我已经从事Messenger项目已有一段时间了,我需要在JList
中设置特定元素的颜色。我已经在互联网上阅读了很多东西,但并没有得到一个简单的解释。确切地说,我正在检查用户是否有未读消息以及是否有未读消息。做一些表明该特定用户有消息的操作。我想到的是更改该元素的颜色,但我还不知道该怎么做。我创建了一个小的可执行代码,在其中我只想更改那些标志为true的代码的颜色。可以生成如下。
任何人都可以在此代码中相应地使用ListCellRenderer
,以便我知道该怎么做。
package newpackage;
import javax.swing.DefaultListModel;
public class NewJFrame extends javax.swing.JFrame {
public boolean f0,f1,f2,f3,f4;
/**
* Creates new form NewJFrame
*/
public NewJFrame() {
f1=f2=f0=true;
f3=f4=false;
initComponents();
lst.setModel(addToList());
}
public DefaultListModel addToList() {
DefaultListModel<String> dlm = new DefaultListModel<String>();
for (int i = 0; i < 5; i++) {
dlm.addElement("Item"+i);
}
return dlm;
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
lst = new javax.swing.JList<>();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jScrollPane1.setViewportView(lst);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 117, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(277, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(36, 36, 36)
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 250, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(14, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new NewJFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JList<String> lst;
// End of variables declaration
}
编辑1:好吧,我阅读了文章并设置了自定义渲染器。它按预期运行,但不像我想要的那样。在我的代码中,setCellRenderer
方法被多次调用,并且每次都应该更改JList
的不同元素的颜色,这样做很好,但是我不希望渲染器更改以前更改的颜色元素以正常方式生成。用短代码重新生成问题将很困难,因此我将举一个小例子来说明。让我们假设我的JList
包含4个元素item1,item2,item3,item4。现在第一次调用setCellRenderer
方法时,它将item1的颜色更改为只说绿色,而其他所有元素当前都为黑色。现在再次调用setCellRenderer
方法时,它更改了元素的颜色,即说item3变为绿色,它不应执行的操作是再次将item1的颜色更改为黑色,使其保持绿色。任何人都可以提出一种解决方法。