Java android项目导入NetworkOnMainThreadException

Question

在不同的环境上导入项目后，我在调用主类的onCreate方法内的函数时遇到了NetworkOnMainThreadException异常。

该函数充当初始化不同变量的收集器，因此我认为它实际上不应做坏事情...

这是onCreate：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    init_vars();        
}

这是函数：

public void init_vars() {

    this.chat = new Chat();

    // init mode
    Map<String, String> l_mode = new HashMap<String, String>();
    l_mode.put("0", "world");
    l_mode.put("1", "free");
    l_mode.put("2", "joint");
    l_mode.put("3", "tool");
    l_mode.put("4", "comp");
    l_mode.put("selected", "0");
    l_mode.put("default", "0");
    setB_mode(l_mode);

    // init power
    Map<String, String> l_on_off = new HashMap<String, String>();
    l_on_off.put("0", "off");
    l_on_off.put("1", "on");
    l_on_off.put("selected", "0");
    l_on_off.put("default", "0");
    setB_on_off(l_on_off);

    // init power mode
    Map<String, String> l_system_mode = new HashMap<String, String>();
    l_system_mode.put("0", "auto");
    l_system_mode.put("1", "manual");
    l_system_mode.put("selected", "0");
    l_system_mode.put("default", "0");
    setB_system_mode(l_system_mode);

    // init disp
    Map<String, String> l_disp = new HashMap<String, String>();
    l_disp.put("0", "joint ");
    l_disp.put("1", "world ");
    l_disp.put("2", "status ");
    l_disp.put("3", "I/O ");
    l_disp.put("4", "last_error ");
    l_disp.put("selected", "0");
    l_disp.put("default", "0");
    setB_disp(l_disp);
    // set initial text
    TextView editText = (TextView) findViewById(R.id.editText1);
    editText.setText("Some text");

    // init errors array
    // NOT USED
    Map<String, String> l_error_types = new HashMap<String, String>();
    // set predefined error messages
    l_error_types.put("0", "error_message = go home");
    l_error_types.put("1", "error_message = go away");
    setB_error_types(l_error_types);
    // init errors reported
    // define a new error here like this:
    // l_errors.put("0", "1"); //1 represents error type
    Map<String, String> l_errors = new HashMap<String, String>();
    l_errors.put("0", "Error test 0");
    l_errors.put("1", "Error test 1");
    l_errors.put("2", "Error test 1");
    l_errors.put("3", "Error test 4");
    l_errors.put("4", "Error test 5");
    setB_errors(l_errors);
}

和logcat：

    08-22 11:56:40.512: E/AndroidRuntime(1146): FATAL EXCEPTION: main
    08-22 11:56:40.512: E/AndroidRuntime(1146): Process: com.example.robot_industrial, PID: 1146
    08-22 11:56:40.512: E/AndroidRuntime(1146): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.robot_industrial/com.example.robot_industrial.MainActivity}: android.os.NetworkOnMainThreadException
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.ActivityThread.access$700(ActivityThread.java:135)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.os.Handler.dispatchMessage(Handler.java:102)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.os.Looper.loop(Looper.java:137)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.ActivityThread.main(ActivityThread.java:4998)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.lang.reflect.Method.invokeNative(Native Method)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.lang.reflect.Method.invoke(Method.java:515)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at dalvik.system.NativeStart.main(Native Method)
    08-22 11:56:40.512: E/AndroidRuntime(1146): Caused by: android.os.NetworkOnMainThreadException
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1145)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at libcore.io.IoBridge.connect(IoBridge.java:112)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.net.Socket.startupSocket(Socket.java:567)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.net.Socket.tryAllAddresses(Socket.java:128)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.net.Socket.<init>(Socket.java:178)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at java.net.Socket.<init>(Socket.java:150)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at com.example.robot_industrial.Chat.<init>(Chat.java:17)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at com.example.robot_industrial.MainActivity.init_vars(MainActivity.java:694)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at com.example.robot_industrial.MainActivity.onCreate(MainActivity.java:72)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.Activity.performCreate(Activity.java:5243)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
    08-22 11:56:40.512: E/AndroidRuntime(1146):     ... 11 more

关于我在做什么错的任何想法吗？

Answer 1

您正在创建Chat对象的实例，该实例正在打开包含某些内容的套接字连接。 如异常所示，请不要在主应用程序线程上进行网络I / O。 请在某种形式的后台线程上初始化并使用您的Chat对象。

Answer 2

在AsyncTask中执行与网络相关的操作

当应用程序尝试在其主线程上执行联网操作时，将引发此异常。

这发生在Android 3.0及更高版本中。 在Android 3.0及更高版本中，它们已限制使用网络操作（访问Internet的功能）在主线程/ UI线程中运行（活动中的create方法和resume方法所产生的结果）。

这是为了鼓励使用单独的线程进行网络操作。 有关如何正确执行网络活动的更多详细信息，请参见AsyncTask 。

您也可以在这里参考Android AsyncTask

public class ExcuteNetworkOperation extends AsyncTask<Void, Void, String>{

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            /**
             * show dialog
             */
            super.onPreExecute();
        }

        @Override
        protected String doInBackground(Void... params) {
            // TODO Auto-generated method stub
            /**
             * Do network related stuff
             * return string response.
             */
            return null;
        }

        @Override
        protected void onPostExecute(String result) {
            // TODO Auto-generated method stub
            /**
             * update ui thread and remove dialog
             */
            super.onPostExecute(result);
        }
    }