2006-9-12
前天把
SWT
的多线程终于搞定，本来想写点心得，苦于没时间，今天刚好有时间，就写了如下拙作，
^_^
。
1
．先看看
JAVA JDK
里的多线程：
JDK
里的多项程里有两种方式：
extends Thread
和
implements Runnable
，当调用线程类的
start()
方法，本质是调用
run()
，线程执行。
e.g.
package com.javathread;
public class TestThread {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Thread t1 = new NewThread();// Create two new Thread
t1.setName("t1");
Thread t2 = new NewThread();
t2.setName("t2");
// new NewThread().start();//call the newThread
try {
for (int i = 5; i > 0; i--) {
System.out.println("main Thread " + i);
t1.start();
t2.start();
Thread.sleep(1000);
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("Exiting main Thread!");
}
}
/*
* create a Thread class
*/
class NewThread extends Thread {
public void run() {
System.out.println("new Thread " + this.getName());
}
}
输出结果：
main Thread 5
new Thread t1
new Thread t2
main Thread 4
main Thread 3
main Thread 2
main Thread 1
Exiting main Thread!
Implements Runnable()
package com.javathread;
public class TestThread {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
new NewThread("one");// Create two new Thread
new NewThread("two");
// new NewThread().start();//call the newThread
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println("Exiting main Thread!");
}
}
/*
* create a Thread class
*/
class NewThread implements Runnable {
String name;
Thread t;
NewThread(String name) {
this.name = name;
t = new Thread(this, name);
System.out.println("New Thread " + t);
t.start();
}
public void run() {
try {
for (int i = 5; i > 0; i--) {
System.out.println(name + ":" + i);
Thread.sleep(1000);
}
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
但是
SWT
的线程和
JDK
的有点区别
当启动一个
SWT
的线程时候，要回过来操作
shell
上的控件
必须要调用
Display
的
SyncExec
同步或者
asyncExec
异步，来重新取得
shell
举个例子
如下：
我们新建
SWT Application
，加一个
button
启动另一个线程，
代码如下所示：
package com;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
public class Test {
private static Display display = Display.getDefault();
private static Shell shell = new Shell();
public static void main(String[] args) {
Test test = new Test();
test.open();
// final Shell shell = new Shell();
}
public void open() {
shell.setSize(500, 375);
shell.setText("SWT Application");
shell.open();
final Button startnewthreadButton = new Button(shell, SWT.NONE);
startnewthreadButton.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent e) {
new TestThread().start();
}
});
startnewthreadButton.setText("startnewthread");
startnewthreadButton.setBounds(135, 116, 90, 25);
shell.layout();
while (!shell.isDisposed()) {
if (!display.readAndDispatch())
display.sleep();
}
}
/*
* create a new Thread class
*/
private class TestThread extends Thread {
public void run() {
/*
* call Swt controls must use Dispaly.syncExec or Display.asyncExec
*/
if (!Test.display.isDisposed()) {
Test.display.syncExec(new Runnable() {//
这段代码很重要
public void run() {
MessageDialog.openInformation(null, "fd", "fd");
}
});
}
}
}
}
如果不加加红这段代码
直接
MessageDialog.openInformation(null,”fd”,”fd”);
程序会抛出异常：
ja
va.lang.ExceptionInInitializerError
好了
有问题
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