页脚不会显示在TableView上，除非我滚动

Question

我在页面底部显示的TableView添加了一个页脚。但是，除非我向下滚动，否则页脚不可见，然后显示。

这里就是我说的：

我没有填充TableView，但我不认为这是一个问题。下面是我为页脚编写的代码：

func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat { 
    return 50 
} 

func tableView(_ tableView: UITableView, viewForFooterInSection section: Int) -> UIView? { 

    footerView.translatesAutoresizingMaskIntoConstraints = false 
    view.addSubview(footerView) 

    //x, y, w, h constraints 
    footerView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true 
    footerView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true 
    footerView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true 
    footerView.heightAnchor.constraint(equalToConstant: 50).isActive = true 

    //Send Button 
    let sendButton = UIButton(type: .system) 
    sendButton.setTitle("Send", for: .normal) 
    sendButton.translatesAutoresizingMaskIntoConstraints = false 
    sendButton.addTarget(self, action: #selector(handleSend), for: .touchUpInside) 
    footerView.addSubview(sendButton) 

    //x, y, w, h Button constraints 
    sendButton.rightAnchor.constraint(equalTo: footerView.rightAnchor).isActive = true 
    sendButton.centerYAnchor.constraint(equalTo: footerView.centerYAnchor).isActive = true 
    sendButton.widthAnchor.constraint(equalToConstant: 80).isActive = true 
    sendButton.heightAnchor.constraint(equalTo: footerView.heightAnchor).isActive = true 

    //Text Field 
    footerView.addSubview(inputTextField) 

    //x, y, w, h Text Field constraints 
    inputTextField.leftAnchor.constraint(equalTo: footerView.leftAnchor, constant: 8).isActive = true 
    inputTextField.centerYAnchor.constraint(equalTo: footerView.centerYAnchor).isActive = true 
    inputTextField.rightAnchor.constraint(equalTo: sendButton.leftAnchor).isActive = true 
    inputTextField.heightAnchor.constraint(equalTo: footerView.heightAnchor).isActive = true 

    // Separator 
    let separatorLineView = UIView() 
    separatorLineView.backgroundColor = UIColor(red: CGFloat(220/255), green: CGFloat(220/255), blue: CGFloat(220/255), alpha: 0.1) 
    separatorLineView.translatesAutoresizingMaskIntoConstraints = false 
    footerView.addSubview(separatorLineView) 

    //x, y, w, h separator constraints 
    separatorLineView.leftAnchor.constraint(equalTo: footerView.leftAnchor).isActive = true 
    separatorLineView.topAnchor.constraint(equalTo: footerView.topAnchor).isActive = true 
    separatorLineView.widthAnchor.constraint(equalTo: footerView.widthAnchor).isActive = true 
    separatorLineView.heightAnchor.constraint(equalToConstant: 1).isActive = true 

    return footerView 
} 

我想页脚的工作是尽快用户导航到视图展现出来，然后向上移动的键盘显示出来的方式，并在键盘被解散时向下移动。

Answer 1

您不应该将footerView作为子视图添加到另一个UIView。

您应该删除下面的代码：

footerView.translatesAutoresizingMaskIntoConstraints = false 
    view.addSubview(footerView) 

    //x, y, w, h constraints 
    footerView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true 
    footerView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true 
    footerView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true 
    footerView.heightAnchor.constraint(equalToConstant: 50).isActive = true 

的UITableView将处理页脚视图的位置。

如果我怀疑你打算将footerView固定在视图的底部，那么你不应该将它作为表视图的页脚视图返回。它应该与UITableView分层结构分开。