package com.shishuo.myplugin1.test;
public class Main {
private static int count=0
;
private static Thread thread;
public static void update(){
new Thread{
//建立一个新的线程，实现每隔三秒count累加一次，到10后变为0
public void run(){
while(count<=10
){
//在线程中加入监听机制，旨在实现count每一次发生变化都会触发监听事件
//EventProducer是事件源
EventProducer producer=
new EventProducer();
//为事件源添加监听器，参数为监听事件
producer.addListener(
new EventConsumer);
//触发
producer.setValue(""+
count);
try{
Thread.sleep(3000
);
}catch（Exception e）{
e.printStackTrace();
}
count++
;
if(count==10
){
count=0
;
}
}
}
}.start();
}
}
package com.shishuo.myplugin1.test;
public class EventProducer{
//监听器要在事件源上注册
ListenerRegister register=
new ListenerRegister();
private String value=""
;
public String getValue(){
return value;
}
public void setValue(String newValue){
//当有事件触发时，事件源要把事件传递给监听器，监听器会根据事件对象采取相应的方法响应这个事件
value=
newValue;
ValueChangeEvent event=
new ValueChangeEvent(
this,value);
fireAEvent(event);
}
public void addListener(ValueChangeListener a){
register.addListener(a);
}
public void removeListener(ValueChangeListener){
register.removeListener(a);
}
public void fireAEvent(ValueChangeEvent event){
register.fireAEvent;
}
}
package com.shishuo.myplugin1.test;
import java.util.Vector;
public class ListenerRegister{
//存放监听器的Vector
private Vector<ValueChangeListener> listeners=
new Vector<ValueChangeListener>
();
public synchronized void addListener(ValueChangeListener a){
listeners.addElement(a);
}
public synchronized void removeListener(ValueChangeListener a){
listeners.removeElement(a);
}
public void fireAEvent(ValueChangeEvent evt){
Vector<ValueChangeEvent> currentListeners=
null;
synchronized(
this){
currentListener=(Vector<ValueChangeEvent>
)listeners.clone();
}
for(
int i;i<currentListener.size();i++
){
//事件发生后，监听器接收来自事件源的事件，根据不同的事件调用相应的方法
//遍历监听器数组中的监听器，根据事件调用相应的响应方法
ValueChangeListener listener=
(ValueChangeListener)currentListeners.elementAt(i);
listener.performed(evt);
}
}
}
package com.shishuo.myplugin1.test;
import java.util.EventObject;
//事件
public class ValueChangeEvent
extends EventObject
{
private static final long serialVersionUID=767352958358520268L
;
private String value;
public ValueChangeEvent(Object source){
this(source,"0"
);
}
public ValueChangeEvent(Object source,String newValue){
super(source);
value=
newValue;
}
public String getValue(){
return value;
}
}
package com.shishuo.myplugin1.test;
import java.util.EventListener;
//监听器接口
public interface ValueChangeListener
extends EventListener{
public abstract void performed(ValueChangeEvent e);
}
package com.shishuo.myplugin1.test;
import org.eclipse.swt.widgets.*
;
import com.shishuo.myplugin1.test.Views.view1;
public class EventConsumer
implements ValueChangeListener{
//以下方法是事件发生后采取的动作
@Override
public void performed(
final ValueChangeEvent e){
//在非UI线程中访问UI，必须要有以下语句否则会报以下异常
Display.getDefault().syncExec(
new Runnable(){
public void run(){
//这里写对SWT控件的设置
Text text=
View1.text1;
text.setText(""+
e.getValue());
}
});
}
}
不添加syncExec语句会报以下异常：
Exception in thread "Thread-0"
org.eclipse.swt.SWTException: Invalid thread access
at org.eclipse.swt.SWT.error(SWT.java:4441
)
at org.eclipse.swt.SWT.error(SWT.java:4356
)
at org.eclipse.swt.SWT.error(SWT.java:4327
)
at org.eclipse.swt.widgets.Widget.error(Widget.java:476
)
at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:367
)
at org.eclipse.swt.widgets.Text.getText(Text.java:1350
)
at test.Snippet108$1$1.run(Snippet108.java:24)
最后的结果就是在Text中每隔三秒更新一次显示内容为0~9
转载于:https://www.cnblogs.com/honeyshuo/p/4995152.html
