Android界面刷新的方法分享

android提供了invalidate方法实现界面刷新，但是invalidate不能直接在线程中调用，因为他是违背了单线程模型：android ui操作并不是线程安全的，并且这些操作必须在ui线程中调用。

android程序中可以使用的界面刷新方法有两种，分别是利用handler和利用postinvalidate()来实现在线程中刷新界面。

利用handler刷新界面
实例化一个handler对象，并重写handlemessage方法调用invalidate()实现界面刷新；而在线程中通过sendmessage发送界面更新消息。

// 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();

                            }

                     }

              }

       }

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();

                     }

              }

       }