如何根据先前的选择重新组织 JCombobox（Java Swing）

huangapple
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英文:

How to reorganize JCombobox depends on prior choice (Java Swing)

问题

  1.         JPanel test = new JPanel();
  2.         test.setLayout(new FlowLayout());
  3.         add(test);
  5.         top = rc.getParsedData("top");
  6.         ArrayList<String> topList = rc.getLocationList(top);
  7.         location1 = new JComboBox(topList.toArray(new String[topList.size()]));
  8.         location1.addActionListener(e -> {
  9.             try {
  10.                 rc.setCode(top, location1.getSelectedItem().toString());
  11.                 mdl = rc.getParsedData("mdl");
  12.                 ArrayList<String> mdlList = rc.getLocationList(mdl);
  13.                 location2 = new JComboBox(mdlList.toArray(new String[mdlList.size()]));
  14.             } catch (IOException | ParseException ioException) {
  15.                 ioException.printStackTrace();
  16.             }
  17.         });
  19.         test.add(location1);
  20.         
  21.         location2.addActionListener(e -> {
  22.             try {
  23.                 leaf = rc.getParsedData("leaf");
  24.                 rc.setCode(mdl, location2.getSelectedItem().toString());
  25.                 ArrayList<String> leafList = rc.getLocationList(leaf);
  26.                 location3 = new JComboBox(leafList.toArray(new String[leafList.size()]));
  27.                 rc.setXY(leaf, location3.getSelectedItem().toString());
  28.             } catch (IOException | ParseException ioException) {
  29.                 ioException.printStackTrace();
  30.             }
  31.         });
  32.         test.add(location2);
  33.         
  34.         test.add(location3);
英文:

I'm about to make selection menus consist of 3 JComboboxes, and they are related to prior choice.<br>
When I choose first menu, I need to update next JCombobox by requesting JSON, and so on for last menu.<br>
What I tried : put addActionListener to update next JCombobox, but it seems not working.<br>
It's hard to find problem as I cannot catch it through debugger.<br>
The method 'getParsedData' returns JSONArray came from JSON file.

  1.         JPanel test = new JPanel();
  2.         test.setLayout(new FlowLayout());
  3.         add(test);
  5.         top = rc.getParsedData(&quot;top&quot;);
  6.         ArrayList&lt;String&gt; topList = rc.getLocationList(top);
  7.         location1 = new JComboBox(topList.toArray(new String[topList.size()]));
  8.         location1.addActionListener(e -&gt; {
  9.             try {
  10.                 rc.setCode(top, location1.getSelectedItem().toString());
  11.                 mdl = rc.getParsedData(&quot;mdl&quot;);
  12.                 ArrayList&lt;String&gt; mdlList = rc.getLocationList(mdl);
  13.                 location2 = new JComboBox(mdlList.toArray(new String[mdlList.size()]));
  14.             } catch (IOException | ParseException ioException) {
  15.                 ioException.printStackTrace();
  16.             }
  17.         });
  19.         test.add(location1);
  20.         
  21.         location2.addActionListener(e -&gt; {
  22.             try {
  23.                 leaf = rc.getParsedData(&quot;leaf&quot;);
  24.                 rc.setCode(mdl, location2.getSelectedItem().toString());
  25.                 ArrayList&lt;String&gt; leafList = rc.getLocationList(leaf);
  26.                 location3 = new JComboBox(leafList.toArray(new String[leafList.size()]));
  27.                 rc.setXY(leaf, location3.getSelectedItem().toString());
  28.             } catch (IOException | ParseException ioException) {
  29.                 ioException.printStackTrace();
  30.             }
  31.         });
  32.         test.add(location2);
  33.         
  34.         test.add(location3);

答案1

得分: 1

不要回答我要翻译的问题。以下是要翻译的内容：

每当ActionListener被激活时，不要创建一个新的JComboBox（使用new JComboBox(...)）；而应该更新现有的location2/location3实例。

对于location2，您可以通过首先调用location2.removeAllItems()来实现。然后，您应该遍历您的mdList，并对每个mdList项目调用location2.addItem()。

英文:

Instead of creating a new JComboBox each time the ActionListener gets active (using <code>new JComboBox(...))</code> you should update the existing location2/location3-instances.

For location2 you can do that by first calling
<code>location2.removeAllItems()</code>. Afterwards you should iterate over your mdList and call <code>location2.addItem()</code> for each mdList-item.

huangapple
  • 本文由 发表于 2020年8月25日 13:58:02
  • 转载请务必保留本文链接：https://go.coder-hub.com/63572840.html
  • java
  • jcombobox
  • swing
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