Name and number save,read,delete,update in SQLite database, Listview from SQLite Database

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:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.jovial.countrylist.MainActivity">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Black Name"
        android:id="@+id/etName"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Black Number"
        android:inputType="phone"
        android:id="@+id/etEmail"/>


    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <!--Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/btnBrowes"
            android:text="..."/-->
        <Button
            android:enabled="false"
            android:id="@+id/btnSave"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Save"/>
        <!--Button
            android:id="@+id/btbView"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="view"/-->
        <Button
            android:enabled="false"
            style="@android:style/Widget.Holo.Button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/delete_all"
            android:id="@+id/btndel"/>

        <!--Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Count"
            android:id="@+id/btncount"/-->
    </LinearLayout>
    <ListView
        android:padding="5dp"
        android:layout_marginTop="20dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/listview">

    </ListView>
    <TextView
        android:textColor="#a8a9a8"
        android:text="@string/nothing_to_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/emptyView"
        android:gravity="center"
        style="@android:style/TextAppearance.Large"
        />
</LinearLayout>

ActivityMainDatabaseCRUD.java

package com.jovial.countrylist;

import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.provider.ContactsContract;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Display;
import android.view.View;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

    EditText name,email;
    String nameValue = "",emailValue = "";
    Button save,view,reset,count,browse;
    DBAdapter db;
    SimpleCursorAdapter dataAdapter;
    String[] columns;
    int[] to;
    ListView listview;

    int REQUEST_CODE = 1;

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

        db = new DBAdapter(this);
        populate();

        //---Name and Email Text Watcher----
        email = (EditText)findViewById(R.id.etEmail);
        name = (EditText)findViewById(R.id.etName);
        name.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
                save.setEnabled(!name.getText().toString().trim().isEmpty());
            }

            @Override
            public void afterTextChanged(Editable editable) {

            }
        });

        //---Buttons Initialization---
        save = (Button)findViewById(R.id.btnSave);
        //view = (Button)findViewById(R.id.btbView);
        reset = (Button)findViewById(R.id.btndel);
        //count = (Button)findViewById(R.id.btncount);
       // browse = (Button)findViewById(R.id.btnBrowes);

        /*/---browse Contacts
        browse.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(Intent.ACTION_PICK,ContactsContract.CommonDataKinds.Phone.CONTENT_URI);
                intent.setType(ContactsContract.Contacts.CONTENT_TYPE);
                startActivityForResult(intent,REQUEST_CODE);
            }
        });*/

        //---add contacts----
        save.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                db.open();
                if(!db.checkExistance(name.getText().toString(),email.getText().toString())){
                    long id = db.insertContact(name.getText().toString(),email.getText().toString());
                    db.close();
                    if(id == -1){
                        Toast.makeText(MainActivity.this, "Error Occured", Toast.LENGTH_SHORT).show();
                    }
                    else{
                        populate();
                        Toast.makeText(MainActivity.this, "Added :" + name.getText(), Toast.LENGTH_SHORT).show();
                    }
                }else{
                    Toast.makeText(MainActivity.this, "Duplicat Contact"  , Toast.LENGTH_SHORT).show();
                }

                db.close();

            }
        });

        /*/---get all contacts
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(db.getContactsCount() > 0){
                    db.open();
                    Cursor c = db.getAllContacts();
                    if(c.moveToFirst()){
                        do{
                            DisplayContacts(c);
                        }while (c.moveToNext());
                    }
                    db.close();
                }else{
                    Toast.makeText(MainActivity.this, "Empty Database", Toast.LENGTH_SHORT).show();
                }

            }
        });*/

        //---Delete all contacts
        reset.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                db.open();
                db.deleteContacts();
                db.close();
                populate();
            }
        });

        /*/---counts----
        count.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(db.getContactsCount() != 0){
                    Toast.makeText(MainActivity.this, db.getContactsCount() + " :Contacts", Toast.LENGTH_SHORT).show();
                }else{
                    Toast.makeText(MainActivity.this, "Empty Database", Toast.LENGTH_SHORT).show();
                }
            }
        });*/

        //--List View ---
        listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Cursor cursor = (Cursor)listview.getItemAtPosition(i);
                long rowId = cursor.getLong(cursor.getColumnIndexOrThrow("_id"));
                Toast.makeText(MainActivity.this, "ID: " + rowId, Toast.LENGTH_SHORT).show();
                db.open();
                db.deleteContact(rowId);
                db.close();
                populate();
            }
        });
        if (db.getContactsCount() > 0)
            reset.setEnabled(true);
    }
    public void DisplayContacts(Cursor c){
        Toast.makeText(this, "ID: " +c.getString(0)+ "\nNAME: " +c.getString(1) + "\nEMAIL: " + c.getString(2), Toast.LENGTH_SHORT).show();
    }
    public void populate(){
        //---Creating List View---
        listview = (ListView)findViewById(R.id.listview);
        if(db.getContactsCount() > 0){
            Cursor c2 = db.getAllContacts();
            //columns to found
            columns = new String[]{
                    DBAdapter.KEY_NAME,
                    DBAdapter.KEY_EMAIL
            };
            //xml ids
            to = new int[]{
                    R.id.name,
                    R.id.email
            };
            //Creating adapter
            dataAdapter = new SimpleCursorAdapter(
                    this,R.layout.list_view,
                    c2,
                    columns,
                    to,
                    0);
            listview.setAdapter(dataAdapter);
        }
        else{
            //xml ids
            to = new int[]{R.id.name, R.id.email};
            //Creating adapter
            dataAdapter = new SimpleCursorAdapter(
                    this,R.layout.list_view,
                    null,
                    null,
                    to,
                    0);
            listview.setAdapter(dataAdapter);
            listview.setEmptyView(findViewById(R.id.emptyView));
        }
    }

    public void onActivityResult(int ReqCode,int resCode,Intent data){
        if(ReqCode == REQUEST_CODE && resCode == RESULT_OK){
            Uri uri = data.getData();
            Cursor cursor = getContentResolver().query(uri,null,null,null,null);
            if(cursor != null && cursor.getCount() > 0){
                cursor.moveToFirst();
                int numberColumn = cursor.getColumnIndexOrThrow(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME);
                name.setText(cursor.getString(numberColumn));
                cursor.close();
            }
            super.onActivityResult(ReqCode, resCode, data);
        }
    }
}

AndroidManifist.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.jovial.countrylist">

    <uses-permission
        android:name="android.permission.MODIFY_PHONE_STATE"
        tools:ignore="ProtectedPermissions" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.CALL_PHONE" />
    <uses-permission android:name="android.permission.PROCESS_INCOMING_CALLS" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

       
    </application>

</manifest>

ContactsDBAdapter.java

package com.jovial.countrylist;

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

/**
 * Created by JOVIAL on 11/26/2016.
 */

public class DBAdapter {

    ///Constants
    public  static final String KEY_ROWID = "_id";
    public  static final String KEY_NAME = "name";
    public  static final String KEY_EMAIL = "email";
    public  static final String TAG = "DBAdapter";

    public  static final String DATABASE_NAME = "MyDB";
    public  static final String DATABASE_TABLE = "contacts";
    private static final String DATABASE_CREATE = "create table contacts (_id integer primary key autoincrement," + "name text not null, email text not null);";
    public  static final int DATABASE_VERSION = 1;

    private final Context context;
    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

    public DBAdapter(Context context) {
        this.context = context;
        DBHelper = new DatabaseHelper(context);
    }
    //DatabaseHelper
    private static class DatabaseHelper extends SQLiteOpenHelper{

        DatabaseHelper(Context context){
            super(context,DATABASE_NAME,null,DATABASE_VERSION);
        }
        @Override
        public void onCreate(SQLiteDatabase sqLiteDatabase) {
            try{
                sqLiteDatabase.execSQL(DATABASE_CREATE);
            }catch (SQLException e){
                e.printStackTrace();
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
            Log.w(TAG,"UPGRADING DATABASE VERSION FROM" + i + " TO " + i1);
            sqLiteDatabase.execSQL("DROP TABLE IF EXISTS "+ DATABASE_TABLE);
            onCreate(sqLiteDatabase);
        }
    }
    //---open database --
    public DBAdapter open() throws SQLException{
        db = DBHelper.getWritableDatabase();
        return this;
    }

    //---close database---
    public void close(){
        db.close();
    }

    //--Insert a contact----
    public long insertContact(String name,String email){
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_NAME,name);
        initialValues.put(KEY_EMAIL,email);
        return db.insert(DATABASE_TABLE,null,initialValues);
    }

    //---delete a contact----
    public boolean deleteContact(long rowId){
        Toast.makeText(context, "Removed", Toast.LENGTH_SHORT).show();
        return db.delete(DATABASE_TABLE,KEY_ROWID + "=" + rowId,null) > 0;

    }

    // Getting contacts Count
    public int getContactsCount() {
        String COUNT_QUERY = "SELECT * FROM " + DATABASE_TABLE;
        open();
        Cursor cursor = db.rawQuery(COUNT_QUERY,null);
        return cursor.getCount();
    }
    //---delete all contacts---
    public void deleteContacts(){
        if(getContactsCount() > 0){
            open();
            Cursor c = getAllContacts();
            if(c.moveToFirst()){
                do{
                    db.delete(DATABASE_TABLE,KEY_ROWID + "=" + c.getString(0),null);
                }while (c.moveToNext());
            }
            db.close();
            Toast.makeText(context, "Database Cleared", Toast.LENGTH_SHORT).show();
        }else{
            Toast.makeText(context, "Nothing to Clear", Toast.LENGTH_SHORT).show();
        }

    }

    //---Get All Contact---
    public Cursor getAllContacts(){
        return db.query(DATABASE_TABLE,new String[]{KEY_ROWID,KEY_NAME,KEY_EMAIL},null,null,null,null,null);
    }

    public Cursor getContact(long rorId) throws SQLException{
        Cursor mCursor = db.query(true,DATABASE_TABLE,new String[]{KEY_ROWID,KEY_NAME,KEY_EMAIL},KEY_ROWID + "=" + rorId,null,null,null,null,null);
        if (mCursor != null){
            mCursor.moveToFirst();
        }
        return mCursor;
    }

    public boolean checkExistance(String name,String number){
        boolean duplicate = false;
        open();
        String COUNT_QUERY = "SELECT " + KEY_ROWID +" FROM " + DATABASE_TABLE + " WHERE " + KEY_NAME +"=" +"'"+name+"' OR "+ KEY_EMAIL +"=" +"'"+number+"'";
        Cursor c = db.rawQuery(COUNT_QUERY,null);
        if(c.getCount() > 0){
            duplicate = true;
        }
        return duplicate;
    }

}

ContactsDBModel.java

package com.jovial.countrylist;

/**
 * Created by JOVIAL on 11/26/2016.
 */

public class Contacts {
//    String name = null;
//    String email = null;
//
//    public String getName() { return name; }
//
//    public void setName(String name) {
//        this.name = name;
//    }
//
//    public String getEmail() {
//        return email;
//    }
//
//    public void setEmail(String email) {
//        this.email = email;
//    }
}

ListViewItem.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginTop="10dp"
    android:padding="10dp">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="20dp"
        android:text="@string/app_name"
        android:id="@+id/name"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/app_name"
        android:id="@+id/email"/>

</LinearLayout>