package com.example.higherorlower;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import java.util.Random;

public class MainActivity extends AppCompatActivity {

    public void Go(View view) {

        EditText enteredNumber = findViewById(R.id.enteredNumber);
        String entryAsString = enteredNumber.getText().toString();
//        int entryAsInt = Integer.parseInt(entryAsString);
        if (!entryAsString.equals(""))
            if (Integer.parseInt(entryAsString) >= 0 && Integer.parseInt(entryAsString) <= 20)
                if (Integer.parseInt(entryAsString) > randomNum) {
                    Toast.makeText(this, "Choose a lesser number", Toast.LENGTH_SHORT).show();
                    enteredNumber.setText("");
                } else if (Integer.parseInt(entryAsString) < randomNum) {
                    Toast.makeText(this, "Choose a higher number", Toast.LENGTH_SHORT).show();
                    enteredNumber.setText("");
                } else {
                    Toast.makeText(this, "Bingo! " + randomNum + " was the number I was thinking", Toast.LENGTH_SHORT).show();
                    random1();
                    enteredNumber.setText("");

                }
            else {
                Toast.makeText(this, "You are guessing number out of the limit!", Toast.LENGTH_LONG).show();
                enteredNumber.setText("");
            }
        else {
//            Toast.makeText(this, "", Toast.LENGTH_SHORT).show();
        }
    }

    int randomNum;

    public void random1() {
        Random r = new Random();
        randomNum = r.nextInt(20);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        random1();
    }
}


******************************************************************************

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    android:onClick="Go"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="37dp"
        android:layout_marginTop="63dp"
        android:layout_marginEnd="36dp"
        android:layout_marginBottom="558dp"
        android:text="@string/i_have_a_number_in_my_mind_between_0_and_20_can_you_guess_it"
        android:textAlignment="center"
        android:textSize="16sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <EditText
        android:id="@+id/enteredNumber"
        android:layout_width="329dp"
        android:layout_height="51dp"
        android:layout_marginStart="10dp"
        android:layout_marginEnd="10dp"
        android:layout_marginBottom="452dp"
        android:ems="10"
        android:hint="@string/enter_the_number_you_re_guessing"
        android:inputType="number"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.545"
        app:layout_constraintStart_toStartOf="parent"
        android:importantForAutofill="no" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="135dp"
        android:layout_marginTop="23dp"
        android:layout_marginEnd="137dp"
        android:layout_marginBottom="381dp"
        android:clickable="false"
        android:onClick="Go"
        android:soundEffectsEnabled="false"
        android:text="@string/enter"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/enteredNumber" />

</androidx.constraintlayout.widget.ConstraintLayout>