我的 Java JFrame 項目有一個乏味的問題。我想要做的（并尋找如何做）是從無ListBoxGUI 類實時添加元素，或者換句話說“異步”，而不凍結(jié)我的應(yīng)用程序。這清楚嗎？我試過SwingWorker和線程但沒有結(jié)果。我所能做的就是在所有進(jìn)程完成后更新列表框（顯然我的應(yīng)用程序凍結(jié)了，因為我的進(jìn)程很長）。這是我的架構(gòu)：控制器package controller;import business.MyBusiness;import util.MyLog;import view.MyView;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;public class MyController { MyLog log; MyBusiness business; MyView view; public MyController(){ log = new MyLog(); business = new MyBusiness(log.getLog()); view = new MyView(log.getLog()); } public void runProcess() { view.addButtonListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { business.runProcess(); }} ); }}商業(yè)package business;import MyLog;import java.util.List;import javax.swing.DefaultListModel;import javax.swing.SwingWorker;public class MyBusiness { private int counter = 0; private DefaultListModel<String> model; private MyLog log; public MyBusiness(DefaultListModel<String> model) { this.model = model;a } public void runProcess() { SwingWorker<Void, String> worker = new SwingWorker<Void, String>() { @Override protected Void doInBackground() throws Exception { for (int i = 0; i < 10; i++) { publish("log message number " + counter++); Thread.sleep(2000); } return null; } @Override protected void process(List<String> chunks) { // this is called on the Swing event thread for (String text : chunks) { model.addElement(""); } } }; worker.execute(); }}
2 回答
藍(lán)山帝景
TA貢獻(xiàn)1843條經(jīng)驗 獲得超7個贊
這是一個過度簡化的示例，String說明使用SwingWorker.
為了使 a 的基本使用SwingWorker更容易理解，它被過度簡化。
這是一個單文件mcve，這意味著您可以將整個代碼復(fù)制粘貼到一個文件 (MyView.java) 中并執(zhí)行：
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionListener;
import java.util.List;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.SwingWorker;
//gui only, unaware of logic
public class MyView extends JFrame {
private JList<String> loglist;
private JButton log;
public MyView(DefaultListModel<String> model) {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
log = new JButton("Start Process");
add(log, BorderLayout.PAGE_START);
loglist = new JList<>(model);
loglist.setPreferredSize(new Dimension(200,300));
add(loglist, BorderLayout.PAGE_END);
pack();
setVisible(true);
}
void addButtonListener(ActionListener listener) {
log.addActionListener(listener);
}
public static void main(String args[]) {
new MyController();
}
}
//represents the data (and some times logic) used by GUI
class Model {
private DefaultListModel<String> model;
Model() {
model = new DefaultListModel<>();
model.addElement("No logs yet");
}
DefaultListModel<String> getModel(){
return model;
}
}
//"wires" the GUI, model and business process
class MyController {
MyController(){
Model model = new Model();
MyBusiness business = new MyBusiness(model.getModel());
MyView view = new MyView(model.getModel());
view .addButtonListener(e -> business.start());
}
}
//represents long process that needs to update GUI
class MyBusiness extends SwingWorker<Void, String>{
private static final int NUMBER_OF_LOGS = 9;
private int counter = 0;
private DefaultListModel<String> model;
public MyBusiness(DefaultListModel<String> model) {
this.model= model;
}
@Override //simulate long process
protected Void doInBackground() throws Exception {
for(int i = 0; i < NUMBER_OF_LOGS; i++) {
//Successive calls to publish are coalesced into a java.util.List,
//which is by process.
publish("log message number " + counter++);
Thread.sleep(1000);
}
return null;
}
@Override
protected void process(List<String> logsList) {
//process the list received from publish
for(String element : logsList) {
model.addElement(element);
}
}
void start() {
model.clear(); //clear initial model content
super.execute();
}
}
哆啦的時光機
TA貢獻(xiàn)1779條經(jīng)驗 獲得超6個贊
首先是一些規(guī)則和建議：
您的模型或此處的“業(yè)務(wù)”代碼應(yīng)該不了解 GUI，并且不應(yīng)依賴于 GUI 結(jié)構(gòu)
同樣，所有 Swing 代碼都應(yīng)在事件線程上調(diào)用，所有長時間運行的代碼都應(yīng)在后臺線程中調(diào)用
如果您有長時間運行的更改狀態(tài)的代碼，并且如果該狀態(tài)需要反映在 GUI 中，這意味著您需要某種回調(diào)機制，模型以某種方式通知重要方其狀態(tài)已經(jīng)改變。這可以使用 PropertyChangeListeners 或通過將某種類型的回調(diào)方法注入模型來完成。
使視圖變得愚蠢。它從用戶那里獲取輸入并通知控制器，它由控制器更新。幾乎所有的程序“大腦”都位于控制器和模型中。例外——一些輸入驗證通常在視圖中完成。
不要忽略基本的 Java OOP 規(guī)則——通過保持字段私有來隱藏信息，并允許外部類僅通過您完全控制的公共方法更新狀態(tài)。
該MCVE結(jié)構(gòu)是一個很好的學(xué)習(xí)和使用，即使不問一個問題在這里。學(xué)習(xí)簡化您的代碼并隔離您的問題以最好地解決它。
例如，可以將此代碼復(fù)制并粘貼到所選 IDE 中的單個文件中，然后運行：
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.util.List;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
import javax.swing.*;
public class Mcve1 {
private static void createAndShowGui() {
// create your model/view/controller and hook them together
MyBusiness1 model = new MyBusiness1();
MyView1 myView = new MyView1();
new MyController1(model, myView); // the "hooking" occurs here
// create and start the GUI
JFrame frame = new JFrame("MCVE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(myView);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
// start GUI on Swing thread
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
@SuppressWarnings("serial")
class MyView1 extends JPanel {
private MyController1 controller;
private DefaultListModel<String> logListModel = new DefaultListModel<>();
private JList<String> logList = new JList<>(logListModel);
public MyView1() {
logList.setFocusable(false);
logList.setPrototypeCellValue("abcdefghijklabcdefghijklabcdefghijklabcdefghijkl");
logList.setVisibleRowCount(15);
add(new JScrollPane(logList, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED));
// my view's buttons just notify the controller that they've been pushed
// that's it
add(new JButton(new AbstractAction("Do stuff") {
{
putValue(MNEMONIC_KEY, KeyEvent.VK_D);
}
@Override
public void actionPerformed(ActionEvent evt) {
if (controller != null) {
controller.doStuff(); // notification done here
}
}
}));
}
public void setController(MyController1 controller) {
this.controller = controller;
}
// public method to allow controller to update state
public void updateList(String newValue) {
logListModel.addElement(newValue);
}
}
class MyController1 {
private MyBusiness1 myBusiness;
private MyView1 myView;
// hook up concerns
public MyController1(MyBusiness1 myBusiness, MyView1 myView) {
this.myBusiness = myBusiness;
this.myView = myView;
myView.setController(this);
}
public void doStuff() {
// long running code called within the worker's doInBackground method
SwingWorker<Void, String> worker = new SwingWorker<Void, String>() {
@Override
protected Void doInBackground() throws Exception {
// pass a call-back method into the method
// so that this worker is notified of changes
myBusiness.longRunningCode(new Consumer<String>() {
// call back code
@Override
public void accept(String text) {
publish(text); // publish to the process method
}
});
return null;
}
@Override
protected void process(List<String> chunks) {
// this is called on the Swing event thread
for (String text : chunks) {
myView.updateList(text);
}
}
};
worker.execute();
}
}
class MyBusiness1 {
private Random random = new Random();
private String text;
public void longRunningCode(Consumer<String> consumer) throws InterruptedException {
consumer.accept("Starting");
// mimic long-running code
int sleepTime = 500 + random.nextInt(2 * 3000);
TimeUnit.MILLISECONDS.sleep(sleepTime);
consumer.accept("This is message for initial process");
// ...
// Doing another long process and then print log
// ...
sleepTime = 500 + random.nextInt(2 * 3000);
TimeUnit.MILLISECONDS.sleep(sleepTime);
consumer.accept("This is not complete. Review");
// ...
// Doing another long process and then print log
// ...
sleepTime = 500 + random.nextInt(2 * 3000);
TimeUnit.MILLISECONDS.sleep(sleepTime);
consumer.accept("Ok this works. Have fun");
}
public String getText() {
return text;
}
}
另一種做同樣事情的方法是使用符合 Swing 的 PropertyChangeSupport 和 PropertyChangeListeners。例如：
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.beans.*;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import javax.swing.*;
import javax.swing.event.SwingPropertyChangeSupport;
public class Mcve2 {
private static void createAndShowGui() {
MyBusiness2 myBusiness = new MyBusiness2();
MyView2 myView = new MyView2();
new MyController2(myBusiness, myView);
JFrame frame = new JFrame("MCVE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(myView);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
@SuppressWarnings("serial")
class MyView2 extends JPanel {
private MyController2 controller;
private DefaultListModel<String> logListModel = new DefaultListModel<>();
private JList<String> logList = new JList<>(logListModel);
public MyView2() {
logList.setFocusable(false);
logList.setPrototypeCellValue("abcdefghijklabcdefghijklabcdefghijklabcdefghijkl");
logList.setVisibleRowCount(15);
add(new JScrollPane(logList, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED));
add(new JButton(new AbstractAction("Do stuff") {
{
putValue(MNEMONIC_KEY, KeyEvent.VK_D);
}
@Override
public void actionPerformed(ActionEvent evt) {
if (controller != null) {
controller.doStuff();
}
}
}));
}
public void setController(MyController2 controller) {
this.controller = controller;
}
public void updateList(String newValue) {
logListModel.addElement(newValue);
}
}
class MyController2 {
private MyBusiness2 myBusiness;
private MyView2 myView;
public MyController2(MyBusiness2 myBusiness, MyView2 myView) {
this.myBusiness = myBusiness;
this.myView = myView;
myView.setController(this);
myBusiness.addPropertyChangeListener(MyBusiness2.TEXT, new TextListener());
}
public void doStuff() {
new Thread(() -> {
try {
myBusiness.longRunningCode();
} catch (InterruptedException e) {
e.printStackTrace();
}
}) .start();
}
private class TextListener implements PropertyChangeListener {
@Override
public void propertyChange(PropertyChangeEvent evt) {
String newValue = (String) evt.getNewValue();
myView.updateList(newValue);
}
}
}
class MyBusiness2 {
public static final String TEXT = "text";
private SwingPropertyChangeSupport pcSupport = new SwingPropertyChangeSupport(this);
private Random random = new Random();
private String text;
public void longRunningCode() throws InterruptedException {
setText("Starting");
// mimic long-running code
int sleepTime = 500 + random.nextInt(2 * 3000);
TimeUnit.MILLISECONDS.sleep(sleepTime);
setText("This is message for initial process");
// ...
// Doing another long process and then print log
// ...
sleepTime = 500 + random.nextInt(2 * 3000);
TimeUnit.MILLISECONDS.sleep(sleepTime);
setText("This is not complete. Review");
// ...
// Doing another long process and then print log
// ...
sleepTime = 500 + random.nextInt(2 * 3000);
TimeUnit.MILLISECONDS.sleep(sleepTime);
setText("Ok this works. Have fun");
}
public void setText(String text) {
String oldValue = this.text;
String newValue = text;
this.text = text;
pcSupport.firePropertyChange(TEXT, oldValue, newValue);
}
public String getText() {
return text;
}
public void addPropertyChangeListener(PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(listener);
}
public void removePropertyChangeListener(PropertyChangeListener listener) {
pcSupport.removePropertyChangeListener(listener);
}
public void addPropertyChangeListener(String name, PropertyChangeListener listener) {
pcSupport.addPropertyChangeListener(name, listener);
}
public void removePropertyChangeListener(String name, PropertyChangeListener listener) {
pcSupport.removePropertyChangeListener(name, listener);
}
}
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