PDM2 20201124

package com.joythis.android.mycaller;

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

import androidx.annotation.Nullable;

import java.util.ArrayList;

public class ContactDB extends SQLiteOpenHelper {
    public final static int CONTACTS_DB_VERSION = 33;
    public final static String CONTACTS_DB_NAME = "CONTACTS.DB";

    public final static String TABLE_CONTACTS = "tContacts";

    public final static String COL_ID = "_id";
    public final static String COL_NAME = "cName";
    public final static String COL_NUMBER = "cNumber";

    public final static String DROP_CONTACTS =
        "DROP TABLE IF EXISTS "+TABLE_CONTACTS+";";

    /*
    create table if not exists tContacts(
        _id integer primary key autoincrement,
        cName text not null,
        cNumber text not null
    );
     */
    public final static String CREATE_TABLE_CONTACTS =
        "CREATE TABLE IF NOT EXISTS "+
        TABLE_CONTACTS+"(\n"+
        COL_ID+" INTEGER PRIMARY KEY AUTOINCREMENT,\n"+
        COL_NAME+" TEXT NOT NULL,\n"+
        COL_NUMBER+" TEXT NOT NULL\n"+
        ");\n";

    public ContactDB(
        @Nullable Context context
    )
    {
        super(
            context,
            CONTACTS_DB_NAME,
            null,
            CONTACTS_DB_VERSION
        );
    }//ContactDB

    public ContactDB(
        @Nullable Context context,
        @Nullable String name,
        @Nullable SQLiteDatabase.CursorFactory factory,
        int version
    )
    {
        super(context, name, factory, version);
    }//ContactDB

    /*
    this method will install the necessary
    infrastructure (create the table(s))

    this method will be AUTOMATICALLY called by the
    framework upon the 1st need to read or write data
    in "Contact" related table(s)
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
        installDB(db);
    }//onCreate

    /*
    will be automatically called whenever the database
    version changes
     */
    @Override
    public void onUpgrade
    (SQLiteDatabase db, int oldVersion, int newVersion)
    {
        try {
            if (newVersion > oldVersion) {
                db.execSQL(DROP_CONTACTS);
                installDB(db);
            }
        }
        catch(Exception e){
            Log.e(
               getClass().getName(),
               e.toString()
            );
        }
    }//onUpgrade

    void installDB(SQLiteDatabase pDB){
        if (pDB!=null){
            try {
                pDB.execSQL(CREATE_TABLE_CONTACTS);
            }
            catch(Exception e){
                Log.e(
                    getClass().getName(),
                    e.toString()
                );
            }
        }//if
    }//installDB

    public long insertContact (Contact pC){
        int iRet = -1;

        SQLiteDatabase db = this.getWritableDatabase();

        if (db!=null){
            String strName = pC.getmName();
            String strNumber = pC.getmNumber();

            ContentValues pairsCV = new ContentValues();
            pairsCV.put(COL_NAME, strName);
            pairsCV.put(COL_NUMBER, strNumber);

            //-1 on insert failure
            long idOfTheNewlyInsertedRecord = db.insert(
                TABLE_CONTACTS,
                null,
                pairsCV
            );

            db.close();
            return idOfTheNewlyInsertedRecord;

        }//if

        return iRet;
    }//insertContact

    public final static String SQL_SELECT_BY_NAME_ASC =
        "SELECT * FROM "+TABLE_CONTACTS+" ORDER BY "+COL_NAME+" ASC;";
    public final static String SQL_SELECT_BY_NAME_DESC =
        "SELECT * FROM "+TABLE_CONTACTS+" ORDER BY "+COL_NAME+" DESC;";

    public final static String SQL_SELECT_BY_NUMBER_ASC =
        "SELECT * FROM "+TABLE_CONTACTS+" ORDER BY "+COL_NUMBER+" ASC;";
    public final static String SQL_SELECT_BY_NUMBER_DESC =
        "SELECT * FROM "+TABLE_CONTACTS+" ORDER BY "+COL_NUMBER+" DESC;";

    public final static String SQL_SELECT_BY_ID_ASC =
        "SELECT * FROM "+TABLE_CONTACTS+" ORDER BY "+COL_ID+" ASC;";
    public final static String SQL_SELECT_BY_ID_DESC =
        "SELECT * FROM "+TABLE_CONTACTS+" ORDER BY "+COL_ID+" DESC;";

    public ArrayList<Contact> selectAllByNameASC(){
        return selectByQuery(SQL_SELECT_BY_NAME_ASC);
    }//selectAllByNameASC

    public ArrayList<Contact> selectAllByNameDESC(){
        return selectByQuery(SQL_SELECT_BY_NAME_DESC);
    }//selectAllByNameDESC

    public ArrayList<Contact> selectAllByNumberASC(){
        return selectByQuery(SQL_SELECT_BY_NUMBER_ASC);
    }//selectAllByNumberASC

    public ArrayList<Contact> selectAllByNumberDESC(){
        return selectByQuery(SQL_SELECT_BY_NUMBER_DESC);
    }//selectAllByNumberDESC

    public ArrayList<Contact> selectAllByInsertDateASC(){
        return selectByQuery(SQL_SELECT_BY_ID_ASC);
    }//selectAllByInsertDateASC

    public ArrayList<Contact> selectAllByInsertDateDESC(){
        return selectByQuery(SQL_SELECT_BY_ID_DESC);
    }//selectAllByInsertDateDESC

    private ArrayList<Contact> selectByQuery (
        String pStrQuery
    )
    {
        ArrayList<Contact> aRet = new ArrayList<Contact>();

        try{
            SQLiteDatabase db = this.getReadableDatabase();

            if (db!=null) {
                Cursor cursor = db.rawQuery(
                    pStrQuery,
                    null
                );

                if (cursor != null) {
                    cursor.moveToFirst();
                    while (!cursor.isAfterLast()) {
                        int idxOfId = cursor.getColumnIndex(COL_ID); //0
                        int _id = cursor.getInt(idxOfId);

                        int idxOfName = cursor.getColumnIndex(COL_NAME);//1
                        String strName = cursor.getString(idxOfName);

                        //String strName = cursor.getString(1);

                        int idxOfNumber = cursor.getColumnIndex(COL_NUMBER); //2
                        String strNumber = cursor.getString(2);

                        Contact c = new Contact(
                                strName,
                                strNumber
                        );

                        aRet.add(c);

                        cursor.moveToNext();
                    }//while there are records to be read and included in the return

                    db.close();
                }//if there is a cursor objet to navigate through the objects that the select returned
            }//if we got a readable database
        }
        catch (Exception e){
            Log.e(
                getClass().getName(),
                e.toString()
            );
        }

        return aRet;
    }//selectAll
}//ContactDB

//**

package com.joythis.android.mycaller;

public class Contact {
    //private long mId;
    private String mName;
    private String mNumber;

    public String getmName() {
        return mName;
    }

    public String getmNumber() {
        return mNumber;
    }

    public Contact
    (
        String pName,
        String pNumber
    ){
        this.mName = pName;
        this.mNumber = pNumber;
    }//Contact

    @Override
    public String toString(){
        String strRet = "";

        strRet =
            String.format(
                "%s : %s",
                this.mName,
                this.mNumber
            );

        return strRet;
    }//toString
}//Contact

//**

package com.joythis.android.mycaller;

import android.app.Activity;
import android.widget.Toast;

public class AmUtil {
    Activity mActivity;

    public AmUtil(Activity pA){
        this.mActivity = pA;
    }//AmUtil

    public void fb(String pMsg){
        Toast t = Toast.makeText(
            this.mActivity,
            pMsg,
            Toast.LENGTH_LONG
        );
        t.show();
    }//fb
}//AmUtil

//**
package com.joythis.android.mycaller;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {


    Button.OnClickListener mBtnClickHandler = new Button.OnClickListener() {
        @Override
        public void onClick(View v) {
            switch(v.getId()){
                case R.id.idBtnInsertContact:
                    actionInsertContact();
                    break;
            }//switch
        }//onClick
    };//mBtnClickHandler

    void actionInsertContact(){
        String strContactName = mEtContactName.getText().toString();
        String strContactNumber = mEtContactNumber.getText().toString();

        Contact c = new Contact(
            strContactName,
            strContactNumber
        );

        long iWhereItWasInserted = mContactDB.insertContact(c);

        /*
        Toast t = Toast.makeText(
            this,
            String.valueOf(iWhereItWasInserted),
            Toast.LENGTH_LONG
        );
        t.show();
         */
        mUtil.fb(
            String.valueOf(iWhereItWasInserted)
        );

        syncLvContactsWithDB();
    }//actionInsertContact

    //data member to enable access to database operations
    //such as insert and select
    ContactDB mContactDB;
    Context mContext;

    AmUtil mUtil;

    EditText mEtContactName, mEtContactNumber;
    Button mBtnInsertContact;
    ListView mLvContacts;
    ArrayList<Contact> mAlContacts;
    ArrayAdapter<Contact> mAd;

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

        init();
    }//onCreate

    void init(){
        mContext = this;
        mUtil = new AmUtil(this);

        mEtContactName = findViewById(R.id.idEtContactName);
        mEtContactNumber = findViewById(R.id.idEtContactNumber);

        mBtnInsertContact = findViewById(R.id.idBtnInsertContact);
        mBtnInsertContact.setOnClickListener(
            mBtnClickHandler //data abstraction
        );

        mLvContacts = findViewById(R.id.idLvContacts);

        mAlContacts = new ArrayList<>();

        mContactDB = new ContactDB(mContext);

        mAd = new ArrayAdapter<>(
            mContext,
            android.R.layout.simple_list_item_1,
            mAlContacts
        );
        mLvContacts.setAdapter(mAd);

        syncLvContactsWithDB();

        /*
        mContactDB.insertContact
            (new Contact("Artur", "123"));

        ArrayList<Contact> all = mContactDB.selectAll();
         */

    }//init

    void syncLvContactsWithDB(){
        ArrayList<Contact> alTemp =
            mContactDB.selectAllByInsertDateDESC();
        if (alTemp!=null && alTemp.size()>0){
            mAlContacts.clear();
            for (Contact c : alTemp){
                mAlContacts.add(c);
            }//for
            mAd.notifyDataSetChanged();
        }//if
    }//syncLvContactsWithDB
}//MainActivity