Question

嘿，伙计们，我对编码有点新意，但我正在尽力拍摄。我一直在关注此登录和注册教程here。我下载了他的源代码并添加了我的数据库信息，它可以在eclipse中使用他的项目。但是当我在我的项目中运行它时，当我点击“登录”或“注册”时它会退出。我使用断点检查了调试器，发现错误似乎在这一行：

            HttpResponse httpResponse = httpClient.execute(httpPost);

老实说，我不确定问题是什么，可以真正使用一些帮助。请记住，因为我是初学者，我可能还不了解一些高级功能/术语。下面是我的主程序包（brg.application.alarmmonitor）下的Login.java Register.java代码和作为库（brg.application.alarmmonitor.library）的DatabaseHandler.java JSONParser.java UserFunctions.java以及来自Eclipse中的LogCat。

Login.java

package brg.application.alarmmonitor;

import org.json.JSONException;
import org.json.JSONObject;

import brg.application.alarmmonitor.Dashboard;
import brg.application.alarmmonitor.Register;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import brg.application.alarmmonitor.library.DatabaseHandler;
import brg.application.alarmmonitor.library.UserFunctions;

public class Login extends Activity {
Button btnLogin;
Button btnLinkToRegister;
EditText inputEmail;
EditText inputPassword;
TextView loginErrorMsg;

// JSON Response node names
private static String KEY_SUCCESS = "success";
//private static String KEY_ERROR = "error";
//private static String KEY_ERROR_MSg = "error_msg";
private static String KEY_UID = "uid";
private static String KEY_NAME = "name";
private static String KEY_EMAIL = "email";
private static String KEY_CREATED_AT = "created_at";

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

    // Importing all assets like buttons, text fields
    inputEmail = (EditText) findViewById(R.id.loginEmail);
    inputPassword = (EditText) findViewById(R.id.loginPassword);
    btnLogin = (Button) findViewById(R.id.btnLogin);
    btnLinkToRegister = (Button) findViewById(R.id.link_to_register);
    loginErrorMsg = (TextView) findViewById(R.id.login_error);

    // Login button Click Event
    btnLogin.setOnClickListener(new View.OnClickListener() {

        public void onClick(View view) {
            String email = inputEmail.getText().toString();
            String password = inputPassword.getText().toString();
            UserFunctions userFunction = new UserFunctions();
            Log.d("Button", "Login");
            JSONObject json = userFunction.loginUser(email, password);

            // check for login response
            try {
                if (json.getString(KEY_SUCCESS) != null) {
                    loginErrorMsg.setText("");
                    String res = json.getString(KEY_SUCCESS); 
                    if(Integer.parseInt(res) == 1){
                        // user successfully logged in
                        // 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(), Dashboard.class);

                        // Close all views before launching Dashboard
                        dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                        startActivity(dashboard);

                        // Close Login Screen
                        finish();
                    }else{
                        // Error in login
                        loginErrorMsg.setText("Incorrect username/password");
                    }
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }
    });

    // Link to Register Screen
    btnLinkToRegister.setOnClickListener(new View.OnClickListener() {

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

Register.java

package brg.application.alarmmonitor;

import org.json.JSONException;


import org.json.JSONObject;

import brg.application.alarmmonitor.Dashboard;
import brg.application.alarmmonitor.Login;
import brg.application.alarmmonitor.R;

import brg.application.alarmmonitor.library.DatabaseHandler;
import brg.application.alarmmonitor.library.UserFunctions;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class Register extends Activity {
Button btnRegister;
Button btnLinkToLogin;
EditText inputFullName;
EditText inputEmail;
EditText inputPassword;
TextView registerErrorMsg;

// JSON Response node names
private static String KEY_SUCCESS = "success";
//private static String KEY_ERROR = "error";
//private static String KEY_ERROR_MSG = "error_msg";
private static String KEY_UID = "uid";
private static String KEY_NAME = "name";
private static String KEY_EMAIL = "email";
private static String KEY_CREATED_AT = "created_at";

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

    // Importing all assets like buttons, text fields
    inputFullName = (EditText) findViewById(R.id.reg_name);
    inputEmail = (EditText) findViewById(R.id.reg_email);
    inputPassword = (EditText) findViewById(R.id.reg_password);
    btnRegister = (Button) findViewById(R.id.btnRegister);
    btnLinkToLogin = (Button) findViewById(R.id.link_to_login);
    registerErrorMsg = (TextView) findViewById(R.id.reg_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();
            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(), Dashboard.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(),
                    Login.class);
            startActivity(i);
            // Close Registration View
            finish();
        }
    });
}
}

DatabaseHandler.java

package brg.application.alarmmonitor.library;

import java.util.HashMap;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DatabaseHandler extends SQLiteOpenHelper {

// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;

// Database Name
private static final String DATABASE_NAME = "a8855590_alarm";

// Login table name
private static final String TABLE_LOGIN = "login";

// Login Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_EMAIL = "email";
private static final String KEY_UID = "uid";
private static final String KEY_CREATED_AT = "created_at";

public DatabaseHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
    String CREATE_LOGIN_TABLE = "CREATE TABLE " + TABLE_LOGIN + "("
            + KEY_ID + " INTEGER PRIMARY KEY,"
            + KEY_NAME + " TEXT,"
            + KEY_EMAIL + " TEXT UNIQUE,"
            + KEY_UID + " TEXT,"
            + KEY_CREATED_AT + " TEXT" + ")";
    db.execSQL(CREATE_LOGIN_TABLE);
}

// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_LOGIN);

    // Create tables again
    onCreate(db);
}

/**
 * Storing user details in database
 * */
public void addUser(String name, String email, String uid, String created_at) {
    SQLiteDatabase db = this.getWritableDatabase();

    ContentValues values = new ContentValues();
    values.put(KEY_NAME, name); // Name
    values.put(KEY_EMAIL, email); // Email
    values.put(KEY_UID, uid); // Email
    values.put(KEY_CREATED_AT, created_at); // Created At

    // Inserting Row
    db.insert(TABLE_LOGIN, null, values);
    db.close(); // Closing database connection
}

/**
 * Getting user data from database
 * */
public HashMap<String, String> getUserDetails(){
    HashMap<String,String> user = new HashMap<String,String>();
    String selectQuery = "SELECT  * FROM " + TABLE_LOGIN;

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    // Move to first row
    cursor.moveToFirst();
    if(cursor.getCount() > 0){
        user.put("name", cursor.getString(1));
        user.put("email", cursor.getString(2));
        user.put("uid", cursor.getString(3));
        user.put("created_at", cursor.getString(4));
    }
    cursor.close();
    db.close();
    // return user
    return user;
}

/**
 * Getting user login status
 * return true if rows are there in table
 * */
public int getRowCount() {
    String countQuery = "SELECT  * FROM " + TABLE_LOGIN;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);
    int rowCount = cursor.getCount();
    db.close();
    cursor.close();

    // return row count
    return rowCount;
}

/**
 * Re crate database
 * Delete all tables and create them again
 * */
public void resetTables(){
    SQLiteDatabase db = this.getWritableDatabase();
    // Delete All Rows
    db.delete(TABLE_LOGIN, null, null);
    db.close();
}

}

JSONParser.java

package brg.application.alarmmonitor.library;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

public class JSONParser {

static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}

public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {

    // Making HTTP request
    try {
        // defaultHttpClient
        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(url);
        httpPost.setEntity(new UrlEncodedFormEntity(params));

        HttpResponse httpResponse = httpClient.execute(httpPost);
        HttpEntity httpEntity = httpResponse.getEntity();
        is = httpEntity.getContent();

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (ClientProtocolException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

    try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                is, "iso-8859-1"), 8);
        StringBuilder sb = new StringBuilder();
        String line = null;
        while ((line = reader.readLine()) != null) {
            sb.append(line + "\n");
        }
        is.close();
        json = sb.toString();
        Log.e("JSON", json);
    } catch (Exception e) {
        Log.e("Buffer Error", "Error converting result " + e.toString());
    }

    // try parse the string to a JSON object
    try {
        jObj = new JSONObject(json);            
    } catch (JSONException e) {
        Log.e("JSON Parser", "Error parsing data " + e.toString());
    }

    // return JSON String
    return jObj;

}
}

UserFunctions.java

package brg.application.alarmmonitor.library;

import java.util.ArrayList;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;

import android.content.Context;

public class UserFunctions {

private JSONParser jsonParser;

private static String loginURL = "http://alarmmonitor.comyr.com/android_login_api/";
private static String registerURL = "http://alarmmonitor.comyr.com/android_login_api/";

private static String login_tag = "login";
private static String register_tag = "register";

// constructor
public UserFunctions(){
    jsonParser = new JSONParser();
}

/**
 * function make Login Request
 * @param email
 * @param password
 * */
public JSONObject loginUser(String email, String password){
    // Building Parameters
    List<NameValuePair> params = new ArrayList<NameValuePair>();
    params.add(new BasicNameValuePair("tag", login_tag));
    params.add(new BasicNameValuePair("email", email));
    params.add(new BasicNameValuePair("password", password));
    JSONObject json = jsonParser.getJSONFromUrl(loginURL, params);
    // return json
    // Log.e("JSON", json.toString());
    return json;
}

/**
 * function make Register Request
 * @param name
 * @param email
 * @param password
 * */
public JSONObject registerUser(String name, String email, String password){
    // Building Parameters
    List<NameValuePair> params = new ArrayList<NameValuePair>();
    params.add(new BasicNameValuePair("tag", register_tag));
    params.add(new BasicNameValuePair("name", name));
    params.add(new BasicNameValuePair("email", email));
    params.add(new BasicNameValuePair("password", password));

    // getting JSON Object
    JSONObject json = jsonParser.getJSONFromUrl(registerURL, params);
    // return json
    return json;
}

/**
 * Function get Login status
 * */
public boolean isUserLoggedIn(Context context){
    DatabaseHandler db = new DatabaseHandler(context);
    int count = db.getRowCount();
    if(count > 0){
        // user logged in
        return true;
    }
    return false;
}

/**
 * Function to logout user
 * Reset Database
 * */
public boolean logoutUser(Context context){
    DatabaseHandler db = new DatabaseHandler(context);
    db.resetTables();
    return true;
}

}

LogCat错误

11-04 18:02:28.570: D/Button(1725): Login
11-04 18:02:28.579: D/dalvikvm(1725): GC_CONCURRENT freed 101K, 7% free 3017K/3228K, paused 2ms+0ms, total 3ms
11-04 18:02:28.579: D/AndroidRuntime(1725): Shutting down VM
11-04 18:02:28.579: W/dalvikvm(1725): threadid=1: thread exiting with uncaught exception (group=0xb2d5a908)
11-04 18:02:28.579: E/AndroidRuntime(1725): FATAL EXCEPTION: main
11-04 18:02:28.579: E/AndroidRuntime(1725): android.os.NetworkOnMainThreadException
11-04 18:02:28.579: E/AndroidRuntime(1725):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at java.net.InetAddress.getAllByName(InetAddress.java:214)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at brg.application.alarmmonitor.library.JSONParser.getJSONFromUrl(JSONParser.java:42)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at brg.application.alarmmonitor.library.UserFunctions.loginUser(UserFunctions.java:38)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at brg.application.alarmmonitor.Login$1.onClick(Login.java:57)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at android.view.View.performClick(View.java:4202)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at android.view.View$PerformClick.run(View.java:17340)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at android.os.Handler.handleCallback(Handler.java:725)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at android.os.Handler.dispatchMessage(Handler.java:92)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at android.os.Looper.loop(Looper.java:137)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at android.app.ActivityThread.main(ActivityThread.java:5039)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at java.lang.reflect.Method.invokeNative(Native     Method)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at java.lang.reflect.Method.invoke(Method.java:511)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-04 18:02:28.579: E/AndroidRuntime(1725):     at dalvik.system.NativeStart.main(Native Method)

我知道这是很多代码，对不起，但我想确保你拥有所需的所有代码来帮助我解决问题。再次感谢！

乔纳森

编辑：好的，所以我试图改变Login.java使用AsyncTask，我查看了一些事情，看到我需要使用publishProgress但是现在当我点击登录时它只是说“登录...”很长一段时间直到最后退出。这是新的代码和错误：

Login.java

package brg.application.alarmmonitor;

import org.json.JSONException;
import org.json.JSONObject;

import brg.application.alarmmonitor.Dashboard;
import brg.application.alarmmonitor.Register;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.os.AsyncTask;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import brg.application.alarmmonitor.library.DatabaseHandler;
import brg.application.alarmmonitor.library.UserFunctions;

public class Login extends Activity {
Button btnLogin;
Button btnLinkToRegister;
EditText inputEmail;
EditText inputPassword;
TextView loginErrorMsg;

// JSON Response node names
private static String KEY_SUCCESS = "success";
//private static String KEY_ERROR = "error";
//private static String KEY_ERROR_MSg = "error_msg";
private static String KEY_UID = "uid";
private static String KEY_NAME = "name";
private static String KEY_EMAIL = "email";
private static String KEY_CREATED_AT = "created_at";

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

    // Importing all assets like buttons, text fields
    inputEmail = (EditText) findViewById(R.id.loginEmail);
    inputPassword = (EditText) findViewById(R.id.loginPassword);
    btnLogin = (Button) findViewById(R.id.btnLogin);
    btnLinkToRegister = (Button) findViewById(R.id.link_to_register);
    loginErrorMsg = (TextView) findViewById(R.id.login_error);

    // Login button Click Event
/**     btnLogin.setOnClickListener(new View.OnClickListener() {

        public void onClick(View view) {
            String email = inputEmail.getText().toString();
            String password = inputPassword.getText().toString();
            UserFunctions userFunction = new UserFunctions();
            Log.d("Button", "Login");
            JSONObject json = userFunction.loginUser(email, password);
**/


class LoginTask extends AsyncTask<String, String, String>  {

    ProgressDialog dialog = new ProgressDialog (Login.this);

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        dialog.setMessage("Logging in...");
        dialog.setIndeterminate(false);
        dialog.setCancelable(true);
        dialog.show();
    }

    protected void onProgressUpdate(String... message) {
        loginErrorMsg.setText(message[0]);
    }

    @Override
    protected String doInBackground(String... args) {
        // TODO Auto-generated method stub
        String email = inputEmail.getText().toString();
        String password = inputPassword.getText().toString();

        UserFunctions userFunction = new UserFunctions();
        JSONObject json = userFunction.loginUser(email, password);

        Log.d("Button", "Login");

        // check for login response
        try {
            if (json.getString(KEY_SUCCESS) != null) {
                //loginErrorMsg.setText("");
                publishProgress(json.getString("loginErrorMsg"));
                String res = json.getString(KEY_SUCCESS); 
                if(Integer.parseInt(res) == 1){
                    // user successfully logged in
                    // 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(), Dashboard.class);

                    // Close all views before launching Dashboard
                    dashboard.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(dashboard);

                    // Close Login Screen
                    finish();
                }else{
                    // Error in login
                    //loginErrorMsg.setText("Incorrect username/password");
                    publishProgress(json.getString("Incorrect email/password"));
                }
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;

    }

    @SuppressWarnings("unused")
    protected void onPostExecute() {
        dialog.dismiss();
    }

}

btnLogin.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        new LoginTask().execute();
    }
});         

    // Link to Register Screen
    btnLinkToRegister.setOnClickListener(new View.OnClickListener() {

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

LogCat错误：

11-05 17:40:30.610: E/Buffer Error(2046): Error converting result java.lang.NullPointerException: lock == null
11-05 17:40:30.610: E/JSON Parser(2046): Error parsing data org.json.JSONException: End of input at character 0 of 
11-05 17:40:30.610: D/Button(2046): Login
11-05 17:40:30.610: W/dalvikvm(2046): threadid=10: thread exiting with uncaught exception (group=0xb2d2c908)
11-05 17:40:30.610: E/AndroidRuntime(2046): FATAL EXCEPTION: AsyncTask #1
11-05 17:40:30.610: E/AndroidRuntime(2046): java.lang.RuntimeException: An error occured while executing doInBackground()
11-05 17:40:30.610: E/AndroidRuntime(2046):     at android.os.AsyncTask$3.done(AsyncTask.java:299)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at java.util.concurrent.FutureTask.run(FutureTask.java:239)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at java.lang.Thread.run(Thread.java:856)
11-05 17:40:30.610: E/AndroidRuntime(2046): Caused by: java.lang.NullPointerException
11-05 17:40:30.610: E/AndroidRuntime(2046):     at brg.application.alarmmonitor.Login$1LoginTask.doInBackground(Login.java:93)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at brg.application.alarmmonitor.Login$1LoginTask.doInBackground(Login.java:1)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at android.os.AsyncTask$2.call(AsyncTask.java:287)
11-05 17:40:30.610: E/AndroidRuntime(2046):     at java.util.concurrent.FutureTask.run(FutureTask.java:234)
11-05 17:40:30.610: E/AndroidRuntime(2046):     ... 4 more

Answer 1

android.os.NetworkOnMainThreadException

您正在主线程内调用网络进程，这不是（通常）允许的。你应该在一个单独的线程中调用getJSONFromUrl（...）。

您可以使用原始线程调用它：

Thread thread = new Thread(new Runnable()
{
    @Override
    public void run()
    {
        getJSONFromUrl(...);
    }
}
thread.start()

或使用AsyncTask http://developer.android.com/reference/android/os/AsyncTask.html

考虑到您需要将代码更改为“等待”，直到getJSONFromUrl（...）被强制执行，然后您可以继续执行程序流程。

编辑：我将添加一些关于如何继续流程的内容。在你的情况下，你可以做类似的事情：

btnLogin.setOnClickListener(new View.OnClickListener() {

    public void onClick(View view) {
        String email = inputEmail.getText().toString();
        String password = inputPassword.getText().toString();
        UserFunctions userFunction = new UserFunctions();
        Log.d("Button", "Login");

        // Here you should show a loading dialog or somthing, as this can take a couple o seconds

        Thread thread = new Thread(new Runnable()
        {
            @Override
            public void run()
            {
                JSONObject json = userFunction.loginUser(email, password);

                runOnUiThread(new Runnable()
                {
                    @Override
                    public void run()
                    {
                        ContinueFlow(); 
                    }
                }
            }

        }
    }
}

其中“ContinueFlow（）”将是一种方法，现在所有这些都在

之下

JSONObject json = userFunction.loginUser(email, password);

如您所见，您必须在UI线程中调用所有其他内容（这就是runOnUiThread的动机）

使用AsyncTask（我认为更干净）你不必乱用ui线程（你只需要在doInBackground中执行所有网络内容，并继续使用onComplete（...）中的流）

Answer 2

Android禁止从应用程序的主线程使用网络操作：doc

我的建议是使用ASyncTask来执行您的网络操作。

HttpResponse引发的运行时错误httpResponse = httpClient.execute（httpPost）;

2 个答案: