Question

我试图弄清楚如何确定jquery数据表中是否有一行可见。

我希望能够使用向上/向下按钮导航数据表视口。当窗口分辨率发生变化时，数据表的视口高度也会发生变化。我需要确保没有行只是部分显示，所以当我在表格中向下翻页时，底行完全而不是部分地到达表格的顶部。

对此有何想法？提前谢谢

编辑：我正在使用的一些代码。请注意，我使用ScrollTo插件滚动到数据表中的特定tr。

                makeTableScroller = function () {
        offset = 0;
        return function (tableInfo) {
            var tableId = tableInfo.tableId;
            var containerTop = 0; 
            var containerBottom = containerTop + $(tableInfo.tableId).height();
            var tableHeight = containerTop + containerBottom;
            var totalItemsInTable = tableInfo.settings.fnRecordsDisplay();
            var totalAvailableRows = $(tableInfo.tableId).find('tr').length;
            var rowHeight = tableInfo.settings.oScroller.s.rowHeight;
            var scrollBy = Math.floor(tableHeight / rowHeight);
            scrollBy = Math.floor(totalAvailableRows / scrollBy);

            if (tableInfo.event.keyCode === KeyCodes.PageDown) {
                offset += scrollBy;
                console.log(offset);
            }
            else if (tableInfo.event.keyCode === KeyCodes.PageUp) {
                if (offset - scrollBy <= 1) {
                    offset = 1;
                }
                else {
                    offset -= scrollBy - 1;
                }
                if (offset === 1) {
                    $(tableId).scrollTop(offset);
                }
            }

            $(tableId).find('tr:eq(' + offset + ')').ScrollTo();
        }
    }

Answer 1

很久以前我做过同样的事情，在页面上打字/向下我用了箭头：

// "open" is class that holds current row

// DOWN
if (e.keyCode === 40) {
  // move open class to next row in table
  $('.open').removeClass('open').next('tr').addClass('open');

  // get vertical position of current body scroll
  var scrollY = $(window).scrollTop();

  // get vertical position of current row
  var scrollTrY = $('.open').offset().top;

  // height of window visible part
  var height = $(window).height();

  // height of current row
  var trHeight = $('.open').height();

  // check if are going to element that is not visible
  if ((scrollTrY + trHeight) > (scrollY + height)) {
    // condision is meet, we need to scroll to that row

    // menu height
    var menuOffset = 0;

    // calculate new position
    var newScrollPos = (scrollTrY - menuOffset) + 'px';

    $('body,html').animate({
      scrollTop: newScrollPos
    });
  }

  return false;
}

// Do the same thing for up key event

将其放入关键事件功能中：

$(window).keydown(function(e) {
...
}

以下是整个示例（使用向下和向上箭头，但首先点击表格以获得焦点）：

jQuery(document).ready(function($) {

  $('#example').dataTable({
    paging: false
  });
  
  // set open flag to first row
  if($('.open').length === 0) {
     $('.odd:first').addClass('open');
  }

  // key events
  $(window).keydown(function(e) {
    
    // DOWN
    if (e.keyCode === 40) {
      // move open class to next row in table
      $('.open').removeClass('open').next('tr').addClass('open');
      
      // get vertical position of current body scroll
      var scrollY = $(window).scrollTop();

      // get vertical position of current row
      var scrollTrY = $('.open').offset().top;

      // height of window visible part
      var height = $(window).height();

      // height of current row
      var trHeight = $('.open').height();

      // check if are going to element that is not visible
      if ((scrollTrY + trHeight) > (scrollY + height)) {
        // condision is meet, we need to scroll to that row
        console.log(scrollY, height);
        // menu height
        var menuOffset = 0;

        // calculate new position
        var newScrollPos = (scrollTrY - menuOffset) + 'px';

        $('body,html').animate({
          scrollTop: newScrollPos
        });
      }

      return false;
    }

    // Now do the same thing for up key event

    // UP
    if (e.keyCode === 38) {

      $('.open').removeClass('open').prev('tr').addClass('open');

      var scrollY = $(window).scrollTop();
      var scrollTrY = $('.open').offset().top;
      var height = $(window).height();
      var trHeight = $('.open').height();

      // menu height
      var menuOffset = 0;

      if (scrollTrY - menuOffset < scrollY) {
        var newScrollPos = (scrollTrY + trHeight - height) + 'px';

        $('body,html').animate({
          scrollTop: newScrollPos
        });
      }

      return false;
    }
  });
});

body {
  height: 1000px;
}

.open {
  background-color: yellow !important;
}

.open td {
  background-color: yellow !important;
}

<link href="//cdn.datatables.net/1.10.4/css/jquery.dataTables.min.css" rel="stylesheet" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="//cdn.datatables.net/1.10.4/js/jquery.dataTables.min.js"></script>
<table id="example" class="display" cellspacing="0" width="100%">
  <thead>
    <tr>
      <th>Name</th>
      <th>Position</th>
      <th>Office</th>
      <th>Age</th>
      <th>Start date</th>
      <th>Salary</th>
    </tr>
  </thead>

  <tfoot>
    <tr>
      <th>Name</th>
      <th>Position</th>
      <th>Office</th>
      <th>Age</th>
      <th>Start date</th>
      <th>Salary</th>
    </tr>
  </tfoot>
  <tbody>
    <tr>
      <td>Tiger Nixon</td>
      <td>System Architect</td>
      <td>Edinburgh</td>
      <td>61</td>
      <td>2011/04/25</td>
      <td>$320,800</td>
    </tr>
    <tr>
      <td>Garrett Winters</td>
      <td>Accountant</td>
      <td>Tokyo</td>
      <td>63</td>
      <td>2011/07/25</td>
      <td>$170,750</td>
    </tr>
    <tr>
      <td>Ashton Cox</td>
      <td>Junior Technical Author</td>
      <td>San Francisco</td>
      <td>66</td>
      <td>2009/01/12</td>
      <td>$86,000</td>
    </tr>
    <tr>
      <td>Cedric Kelly</td>
      <td>Senior Javascript Developer</td>
      <td>Edinburgh</td>
      <td>22</td>
      <td>2012/03/29</td>
      <td>$433,060</td>
    </tr>
    <tr>
      <td>Airi Satou</td>
      <td>Accountant</td>
      <td>Tokyo</td>
      <td>33</td>
      <td>2008/11/28</td>
      <td>$162,700</td>
    </tr>
    <tr>
      <td>Brielle Williamson</td>
      <td>Integration Specialist</td>
      <td>New York</td>
      <td>61</td>
      <td>2012/12/02</td>
      <td>$372,000</td>
    </tr>
    <tr>
      <td>Herrod Chandler</td>
      <td>Sales Assistant</td>
      <td>San Francisco</td>
      <td>59</td>
      <td>2012/08/06</td>
      <td>$137,500</td>
    </tr>
    <tr>
      <td>Rhona Davidson</td>
      <td>Integration Specialist</td>
      <td>Tokyo</td>
      <td>55</td>
      <td>2010/10/14</td>
      <td>$327,900</td>
    </tr>
    <tr>
      <td>Colleen Hurst</td>
      <td>Javascript Developer</td>
      <td>San Francisco</td>
      <td>39</td>
      <td>2009/09/15</td>
      <td>$205,500</td>
    </tr>
    <tr>
      <td>Sonya Frost</td>
      <td>Software Engineer</td>
      <td>Edinburgh</td>
      <td>23</td>
      <td>2008/12/13</td>
      <td>$103,600</td>
    </tr>
    <tr>
      <td>Jena Gaines</td>
      <td>Office Manager</td>
      <td>London</td>
      <td>30</td>
      <td>2008/12/19</td>
      <td>$90,560</td>
    </tr>
    <tr>
      <td>Quinn Flynn</td>
      <td>Support Lead</td>
      <td>Edinburgh</td>
      <td>22</td>
      <td>2013/03/03</td>
      <td>$342,000</td>
    </tr>
    <tr>
      <td>Charde Marshall</td>
      <td>Regional Director</td>
      <td>San Francisco</td>
      <td>36</td>
      <td>2008/10/16</td>
      <td>$470,600</td>
    </tr>
    <tr>
      <td>Haley Kennedy</td>
      <td>Senior Marketing Designer</td>
      <td>London</td>
      <td>43</td>
      <td>2012/12/18</td>
      <td>$313,500</td>
    </tr>
    <tr>
      <td>Tatyana Fitzpatrick</td>
      <td>Regional Director</td>
      <td>London</td>
      <td>19</td>
      <td>2010/03/17</td>
      <td>$385,750</td>
    </tr>
    <tr>
      <td>Michael Silva</td>
      <td>Marketing Designer</td>
      <td>London</td>
      <td>66</td>
      <td>2012/11/27</td>
      <td>$198,500</td>
    </tr>
    <tr>
      <td>Paul Byrd</td>
      <td>Chief Financial Officer (CFO)</td>
      <td>New York</td>
      <td>64</td>
      <td>2010/06/09</td>
      <td>$725,000</td>
    </tr>
    <tr>
      <td>Gloria Little</td>
      <td>Systems Administrator</td>
      <td>New York</td>
      <td>59</td>
      <td>2009/04/10</td>
      <td>$237,500</td>
    </tr>
    <tr>
      <td>Bradley Greer</td>
      <td>Software Engineer</td>
      <td>London</td>
      <td>41</td>
      <td>2012/10/13</td>
      <td>$132,000</td>
    </tr>
    <tr>
      <td>Dai Rios</td>
      <td>Personnel Lead</td>
      <td>Edinburgh</td>
      <td>35</td>
      <td>2012/09/26</td>
      <td>$217,500</td>
    </tr>
    <tr>
      <td>Jenette Caldwell</td>
      <td>Development Lead</td>
      <td>New York</td>
      <td>30</td>
      <td>2011/09/03</td>
      <td>$345,000</td>
    </tr>
    <tr>
      <td>Yuri Berry</td>
      <td>Chief Marketing Officer (CMO)</td>
      <td>New York</td>
      <td>40</td>
      <td>2009/06/25</td>
      <td>$675,000</td>
    </tr>
    <tr>
      <td>Caesar Vance</td>
      <td>Pre-Sales Support</td>
      <td>New York</td>
      <td>21</td>
      <td>2011/12/12</td>
      <td>$106,450</td>
    </tr>
    <tr>
      <td>Doris Wilder</td>
      <td>Sales Assistant</td>
      <td>Sidney</td>
      <td>23</td>
      <td>2010/09/20</td>
      <td>$85,600</td>
    </tr>
    <tr>
      <td>Angelica Ramos</td>
      <td>Chief Executive Officer (CEO)</td>
      <td>London</td>
      <td>47</td>
      <td>2009/10/09</td>
      <td>$1,200,000</td>
    </tr>
    <tr>
      <td>Gavin Joyce</td>
      <td>Developer</td>
      <td>Edinburgh</td>
      <td>42</td>
      <td>2010/12/22</td>
      <td>$92,575</td>
    </tr>
    <tr>
      <td>Jennifer Chang</td>
      <td>Regional Director</td>
      <td>Singapore</td>
      <td>28</td>
      <td>2010/11/14</td>
      <td>$357,650</td>
    </tr>
    <tr>
      <td>Brenden Wagner</td>
      <td>Software Engineer</td>
      <td>San Francisco</td>
      <td>28</td>
      <td>2011/06/07</td>
      <td>$206,850</td>
    </tr>
    <tr>
      <td>Fiona Green</td>
      <td>Chief Operating Officer (COO)</td>
      <td>San Francisco</td>
      <td>48</td>
      <td>2010/03/11</td>
      <td>$850,000</td>
    </tr>
    <tr>
      <td>Shou Itou</td>
      <td>Regional Marketing</td>
      <td>Tokyo</td>
      <td>20</td>
      <td>2011/08/14</td>
      <td>$163,000</td>
    </tr>
    <tr>
      <td>Michelle House</td>
      <td>Integration Specialist</td>
      <td>Sidney</td>
      <td>37</td>
      <td>2011/06/02</td>
      <td>$95,400</td>
    </tr>
    <tr>
      <td>Suki Burks</td>
      <td>Developer</td>
      <td>London</td>
      <td>53</td>
      <td>2009/10/22</td>
      <td>$114,500</td>
    </tr>
    <tr>
      <td>Prescott Bartlett</td>
      <td>Technical Author</td>
      <td>London</td>
      <td>27</td>
      <td>2011/05/07</td>
      <td>$145,000</td>
    </tr>
    <tr>
      <td>Gavin Cortez</td>
      <td>Team Leader</td>
      <td>San Francisco</td>
      <td>22</td>
      <td>2008/10/26</td>
      <td>$235,500</td>
    </tr>
    <tr>
      <td>Martena Mccray</td>
      <td>Post-Sales support</td>
      <td>Edinburgh</td>
      <td>46</td>
      <td>2011/03/09</td>
      <td>$324,050</td>
    </tr>
    <tr>
      <td>Unity Butler</td>
      <td>Marketing Designer</td>
      <td>San Francisco</td>
      <td>47</td>
      <td>2009/12/09</td>
      <td>$85,675</td>
    </tr>
    <tr>
      <td>Howard Hatfield</td>
      <td>Office Manager</td>
      <td>San Francisco</td>
      <td>51</td>
      <td>2008/12/16</td>
      <td>$164,500</td>
    </tr>
    <tr>
      <td>Hope Fuentes</td>
      <td>Secretary</td>
      <td>San Francisco</td>
      <td>41</td>
      <td>2010/02/12</td>
      <td>$109,850</td>
    </tr>
    <tr>
      <td>Vivian Harrell</td>
      <td>Financial Controller</td>
      <td>San Francisco</td>
      <td>62</td>
      <td>2009/02/14</td>
      <td>$452,500</td>
    </tr>
    <tr>
      <td>Timothy Mooney</td>
      <td>Office Manager</td>
      <td>London</td>
      <td>37</td>
      <td>2008/12/11</td>
      <td>$136,200</td>
    </tr>
    <tr>
      <td>Jackson Bradshaw</td>
      <td>Director</td>
      <td>New York</td>
      <td>65</td>
      <td>2008/09/26</td>
      <td>$645,750</td>
    </tr>
    <tr>
      <td>Olivia Liang</td>
      <td>Support Engineer</td>
      <td>Singapore</td>
      <td>64</td>
      <td>2011/02/03</td>
      <td>$234,500</td>
    </tr>
    <tr>
      <td>Bruno Nash</td>
      <td>Software Engineer</td>
      <td>London</td>
      <td>38</td>
      <td>2011/05/03</td>
      <td>$163,500</td>
    </tr>
    <tr>
      <td>Sakura Yamamoto</td>
      <td>Support Engineer</td>
      <td>Tokyo</td>
      <td>37</td>
      <td>2009/08/19</td>
      <td>$139,575</td>
    </tr>
    <tr>
      <td>Thor Walton</td>
      <td>Developer</td>
      <td>New York</td>
      <td>61</td>
      <td>2013/08/11</td>
      <td>$98,540</td>
    </tr>
    <tr>
      <td>Finn Camacho</td>
      <td>Support Engineer</td>
      <td>San Francisco</td>
      <td>47</td>
      <td>2009/07/07</td>
      <td>$87,500</td>
    </tr>
    <tr>
      <td>Serge Baldwin</td>
      <td>Data Coordinator</td>
      <td>Singapore</td>
      <td>64</td>
      <td>2012/04/09</td>
      <td>$138,575</td>
    </tr>
    <tr>
      <td>Zenaida Frank</td>
      <td>Software Engineer</td>
      <td>New York</td>
      <td>63</td>
      <td>2010/01/04</td>
      <td>$125,250</td>
    </tr>
    <tr>
      <td>Zorita Serrano</td>
      <td>Software Engineer</td>
      <td>San Francisco</td>
      <td>56</td>
      <td>2012/06/01</td>
      <td>$115,000</td>
    </tr>
    <tr>
      <td>Jennifer Acosta</td>
      <td>Junior Javascript Developer</td>
      <td>Edinburgh</td>
      <td>43</td>
      <td>2013/02/01</td>
      <td>$75,650</td>
    </tr>
    <tr>
      <td>Cara Stevens</td>
      <td>Sales Assistant</td>
      <td>New York</td>
      <td>46</td>
      <td>2011/12/06</td>
      <td>$145,600</td>
    </tr>
    <tr>
      <td>Hermione Butler</td>
      <td>Regional Director</td>
      <td>London</td>
      <td>47</td>
      <td>2011/03/21</td>
      <td>$356,250</td>
    </tr>
    <tr>
      <td>Lael Greer</td>
      <td>Systems Administrator</td>
      <td>London</td>
      <td>21</td>
      <td>2009/02/27</td>
      <td>$103,500</td>
    </tr>
    <tr>
      <td>Jonas Alexander</td>
      <td>Developer</td>
      <td>San Francisco</td>
      <td>30</td>
      <td>2010/07/14</td>
      <td>$86,500</td>
    </tr>
    <tr>
      <td>Shad Decker</td>
      <td>Regional Director</td>
      <td>Edinburgh</td>
      <td>51</td>
      <td>2008/11/13</td>
      <td>$183,000</td>
    </tr>
    <tr>
      <td>Michael Bruce</td>
      <td>Javascript Developer</td>
      <td>Singapore</td>
      <td>29</td>
      <td>2011/06/27</td>
      <td>$183,000</td>
    </tr>
    <tr>
      <td>Donna Snider</td>
      <td>Customer Support</td>
      <td>New York</td>
      <td>27</td>
      <td>2011/01/25</td>
      <td>$112,000</td>
    </tr>
  </tbody>
</table>

//注意：有些情况不像第一行或最后一行那样处理。

如何确定行是否在数据表中可见

1 个答案: