ANDROID开发 ANDROID线程开发

为了方便大家理解，我写一个简单的Demo.功能就是每2秒中将应用的Title更换一次。具体步骤如下:

第一步:新建一个Android工程命名为ThreadDemo。第二步:修改ThreadDemo.java,代码如下:

1packagecom.tutor.thread;2importandroid.app.Activity;3importandroid.os.Bundle;4importandroid.os.Handler;5importandroid.util.Log;6publicclassThreadDemoextendsActivity{789101112131415161718192021222324};@OverridepublicvoidonCreate(BundlesavedInstanceState){}publicvoidrun(){privateRunnablemRunnable=newRunnable(){privatestaticfinalStringTAG=\"ThreadDemo\";privateintcount=0;privateHandlermHandler=newHandler();//为了方便查看，我们用Log打印出来Log.e(TAG,Thread.currentThread().getName()+\"\"+count);count++;setTitle(\"\"+count);//每2秒执行一次mHandler.postDelayed(mRunnable,2000);25262728293031}}super.onCreate(savedInstanceState);setContentView(R.layout.main);//通过Handler启动线程mHandler.post(mRunnable);第三步:运行上述工程，查看运行效果:

当然上面不是重点，退出应用时，线程还在跑，打开Logcat视窗或者cmd终端查看，如下(刚吃了午餐回来，线程还在跑着):

当我们再次启动应用时，会重新启动一个新的线程，如下图所示:

所以我们在应用退出时，要将线程销毁，我们只要在Activity中的，onDestory()方法处理一下就OK了，如下代码所示:

12345@OverrideprotectedvoidonDestroy(){mHandler.removeCallbacks(mRunnable);super.onDestroy();}所以ThreadDemo.java的完整代码如下:

1packagecom.tutor.thread;2importandroid.app.Activity;3importandroid.os.Bundle;4importandroid.os.Handler;5importandroid.util.Log;6publicclassThreadDemoextendsActivity{7891011121314151617181920212223242526272829303132333435@OverrideprotectedvoidonDestroy(){}};@OverridepublicvoidonCreate(BundlesavedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);}publicvoidrun(){privateRunnablemRunnable=newRunnable(){privatestaticfinalStringTAG=\"ThreadDemo\";privateintcount=0;privateHandlermHandler=newHandler();//为了方便查看，我们用Log打印出来Log.e(TAG,Thread.currentThread().getName()+\"\"+count);count++;setTitle(\"\"+count);//每2秒执行一次mHandler.postDelayed(mRunnable,2000);//通过Handler启动线程mHandler.post(mRunnable);//将线程销毁掉mHandler.removeCallbacks(mRunnable);super.onDestroy();3637}}