Ndtyjky

Its not compiling and i have no idea why... New to sqlite and tried to follow some question's answer on stack overflow but not able to figure it out. Modal class is MainDataHelper

Code

     MainDataHelper myDatabaseHelper = new MainDataHelper(getActivity());

    myDatabaseHelper.openDataBase();



    String text = myDatabaseHelper.getMostMessagesSent(); //this is the method to query



    myDatabaseHelper.close();



    mMostMessagesSent.setText(text);

    mMostMessagesSent.setTextColor(Color.WHITE);

Helper

public class MainDataHelper extends Activity {

private int TotalMessagesSent;

private int TotalMessagesRecieved;

private int TotalMessages;

private String TotalTimeSpent;

private String MostMessagesSent;

private String MostMessagesRecieved;

private String MostTexted;

private String MostTimeSpent;

private int QuizTaken;

private int QuizTakers;

private int Reviewed;

private int Reviews;



public MainDataHelper() {

    TotalMessagesSent = 0;

    TotalMessagesRecieved = 0;

    TotalMessages = 0;

    TotalTimeSpent = "";

    MostMessagesSent = "";

    MostMessagesRecieved = "";

    MostTexted = "";

    MostTimeSpent = "";

    QuizTaken = 0;

    QuizTakers = 0;

    Reviewed = 0;

    Reviews = 0;

}

public MainDataHelper( int TotalMessagesSent, int TotalMessagesRecieved, int TotalMessages, String TotalTimeSpent,String MostMessagesSent, String MostMessagesRecieved, String MostTexted, String MostTimeSpent,int QuizTaken, int QuizTakers, int Reviewed, int Reviews) {

    TotalMessagesSent = TotalMessagesSent;

    TotalMessagesRecieved = TotalMessagesRecieved;

    TotalMessages = TotalMessages;

    TotalTimeSpent = TotalTimeSpent;

    MostMessagesSent = MostMessagesSent;

    MostMessagesRecieved = MostMessagesRecieved;

    MostTexted = MostTexted;

    MostTimeSpent = MostTimeSpent;

    QuizTaken = QuizTaken;

    QuizTakers = QuizTakers;

    Reviewed = Reviewed;

    Reviews = Reviews;

}



public int getTotalMessagesSent() {

    return TotalMessagesSent;

}

public int getTotalMessagesRecieved() {

    return TotalMessagesRecieved;

}

public int getTotalMessages() {

    return TotalMessages;

}

public String getTotalTimeSpent() {

    return TotalTimeSpent;

}

public String getMostMessagesSent() {

    return MostMessagesSent;

}

public String getMostMessagesRecieved() {

    return MostMessagesRecieved;

}

public String getMostTexted() {

    return MostTexted;

}

public String getMostTimeSpent() {

    return MostTimeSpent;

}

public int getQuizTaken() {

    return QuizTaken;

}

public int getQuizTakers() {

    return QuizTakers;

}

public int getReviewed() {

    return Reviewed;

}

public int getReviews() {

    return Reviews;

}





public void setTotalMessagesSent(int TotalMessagesSent) {

    TotalMessagesSent = TotalMessagesSent;

}

public void setTotalMessagesRecieved(int TotalMessagesRecieved) {

    TotalMessagesRecieved = TotalMessagesRecieved;

}

public void setTotalMessages(int TotalMessages) {

    TotalMessages = TotalMessages;

}

public void setTotalTimeSpent(String TotalTimeSpent) { TotalTimeSpent = TotalTimeSpent; }

public void setMostMessagesSent(String MostMessagesSent) {

    MostMessagesSent = MostMessagesSent;

}

public void setMostMessagesRecieved(String MostMessagesRecieved) {

    MostMessagesRecieved = MostMessagesRecieved;

}

public void setMostTexted(String MostTexted) {

    MostTexted = MostTexted;

}

public void setMostTimeSpent(String MostTimeSpent) { MostTimeSpent = MostTimeSpent; }

public void setQuizTaken(int QuizTaken) {

    QuizTaken = QuizTaken;

}

public void setQuizTakers(int QuizTakers) {

    QuizTakers = QuizTakers;

}

public void setReviewed(int Reviewed) { Reviewed = Reviewed; }



public void setReviews(int Reviews) {

    Reviews = Reviews;

}

}

......................................................................................................................................................................................................................

It's not compiling due to a few reasons.

1. First MainDataHelper does not have a constructor that accepts/takes an Activity. MainDataHelper has two constructors one takes no parameters, the other takes 12 parameters. You have to use one of the available constructors when instantiating a MainDataHelper object.

e.g. MainDataHelper myDatabaseHelper = new MainDataHelper(); would compile.

2. There is no openDatabase method in MainDataHelper, you would either have to add such a method or do away with the line myDatabaseHelper.openDataBase();





3. There is no close method in MainDataHelper, you would either have to add such a method or do away with the line myDatabaseHelper.close();

Considering that you want to use an SQLite database then you will use a sub-class of the SQLiteOpenHelper class that would be invoked from an Activity or a Fragment (or even many of these).

Before even considering writing a line of code you would need to understand you requirements for the database and have some sort of design (schema). Ignoring that and assuming (for demonstration) that you want a simple database with one table called questions and has one column called question then the following could be such a class (in this case MainDataBaseHelper.java) :-

public class MainDatabaseHelper extends SQLiteOpenHelper {



    public static final String DATABASENAME = "question.db"; //<<<<<<<<<< name of the database

    public static final int DATABASEVERSION = 1; //<<<<<<<<<< version number of the database

    public static final String TABLE_QUESTION = "question"; //<<<<<<<<<< name of the quiz table

    public static final String COLUMN_QUESTION_QUESTION = "question";



    public MainDatabaseHelper(Context context) {

        super(context, DATABASENAME, null, DATABASEVERSION);

    }



    //<<<<<<<<<< Called ONCE when the database is first created (first time an attempt is made to open if)

    @Override

    public void onCreate(SQLiteDatabase db) {

        String crt_questiontable_sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUESTION + "(" +

                COLUMN_QUESTION_QUESTION + " TEXT" +

                ")";

        db.execSQL(crt_questiontable_sql);

    }



    @Override

    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {



    }



    public long addQuestion(String question) {

        ContentValues cv = new ContentValues();

        cv.put(COLUMN_QUESTION_QUESTION,question);

        return this.getWritableDatabase().insert(TABLE_QUESTION,null,cv);

    }



    public Cursor getAllQuestions() {

        return this.getWritableDatabase().query(TABLE_QUESTION,null,null,null,null,null,null);

    }

}

With the above class existing your code could then be (as a simple example) :-

    MainDatabaseHelper myDBHlpr = new MainDatabaseHelper(getActivity()); // Instantiate a MainDatabasehelper object called myDBHlpr



    // Add some questions to the questions table

    myDBHlpr.addQuestion("This is the first question");

    myDBHlpr.addQuestion("This is another question");

    myDBHlpr.addQuestion("Yet another question");



    // Now get all of the questions

    Cursor csr = myDBHlpr.getAllQuestions();



    Log.d("DBINFO","There are " + String.valueOf(csr.getCount()) + " questions in the database.");

    // Loop through all the questions

    while (csr.moveToNext()) {

        Log.d("DBINFO",

                "Question " +

                        String.valueOf(csr.getPosition() + 1) +

                        " is " + csr.getString(csr.getColumnIndex(MainDatabaseHelper.COLUMN_QUESTION_QUESTION))

        );

        mMostMessagesSent.setText(csr.getString(csr.getColumnIndex(MainDatabaseHelper.COLUMN_QUESTION_QUESTION));

    }

    csr.close(); //<<<<<<<<<< Should always close Cursor when done with it.



    //mMostMessagesSent.setText(text); //<<<<<<<<<< done in the loop through the cursor (for demonstration very likely only the last question will be seen)

    mMostMessagesSent.setTextColor(Color.WHITE);

When run (for the first time) the log would then include :-

11-12 20:17:16.345 1376-1376/? D/DBINFO: There are 3 questions in the database.

11-12 20:17:16.345 1376-1376/? D/DBINFO: Question 1 is This is the first question

11-12 20:17:16.345 1376-1376/? D/DBINFO: Question 2 is This is another question

11-12 20:17:16.345 1376-1376/? D/DBINFO: Question 3 is Yet another question

Additionally the last question (which may or may not be the last question added) will be displayed in the TextView.

• Note 3 rows would be added to the table each time the above is run.


• Note this is purely intended as an introduction/demonstration there is a great deal more that needs to be done, such as designing the database.