Error while testing SQLite

[Abhinay imandi]

Hello Guys,

I'm new to Android Development and I'm working with SQLite for my application.

When I run the app in the VM or in my handheld device when I'm inserting data into the table i'm getting a loop of an error/warning stating like this

08-15 03:43:10.180 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5520K, 49% free 6702K/12928K, paused 13ms, total 13ms
08-15 03:43:10.230 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5492K, 49% free 6697K/12928K, paused 13ms, total 13ms
08-15 03:43:10.270 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5452K, 49% free 6708K/12928K, paused 14ms, total 14ms
<<
08-15 03:43:10.310 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5454K, 49% free 6710K/12928K, paused 12ms, total 12ms
08-15 03:43:10.340 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5466K, 49% free 6700K/12928K, paused 11ms, total 11ms
08-15 03:43:10.370 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5414K, 49% free 6714K/12928K, paused 12ms, total 12ms
08-15 03:43:10.410 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5401K, 48% free 6723K/12928K, paused 12ms, total 12ms
08-15 03:43:10.440 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5417K, 49% free 6703K/12928K, paused 12ms, total 12ms
08-15 03:43:10.471 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5422K, 49% free 6704K/12928K, paused 12ms, total 12ms
08-15 03:43:10.511 20006-20006/com.example.miracle.sqlexample D/dalvikvm: GC_FOR_ALLOC freed 5421K, 49% free 6705K/12928K, paused 13ms, total 13ms

and this is getting repeated untill I quit the application.
below is the source code that I'm using for.

MainActivity.java

package com.example.miracle.sqlexample;

import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.TextView; 
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    EditText input;
    Button ins,del;
    TextView result;
    DBHelper db;

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

        input = (EditText)findViewById(R.id.insertText);
        ins = (Button)findViewById(R.id.insertBtn);
        del = (Button)findViewById(R.id.deleteBtn);
        result = (TextView)findViewById(R.id.resultView);
        db = new DBHelper(this,null,null,1);
    }

    public void insertData(View v)
    {
        Boolean insert = false ;
        insert = db.insertEmp(input.getText().toString());

        if(insert == true)
        {
            Toast.makeText(this,"Employee Name Inserted",Toast.LENGTH_LONG).show();
        }
        printDb();
    }

    public void deleteData(View v)
    {
      Boolean delete = db.delEmp(input.getText().toString());

        if(delete == true)
        {
            Toast.makeText(this,"Employee Name Deleted",Toast.LENGTH_LONG).show();
        }
        printDb();
    }

    public void printDb()
    {
        String resultDB = db.printDB();
        result.setText(resultDB);
    }
}

DBHelper.java

package com.example.miracle.sqlexample;

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

/** 
* Created by Miracle on 15-Aug-16. 
*/ 
public class DBHelper extends SQLiteOpenHelper {

    public static final String DATABASE_NAME = "Emp.db";
    public static final String Employee_TABLE_NAME = "Employee";
    public static final String Employee_COLUMN_EMPNAME = "EmployeeName";

    public DBHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context, DATABASE_NAME, null, 1);
    }

    @Override
    public void onCreate(SQLiteDatabase sqlDB) {

        sqlDB.execSQL("create table "+Employee_TABLE_NAME+" ("+Employee_COLUMN_EMPNAME+" text)");
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqlDB, int i, int i1) {

        sqlDB.execSQL("drop table if exists "+Employee_TABLE_NAME);
        onCreate(sqlDB);
    }

    //Insert EmpName

    public boolean insertEmp(String EmpName)
    {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues cValues = new ContentValues();
        cValues.put(Employee_COLUMN_EMPNAME,EmpName);
        db.insert(Employee_TABLE_NAME,null,cValues);
        db.close();
        return true;
    }

    public boolean delEmp(String EmpName)
    {
        SQLiteDatabase db = this.getWritableDatabase();
        db.delete(Employee_TABLE_NAME,"EmployeeName = ?",new String[]{EmpName});
        return true;
    }

    public String printDB()
    {
        String dbString = null;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor c = db.rawQuery("select * from "+Employee_TABLE_NAME,null);

        c.moveToFirst();

        while(!c.isAfterLast())
        {
            if(c.getString(c.getColumnIndex("EmployeeName"))!=null)
            {
                dbString += c.getString(c.getColumnIndex("EmployeeName"));
                dbString += "\n";
            }
        }

        db.close();
        return dbString;
    }
}

please provide me with your suggestions.

Thanks,
Abhinay

[Ron McLeod]

Those messages are not errors, but they do indicate that garbage is being is continuously being collected, and that shouldn't be with this application.

Check your DBHelper#printDb method.  Inside your while loop, you are never moving to the next row, so your code is using the value of the first row over and over, creating new objects each time.  The check to see if the cursor is pointing to after the last row will always return false so the code will never exit the loop.

Also - you should not be closing the database in the insertEmp and printDB methods - leave it open until the application is stopped.

And - the delEmp and insertEmp always return true, regardless of whether they were successful or not - check the return values for insert and delete to determine if the database operations were successful or not.

[Abhinay imandi]

Thanks Ron. It's working now.