View difference between Paste ID: 4Ri8AYFt and qcKtBGqk

 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"
     android:layout_margin="16dp">
 
     <!-- place for logo -->
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_weight="1"
         android:orientation="vertical"
         android:gravity="center">
         <TextView
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:text="MY TASK"
             android:textSize="64sp"/>
     </LinearLayout>
 
     <!-- place for user input -->
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_weight="1"
         android:orientation="vertical"
         android:gravity="center">
         <EditText
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:hint="@string/userName"
             android:id="@+id/txtUser"/>
         <EditText
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:hint="@string/userPass"
             android:inputType="textPassword"
             android:layout_marginTop="20dp"
             android:id="@+id/txtPass"/>
     </LinearLayout>
 
     <!-- place for buttons-->
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_weight="1"
         android:orientation="horizontal"
         android:gravity="top">
         <Button
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="@string/register"
             android:textColor="#ffffff"
             android:background="#009fff"
             android:textSize="22sp"
             android:layout_weight="1"
             android:layout_margin="20dp"
             android:id="@+id/btnRegister"/>
         <Button
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:text="@string/login"
             android:textColor="#ffffff"
             android:background="#009fff"
             android:textSize="22sp"
             android:layout_weight="1"
             android:layout_margin="20dp"
             android:id="@+id/btnLogin"/>
     </LinearLayout>
 
 </LinearLayout>
 
 
 activity_register.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_margin="16dp">
 
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_weight="2"
         android:orientation="vertical"
        >
         <TextView
             android:layout_width="wrap_content"
             android:layout_height="match_parent"
             android:text="LOGO"
             android:textSize="62sp"
             android:layout_gravity="center"
             />
     </LinearLayout>
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_weight="1"
         android:orientation="vertical"
         android:layout_margin="30dp">
         <EditText
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:id="@+id/regUserName"
             android:hint="Enter a user name..."
             android:layout_weight="1"
             android:gravity="bottom"/>
         <EditText
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:id="@+id/regPass1"
             android:hint="Enter your password...."
             android:layout_weight="1"
             android:gravity="bottom"
             android:inputType="textPassword"/>
         <EditText
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:id="@+id/regPass2"
             android:hint="Re-Enter your password..."
             android:layout_weight="1"
             android:gravity="bottom"
             android:inputType="textPassword"
             />
     </LinearLayout>
     <LinearLayout
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_weight="2"
         android:orientation="horizontal">
         <Button
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:text="@string/register"
             android:textColor="#ffffff"
             android:background="#009fff"
             android:textSize="32sp"
             android:layout_weight="1"
             android:layout_margin="10dp"
             android:id="@+id/btnRegRegister"/>
         <Button
             android:layout_width="match_parent"
             android:layout_height="match_parent"
             android:text="cancel"
             android:textColor="#ffffff"
             android:background="#009fff"
             android:textSize="32sp"
             android:layout_weight="1"
             android:layout_margin="10dp"
             android:id="@+id/btnRegCancel"/>
     </LinearLayout>
 </LinearLayout>
 
 android manifest (example only)
 ======================================
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.example.teacher.mytasks">
 
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         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>
         <activity android:name=".RegisterActivity"/>
     </application>
 
 </manifest>
 
 
 RegisterActivity.java
 =========================
 
 import android.content.Context;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatActivity;
 import android.view.View;
 import android.widget.Button;
 import android.widget.EditText;
 import android.widget.Toast;
 
 /**
  * Created by teacher on 12/21/2017.
  */
 
 public class RegisterActivity extends AppCompatActivity {
     Context context;
     EditText regUser,regPass1,regPass2;
     Button btnRegister,btnCancel;
     UtlUserSP userUtil=new UtlUserSP();
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_register);
         setPointer();
     }
 
     private void setPointer() {
         this.context=this;
         userUtil.setContext(context);
         regUser=findViewById(R.id.regUserName);
         regPass1=findViewById(R.id.regPass1);
         regPass2=findViewById(R.id.regPass2);
         btnCancel=findViewById(R.id.btnRegCancel);
         btnCancel.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
                 finish();
             }
         });
         btnRegister =findViewById(R.id.btnRegRegister);
         btnRegister.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
                 //check if password o.k.
                 if (!regPass1.getText().toString().equals(regPass2.getText().toString()))
                 {
                     Toast.makeText(context, "Password not match", Toast.LENGTH_SHORT).show();
                     return;
                 }
                 if (regPass1.getText().toString().length()<3)
                 {
                     Toast.makeText(context, "Password must be 3 letter minimum", Toast.LENGTH_SHORT).show();
                     return;
                 }
                 if(!userUtil.registerUser(regUser.getText().toString(),regPass1.getText().toString()))
                 {
                     Toast.makeText(context, "Error in user registration....", Toast.LENGTH_SHORT).show();
                     return;
                 }
                 Toast.makeText(context, "new user is add...", Toast.LENGTH_SHORT).show();
                 finish();
             }
         });
 
     }
 }
 
 
 
 MainActivity.java
 ======================
 import android.content.Context;
 import android.content.Intent;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.Button;
 import android.widget.EditText;
 
 public class MainActivity extends AppCompatActivity {
     EditText txtUser, txtPass;
     Button btnLogin, btnRegister;
     Context context;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         setPointer();
     }
 
     private void setPointer() {
         this.context = this;
         txtUser = findViewById(R.id.txtUser);
         txtPass = findViewById(R.id.txtPass);
         btnLogin = findViewById(R.id.btnLogin);
         btnRegister = findViewById(R.id.btnRegister);
 
         btnRegister.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
                 Intent myIntent=new Intent(context,RegisterActivity.class);
                 startActivity(myIntent);
             }
         });
     }
 }
 
 
 
 
 UtlUserSp.java
 =====================
 package com.example.teacher.mytasks;
 
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.widget.Toast;
 
 /**
  * Created by teacher on 12/21/2017.
  */
 
 public class UtlUserSP implements UserAble {
     Context context;
 
     public UtlUserSP() { }
 
     @Override
     public void setContext(Context context) {
         this.context=context;
     }
 
     @Override
     public boolean registerUser(String userName, String userPass) {
         //User Exists
         if (userExists(userName)) {
             Toast.makeText(context, "user already exists...", Toast.LENGTH_SHORT).show();
             return false;
         }
         //save user and password
 
         //declaration of shared preference
         SharedPreferences prefs = context.getSharedPreferences("myPrefs", Context.MODE_PRIVATE);
 
         //declaration of shared preference editor
         SharedPreferences.Editor editor = prefs.edit();
 
         //put data inside, we use hash map, so we need KEY,VALUE (k,v)
         editor.putString(userName, userPass);
 
         //sending data to my shared preferences file.
         editor.commit();
         return true;
     }
 
     @Override
     public boolean userExists( String userName) {
         //declaration of shared prefernces
         SharedPreferences prefs=context.getSharedPreferences("myPrefs",Context.MODE_PRIVATE);
 
         //get user pass
         String spPass=prefs.getString(userName,"na");
 
         //return if users exists, if not (na) return false
         return !spPass.equals("na");
     }
 
     @Override
     public boolean checkUser( String userName, String userPass) {
         return false;
     }
 }