Android界面刷新的方法分享

Android提供了Invalidate方法實現界面刷新，但是Invalidate不能直接在線程中調用，因為他是違背了單線程模型：Android UI操作並不是線程安全的，並且這些操作必須在UI線程中調用。

Android程序中可以使用的界面刷新方法有兩種，分別是利用Handler和利用postInvalidate()來實現在線程中刷新界面。

利用Handler刷新界面
實例化一個Handler對象，並重寫handleMessage方法調用invalidate()實現界面刷新；而在線程中通過sendMessage發送界面更新消息。

復制代碼 代碼如下:
// 在onCreate()中開啟線程

       new Thread(new GameThread()).start();、

       // 實例化一個handler

       Handler myHandler   = new Handler()

       {

              //接收到消息後處理

              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;

                            //發送消息

                            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則比較簡單，不需要handler，直接在線程中調用postInvalidate即可。

復制代碼 代碼如下:
 class GameThread implements Runnable

       {

              public void run()

              {

                     while (!Thread.currentThread().isInterrupted())

                     {

                            try

                            {

                                   Thread.sleep(100);

                            }

                            catch (InterruptedException e)

                            {

                                   Thread.currentThread().interrupt();

                            }

                            //使用postInvalidate可以直接在線程中更新界面

                            mGameView.postInvalidate();

                     }

              }

       }