Android Programming: part 36 - Read Assets Database

MainActivity.java :

package first.learn.databasereadlearn;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.os.Bundle;
import android.widget.ListView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    DbController dbController ;
    Context mContext;

    ListView listView2 ;

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

        mContext = this;

        listView2 = (ListView) findViewById(R.id.listView2);


        dbController = new DbController(mContext, "ahsan.db");

        dbController.openAssetsDb();


        ArrayList<ModelStudent> modelStudentArrayList = new ArrayList<>();

        modelStudentArrayList = dbController.getDatabaseContent();


        if(modelStudentArrayList.size()>0){

            ModelStudent m = modelStudentArrayList.get(0);

            System.out.println("Data Base : Name : "+ m.getName());


        }else {

            System.out.println("Data Base : No Data Found");

        }



        StudentAdapter adapter = new StudentAdapter(mContext, R.layout.list_item, modelStudentArrayList);
        listView2.setAdapter(adapter);





    }



}

activity_main.xml :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical">


    <ListView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/listView2"/>



</LinearLayout>

dbOpenHelper. java :

package first.learn.databasereadlearn;



import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;


public class ExternalDbOpenHelper extends SQLiteOpenHelper {

    //���� � ����� � ������ �� ����������
    public static String DB_PATH;
    public static String DB_NAME;
    public SQLiteDatabase database;
    public final Context mContext;



    public SQLiteDatabase getDb() {
        return database;
    }

    public ExternalDbOpenHelper(Context context, String databaseName) {
        super(context, databaseName, null, 1);
        this.mContext = context;

        System.out.println("Database Name:-----3 = "+ databaseName);
        String packageName = context.getPackageName();
        DB_PATH = String.format("//data//data//%s//databases//", packageName);
        DB_NAME = databaseName;
        openDataBase();
    }



    public SQLiteDatabase openDataBase() throws SQLException {
        String path = DB_PATH + DB_NAME;
        if (database == null) {
            createDataBase();
            database = SQLiteDatabase.openDatabase(path, null,
                    SQLiteDatabase.OPEN_READWRITE);
        }
        System.out.println("Database Path:-----2 = "+ database.getPath());
        return database;
    }



    public void createDataBase() {
        boolean dbExist = checkDataBase();
        if (!dbExist) {
            this.getReadableDatabase();
            this.close();
            try {
                copyDataBase();
            } catch (IOException e) {
                Log.e(this.getClass().toString(), "Copying error");
                throw new Error("Error copying database!");
            }
        } else {
            Log.i("tag", "Token ExternalDbOpenHelper Database already exists");
            //Log.i(this.getClass().toString(), "Database already exists");

        }
    }
    private boolean checkDataBase() {
        boolean isValid = false ;
        SQLiteDatabase checkDb = null;
        try {
            String path = DB_PATH + DB_NAME;
          //  checkDb = SQLiteDatabase.openDatabase(path, null, SQLiteDatabase.OPEN_READONLY);
            isValid = isValidSQLite(path, 32);

        } catch (SQLException e) {
            Log.e(this.getClass().toString(), "Error while checking db");
            Log.i("tag", "check db Execption");
        }
        if (checkDb != null) {
            checkDb.close();
        }
       // return checkDb != null;

        return isValid;
    }

    private void copyDataBase() throws IOException {

        InputStream externalDbStream = mContext.getAssets().open(DB_NAME);

        String outFileName = DB_PATH + DB_NAME;

        OutputStream localDbStream = new FileOutputStream(outFileName);

        byte[] buffer = new byte[1024];
        int bytesRead;
        while ((bytesRead = externalDbStream.read(buffer)) > 0) {
            localDbStream.write(buffer, 0, bytesRead);
        }
        localDbStream.close();
        externalDbStream.close();
        Log.i("tag", "Database copied");

    }



    @Override
    public synchronized void close() {
        if (database != null) {
            database.close();
        }
        super.close();
    }
    @Override
    public void onCreate(SQLiteDatabase db) {}
    // @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}

    @Override
    public void onOpen(SQLiteDatabase db) {
        super.onOpen(db);
        db.disableWriteAheadLogging();
    }

    @Override
    public void onConfigure(SQLiteDatabase db) {
        super.onConfigure(db);
        db.disableWriteAheadLogging();
    }




    ///////////////////////////////////////////////////////





    public boolean isValidSQLite(String dbPath, int minSizeInMb) {
        File file = new File(dbPath);

        if (!file.exists() || !file.canRead()) {
            return false;
        }

        boolean isReadable = false ;

        try {
            FileReader fr = new FileReader(file);
            char[] buffer = new char[16];

            try {
                fr.read(buffer, 0, 16);
            } catch (IOException e) {
                e.printStackTrace();
            }
            String str = String.valueOf(buffer);
            fr.close();

            isReadable = str.equals("SQLite format 3\u0000");

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

        }

        if (file.length() > (1024 * 1024 * minSizeInMb) && isReadable) {
            return true;
        }else {
            try {
                file.delete();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return  false ;
        }
    }


}

dbController.java :

package first.learn.databasereadlearn;

import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;

import java.util.ArrayList;

public class DbController {

    Context mContext ;
    SQLiteDatabase database ;
    String DBName ;


    public DbController(Context mContext, String DBName) {
        this.mContext = mContext;
        this.DBName = DBName;
    }


    public  DbController openAssetsDb () throws SQLException {

        ExternalDbOpenHelper externalDbOpenHelper = new ExternalDbOpenHelper(mContext, DBName);
        database =   externalDbOpenHelper.openDataBase();

        return  this ;
    }



    /*

    CREATE TABLE "Student" (
   "studentId"    INTEGER,
   "RollNumber"   TEXT,
   "Name" TEXT,
   "Age"  TEXT,
   "Address"  TEXT,
   "PhoneNumber"  TEXT,
   PRIMARY KEY("studentId" AUTOINCREMENT)
);


     */




    public ArrayList<ModelStudent> getDatabaseContent () {

        ArrayList<ModelStudent> modelStudentArrayList = new ArrayList<>();

        if(database!=null){

            System.out.println( "Database Not Null ");

            Cursor cursor ;

            cursor = database.rawQuery("select * from Student", null );

            if(cursor!=null){
                cursor.moveToFirst();
            }

            if(cursor!=null && cursor.moveToFirst()){

                if(!cursor.isAfterLast()){

                    do {

                      String rollNumber = cursor.getString(cursor.getColumnIndexOrThrow("RollNumber"));
                      String name =  cursor.getString(cursor.getColumnIndexOrThrow("Name"));
                      String age = cursor.getString(cursor.getColumnIndexOrThrow("Age"));
                      String address = cursor.getString(cursor.getColumnIndexOrThrow("Address"));
                      String phoneNumber = cursor.getString(cursor.getColumnIndexOrThrow("PhoneNumber"));

                      ModelStudent m = new ModelStudent();
                      m.setRollNumber(rollNumber);
                      m.setName(name);
                      m.setAge(age);
                      m.setAddress(address);
                      m.setPhoneNumber(phoneNumber);

                      modelStudentArrayList.add(m);

                    }while (cursor.moveToNext());

                    cursor.close();



                }

            }


        } else  {

            System.out.println( "Database Null ");

        }

        return  modelStudentArrayList;


    }


}

ModelStudent.java :

package first.learn.databasereadlearn;

public class ModelStudent {


    String StudentId, Name, RollNumber, Age, Address, PhoneNumber;

    public ModelStudent() {
    }


    public ModelStudent(String studentId, String name, String rollNumber, String age, String address, String phoneNumber) {
        StudentId = studentId;
        Name = name;
        RollNumber = rollNumber;
        Age = age;
        Address = address;
        PhoneNumber = phoneNumber;
    }

    public String getStudentId() {
        return StudentId;
    }

    public void setStudentId(String studentId) {
        StudentId = studentId;
    }

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getRollNumber() {
        return RollNumber;
    }

    public void setRollNumber(String rollNumber) {
        RollNumber = rollNumber;
    }

    public String getAge() {
        return Age;
    }

    public void setAge(String age) {
        Age = age;
    }

    public String getAddress() {
        return Address;
    }

    public void setAddress(String address) {
        Address = address;
    }

    public String getPhoneNumber() {
        return PhoneNumber;
    }

    public void setPhoneNumber(String phoneNumber) {
        PhoneNumber = phoneNumber;
    }
}

Adapter.java :

package first.learn.databasereadlearn;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

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

public class StudentAdapter extends ArrayAdapter<ModelStudent> {

    Context mContext ;
    ArrayList <ModelStudent> modelStudentArrayList ;

    public StudentAdapter(@NonNull Context context, int resource, @NonNull ArrayList<ModelStudent> objects) {
        super(context, resource, objects);

        mContext  = context ;
        modelStudentArrayList  = objects;
    }


    @NonNull
    @Override
    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {

        View view ;

        if(convertView == null){

            LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate(R.layout.list_item, null);
        }else  {
            view = convertView ;
        }


       TextView tvMobile = ( TextView) view.findViewById(R.id.tvMobile);
       TextView tvAge = ( TextView) view.findViewById(R.id.tvAge);
       TextView tvName = ( TextView) view.findViewById(R.id.tvName);
       TextView tvRoll = ( TextView) view.findViewById(R.id.tvRoll);
       TextView tvAddress = (TextView)view.findViewById(R.id.tvAddress);

       ModelStudent modelStudent = modelStudentArrayList.get(position);

       tvName.setText(modelStudent.getName());
       tvAge.setText(modelStudent.getAge());
       tvMobile.setText(modelStudent.getPhoneNumber());
       tvRoll.setText(modelStudent.getRollNumber());
        tvAddress.setText(modelStudent.getAddress());


        return view ;
    }
}

list_item.xml :

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:layout_margin="8dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:weightSum="2"
        >

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:orientation="vertical">
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Roll : "/>


            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Name : "/>

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Age : "/>

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Address : "/>

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Mobile : "/>



        </LinearLayout>


        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:orientation="vertical">

            <TextView
                android:id="@+id/tvRoll"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Roll : "/>


            <TextView
                android:id="@+id/tvName"

                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Name : "/>

            <TextView
                android:id="@+id/tvAge"

                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Age : "/>

            <TextView
                android:id="@+id/tvAddress"

                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Address : "/>

            <TextView
                android:id="@+id/tvMobile"

                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Mobile : "/>




        </LinearLayout>

    </LinearLayout>


    <View
        android:padding="2dp"
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@color/black"/>







</LinearLayout>

Android Programming

part 36 - Read Assets Database

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