android应用崩溃并导致注册错误

Question

I have in the process of developing a registration app using Android Studios, however once users try to register the application just says error in registration and the LogCat does not give any error, as well as when debugging the app, I still get no errors.

Please can you help and tell me where I am going wrong as the code is correct as it was working couple of months ago, however since I have returned from holiday it just says "Error occurred in registration".

User data gets entered into the database however it does not allow the user to move onto the next activity as it says "Error occurred in registration". Please can you help or advise?

LogCat

  01-07 15:14:42.933 2161-4203/com.Oakland E/JSON Parser: Error parsing data org.json.JSONException: Value 2016-01-07 of type java.lang.String cannot be converted to JSONObject
01-07 15:14:42.938 2161-2161/com.Oakland E/AndroidRuntime: FATAL EXCEPTION: main
                                                                       Process: com.Oakland, PID: 2161
                                                                       java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.getString(java.lang.String)' on a null object reference
                                                                           at com.Oakland.Register$ProcessRegister.onPostExecute(Register.java:211)
                                                                           at com.Oakland.Register$ProcessRegister.onPostExecute(Register.java:171)

Line 211- if (json.getString(KEY_SUCCESS) != null) {

Register.Java

@Override
    protected JSONObject doInBackground(String... args) {


        UserFunctions userFunction = new UserFunctions();
        JSONObject json = userFunction.registerUser(fname, lname, email, uname, password);

        return json;


    }
    @Override
    protected void onPostExecute(JSONObject json) {
        try {
            if (json != null && json.getString(KEY_SUCCESS) != null) {
                if (json != null && json.getString(KEY_SUCCESS) != null)
                registerErrorMsg.setText("");
                String res = json.getString(KEY_SUCCESS);

                String red = json.getString(KEY_ERROR);

                if(Integer.parseInt(res) == 1){
                    pDialog.setTitle("Getting Data");
                    pDialog.setMessage("Loading Info");

                    registerErrorMsg.setText("Successfully Registered");


                    DatabaseHandler db = new DatabaseHandler(getApplicationContext());
                    JSONObject json_user = json.getJSONObject("user");

                    /**
                     * Removes all the previous data in the SQlite database
                     **/

                    UserFunctions logout = new UserFunctions();
                    logout.logoutUser(getApplicationContext());
                    db.addUser(json_user.getString(KEY_FIRSTNAME),json_user.getString(KEY_LASTNAME),json_user.getString(KEY_EMAIL),json_user.getString(KEY_USERNAME),json_user.getString(KEY_UID),json_user.getString(KEY_CREATED_AT));
                    /**
                     * Stores registered data in SQlite Database
                     * Launch Registered screen
                     **/

                    Intent registered = new Intent(getApplicationContext(), Registered.class);

                    /**
                     * Close all views before launching Registered screen
                     **/
                    registered.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    pDialog.dismiss();
                    startActivity(registered);


                    finish();
                }

                else if (Integer.parseInt(red) ==2){
                    pDialog.dismiss();
                    registerErrorMsg.setText("User already exists");
                }
                else if (Integer.parseInt(red) ==3){
                    pDialog.dismiss();
                    registerErrorMsg.setText("Invalid Email id");
                }

            }


            else{
                pDialog.dismiss();

                registerErrorMsg.setText("Error occurred in registration");
            }

        } catch (JSONException e) {
            e.printStackTrace();


        }
    }}
public void NetAsync(View view){
    new NetCheck().execute();
}}

UserFunction.Java

//URL of the PHP API

    private static String registerURL = "http://10.0.2.2/Register_api/";

private static String register_tag = "register";



    /**
         * Function to  Register
         **/
        public JSONObject registerUser(String fname, String lname, String email, String uname, String password){
            // Building Parameters
            List params = new ArrayList();
            params.add(new BasicNameValuePair("tag", register_tag));
            params.add(new BasicNameValuePair("fname", fname));
            params.add(new BasicNameValuePair("lname", lname));
            params.add(new BasicNameValuePair("email", email));
            params.add(new BasicNameValuePair("uname", uname));
            params.add(new BasicNameValuePair("password", password));
            JSONObject json = jsonParser.getJSONFromUrl(registerURL,params);
            return json;
        }

Jsonpasar.java

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;

    }
}

DatabaseHandler.java

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 = "cloud_contacts";

    // 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_FIRSTNAME = "fname";
    private static final String KEY_LASTNAME = "lname";
    private static final String KEY_EMAIL = "email";
    private static final String KEY_USERNAME = "uname";
    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_FIRSTNAME + " TEXT,"
                + KEY_LASTNAME + " TEXT,"
                + KEY_EMAIL + " TEXT UNIQUE,"
                + KEY_USERNAME + " TEXT,"
                + 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 fname, String lname, String email, String uname, String uid, String created_at) {
        SQLiteDatabase db = this.getWritableDatabase();

        ContentValues values = new ContentValues();
        values.put(KEY_FIRSTNAME, fname); // FirstName
        values.put(KEY_LASTNAME, lname); // LastName
        values.put(KEY_EMAIL, email); // Email
        values.put(KEY_USERNAME, uname); // UserName
        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("fname", cursor.getString(1));
            user.put("lname", cursor.getString(2));
            user.put("email", cursor.getString(3));
            user.put("uname", cursor.getString(4));
            user.put("uid", cursor.getString(5));
            user.put("created_at", cursor.getString(6));
        }
        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();
    }

Answer 1

I would suggest to use Jackson to create JSON strings. You just set object and convert to json string. Also converting to object is easy.

Error is connected with parsing error. Hmm. That's weird. You say user is added to database but if "Error occurred in registration" shows, code with addUser couldn't be executed because it's inside if. I don't get application flow :( Can you tell more in comment? Also "registerUser" doesn't register user but only create json as I see.

db.addUser(json_user.getString(KEY_FIRSTNAME),json_user.getString(KEY_LASTNAME),json_user.getString(KEY_EMAIL),json_user.getString(KEY_USERNAME),json_user.getString(KEY_UID),json_user.getString(KEY_CREATED_AT));