Intro to Realm.io workshop project.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    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"
    android:padding="16dp"
    tools:context="com.benzneststudios.myrealmproject.MainActivity">

    <Button
        android:id="@+id/btn_generate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:padding="16dp"
        android:text="Generate 100 students"
        android:textSize="18sp"/>

    <EditText
        android:id="@+id/edt_data"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:inputType="textMultiLine"
        />
</LinearLayout>

MainActivity.java

package com.benzneststudios.myrealmproject;

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

import java.util.ArrayList;

import io.realm.Realm;
import io.realm.RealmResults;

public class MainActivity extends AppCompatActivity {

    private Realm realm;
    Button btnGenerate;
    EditText edtData;

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

        realm = Realm.getDefaultInstance();

        btnGenerate = (Button) findViewById(R.id.btn_generate);
        btnGenerate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                generateStudent();
            }
        });

        edtData = (EditText) findViewById(R.id.edt_data);
    }

    private void showStudent() {
        RealmResults<Student> listStudent = getAllStudent();
        Log.d("STUDENT", "SIZE = " + listStudent.size());
        String str = "";
        for (Student student : listStudent) {
            str += "\nID = " + student.getStudentId() +
                    " , " + student.getStudentName() +
                    " , (" + student.getStudentScore() + ")";
            edtData.setText(str);
        }
    }

    private void generateStudent(){
        clearStudent();
        insertStudent();
    }

    private void insertStudent() {

        final ArrayList<Student> listStudentGenerate = getSampleStudentData(100);

        realm.executeTransactionAsync(
                new Realm.Transaction() {
                    @Override
                    public void execute(Realm realm) {
                        for (final Student s : listStudentGenerate) {
                            Student student = realm.createObject(Student.class);
                            student.setStudentId(s.getStudentId());
                            student.setStudentName(s.getStudentName());
                            student.setStudentScore(s.getStudentScore());
                            Log.d("STUDENT", "Add student id = " + s.getStudentId());
                        }
                    }
                }, new Realm.Transaction.OnSuccess() {
                    @Override
                    public void onSuccess() {
                        Toast.makeText(getApplicationContext(), "Generate student complete.", Toast.LENGTH_SHORT).show();
                        showStudent();
                    }

                }, new Realm.Transaction.OnError() {
                    @Override
                    public void onError(Throwable error) {
                        error.printStackTrace();
                        Toast.makeText(getApplicationContext(), "", Toast.LENGTH_SHORT).show();
                    }
                });
    }

    private void clearStudent() {
        realm.beginTransaction();
        realm.delete(Student.class);
        realm.commitTransaction();
    }

    public ArrayList<Student> getSampleStudentData(int size) {
        String name[] = {"Raj Koothrappali", "Penny Hofstadter", "Leonard Hopstater", "Sheldon cooper", "Howard Wolowitz"};
        ArrayList<Student> listStudent = new ArrayList<>();
        for (int i = 1; i <= size; i++) {
            Student student = new Student();
            student.setStudentId(i);
            student.setStudentName(name[i % name.length]);
            student.setStudentScore((int) (Math.random() * 100));
            listStudent.add(student);
        }
        return listStudent;
    }

    public RealmResults<Student> getAllStudent() {
        RealmResults<Student> result = realm.where(Student.class).findAll();
        return result;
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        realm.close();
    }

    private void updateStudent(){
        final Student student = new Student();
        student.setStudentId(1);
        student.setStudentName("Benznest");
        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                realm.copyToRealmOrUpdate(student);
            }
        });
    }
}

MyApplication.java

package com.benzneststudios.myrealmproject;

import android.app.Application;

import io.realm.Realm;
import io.realm.RealmConfiguration;

/**
 * Created by benznest on 22-Sep-16.
 */

public class MyApplication extends Application{
    @Override
    public void onCreate() {
        super.onCreate();
        initRealm();
    }

    private void initRealm() {
        RealmConfiguration realmConfiguration = new RealmConfiguration.Builder(this)
                .name("android.realm")
                .schemaVersion(0)
                .deleteRealmIfMigrationNeeded()
                .build();
        Realm.setDefaultConfiguration(realmConfiguration);
    }
}

Student.java

package com.benzneststudios.myrealmproject;

import io.realm.RealmObject;
import io.realm.annotations.PrimaryKey;
import io.realm.annotations.Required;

/**
 * Created by benznest on 22-Sep-16.
 */

public class Student extends RealmObject {
    @PrimaryKey
    int studentId;

    @Required
    String studentName;

    int studentScore;

    public int getStudentId() {
        return studentId;
    }

    public void setStudentId(int studentId) {
        this.studentId = studentId;
    }

    public String getStudentName() {
        return studentName;
    }

    public void setStudentName(String studentName) {
        this.studentName = studentName;
    }

    public int getStudentScore() {
        return studentScore;
    }

    public void setStudentScore(int studentScore) {
        this.studentScore = studentScore;
    }

}