%uA0java.util.Observable.deleteObserver(Observer o)%uA0方法从这个集合对象observers中删除指定的observer o。
声明
以下是java.util.Observable.deleteObserver()方法的声明
public void deleteObserver(Observer o)
参数
-
o%uA0-- observer可以从一组observers中删除。
返回值
NA异常
NA例子
下面的示例演示java.util.Observable.deleteObserver(Observer) 方法的用法。
package com.yiibai
import java.util.Observable
import java.util.Observer
class ObservedObject extends Observable {
private String watchedValue
public ObservedObject(String value) {
watchedValue = value
}
public void setValue(String value) {
// if value has changed notify observers
if(!watchedValue.equals(value)) {
System.out.println("Value changed to new value: "+value)
watchedValue = value
// mark as value changed
setChanged()
// trigger notification
notifyObservers(value)
}
}
}
public class ObservableDemo implements Observer {
public static void main(String[] args) {
// create watched and watcher objects
ObservedObject watched = new ObservedObject("Original Value")
// watcher object listens to object change
ObservableDemo watcher = new ObservableDemo()
// trigger value change
watched.setValue("Value before addObserver")
// add observer to the watched object
watched.addObserver(watcher)
// trigger value change
watched.setValue("Value after addObserver")
// delete observer
watched.deleteObserver(watcher)
// trigger value change
watched.setValue("Value after deleteObserver")
}
public void update(Observable obj, Object arg) {
System.out.println("Update called with Arguments: "+arg)
}
}
让我们来编译和运行上面的程序，这将产生以下结果：
Value changed to new value: Value before addObserver Value changed to new value: Value after addObserver Update called with Arguments: Value after addObserver Value changed to new value: Value after deleteObserver