SwingJava。util。多帧观测器
我试图用多个JFrame实例实现Observer模式。但是,当调用notifyObservers()
时,只更新最后一个实例化的JFrame实例
这是我的代码:
购物中心。java
import java.util.ArrayList;
import java.util.Observable;
public class Mall extends Observable{
private ArrayList<String> stores;
public Mall(){
stores = new ArrayList<String>();
}
public void addNewStore(String store){
stores.add(store);
System.out.println(store);
setChanged();
notifyObservers(store);
}
public ArrayList<String> getStores(){
return stores;
}
}
定制框架。java
public class CustomerFrame extends javax.swing.JFrame {
public CustomerFrame() {
initComponents();
}
public CustomerFrame(Mall theMall) {
initComponents();
MallObserver mallObs = new MallObserver();
theMall.addObserver(mallObs);
}
private void initComponents() {
jScrollPane1 = new javax.swing.JScrollPane();
jList1 = new javax.swing.JList();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jList1.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
jScrollPane1.setViewportView(jList1);
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, 249, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(141, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 165, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(124, Short.MAX_VALUE))
);
pack();
}
public static javax.swing.JList jList1;
private javax.swing.JScrollPane jScrollPane1;
}
MallObserver。java
import java.util.Observable;
import java.util.Observer;
import javax.swing.DefaultListModel;
public class MallObserver implements Observer{
private Mall mallUpdate;
@Override
public void update(Observable o, Object arg) {
mallUpdate = (Mall) o;
DefaultListModel listModel = new DefaultListModel();
for(int i = 0; i < mallUpdate.getStores().size(); i++)
listModel.addElement(mallUpdate.getStores().get(i));
CustomerFrame.jList1.setModel(listModel);
}
}
AdminFrame。java
public class AdminFrame extends javax.swing.JFrame {
Mall theMall;
public AdminFrame() {
initComponents();
theMall = new Mall();
}
@SuppressWarnings("unchecked")
private void initComponents() {
jTextField1 = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jTextField1.setText("jTextField1");
jLabel1.setText("jLabel1");
jButton1.setText("Add Store");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setText("New Customer");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(143, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jButton2)
.addComponent(jButton1)
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel1)
.addGap(26, 26, 26)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addGap(138, 138, 138))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(129, 129, 129)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(jButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButton2)
.addContainerGap(88, Short.MAX_VALUE))
);
pack();
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
CustomerFrame newCust = new CustomerFrame();
newCust.setVisible(true);
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
theMall.addNewStore(jTextField1.getText());
}
public static void main(String args[]) {
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(AdminFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(AdminFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(AdminFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(AdminFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new AdminFrame().setVisible(true);
}
});
}
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JLabel jLabel1;
private javax.swing.JTextField jTextField1;
}
这个想法是,当顾客进入商店时,商店会为顾客打开一个新的JFrame。当admin添加存储时,所有JFrameCustomerFrame.java
都将更新其列表项。然而,在我的例子中,只有最后实例化的CustomerFrame.java
会得到更新,而其他的保持不变
通过打开2个新客户并尝试在AdminFrame.java
添加存储,可以重现上述问题
这里有什么问题
# 1 楼答案
您不能从MallCustomer的
update(...)
方法中调用thisFrame
上的任何方法。而不是将模型设置为storeList
(这到底是从哪里来的?),为CustomerFrame提供一个公共方法,比如调用setStoreListModel(ListModel listModel)
,在update
中调用,并传入storeModel即
及
注意:代码未编译或测试
编辑
我可以看到您有几个问题:
initComponents()
之前创建Mall实例。这样,您就可以在action listener方法中使用相同的Mall实例李>例如: