イベント通知サンプル＜超てけとー版＞。

EventListener.java

package jp.noxi.carbuncle.sample;

/**
 * イベント通知用インターフェース
 */
public interface EventListener {
    /**
     * イベント通知
     *
     * @param key イベントキー
     * @param obj イベントオブジェクト
     */
    public void onEventNotify(String key, Object obj);

}

EventWatcher.java

package jp.noxi.carbuncle.sample;

import java.lang.ref.WeakReference;
import java.util.HashSet;
import java.util.Set;

public class EventWatcher implements EventListener {

    private static EventWatcher sInstance;

    public static synchronized EventWatcher getInstance() {
        if (sInstance == null) {
            sInstance = new EventWatcher();
        }
        return sInstance;
    }

    /**
     * 解放漏れのリークが嫌なのでとりあえずWeakReferenceにしておく
     */
    private final Set<WeakReference<EventListener>> mTargets = new HashSet<WeakReference<EventListener>>();

    private EventWatcher() {
    }

    public void addNotifyTarget(EventListener listener) {
        if (listener == null) return;
        synchronized (mTargets) {
            mTargets.add(new WeakReference<EventListener>(listener));
        }
    }

    public void removeNotifyTarget(EventListener listener) {
        if (listener == null) return;
        synchronized (mTargets) {
            for (WeakReference<EventListener> reference : mTargets) {
                EventListener target = reference.get();
                if (target == listener) {
                    mTargets.remove(reference);
                    return;
                }
            }
        }
    }

    @Override
    public void onEventNotify(String key, Object obj) {
        synchronized (mTargets) {
            for (WeakReference<EventListener> reference : mTargets) {
                EventListener target = reference.get();
                if (target != null) {
                    target.onEventNotify(key, obj);
                }
            }
        }
    }
}

SampleActivity.java

package jp.noxi.carbuncle.sample;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class SampleActivity extends Activity implements EventListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EventWatcher watcher = EventWatcher.getInstance();
        watcher.addNotifyTarget(this);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        EventWatcher watcher = EventWatcher.getInstance();
        watcher.removeNotifyTarget(this);
    }

    @Override
    public void onEventNotify(String key, Object obj) {
        Log.d(key, obj.toString())
    }
}