Question

当用户从detailViewController返回到UITableView时，我希望tableView返回到先前的位置。找到this post的解决方案，但由于我没有保存选定的行，因此无效。这就是我被困住的地方。

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Calculator</title>
  <link href="https://fonts.googleapis.com/css?family=Open+Sans" rel="stylesheet"></head>
<body>
  <div id="calculatorcontainer">
    <div id="maincontainer">      
      <table>
        <tr>
          <td>
            <form action="" method="post" id="theForm">
              <fieldset >
                <legend>Calculator</legend>
                <h4>Use this form to calculate the order total</h4>
                  <div class="form-group">
                    <label for="quantity">Quantity</label>
                      <input class="form-control" id="quantity" type="number" value="1"/>
                  </div>
                  <div class="form-group">
                      <label for="ppu">Price Per Unit</label>
                      <input type="text" class="form-control" id="ppu" placeholder="1.00" required>
                  </div>
                  <div class="form-group">
                      <label for="tax">Tax Rate (%)</label>
                      <input type="text" class="form-control" id="tax" placeholder="0.0" required>
                  </div>
                  <div class="form-group">
                      <label for="discount">Discount (%)</label>
                      <input type="text" class="form-control" id="discount" placeholder="0.00" required>
                  </div>
                  <div class="form-group">
                      <label for="ttl">Total</label>
                      <input type="text" class="form-control" id="output" placeholder="0.00">
                  </div>
                  <div>
                      <button type="submit" class="btn btn-calculate" id="submit">Calculate</button>
                  </div>
             </fieldset>  
            </form>
          </td>
          <td>
            <aside class="imageContainer">
              <img src="https://image.ibb.co/iUhiUv/Screen_Shot_2017_08_03_at_12_12_16_PM.png">
            </aside>     
          </td>
        </tr>
      </table>
   </div><!-- End "maincontainer" -->

   <footer class="footer">
     <h3>Copyright CSUN</h3>
   </footer>
 </div>
</body>
 
</html>

带

func scrollToSelectedRow() {
    let selectedRows = self.tableView.indexPathsForSelectedRows
    if let selectedRow = selectedRows?[0] as NSIndexPath? {
        self.tableView.scrollToRow(at: selectedRow as IndexPath, at: .middle, animated: true)
    }
}

在viewDidAppear中

。

我保存下面的行，将详细信息发送到DetailViewController

    scrollToSelectedRow()

但是，不确定如何将两者联系在一起。

任何帮助表示赞赏

Answer 1

您的代码存在问题

 let selectedRows = self.tableView.indexPathsForSelectedRows
 if let selectedRow = selectedRows?[0] as NSIndexPath? {
    self.tableView.scrollToRow(at: selectedRow as IndexPath, at: .middle, animated: true)
}

如果从未调用过语句

尝试这样做

像这样声明你的索引路径

   var selected = IndexPath(row: NSNotFound, section: NSNotFound)

现在在didselect类

   func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {


    let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
    let nextViewController = storyBoard.instantiateViewController(withIdentifier: "ChatViewController")
    self.present(nextViewController, animated:true, completion:nil)


    self.selected = (indexPath as NSIndexPath) as IndexPath


 }

调用此函数

   func scrollToSelectedRow() {

      if self.selected.row != NSNotFound
        {

         self.tableView.scrollToRow(at: self.selected as IndexPath, at: .middle, animated: true)

        }

}

在

 override func viewWillAppear(_ animated: Bool) {

    scrollToSelectedRow()

}

返回Swift后返回上一个uitableview行

1 个答案: