HomeWorkSchoolVerticalSystem

ActivityMain
=============
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f7fcff"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:gravity="center"
        android:text="Welcome, Login To The System"
        android:textColor="#ff8cd1"
        android:textSize="22sp" />

    <EditText
        android:id="@+id/etname"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:hint="User Name"
        android:textSize="22sp" />

    <EditText
        android:id="@+id/etPassword"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Password"
        android:inputType="textPassword"
        android:textSize="22sp" />

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

        <Button
            android:id="@+id/btnlog"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:layout_weight="1"
            android:textColor="#ff8cd1"
            android:text="Login"
            android:textSize="18sp" />


        <Button
            android:id="@+id/btnreg"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:layout_weight="1"
            android:textColor="#00acff"
            android:text="Register"
            android:textSize="18sp" />

        <Button
            android:id="@+id/btnex"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="10dp"
            android:layout_weight="1"
            android:textColor="#ff8cd1"
            android:text="Exit"
            android:textSize="18sp" />
    </LinearLayout>
    <TextView
        android:id="@+id/tverr"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:gravity="center"
        android:textColor="#e5061d"
        android:textSize="22sp" />
    <TextView
        android:id="@+id/simple"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="15dp"
        android:gravity="center"
        android:text="If You Are A Teacher, \n Please Ask The Responsible \n Person, About The Register. \n \n POWERED BY: \n Anan Smnia \n(C)"
        android:textColor="#51aca9"
        android:textSize="22sp" />
</LinearLayout>

MainActivity.java
=================
package com.example.user.webtop;

import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.graphics.Color;
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;
import android.app.AlertDialog;
import android.content.DialogInterface;


public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private EditText etname;
    private EditText etpass;
    private TextView tve;

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

        connectToLayout();
    }

    private void connectToLayout() {
        etname = (EditText) findViewById(R.id.etname);
        etpass = (EditText) findViewById(R.id.etPassword);
        tve = (TextView) findViewById(R.id.tverr);


        findViewById(R.id.btnex).setOnClickListener(this);
        findViewById(R.id.btnlog).setOnClickListener(this);
        findViewById(R.id.btnreg).setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        String userName = etname.getText().toString();
        String password = etpass.getText().toString();
        if (v.getId() == R.id.btnex) {
            AlertDialog.Builder ad = new AlertDialog.Builder(this);
            ad.setTitle("Are You Sure To Exit ?");
            ad.setPositiveButton("Exit", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    moveTaskToBack(true);
                    android.os.Process.killProcess(android.os.Process.myPid());
                    System.exit(1);
                }
            });
            ad.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();
                }
            });
            ad.show();
        }

        if (v.getId() == R.id.btnlog) {
            tve.setText("");
            userName = etname.getText().toString();
            password = etpass.getText().toString();

            if (userName.length() == 0 || password.length() == 0) {
                tve.setText("Please Fill User Name And Password !");
                tve.setTextColor(Color.rgb(229, 6, 29));
                return;
            } else if (userName.length() > 0 && password.length() > 0) {
                if (isValid(userName, password)) {
                    if (!isTeacher(userName, password)) {
                        Intent i = new Intent(this, StudentActivity.class);
                        i.putExtra("CurrentUser", userName);
                        startActivity(i);
                        etname.setText("");
                        etpass.setText("");
                        tve.setText("");
                    } else  if (isTeacher(userName, password)) {
                        Intent i = new Intent(this, TeacherActivity.class);
                        i.putExtra("CurrentUser", userName);
                        startActivity(i);
                        etname.setText("");
                        etpass.setText("");
                        tve.setText("");
                    }
                } else {
                    tve.setText("Wrong User Name Or Password !");
                    tve.setTextColor(Color.rgb(229, 6, 29));
                }
            }
        }
        if (v.getId() == R.id.btnreg) {
            tve.setText("");
            userName = etname.getText().toString();
            password = etpass.getText().toString();

            if (userName.length() == 0 || password.length() == 0) {
                tve.setText("Please Fill User Name And Password !");
                tve.setTextColor(Color.rgb(229, 6, 29));
                return;
            }

            if (!isUserExist(userName)) {
                addNewUser(userName, password);
                tve.setText("User Was Added !");
                tve.setTextColor(Color.rgb(88, 168, 77));
                etname.setText("");
                etpass.setText("");
            } else {
                tve.setText("Error Adding The User " + userName + " !");
                tve.setTextColor(Color.rgb(229, 6, 29));
            }
        }

    }

    private boolean isTeacher(String userName, String password) {
        if (userName.substring(0, 1).equals("T")  && password.substring(0, 2).equals("00") && password.substring(password.length() - 2).equals("00")) {
            return true;
        }
        return false;
    }


    private boolean isValid(String userName, String password) {

        SharedPreferences prefs = this.getSharedPreferences("myUsers", Context.MODE_PRIVATE);

        String savedPassword = prefs.getString(userName, "");

        return (savedPassword.equals(password));
    }

    private boolean addNewUser(String userName, String password) {
        SharedPreferences prefs = this.getSharedPreferences("myUsers", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putString(userName, password);
        return editor.commit();
    }

    private boolean isUserExist(String userName) {
        SharedPreferences prefs = this.getSharedPreferences("myUsers", Context.MODE_PRIVATE);
        String savedPassword = prefs.getString(userName, "");
        return (!savedPassword.equals(""));
    }

}


person.class
=============
package com.example.user.webtop;

/**
 * Created by user on 20/10/2017.
 */

public class person {

    private String name;
    private String mark;

    public person(String name, String mark){
        this.name=name;
        this.mark=mark;
    }
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getMark() {
        return mark;
    }

    public void setMark(String mark) {
        this.mark = mark;
    }
}

personAdapter.class
====================
package com.example.user.webtop;

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

import java.util.List;

/**
 * Created by user on 20/10/2017.
 */

public class PersonAdapter extends BaseAdapter {
   private Context context;
    private List<person> personsList;

    public PersonAdapter(Context context, List<person> personsList){
        this.context=context;
        this.personsList=personsList;
    }

    @Override
    public int getCount() {
        return this.personsList.size();
    }

    @Override
    public Object getItem(int position) {
        return personsList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View myView = LayoutInflater.from(context).inflate(R.layout.studentshow, null);
        final person ps = personsList.get(position);
        ((TextView) myView.findViewById(R.id.StudentsesName)).setText(ps.getName());
        ((TextView) myView.findViewById(R.id.studentGrade)).setText(ps.getMark());
        return myView;
    }
}
StudentActiviy.java
===============
package com.example.user.webtop;

import android.content.Context;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

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

public class StudentActivity extends AppCompatActivity implements View.OnClickListener {

    private TextView tvname;
    private TextView Clases;
    private String snames;
    private ListView lsvGrades;

    private Button btn;
    List<person> lst;
    Context context;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_student);
        btn = (Button) findViewById(R.id.btnExist);
        tvname = (TextView) findViewById(R.id.Names);
        Clases = (TextView) findViewById(R.id.Classes);
        snames = getIntent().getStringExtra("CurrentUser");
        lsvGrades = (ListView) findViewById(R.id.lsvGrades);
        this.context = this;

        btn.setOnClickListener(this);
        tvname.setText(snames);

        lst = loadFromFile();
        PersonAdapter myAdapter = new PersonAdapter(context, lst);
        lsvGrades.setAdapter(myAdapter);
    }
    private List<person> loadFromFile() {
        SharedPreferences myfile = this.getSharedPreferences("MyPersons", Context.MODE_PRIVATE);
        Object[] keys = myfile.getAll().keySet().toArray();
        List<person> lst = new ArrayList<>();
        for (int i = 0; i < keys.length; i += 1) {
            String namesubject = (String) keys[i];
            String[] ss = namesubject.split("\\|");
            if (ss[1].equals(snames)) {
                lst.add(new person(ss[3], ss[2]));
                Clases.setText(ss[0]);
            }
        }

        return lst;
    }

    @Override
    public void onClick(View v) {
this.finish();
    }
}

Activity_student.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">
    <Button
        android:id="@+id/btnExist"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#00acff"
        android:text="Exit"
        android:textSize="22sp" />
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <TextView
        android:id="@+id/Names"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:gravity="right"
            android:text="aaa"
            android:textColor="#ff8cd1"
        android:layout_marginTop="15dp"
        android:textSize="22sp" />
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="                        "
            android:textColor="#ff8cd1"
            android:layout_marginTop="15dp"
            android:textSize="22sp" />
    <TextView
        android:id="@+id/Classes"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="left"
        android:text="aaa"
        android:textColor="#ff8cd1"
        android:layout_marginTop="15dp"
        android:textSize="22sp" />
    </LinearLayout>
    <ListView
        android:id="@+id/lsvGrades"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"> </ListView>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textSize="22sp" />

</LinearLayout>

Teacher.class
==============
package com.example.user.webtop;

/**
 * Created by user on 19/10/2017.
 */

public class Teacher {
    private String Subject;
    private String Clases;


    public Teacher(String Subject, String Clases) {
        this.Subject = Subject;
        this.Clases = Clases;
    }

    public String getSubject() {
        return Subject;
    }

    public String getClases() {
        return Clases;
    }

    public void setName(String Subject) {
        this.Subject = Subject;
    }

    public void setClases(String Clases) {
        this.Clases = Clases;
    }

}
TeacherAdapter.class
====================
package com.example.user.webtop;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import java.util.List;

public class TeacherAdapter extends BaseAdapter {

    private Context context;
    private List<Teacher> TeachersList;

    public TeacherAdapter(List<Teacher> TeachersList, Context context) {
        this.TeachersList = TeachersList;
        this.context = context;
    }

    @Override
    public int getCount() {
        return this.TeachersList.size();
    }

    @Override
    public Object getItem(int position) {
        return TeachersList.get(position);    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View myView = LayoutInflater.from(context).inflate(R.layout.list_row_layout, null);
        final Teacher teacher = TeachersList.get(position);
        ((TextView) myView.findViewById(R.id.tvsubject)).setText(teacher.getSubject());
        ((TextView) myView.findViewById(R.id.tvclases)).setText(teacher.getClases());
        return myView;
    }
}
TeacherActivity.java
====================
package com.example.user.webtop;

import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

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

public class TeacherActivity extends AppCompatActivity implements View.OnClickListener {
    private TextView tvteachername;
    private String teachername;
    private EditText etٍNewSubject;
    private EditText etNewGrade;
    private Button btnAddItem;
    private Button btnExit;
    private ListView lsvTeachers;
    List<Teacher> lst;
    Context context;

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

        tvteachername = (TextView) findViewById(R.id.tvteachername);
        teachername = getIntent().getStringExtra("CurrentUser");

        tvteachername.setText(teachername.substring(1, teachername.length()));

        this.context = this;
        etٍNewSubject = (EditText) findViewById(R.id.etٍNewSubject);
        etNewGrade = (EditText) findViewById(R.id.etNewGrade);

        btnAddItem = (Button) findViewById(R.id.btnAddTeacher);
        btnExit = (Button) findViewById(R.id.btnExit);
        lsvTeachers = (ListView) findViewById(R.id.lsvItems);
        btnAddItem.setOnClickListener(this);
        btnExit.setOnClickListener(this);

        lst = loadFromFile();
        TeacherAdapter myAdapter = new TeacherAdapter(lst, this);
        lsvTeachers.setAdapter(myAdapter);

        lsvTeachers.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
                final AlertDialog.Builder Dialoga = new AlertDialog.Builder(context);
                Dialoga.setTitle("U Want To Edit " + lst.get(position).getSubject() + " Subject, " + lst.get(position).getClases() + " Class Marks ?");
                Dialoga.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Intent i = new Intent(context, ClassActivity.class);
                        i.putExtra("SubjectName", (String) lst.get(position).getSubject());
                        i.putExtra("ClassName", (String) lst.get(position).getClases());
                        i.putExtra("TeacherName", teachername);

                        startActivity(i);
                        lsvTeachers.setAdapter(new TeacherAdapter(lst, context));
                    }
                });
                Dialoga.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
                Dialoga.show();
            }
        });

        lsvTeachers.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                final String SubjectForRemove = (String) lst.get(position).getSubject();
                final String clasesForRemove = (String) lst.get(position).getClases();
                final AlertDialog.Builder Dialoga = new AlertDialog.Builder(context);
                Dialoga.setTitle("U Want To Delete The " + SubjectForRemove + " Subject, " + clasesForRemove + " Class ?");
                Dialoga.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        SharedPreferences myfile = context.getSharedPreferences("MyTeachers", Context.MODE_PRIVATE);
                        myfile.edit().remove(teachername + "|" + SubjectForRemove + "|" + clasesForRemove).commit();
                        lst = loadFromFile();
                        lsvTeachers.setAdapter(new TeacherAdapter(lst, context));
                    }
                });
                Dialoga.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
                Dialoga.show();


                return false;
            }
        });
    }

    @Override
    public void onClick(View v) {
        if (v.getId() == R.id.btnAddTeacher) {
            String newSubjectName = etٍNewSubject.getText().toString();
            String newClassName = etNewGrade.getText().toString();

            if (!newSubjectName.isEmpty() && !newClassName.isEmpty()) {
                // add the item
                SharedPreferences myfile = this.getSharedPreferences("MyTeachers", Context.MODE_PRIVATE);
                String oldclassandsubject = myfile.getString(teachername + "|" + newSubjectName + "|" + newClassName, "");


                Object[] keys = myfile.getAll().keySet().toArray();
                int c = 0;
                for (int i = 0; i < keys.length; i += 1) {
                    String namesubject = (String) keys[i];
                    String[] ss = namesubject.split("\\|");
                    if (oldclassandsubject.equals("") && (ss[1].toString().equals(newSubjectName) == false && ss[2].toString().equals(newClassName) == false) || (ss[1].toString().equals(newSubjectName) == true && ss[2].toString().equals(newClassName) == false) || (ss[1].toString().equals(newSubjectName) == false && ss[2].toString().equals(newClassName) == true)) {
                        c++;
                    }
                }

                if (keys.length == c)
                    myfile.edit().putString(teachername + "|" + newSubjectName + "|" + newClassName, "1").commit();
                if (keys.length > c)
                    Toast.makeText(this, "The Teacher Of The " + newSubjectName + ", Of " + newClassName + " Class, Found In The System!", Toast.LENGTH_LONG).show();


                // update the list
                lst = loadFromFile();
                lsvTeachers.setAdapter(new TeacherAdapter(lst, this));
                etٍNewSubject.setText("");
                etNewGrade.setText("");
            }
        }
        if (v.getId() == R.id.btnExit) {
            this.finish();
        }


        }

    private List<Teacher> loadFromFile() {
        SharedPreferences myfile = this.getSharedPreferences("MyTeachers", Context.MODE_PRIVATE);
        Object[] keys = myfile.getAll().keySet().toArray();
        List<Teacher> lst = new ArrayList<>();
        for (int i = 0; i < keys.length; i += 1) {
            String namesubject = (String) keys[i];
            String[] ss = namesubject.split("\\|");
            if (ss[0].equals(teachername)) {
                lst.add(new Teacher(ss[1], ss[2]));
            }
        }
        return lst;
    }

}
Activity_Teacher.xml
====================
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
            android:id="@+id/btnExit"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#ff8cd1"
            android:text="Exit"
            android:textSize="22sp" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/tvteachername"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:gravity="center"
            android:textColor="#00acff"
            android:textSize="22sp" />
    </LinearLayout>

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

        <EditText
            android:id="@+id/etٍNewSubject"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:hint="Subject"
            android:textSize="22sp" />

        <EditText
            android:id="@+id/etNewGrade"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:inputType="number"
            android:hint="Class"
            android:textSize="22sp" />

        <Button
            android:id="@+id/btnAddTeacher"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:background="#ff8cd1"
            android:text="Add"
            android:textSize="22sp" />
    </LinearLayout>

    <ListView
        android:id="@+id/lsvItems"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:choiceMode="singleChoice"></ListView>
</LinearLayout>

ClassActivity.java
===================
package com.example.user.webtop;

import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

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

public class ClassActivity extends AppCompatActivity implements View.OnClickListener {

    private String TeachersNames;
    private String SubjectsNames;
    private String ClasesNames;
    private TextView tvTeachers;
    private TextView tvSubjects;
    private TextView tvClaases;
    private EditText etٍNewStudent;
    private EditText etNewMark;
    private Button btnAddStudent;
    private Button btnExits;
    private Button btnpre;
    private ListView lsvPersons;
    List<person> lst;
    Context context;
    int c = 0;

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

        tvTeachers = (TextView) findViewById(R.id.tvTeacherNames);
        tvSubjects = (TextView) findViewById(R.id.tvSubjectsesNames);
        tvClaases = (TextView) findViewById(R.id.tvClaasesNames);
        etٍNewStudent = (EditText) findViewById(R.id.etStudentName);
        etNewMark = (EditText) findViewById(R.id.etStudentMark);
        btnAddStudent = (Button) findViewById(R.id.btnAddStudent);
        btnExits = (Button) findViewById(R.id.btnExits);
        btnpre = (Button) findViewById(R.id.btnPrevius);
        lsvPersons = (ListView) findViewById(R.id.lsvStudents);

        lst = new ArrayList<>();
        this.context = this;

        TeachersNames = getIntent().getStringExtra("TeacherName");
        SubjectsNames = getIntent().getStringExtra("SubjectName");
        ClasesNames = getIntent().getStringExtra("ClassName");
        tvTeachers.setText(TeachersNames.substring(1, TeachersNames.length()));
        tvSubjects.setText(SubjectsNames);
        tvClaases.setText(ClasesNames);

        btnAddStudent.setOnClickListener(this);
        btnExits.setOnClickListener(this);
        btnpre.setOnClickListener(this);

        lst = loadFromFile();
        PersonAdapter pa = new PersonAdapter(context, lst);
        lsvPersons.setAdapter(pa);

        lsvPersons.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, final int position, long id) {
                final AlertDialog.Builder myDialog = new AlertDialog.Builder(context);
                final View myView = LayoutInflater.from(context).inflate(R.layout.mark_update, null);
                myDialog.setView(myView);
                myDialog.setTitle("Update Mark");
                myDialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        String inputDatas = ((EditText) myView.findViewById(R.id.etNewMark)).getText().toString();
                        if (!inputDatas.isEmpty() && Integer.parseInt(inputDatas) > 19 && Integer.parseInt(inputDatas) <= 100) {
                            int newMark = Integer.parseInt(inputDatas);
                            String itemName = lst.get(position).getName();
                            SharedPreferences myfiles = context.getSharedPreferences("MyPersons", Context.MODE_PRIVATE);
                            if (!lst.get(position).getMark().equals("")) {
                                Object[] keys = myfiles.getAll().keySet().toArray();
                                for (int i = 0; i < keys.length; i += 1) {
                                    String personName = (String) keys[i];
                                    String[] ss = personName.split("\\|");
                                    if (ss[0].equals(ClasesNames) && ss[1].equals(itemName) && ss[3].equals(SubjectsNames) && ss[4].equals(TeachersNames) && !ss[2].equals("")) {
                                        myfiles.edit().remove(ClasesNames + "|" + itemName + "|" + ss[2] + "|" + SubjectsNames + "|" + TeachersNames).commit();
                                        myfiles.edit().putString(ClasesNames + "|" + itemName + "|" + inputDatas + "|" + SubjectsNames + "|" + TeachersNames, "1").commit();
                                        lst = loadFromFile();
                                        lsvPersons.setAdapter(new PersonAdapter(context, lst));
                                    }
                                }
                            }
                            if (lst.get(position).getMark().equals("")) {
                                myfiles.edit().putString((ClasesNames + "|" + itemName + "|" + inputDatas + "|" + SubjectsNames + "|" + TeachersNames), "1").commit();
                                lst.remove(position);
                                lst = loadFromFile();
                                lsvPersons.setAdapter(new PersonAdapter(context, lst));
                            }
                        }
                        lst = loadFromFile();
                        lsvPersons.setAdapter(new PersonAdapter(context, lst));
                        dialog.cancel();
                    }

                });
                myDialog.show();
            }
        });

        lsvPersons.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {

                final String MarkForRemove = (String) lst.get(position).getMark();
                final String NameForRemove = (String) lst.get(position).getName();
                final android.support.v7.app.AlertDialog.Builder Dialoga = new android.support.v7.app.AlertDialog.Builder(context);
                Dialoga.setTitle("U Want To Delete The " + NameForRemove + " Student, " + MarkForRemove + " Mark ?");
                Dialoga.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        SharedPreferences myfile = context.getSharedPreferences("MyPersons", Context.MODE_PRIVATE);
                        myfile.edit().remove(ClasesNames + "|" + lst.get(position).getName() + "|" + lst.get(position).getMark() + "|" + SubjectsNames + "|" + TeachersNames).commit();
                        lst = loadFromFile();
                        lsvPersons.setAdapter(new PersonAdapter(context, lst));
                    }
                });
                Dialoga.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
                Dialoga.show();


                return false;
            }
        });

    }

    @Override
    public void onClick(View v) {
        lst = loadFromFile();

        if (v.getId() == R.id.btnAddStudent) {
            lst = loadFromFile();

            boolean flag = false;

            String newPersonName = etٍNewStudent.getText().toString();
            String newPersonMark = etNewMark.getText().toString();
            if (!newPersonName.isEmpty() && !newPersonMark.isEmpty() && Integer.parseInt(newPersonMark) > 19 && Integer.parseInt(newPersonMark) <= 100) {
                SharedPreferences myfile = this.getSharedPreferences("MyPersons", Context.MODE_PRIVATE);
                String classnamemarksubjectteacher = myfile.getString(ClasesNames + "|" + newPersonName + "|" + newPersonMark + "|" + SubjectsNames + "|" + TeachersNames, "");
                SharedPreferences mf = context.getSharedPreferences("MyPersons", Context.MODE_PRIVATE);
                Object[] keys = mf.getAll().keySet().toArray();
                for (int i = 0; i < keys.length; i += 1) {
                    String personName = (String) keys[i];
                    String[] ss = personName.split("\\|");

                    if (ss[1].equals(newPersonName) && !ss[0].equals(ClasesNames) && isUserFound(newPersonName)) {
                        Toast.makeText(this, "The Student, " + newPersonName + " Is Avalibale In Another Class !", Toast.LENGTH_LONG).show();
                        flag = true;

                    } else if (ss[1].equals(newPersonName) && ss[0].equals(ClasesNames) && isUserFound(newPersonName) && isUserNotFoundInTheList(newPersonName)) {
                        myfile.edit().putString(ClasesNames + "|" + newPersonName + "|" + newPersonMark + "|" + SubjectsNames + "|" + TeachersNames, "1").commit();
                        flag = true;
                    } else if (ss[1].equals(newPersonName) && ss[0].equals("") && isUserFound(newPersonName) && isUserNotFoundInTheList(newPersonName)) {
                        myfile.edit().putString(ClasesNames + "|" + newPersonName + "|" + newPersonMark + "|" + SubjectsNames + "|" + TeachersNames, "1").commit();
                        flag = true;

                    }
                }
                if (isUserFound(newPersonName) && flag == false && isUserNotFoundInTheList(newPersonName)) {
                    myfile.edit().putString(ClasesNames + "|" + newPersonName + "|" + newPersonMark + "|" + SubjectsNames + "|" + TeachersNames, "1").commit();
                    flag = false;
                }
                if (!isUserFound(newPersonName))
                    Toast.makeText(this, "The Student " + newPersonName + " Is Not Avalibale In The System, Or It's A Teacher Please Check It !", Toast.LENGTH_LONG).show();
                lst = loadFromFile();
                lsvPersons.setAdapter(new PersonAdapter(this, lst));
                etٍNewStudent.setText("");
                etNewMark.setText("");
            } else {
                Toast.makeText(this, "Some Thing Is Illegal, Please Check The Student Name And The Mark !", Toast.LENGTH_LONG).show();
            }
        }
        if (v.getId() == R.id.btnExits) {
            lst = loadFromFile();

            Intent i = new Intent(this, MainActivity.class);
            this.finish();
            startActivity(i);
        }

        if (v.getId() == R.id.btnPrevius) {
            lst = loadFromFile();

            this.finish();
        }


    }




    private boolean isUserFound(String userName) {
        SharedPreferences prefs = this.getSharedPreferences("myUsers", Context.MODE_PRIVATE);
        String savedPassword = prefs.getString(userName, "");
        if ((!savedPassword.equals("")) && isNotTeacher(userName))
            return true;
        return false;
    }

    private boolean isNotTeacher(String userName) {
        SharedPreferences prefs = this.getSharedPreferences("myUsers", Context.MODE_PRIVATE);
        String savedPassword = prefs.getString(userName, "");
        if (!userName.substring(0, 1).equals("T") || !savedPassword.substring(0, 2).equals("00") ||
                !savedPassword.substring(savedPassword.length() - 2).equals("00"))
            return true;
        return false;
    }

    private List<person> loadFromFile() {
        SharedPreferences myfile = this.getSharedPreferences("MyPersons", Context.MODE_PRIVATE);
        Object[] keys = myfile.getAll().keySet().toArray();
        List<person> lsts = new ArrayList<>();

        for (int i = 0; i < keys.length; i += 1) {
            String personName = (String) keys[i];
            String[] ss = personName.split("\\|");


            if (ss[0].equals(ClasesNames)) {
                if (ss[3].equals(SubjectsNames) && ss[4].equals(TeachersNames)) {
                    lsts.add(new person(ss[1], ss[2]));

                }

            }
        }

        return lsts;
    }

    private boolean isUserNotFoundInTheList(String personname){

        for (int i = 0 ; i <lst.size(); i++){
            if (lst.get(i).getName().equals(personname)) return false;
        }

        return true;
    }

}
Activity_class.xml
===================
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f7fcff"
    android:orientation="vertical">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <Button
            android:id="@+id/btnExits"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#ff8cd1"
            android:layout_weight="2"
            android:text="Exit"
            android:textSize="22sp" />
        <Button
            android:id="@+id/btnPrevius"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="#00acff"
            android:layout_weight="2"
            android:text="Previous"
            android:textSize="22sp" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <TextView
            android:id="@+id/tvTeacherNames"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginTop="15dp"
            android:layout_weight="1"
            android:textColor="#ff8cd1"
            android:textSize="22sp" />

        <TextView
            android:id="@+id/tvSubjectsesNames"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginTop="15dp"
            android:layout_weight="1"
            android:textColor="#00acff"
            android:textSize="22sp" />

        <TextView
            android:id="@+id/tvClaasesNames"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginTop="15dp"
            android:layout_weight="1"
            android:textColor="#ff8cd1"
            android:textSize="22sp" />
    </LinearLayout>


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

        <EditText
            android:id="@+id/etStudentName"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:hint="Name"
            android:textSize="22sp" />

        <EditText
            android:id="@+id/etStudentMark"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:inputType="number"
            android:layout_weight="2"
            android:hint="Mark"
            android:textSize="22sp" />

        <Button
            android:id="@+id/btnAddStudent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="2"
            android:background="#ff8cd1"
            android:text="Add"
            android:textSize="22sp" />
    </LinearLayout>
    <ListView
        android:id="@+id/lsvStudents"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:choiceMode="singleChoice"></ListView>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textColor="#00acff"
        android:textSize="22sp" />
</LinearLayout>

list_row_layout.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="wrap_content"
    android:background="#00acff"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/tvsubject"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textColor="#FFFFFF"
        android:textSize="22sp" />

    <TextView
        android:id="@+id/tvclases"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textColor="#FFFFFF"
        android:textSize="22sp" />

</LinearLayout>
mark_update.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">
    <EditText
        android:id="@+id/etNewMark"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Enter The New Mark"
        android:inputType="number"
        android:textSize="22sp" />

</LinearLayout>
studentshow.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="wrap_content"
    android:background="#ff8cd1"
    android:orientation="horizontal">

    <TextView
        android:id="@+id/StudentsesName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textColor="#FFFFFF"
        android:textSize="22sp" />
    <TextView
        android:id="@+id/studentGrade"
        android:fontFamily="sans-serif-medium"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:textColor="#FFFFFF"
        android:textSize="22sp" />
</LinearLayout>
updatemarks.xml
=================
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="2"
        android:hint="New Mark"
        android:textSize="22sp" />

    <Button
        android:id="@+id/etNewQuentity"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="2"
        android:hint="The New Mark"
        android:textColorHint="#00acff"
        android:textSize="22sp" />

</LinearLayout>