我想一次调用一个线程调用swing方法的一些信息。我的JAVA代码线程是否安全,因为代码仅由一个线程调用?
编辑: 我使用Java 7
我看到了以下主题:
Thread Safety of JTextArea.append
我developped一个小型Swing应用程序。
这是我的主类,它是一个线程安全类。 我调用SwingUtilities.invokeLater方法使它成为线程安全类。
MainClass:
package swingex;
import javax.swing.SwingUtilities;
public final class MainClass extends Thread {
public static void main(String[] _args) {
SwingUtilities.invokeLater(new MainClass());
}
@Override
public void run() {
new MainWindow();
}
}
这里是一个类从JFrame中继承。 我在内容窗格中放置了一个文本区域和一个按钮。
主窗口:
package swingex;
import java.awt.Dimension;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public final class MainWindow extends JFrame {
private JTextArea textArea = new JTextArea(32,32);
//AddText inherits from Thread class
private AddText thread = new AddText(textArea);
public MainWindow() {
JPanel panel_ = new JPanel();
panel_.setLayout(new BoxLayout(panel_, BoxLayout.PAGE_AXIS));
JScrollPane scr_ = new JScrollPane(textArea);
scr_.setPreferredSize(new Dimension(128, 128));
panel_.add(scr_);
//The button is used for adding rows in the text area
JButton button_ = new JButton("Add rows");
//Adding the event
button_.addActionListener(new AddTextEvent(this));
panel_.add(button_);
setContentPane(panel_);
setDefaultCloseOperation(EXIT_ON_CLOSE);
pack();
setVisible(true);
}
//Called by actionPerformed method
public void setText() {
if (thread.isAlive()) {
//prevent from setting the text area by multi threading
return;
}
//For avoiding issues, the text area is affected by less than two threads.
thread = new AddText(textArea);
thread.start();
}
}
点击按钮使睡在螺纹而有5秒,然后该线程添加200行到文本区。 AddText:
package swingex;
import java.awt.Rectangle;
import javax.swing.JTextArea;
import javax.swing.text.BadLocationException;
public final class AddText extends Thread {
private JTextArea textArea;
public AddText(JTextArea _textArea) {
textArea = _textArea;
}
@Override
public void run() {
try {
Thread.sleep(5000);
} catch (InterruptedException _0) {
_0.printStackTrace();
}
//Only one thread can access the code
for (int i = 0; i < 200; i++) {
textArea.append("Text"+i+"\n");
}
int endPosition_ = textArea.getDocument().getLength();
Rectangle bottom_;
try {
bottom_ = textArea.modelToView(endPosition_);
textArea.scrollRectToVisible(bottom_);
} catch (BadLocationException _0) {
_0.printStackTrace();
}
}
}
这个类实现的ActionListener,它用于点击按钮。
AddTextEvent:
package swingex;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public final class AddTextEvent implements ActionListener {
private MainWindow window;
public AddTextEvent(MainWindow _window) {
window = _window;
}
@Override
public void actionPerformed(ActionEvent _e) {
window.setText();
}
}
预先感谢您。
编辑2:我的“新主题”类是以下之一:(其他类保持不变的)
package swingex;
import java.awt.Rectangle;
import javax.swing.JTextArea;
import javax.swing.SwingWorker;
import javax.swing.text.BadLocationException;
/**Now the class AddText inherits from SwingWorker*/
public final class AddText extends SwingWorker<Void, Void> {
private JTextArea textArea;
public AddText(JTextArea _textArea) {
textArea = _textArea;
}
/**The equivalent in the class Thread*/
public void start() {
execute();
}
@Override
public Void doInBackground() {
try {
Thread.sleep(5000);
} catch (InterruptedException _0) {
_0.printStackTrace();
}
for (int i = 0; i < 200; i++) {
textArea.append("Text"+i+"\n");
}
int endPosition_ = textArea.getDocument().getLength();
Rectangle bottom_;
try {
bottom_ = textArea.modelToView(endPosition_);
textArea.scrollRectToVisible(bottom_);
} catch (BadLocationException _0) {
_0.printStackTrace();
}
return null;
}
/**The equivalent in the class Thread*/
public boolean isAlive() {
return !isDone() || !isCancelled();
}
}
编辑3:这是一个自定义类从“摇摆”继承组件:
我的自定义方法是“线程安全的”还是不是?
MyTextArea:
package swingex;
import javax.swing.JTextArea;
public class MyTextArea extends JTextArea {
private String aField = "";
public String getaField() {
return aField;
}
public void setaField(String _aField) {
aField = _aField;
}
}
现在,我使用SwingUtilities类的方法 “的invokeLater” 从SwingWorker的
为什么不使用Swing'Timer'? –
@Catalina岛:我想通过使用类Thread的“睡眠”方法来模拟长时间的治疗。 – cardman
你可以使用'SwingWorker'或'invokeLater()'。 –