example of my task system with login and register

MainActivity.java
========================
package com.example.zeevm.mysharedpref;

import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.support.v7.app.AlertDialog;
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;

public class MainActivity extends AppCompatActivity {

    EditText txtUserName;
    EditText txtUserPass;
    TextView lblMsg;
    Context context;

    private int totalTry=5;
    Button btnLogin;
    Button btnRegister;

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

    private void setPointer()
    {
        this.context=this;
        txtUserName=(EditText)findViewById(R.id.txtUserName);
        txtUserPass=(EditText)findViewById(R.id.txtUserPassword);
        lblMsg=(TextView)findViewById(R.id.lblMsg);
        btnLogin=(Button)findViewById(R.id.btnLogin);
        btnRegister=(Button)findViewById(R.id.btnRegister);

        //listerners
        btnLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
               login();
            }
        });

        btnRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                register();
            }
        });
    }

    private void login()
    {
        String getUser=txtUserName.getText().toString();
        String getPass=txtUserPass.getText().toString();

        if (totalTry==0) {
            Toast.makeText(MainActivity.this, "You are an idiot!!", Toast.LENGTH_SHORT).show();
            return;
        }
        utlShared shared = new utlShared(this);
        if (shared.checkUserPassword(getUser,getPass))
        {
            Intent intent = new Intent(this,Welcome.class);
            intent.putExtra("userName",getUser);
            startActivity(intent);
            finish();
        }
        else {
            if (shared.checkUser(getUser))
            {
                Toast.makeText(context, "Wrong password", Toast.LENGTH_SHORT).show();
            }
            else {
                showLoginErrorDialog();
            }
            //Toast.makeText(MainActivity.this, "Wrong user name or password", Toast.LENGTH_SHORT).show();

        }
    }

    private void register()
    {
        startActivity(new Intent(this,Register.class));
    }

    private void showLoginErrorDialog()
    {
        new AlertDialog.Builder(this)
                //set title to dialog
                .setTitle("User not found")
                //set message to dialog
                .setMessage("Do you want to register new user")
                //set ok(yes) button
                .setPositiveButton("register", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        //close the dialog
                        dialogInterface.dismiss();
                        //start register activity
                        startActivity(new Intent(context,Register.class));

                    }
                })
                //set cancel(no) button
                .setNegativeButton("let me try again", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        dialogInterface.dismiss();
                    }
                })
                //show the dialog
                .show();
    }

}


Register.java
==============
package com.example.zeevm.mysharedpref;

import android.content.Context;
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.Toast;

public class Register extends AppCompatActivity {

    Button btnCancel;
    Button btnRegister;
    Context context;
    EditText txtUser,txtPass,txtPass2;

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

    private void setPointer()
    {
        this.context=this;
        txtUser=(EditText)findViewById(R.id.txtUserName);
        txtPass=(EditText)findViewById(R.id.txtPassword);
        txtPass2=(EditText)findViewById(R.id.txtPassword2);
        btnCancel=(Button)findViewById(R.id.btnCancel);
        btnCancel.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });



        btnRegister=(Button)findViewById(R.id.btnRegisterUser);
        btnRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //check if password equal
                String pass1=txtPass.getText().toString();
                String pass2=txtPass2.getText().toString();
                if (!pass1.equals(pass2))
                {
                    Toast.makeText(context, "Password not match!!!", Toast.LENGTH_SHORT).show();
                    return;
                }
                //calling the utl shared class
                utlShared myShared = new utlShared(context);
                //check if user exists
                String userName=txtUser.getText().toString();
                if (myShared.checkUser(userName))
                {
                    Toast.makeText(context, "User Exists....", Toast.LENGTH_SHORT).show();
                    return;
                }
                //running the method of add user
                myShared.addUser(userName,pass1);
                finish();
            }
        });
    }

}



TaskAdapter.java
=================
package com.example.zeevm.mysharedpref;

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

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

/**
 * Created by zeevm on 9/1/2016.
 */
public class TaskAdapter extends BaseAdapter {

    //transfer context
    Context context;
    //transfer user to use for shared preferences
    String userName;
    //create a list of tasks.....
    List<taskItem> myTasks;

    //constructor, for creating the adapter we need from the user context and userName
    public TaskAdapter(Context context,String userName) {
        this.context = context;
        this.userName=userName;
        //go to user shared preferences and fill the list
        getData();
    }

    //how many item to display
    @Override
    public int getCount() {
        //return the myTasks size....
        return myTasks.size();
    }

    //return a specific item by index
    @Override
    public Object getItem(int i) {
        return myTasks.get(i);
    }

    //return index number
    @Override
    public long getItemId(int i) {
        return 0;
    }

    //create our view
    @Override
    public View getView(int index, View view, ViewGroup viewGroup) {
        //inflate the view inside view object -> viewInflated
        View viewInflated = LayoutInflater.from(context).inflate(R.layout.task_item,null,false);

        //set our inflated view behiver

        //set pointer for our inflated view

        //set pointer for task name....
        final TextView txtTaskName=(TextView)viewInflated.findViewById(R.id.taskName);
        //set pointer for task status....
        final Switch swTask=(Switch)viewInflated.findViewById(R.id.taskDone);

        //set task name, by the index of my myTasks collection
        txtTaskName.setText(myTasks.get(index).taskName);
        //set task status , switch is getting true/false
        swTask.setChecked(myTasks.get(index).taskStatus);


        //create listener event, when switch is pressed
        swTask.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //we using utlShared to update task status
                //create instance of utlShared
                utlShared myShared = new utlShared(context);
                //calling method of task, and giving userName(shared preferences, taskName, taskStatus)
                myShared.task(userName,txtTaskName.getText().toString(),swTask.isChecked());
                //we sending a message to the user, and inform him/her about the change
                Toast.makeText(context, swTask.isChecked()?"Task done...":"Task undone...", Toast.LENGTH_SHORT).show();
            }
        });

        //return the view with the behiver.....
        return viewInflated;
    }

    private void getData()
    {
        //go to specific shared preferences by user name.....
        SharedPreferences taskPref=context.getSharedPreferences(userName,context.MODE_PRIVATE);

        //create instance of our myTasks list
        myTasks = new ArrayList<>();
        //get all tasks from shared preferances
        //the shared preferences is by key and value, therefor we will use Map collection
        //we know that the key is String, but we don't know what type of value we will get. <K,?>
        Map<String,?> tasks=taskPref.getAll();
        // transfer the data from map collection to list collection , single item is like the defination of the tasks <String,?>
        //Entry -> record , enterSet -> set of records
        for(Map.Entry<String,?> singleTask:tasks.entrySet())
        {
            //insert task to list by Key and Value, we check if value is equal to 1, becuase 1=true 0=false
            myTasks.add(new taskItem(singleTask.getKey(),singleTask.getValue().equals("1")));
        }
    }

}



taskItem.java
==================
package com.example.zeevm.mysharedpref;

/**
 * Created by zeevm on 9/1/2016.
 */
public class taskItem {
    public String taskName;
    public boolean taskStatus;

    public taskItem(String taskName, boolean taskStatus) {
        this.taskName = taskName;
        this.taskStatus = taskStatus;
    }
}



utlShared.java
====================
package com.example.zeevm.mysharedpref;

import android.content.Context;
import android.content.SharedPreferences;
import android.util.Log;

/**
 * Created by zeevm on 8/25/2016.
 */
public class utlShared {
    //context to use later
    Context context;
    //declatrtion of shared preferences object
    private SharedPreferences userPref;
    //declaration of shared preferences editor
    private SharedPreferences.Editor editor;

    public utlShared() {}

    public utlShared(Context context)
    {
        //get context to use it
        this.context=context;
        //declaretion of shared preferences with file name and file mode (private,public)
        userPref=context.getSharedPreferences("users",Context.MODE_PRIVATE);
        //declaration of editor
        editor=userPref.edit();
    }

    //get user and password
    public void addUser(String userName, String password)
    {
        //stores in the phone device under data\data\package name
        //put in shared preferences user name and password
        editor.putString(userName,password);
        //commit (save/apply) the changes.
        editor.commit();
    }

    public boolean checkUser(String userName)
    {
        //get name by key->userName
        String checkString = userPref.getString(userName,"na");

        //print to logcat a custom message.....
        Log.e("checkUser", "checkUser: "+checkString );
        //check if userName equals to responded data, if it's na, we don't havce the user...
        return !checkString.equals("na");
    }

    public boolean checkUserPassword(String userName, String userPassword)
    {
        String checkString = userPref.getString(userName,"na");
        return checkString.equals(userPassword);
    }

    public void task(String userName,String taskName,boolean taskDone)
    {
        //pointer to user task shared preferances
        SharedPreferences taskPref=context.getSharedPreferences(userName,Context.MODE_PRIVATE);
        //create editor to change the specific shared preferences
        SharedPreferences.Editor taskEditor=taskPref.edit();

        //add new task -> if true write 1 else write 0
        taskEditor.putString(taskName,taskDone?"1":"0");
        //apply the changes
        taskEditor.commit();
    }


}



Welcome.java
===================
package com.example.zeevm.mysharedpref;

import android.content.Context;
import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.InputType;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

public class Welcome extends AppCompatActivity {

    String userName;
    Context context;
    utlShared myUtl;
    ListView taskList;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_welcome);
        setPointer();

    }

    private void setPointer()
    {
        this.context=this;
        userName=getIntent().getStringExtra("userName");
        myUtl = new utlShared(context);
        taskList=(ListView)findViewById(R.id.taskList);
        setListData();
        Toast.makeText(Welcome.this, "welcome user:"+userName, Toast.LENGTH_SHORT).show();
    }

    private void setListData()
    {
        TaskAdapter adapter = new TaskAdapter(context,userName);
        taskList.setAdapter(adapter);
    }


    public void addTask(View view)
    {
        //create builder
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        //set title
        builder.setTitle("Add task");

        //set up the input
        final EditText newTask = new EditText(context);
        newTask.setHint("Enter new task....");
        newTask.setInputType(InputType.TYPE_CLASS_TEXT);
        builder.setView(newTask);

        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.dismiss();
            }
        });

        builder.setPositiveButton("Add Task", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                String myTaskTest = newTask.getText().toString();
                Toast.makeText(context, "task name:"+myTaskTest, Toast.LENGTH_SHORT).show();
            }
        });

        builder.show();
    }

    public void addCustomTask(View view)
    {
        //create builder
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        //set title
        builder.setTitle("Add new task");

        //inflate view from layout ->custom layout,null,false as defualt values
        View viewInflated= LayoutInflater.from(context).inflate(R.layout.dlg_new_task,null,false);

        final EditText txtCustomTask = (EditText)viewInflated.findViewById(R.id.txtTask);

        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.dismiss();
            }
        });

        builder.setPositiveButton("Add task", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.dismiss();
                String myTask = txtCustomTask.getText().toString();
                //Toast.makeText(context, "task is:"+myText, Toast.LENGTH_SHORT).show();
                myUtl.task(userName,myTask,false);
                /////
                setListData();
            }
        });

        //display our inflated view in screen
        builder.setView(viewInflated);
        //show the dialog
        builder.show();

    }

    public void addYesNo(View view)
    {
        AlertDialog.Builder builder = new AlertDialog.Builder(context);
        builder.setTitle("YES OR NO");
        builder.setMessage("Wanta a fanta???");
        builder.setPositiveButton("YES I WANT", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                Toast.makeText(context, "ENJOY", Toast.LENGTH_LONG).show();
                dialogInterface.dismiss();
            }
        });
        builder.setNegativeButton("ON DIET", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                Toast.makeText(context, "GoodBye Fatty!!", Toast.LENGTH_SHORT).show();
                dialogInterface.dismiss();
            }
        });
        builder.show();
    }
}


activity_main.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="150dp"
        android:orientation="vertical">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:text="LOGO"
            android:textSize="100sp">

        </TextView>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:orientation="vertical">

        <EditText
            android:id="@+id/txtUserName"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Enter your name...."
            android:inputType="text"
            android:textSize="22sp" />

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

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="150dp"
        android:orientation="vertical">

        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Login"
            android:background="#00BFFF"
            android:textColor="#ffffff"
            android:textSize="32sp"
            android:id="@+id/btnLogin"
            android:layout_marginBottom="20dp"/>

        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Register"
            android:background="#00BFFF"
            android:textColor="#ffffff"
            android:textSize="32sp"
            android:id="@+id/btnRegister"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:textSize="32sp"
            android:text="MY LOGIN SYSTEM V1"
            android:gravity="center"
            android:id="@+id/lblMsg"/>
    </LinearLayout>
</LinearLayout>



activity_register.xml
=====================
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:gravity="center"
        android:text="USER REGISTERTION"
        android:textSize="32sp" />

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Enter User Name...."
            android:id="@+id/txtUserName"/>
        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Enter password...."
            android:id="@+id/txtPassword"
            android:layout_below="@id/txtUserName"/>

        <EditText
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:hint="Enter password again..."
            android:id="@+id/txtPassword2"
            android:layout_below="@id/txtPassword"/>
        <Button
            android:layout_width="150dp"
            android:layout_height="wrap_content"
            android:id="@+id/btnRegisterUser"
            android:layout_below="@id/txtPassword2"
            android:text="Register"/>
        <Button
            android:layout_width="150dp"
            android:layout_height="wrap_content"
            android:text="Cancel"
            android:id="@+id/btnCancel"
           android:layout_toEndOf="@id/btnRegisterUser"
            android:layout_below="@id/txtPassword2"/>
    </RelativeLayout>

</LinearLayout>



activity_welcome.xml
=====================
<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:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ADD TASK"
        android:onClick="addCustomTask"
        />

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/taskList"/>
</LinearLayout>



dlg_new_task.xml
======================
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
    android:gravity="center">

<ImageView
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:src="@drawable/task"/>
<EditText
    android:layout_width="200dp"
    android:layout_height="wrap_content"
    android:hint="Enter task"
    android:id="@+id/txtTask"/>
</LinearLayout>



task_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="50dp"
    android:orientation="horizontal"
    android:layoutDirection="rtl"
    android:layout_margin="20dp"
    >

    <Switch
        android:layout_width="40dp"
        android:layout_height="wrap_content"
        android:id="@+id/taskDone"
        />
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:textSize="22sp"
        android:id="@+id/taskName"
        android:text="EXAMPLE FOR TASK"
        />
</LinearLayout>