Question

MULTIPLE_INTERVAL_SELECTION用于一次选择一个或多个连续的索引范围。 SINGLE_INTERVAL_SELECTION用于一次选择一个连续的索引范围。但是这里一次选择一个列表索引。

  import javax.swing.*;
  import java.awt.event.*;

  public class SwingLessonFive extends JFrame {

JButton button1;
JList favoriteMovies, favoriteColors;
DefaultListModel defaultList = new DefaultListModel();
JScrollPane scrollBars;
String infoOnComponent ="";

public static void main(String[] args) {
    new SwingLessonFive();
}

public SwingLessonFive() {
    this.setSize(400,400);
    this.setTitle("My Fifth Frame");
    this.setLocationRelativeTo(null);
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JPanel thePanel = new JPanel();

    button1 = new JButton("Get Answer");
    ListenForButton lForButton = new ListenForButton();
    button1.addActionListener(lForButton);
    thePanel.add(button1);


    String[] movies = {"Kick","Batman","SpiderMan","Lucy"};
    favoriteMovies =  new JList(movies);
    favoriteMovies.setFixedCellHeight(30);
    favoriteMovies.setFixedCellWidth(150);
    favoriteMovies.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION); //this is the part I didn't undertand

    String[] colors = {"Black","Orange","Brown","Pink","Yellow","White","Red"};

    for(String color : colors) {
        defaultList.addElement(color);
    }

    defaultList.add(2, "Purple");

    favoriteColors = new JList(defaultList);
    favoriteColors.setVisibleRowCount(4);
    scrollBars = new JScrollPane(favoriteColors,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
    favoriteColors.setFixedCellHeight(30);
    favoriteColors.setFixedCellWidth(150);



    thePanel.add(favoriteMovies);
    thePanel.add(scrollBars);



    this.add(thePanel);
    this.setVisible(true);

}

private class ListenForButton implements ActionListener {

    public void actionPerformed(ActionEvent ae) {
        if(ae.getSource() == button1) {
            if(defaultList.contains("Black")) {
                infoOnComponent += "Black is in the list \n";
            }

            if(!defaultList.isEmpty()) {
                infoOnComponent +="The list isn't empty\n";
            }

            infoOnComponent += "Elements in the list: "+defaultList.getSize() +"\n";
            infoOnComponent += "Last Element: "+defaultList.lastElement() + "\n";
            infoOnComponent += "First Element: "+defaultList.firstElement()+"\n";
            infoOnComponent += "Get element at index 1 "+defaultList.get(1)+"\n";
            defaultList.remove(0);
            defaultList.removeElement("Yellow");

            Object[] arrayOfList = defaultList.toArray();

            for(Object color: arrayOfList) {
                infoOnComponent += color +"\n";
            }

            JOptionPane.showMessageDialog(SwingLessonFive.this,infoOnComponent,"Information",JOptionPane.INFORMATION_MESSAGE);
            infoOnComponent = "";
        }
    }
}



}

Answer 1

但是这里一次选择一个列表索引。

正确。单击即可选择一行。

要选择多个单行，请在单击

时按住Control键

要选择一系列行，请在单击时按住Shift键。

因此选择取决于选择模式，以及是否使用了移位/控制键。

进行实验，直到获得符合要求的正确选择模式。

SINGLE_INTERVAL_SELECTION未按预期工作

1 个答案: