// 在onCreate()中开启线程
new Thread(new GameThread()).start();、 // 实例化一个handler Handler myHandler = new Handler() { // 接收到消息后处理 public void handleMessage(Message msg) { switch (msg.what) { case Activity01.REFRESH: mGameView.invalidate(); // 刷新界面 break; } super.handleMessage(msg); } }; class GameThread implements Runnable { public void run() { while (!Thread.currentThread().isInterrupted()) { Message message = new Message(); message.what = Activity01.REFRESH; // 发送消息 Activity01.this.myHandler.sendMessage(message); try { Thread.sleep(100); } catch (InterruptedException e) { Thread.currentThread().interrupt(); } } }}
2,使用postInvalidate()刷新界面
使用postInvalidate则比较简单,不需要handler,直接在线程中调用postInvalidate即可。 class GameThread implements Runnable { public void run() { while (!Thread.currentThread().isInterrupted()) { try { Thread.sleep(100); } catch (InterruptedException e) { Thread.currentThread().interrupt(); } // 使用postInvalidate可以直接在线程中更新界面 mGameView.postInvalidate(); } } }
View 类中postInvalidate()方法源码如下,可见它也是用到了handler的: 除了onCreate()是运行在UI线程上的,其实其他大部分方法都是运行在UI线程上的,其实其实只要你没有开启新的线程,你的代码基本上都运行在UI线程上。
- public void postInvalidate() {
- postInvalidateDelayed(0);
- }
- public void postInvalidateDelayed(long delayMilliseconds) {
- // We try only with the AttachInfo because there's no point in invalidating
- // if we are not attached to our window
- if (mAttachInfo != null) {
- Message msg = Message.obtain();
- msg.what = AttachInfo.INVALIDATE_MSG;
- msg.obj = this;
- mAttachInfo.mHandler.sendMessageDelayed(msg, delayMilliseconds);
- }
- }