java.util.Observable.notifyObservers(Object arg)%uA0方法通知其所有观察者，如果这个对象已经改变，然后调用clearChanged方法来指示此对象不再改变。
声明
以下是java.util.Observable.notifyObservers()方法的声明
public void notifyObservers(Object arg)
参数
-
arg%uA0-- 任意的对象
返回值
NA异常
NA例子
下面的示例演示java.util.Observable.notifyObservers(Object)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 with arguments notifyObservers(value) } } } public class ObservableDemo implements Observer { public String name public ObservableDemo(String name) { this.name = name } 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("Watcher") // add observer to the watched object watched.addObserver(watcher) // trigger value change watched.setValue("New Value") } public void update(Observable obj, Object arg) { System.out.println(name+" 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: New Value Watcher called with Arguments: New Value