android中Invalidate和postInvalidate的更新view区别

// 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();
}
}
}
}

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：
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);
}
}