cocos2d-xのtouchイベント内でtoastを表示したいとき。 ref: http://qiita.com/g-1/items/0323cd56a53029f1fa65

file1.java

 //jni経由でコールされるメソッド
 Handler handler = new Handler(Looper.getMainLooper());
 handler.post(new Runnable(){
   public void run(){
     Toast toast = new Toast(…
     …
     toast.show();
   }
 });

Handler.java

public Handler(Callback callback, boolean async) {
        if (FIND_POTENTIAL_LEAKS) {
            final Class<? extends Handler> klass = getClass();
            if ((klass.isAnonymousClass() || klass.isMemberClass() || klass.isLocalClass()) &&
                    (klass.getModifiers() & Modifier.STATIC) == 0) {
                Log.w(TAG, "The following Handler class should be static or leaks might occur: " +
                    klass.getCanonicalName());
            }
        }

        mLooper = Looper.myLooper();
        if (mLooper == null) {
            throw new RuntimeException(
                "Can't create handler inside thread that has not called Looper.prepare()");
        }
        mQueue = mLooper.mQueue;
        mCallback = callback;
        mAsynchronous = async;
    }