Android开发实现简单的观察者与被观察者示例

package watch;
public interface Watcher {
  void update(String str);
}

package watch;
public interface Watched {
  void adWatcherh(Watcher watcher);
  void removeWatcherh(Watcher watcher);
  void notifyAll(String str);
}

package watch;
public class ConWatcher implements Watcher {
  @Override
  public void update(String str) {
    System.out.println(str);
  }
}

package watch;
import java.util.ArrayList;
import java.util.List;
public class ConWatched implements Watched {
  List<Watcher> list = new ArrayList<Watcher>();
  @Override
  public void adWatcherh(Watcher watcher) {
    list.add(watcher);
  }
  @Override
  public void removeWatcherh(Watcher watcher) {
    list.remove(watcher);
  }
  @Override
  public void notifyAll(String str) {
    for (Watcher watcher : list){
      watcher.update(str);
    }
  }
}

package watch;
public class WatchTest {
  public static void main(String[] args) throws Exception{
    ConWatched conWatched = new ConWatched();
    ConWatcher conWatcher1 = new ConWatcher();
    ConWatcher conWatcher2 = new ConWatcher();
    ConWatcher conWatcher3 = new ConWatcher();
    System.out.println("脚本之家测试结果：");
    conWatched.adWatcherh(conWatcher1);
    conWatched.adWatcherh(conWatcher2);
    conWatched.adWatcherh(conWatcher3);
    conWatched.notifyAll("I am coming");
  }
}