Java Android NetworkOnMainThreadException异常

我的活动中有此NetworkMainThread异常。我为这个问题寻找解决办法。在搜索时，我发现应该使用

AsyncTask

。在我尝试了

AsyncTask

之后，我仍然面临同样的问题

这是我的注册活动：

    private class MyAsyncTask extends AsyncTask<String, Void, JSONObject> {

        protected JSONObject doInBackground(String... params) {
            UserFunctions userFunction = new UserFunctions();
            if (params.length != 3)
                return null;
            JSONObject json = userFunction.registerUser(params[0], params[1], params[2]);
            return json;
        }

        protected void onPostExecute(JSONObject json) {
            // check for login response
            try {
                if (json != null && json.getString(KEY_SUCCESS) != null) {
                    registerErrorMsg.setText("");
                    String res = json.getString(KEY_SUCCESS); 
                    if(Integer.parseInt(res) == 1){
                        // user successfully registred
                        // Store user details in SQLite Database
                        DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                        JSONObject json_user = json.getJSONObject("user");

                        // Clear all previous data in database
                        UserFunctions userFunction = new UserFunctions();
                        userFunction.logoutUser(getApplicationContext());
                        db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));                        
                        // Launch Dashboard Screen
                        Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class);
                        // Close all views before launching Dashboard
                        dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                        startActivity(dashboard);
                        // Close Registration Screen
                        finish();
                    }else{
                        // Error in registration
                        registerErrorMsg.setText("Error occured in registration");
                    }
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    }




    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.register);

        // Importing all assets like buttons, text fields
        inputFullName = (EditText) findViewById(R.id.registerName);
        inputEmail = (EditText) findViewById(R.id.registerEmail);
        inputPassword = (EditText) findViewById(R.id.registerPassword);
        btnRegister = (Button) findViewById(R.id.btnRegister);
        btnLinkToLogin = (Button) findViewById(R.id.btnLinkToLoginScreen);
        registerErrorMsg = (TextView) findViewById(R.id.register_error);

        // Register Button Click event
        btnRegister.setOnClickListener(new View.OnClickListener() {         
            public void onClick(View view) {
                String name = inputFullName.getText().toString();
                String email = inputEmail.getText().toString();
                String password = inputPassword.getText().toString();
                new MyAsyncTask().execute(name, email, password);
                UserFunctions userFunction = new UserFunctions();
                JSONObject json = userFunction.registerUser(name, email, password);

                // check for login response
                try {
                    if (json.getString(KEY_SUCCESS) != null) {
                        registerErrorMsg.setText("");
                        String res = json.getString(KEY_SUCCESS); 
                        if(Integer.parseInt(res) == 1){
                            // user successfully registred
                            // Store user details in SQLite Database
                            DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                            JSONObject json_user = json.getJSONObject("user");

                            // Clear all previous data in database
                            userFunction.logoutUser(getApplicationContext());
                            db.addUser(json_user.getString(KEY_NAME), json_user.getString(KEY_EMAIL), json.getString(KEY_UID), json_user.getString(KEY_CREATED_AT));                        
                            // Launch Dashboard Screen
                            Intent dashboard = new Intent(getApplicationContext(), DashboardActivity.class);
                            // Close all views before launching Dashboard
                            dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                            startActivity(dashboard);
                            // Close Registration Screen
                            finish();
                        }else{
                            // Error in registration
                            registerErrorMsg.setText("Error occured in registration");
                        }
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });

        // Link to Login Screen
        btnLinkToLogin.setOnClickListener(new View.OnClickListener() {

            public void onClick(View view) {
                Intent i = new Intent(getApplicationContext(),
                        LoginActivity.class);
                startActivity(i);
                // Close Registration View
                finish();
            }
        });
    }
}

---

我做错了什么？

我打赌userFunction.logoutUser（getApplicationContext（））；向注销用户发出网络请求，从而导致在主线程上访问网络时出现错误（onPostResult在ui线程上运行，与doInBackground相反）

堆栈跟踪表示您在

getJSONFromUrl（）

中调用网络操作，并在

registerUser（）

中的ui线程上调用该操作。这里的代码似乎是罪魁祸首：

new MyAsyncTask().execute(name, email, password);
UserFunctions userFunction = new UserFunctions();
JSONObject json = userFunction.registerUser(name, email, password);

---

首先在后台异步任务中调用

registerUser（）

（好！），然后只有几行代码在主线程上再次调用（坏！）。删除后者。

根据您文章中的代码，您仍然直接从onClickListener处理程序内部调用userFunction.registerUser—就在调用MyAsyncTask.execute之后。logcat输出抱怨的是registerUser调用，而不是AsyncTask中的调用。您的意思是在将该逻辑移动到AsyncTask后删除onClickListener处理程序中的重复调用吗？

谢谢。网络问题已解决。但现在我收到“http.conn.HttpHostConnectException:拒绝连接”错误您的Android设备localhost上不太可能运行web服务器。可能重复的可能重复的

new MyAsyncTask().execute(name, email, password);
UserFunctions userFunction = new UserFunctions();
JSONObject json = userFunction.registerUser(name, email, password);