android.os.NetworkOnMainThreadException

不能在android的主线程中，执行一个网络操作

public void onCreate() {  
     StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()     
            .detectDiskReads()     
            .detectDiskWrites()     
            .detectNetwork()  
            .penaltyLog()     
            .build());     
     StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()     
            .detectLeakedSqlLiteObjects()     
            .detectLeakedClosableObjects()     
            .penaltyLog()     
            .penaltyDeath()     
            .build());  
}