ViewAnimator.java :  » Game » loon-simple » org » loon » framework » android » game » Android Open Source

package org.loon.framework.android.game;

import android.os.Handler;
import android.os.Message;
import android.os.SystemClock;
import android.view.View;

/**
 * 
 * Copyright 2008 - 2010
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 * 
 * @project loonframework
 * @author chenpeng
 * @email ceponline@yahoo.com.cn
 * @version 0.1.0
 */
public class ViewAnimator extends Handler {

  public static final int NEXT = 0;

  private boolean running;
  private View view;
  private long nextTime;
  private int diff;

  public ViewAnimator(View view) {
    this(view, -1);
  }

  public ViewAnimator(View view, int fps) {
    running = false;
    this.view = view;
    this.diff = 1000 / fps;
  }

  public void start() {
    if (!running) {
      running = true;
      Message msg = obtainMessage(NEXT);
      sendMessageAtTime(msg, SystemClock.uptimeMillis());
    }
  }

  public void stop() {
    running = false;
  }

  public void handleMessage(Message msg) {
    if (running && msg.what == NEXT) {
      view.invalidate();
      msg = obtainMessage(NEXT);
      long current = SystemClock.uptimeMillis();
      if (nextTime < current) {
        nextTime = current + diff;
      }
      sendMessageAtTime(msg, nextTime);
      nextTime += diff;
    }
  }
}