TASK (android studio log in page )

main activity xml :
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.jan25.mytask3.MainActivity">

    <LinearLayout
        android:layout_width="376dp"
        android:layout_height="30dp"
        android:orientation="vertical"
        tools:layout_editor_absoluteX="8dp"
        tools:layout_editor_absoluteY="8dp">

        <TextView
            android:id="@+id/logPage"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:text="LogIn Page" />

    </LinearLayout>

    <LinearLayout
        android:layout_width="373dp"
        android:layout_height="142dp"
        android:orientation="vertical"
        tools:layout_editor_absoluteX="6dp"
        tools:layout_editor_absoluteY="122dp">

        <EditText
            android:id="@+id/usertxt"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ems="10"
            android:inputType="textPersonName"
            android:text="@string/userName" />

        <EditText
            android:id="@+id/passtxt"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:ems="10"
            android:inputType="textPersonName"
            android:text="@string/userPass" />

        <Button
            android:id="@+id/btnsign"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:onClick="onClick"
            android:text="@string/button"
            tools:text="Sign In" />

    </LinearLayout>
</android.support.constraint.ConstraintLayout>
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main activity java

package com.example.jan25.mytask3;

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

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    final String USERNAME_DB = "Jan", USERPASS_DB = "123";
    EditText usertxt, passtxt;

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


    }

    public void setPointer() {
        usertxt = findViewById(R.id.usertxt);
        passtxt = findViewById(R.id.passtxt);
    }

    @Override
    public void onClick(View view) {
        String userName = usertxt.getText().toString();
        String userPass = passtxt.getText().toString();

        switch (view.getId()) {
            case R.id.btnsign:
                if (userName.equals(USERNAME_DB)) {
                    if (userPass.equals(USERPASS_DB))
                        Toast.makeText(MainActivity.this, getString(R.string.loginSuccess), Toast.LENGTH_SHORT).show();


                    }
                    else {
                Toast.makeText(MainActivity.this, getString(R.string.loginErrorUserNull), Toast.LENGTH_SHORT).show();

                }
        }
    }
}
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strings

<resources>
    <string name="app_name">myTask3</string>
    <string name="userName">Enter Username </string>
    <string name="userPass">Enter Password </string>
    <string name="button">Sign In </string>
    <string name="loginSuccess">Login successful</string>
    <string name="loginErrorUserNull">Invalid username or password</string>


</resources>
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