JList添加/删除项目 [英] JList add/remove Item

问题描述

您好我必须从JList中选择一个元素到另一个，从第一个
中删除它我创建的方法只插入一个元素，覆盖最后一个元素并且不会从中移除所选项目第一个JList
这是代码：

Hi I have to pick an element from a JList to another, removing it from the first The method I've created inserts only one element, overwriting the last one and doesn't remove the selected item from the first JList Here's the code:

第一个列表

private javax.swing.JList listaRosa;

此方法填充：

private void visualizzaRosaButtonvisualizzaRosa(java.awt.event.ActionEvent evt) {                                                    
    // TODO add your handling code here:
    visualizzaSquadraSelezionata();
    String fileSquadra;
    fileSquadra = squadraDaVisualizzare.getText();
    DefaultListModel listModel = new DefaultListModel();
    try {
        FileInputStream fstream = new FileInputStream("C:/Users/Franky/Documents/NetBeansProjects/JavaApplication5/src/javaapplication5/Rose/"+fileSquadra+"");
        // Get the object of DataInputStream
        DataInputStream in = new DataInputStream(fstream);
        BufferedReader br = new BufferedReader(new InputStreamReader(in));
        String strLine;
        //Read File Line By Line
        while ((strLine = br.readLine()) != null)   {
            listModel.addElement(strLine);
            System.out.println(strLine);
        }
        listaRosa.setModel(listModel);
        //Close the input stream
        in.close();
    } catch (Exception e) {
    }

第二个列表，其中我想插入从第一个中删除的项目：

The second list, where I want to insert items removing from the first:

private javax.swing.JList listaTitolari

这是NOT工作代码：

private void aggiungiTitolareButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                       
    // TODO add your handling code here:
    DefaultListModel listModel = new DefaultListModel();
    String daInserire;
    listModel.addElement(listaRosa.getSelectedValue());
    listModel.removeElement(listaRosa.getSelectedValue());
    listaTitolari.setModel(listModel);
} 

谢谢

推荐答案

问题是

listModel.addElement(listaRosa.getSelectedValue());
listModel.removeElement(listaRosa.getSelectedValue());

您可能正在添加元素并立即删除它，因为添加和删除操作都在同一个listModel上。

you may be adding an element and immediatly removing it since both add and remove operations are on the same listModel.

尝试

private void aggiungiTitolareButtonActionPerformed(java.awt.event.ActionEvent evt) {                                                       

    DefaultListModel lm2 = (DefaultListModel) listaTitolari.getModel();
    DefaultListModel lm1  = (DefaultListModel) listaRosa.getModel();
    if(lm2 == null)
    {
        lm2 = new DefaultListModel();
        listaTitolari.setModel(lm2);
    }
    lm2.addElement(listaTitolari.getSelectedValue());
    lm1.removeElement(listaTitolari.getSelectedValue());        
} 

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