView.showsVerticalScrollIndicator = false;

【讨论】：