我在将JCheckBox放入自定义ListCellRenderer时发现了一个问题，其他一些平台消失了，我现在不知道原因。
这是渲染器：
public class TaskRenderer extends JPanel implements ListCellRenderer<Task> {
/**
*
*/
private static final long serialVersionUID = 1L;
private JLabel lbEdit = new JLabel();
private JLabel lbCheck = new JLabel();
private JLabel lbTitle = new JLabel();
private JLabel lbDescription = new JLabel();
private JPanel panelText;
private JPanel panelEdit;
private JPanel panelCheck;
private JCheckBox checkTask;
public TaskRenderer() {
setLayout(new BorderLayout(5, 5));
panelText = new JPanel(new GridLayout(0, 1));
lbTitle.setFont(lbTitle.getFont ().deriveFont (20.0f));
lbDescription.setFont(lbDescription.getFont ().deriveFont (0.0f));
panelText.add(lbTitle);
panelText.add(lbDescription);
panelEdit = new JPanel();
panelEdit.setBorder(new EmptyBorder(5, 5, 5, 5));
panelEdit.add(lbEdit);
panelCheck = new JPanel();
panelCheck.setBorder(new EmptyBorder(5, 5, 5, 5));
checkTask = new JCheckBox("Tarea completada");
checkTask.setSelected(false);
panelCheck.add(checkTask);
JPanel p = new JPanel(new BorderLayout());
p.add(panelEdit,BorderLayout.WEST);
p.add(panelCheck,BorderLayout.CENTER);
add(p, BorderLayout.WEST);
add(panelText, BorderLayout.CENTER);
}
@Override
public Component getListCellRendererComponent(JList<? extends Task> list,
Task task, int index, boolean isSelected, boolean cellHasFocus) {
list.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION );
ImageIcon editIcon = new ImageIcon("images/edit.png"); // load the image to a imageIcon
Image image2 = editIcon.getImage(); // transform it
Image newimg2 = image2.getScaledInstance(15, 15, java.awt.Image.SCALE_SMOOTH); // scale it the smooth way
editIcon = new ImageIcon(newimg2); // transform it back
lbEdit.setIcon(editIcon);
lbTitle.setText(task.getTitle());
lbDescription.setText(task.getDescription());
lbDescription.setForeground(Color.blue);
// set Opaque to change background color of JLabel
lbTitle.setOpaque(true);
lbDescription.setOpaque(true);
lbEdit.setOpaque(true);
// when select item
if (isSelected) {
lbTitle.setBackground(list.getSelectionBackground());
lbDescription.setBackground(list.getSelectionBackground());
lbEdit.setBackground(list.getSelectionBackground());
if(task.getPriority() == 1) {
setBackground(Color.RED);
}else if (task.getPriority() == 2) {
setBackground(Color.YELLOW);
}else {
setBackground(Color.GREEN);
}
panelEdit.setBackground(list.getSelectionBackground());
} else { // when don't select
if(task.getPriority() == 1) {
setBackground(Color.RED);
}else if (task.getPriority() == 2) {
setBackground(Color.YELLOW);
}else {
setBackground(Color.GREEN);
}
}
return this;
}
}
JLabel说明消失了，另一个问题是，当我选择多个项目时，我只想在每次点击时选择一个项目。
知道什么是错的吗？
答案 0 :(得分：0)
更新了处理TaskListRenderer的类
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.ImageIcon;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.ListCellRenderer;
import javax.swing.ListSelectionModel;
import javax.swing.border.EmptyBorder;
public class TaskRenderer extends JPanel {
/**
*
*/
private static final long serialVersionUID = 1L;
private JList taskList = new JList();
private JLabel lbCheck = new JLabel();
private JLabel lbTitle = new JLabel();
private JLabel lbDescription = new JLabel();
private JPanel panelText;
private JPanel panelEdit;
private JPanel panelCheck;
private JCheckBox checkTask;
public TaskRenderer() {
setLayout(new BorderLayout(5, 5));
panelText = new JPanel(new GridLayout(0, 1));
lbTitle.setFont(lbTitle.getFont().deriveFont(20.0f));
lbDescription.setFont(lbDescription.getFont().deriveFont(0.0f));
panelText.add(lbTitle);
panelText.add(lbDescription);
panelEdit = new JPanel();
panelEdit.setBorder(new EmptyBorder(5, 5, 5, 5));
taskList = new JList<Task>(new Task[] {
new Task("Task1", "T1 Desc", 1, false),
new Task("Task2", "T2 Desc", 2, false),
new Task("Task3", "T3 Desc", 3, false),
new Task("Task4", "T4 Desc", 4, false),
new Task("Task5", "T5 Desc", 5, false) });
taskList.setCellRenderer(new TaskListRenderer());
taskList.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
// Add a mouse listener to handle changing selection
taskList.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent event) {
JList<Task> list = (JList<Task>) event.getSource();
// Get index of item clicked
int index = list.locationToIndex(event.getPoint());
Task item = (Task) list.getModel().getElementAt(index);
// Toggle selected state
item.setSelected(!item.isSelected());
// Repaint cell
list.repaint(list.getCellBounds(index, index));
}
});
panelEdit.add(new JScrollPane(taskList));
panelCheck = new JPanel();
panelCheck.setBorder(new EmptyBorder(5, 5, 5, 5));
checkTask = new JCheckBox("Tarea completada");
checkTask.setSelected(false);
panelCheck.add(checkTask);
JPanel p = new JPanel(new BorderLayout());
p.add(panelEdit, BorderLayout.WEST);
p.add(panelCheck, BorderLayout.CENTER);
add(p, BorderLayout.WEST);
add(panelText, BorderLayout.CENTER);
}
public static void main(String[] args) {
TaskRenderer ren = new TaskRenderer();
JFrame frame = new JFrame();
frame.add(ren);
frame.pack();
frame.setVisible(true);
}
class TaskListRenderer extends JCheckBox implements
ListCellRenderer<Task> {
@Override
public Component getListCellRendererComponent(
JList<? extends Task> list, Task value, int index,
boolean isSelected, boolean cellHasFocus) {
setEnabled(list.isEnabled());
setSelected(value.isSelected());
setFont(list.getFont());
setBackground(list.getBackground());
setForeground(list.getForeground());
setText(value.toString());
System.out.println("Value " + value.getTitle());
ImageIcon editIcon = new ImageIcon("images/edit.png"); // load the
// image
// to a
// imageIcon
Image image2 = editIcon.getImage(); // transform it
Image newimg2 = image2.getScaledInstance(15, 15,
java.awt.Image.SCALE_SMOOTH); // scale it the smooth way
editIcon = new ImageIcon(newimg2); // transform it back
// when select item
if (isSelected) {
lbTitle.setText(value.getTitle());
lbDescription.setText(value.getDescription());
lbDescription.setForeground(Color.blue);
// set Opaque to change background color of JLabel
lbTitle.setOpaque(true);
lbDescription.setOpaque(true);
taskList.setOpaque(true);
lbTitle.setBackground(list.getSelectionBackground());
lbDescription.setBackground(list.getSelectionBackground());
taskList.setBackground(list.getSelectionBackground());
if (value.getPriority() == 1) {
setBackground(Color.RED);
} else if (value.getPriority() == 2) {
setBackground(Color.YELLOW);
} else {
setBackground(Color.GREEN);
}
panelEdit.setBackground(list.getSelectionBackground());
} else { // when don't select
if (value.getPriority() == 1) {
setBackground(Color.RED);
} else if (value.getPriority() == 2) {
setBackground(Color.YELLOW);
} else {
setBackground(Color.GREEN);
}
}
return this;
}
}
}
这是任务类
public class Task {
private String title;
private String description;
private int priority;
private boolean isSelected = false;
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
public int getPriority() {
return priority;
}
public void setPriority(int priority) {
this.priority = priority;
}
public boolean isSelected() {
return isSelected;
}
public Task(String title, String description, int priority,
boolean isSelected) {
super();
this.title = title;
this.description = description;
this.priority = priority;
this.isSelected = isSelected;
}
public void setSelected(boolean isSelected) {
this.isSelected = isSelected;
}
public String toString() {
return this.title;
}
}
出于测试目的，将Task方法添加到TaskRenderer，如果不需要，可随意删除