<uses-permission android:name="android.permission.INTERNET" />

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <!--Edit text for getting course Name-->
    <EditText
        android:id="@+id/idEdtCourseName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="10dp"
        android:layout_marginTop="20dp"
        android:layout_marginEnd="10dp"
        android:hint="Course Name"
        android:importantForAutofill="no"
        android:inputType="text" />

    <!--Edittext for getting course Duration-->
    <EditText
        android:id="@+id/idEdtCourseDuration"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="10dp"
        android:layout_marginTop="20dp"
        android:layout_marginEnd="10dp"
        android:hint="Course Duration in min"
        android:importantForAutofill="no"
        android:inputType="time" />

    <!--Edittext for getting course Description-->
    <EditText
        android:id="@+id/idEdtCourseDescription"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginStart="10dp"
        android:layout_marginTop="20dp"
        android:layout_marginEnd="10dp"
        android:hint="Course Description"
        android:importantForAutofill="no"
        android:inputType="text" />

    <!--Button for adding your course to Firebase-->
    <Button
        android:id="@+id/idBtnSubmitCourse"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:text="Submit Course Details"
        android:textAllCaps="false" />

</LinearLayout>

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

import androidx.appcompat.app.AppCompatActivity;

import com.parse.ParseException;
import com.parse.ParseObject;
import com.parse.SaveCallback;

public class MainActivity extends AppCompatActivity {

    // creating variables for our edit text
    private EditText courseNameEdt, courseDurationEdt, courseDescriptionEdt;

    // creating variable for button
    private Button submitCourseBtn;

    // creating a strings for storing our values from edittext fields.
    private String courseName, courseDuration, courseDescription;

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

        // initializing our edittext and buttons
        courseNameEdt = findViewById(R.id.idEdtCourseName);
        courseDescriptionEdt = findViewById(R.id.idEdtCourseDescription);
        courseDurationEdt = findViewById(R.id.idEdtCourseDuration);
        submitCourseBtn = findViewById(R.id.idBtnSubmitCourse);
        submitCourseBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                // getting data from edittext fields.
                courseName = courseNameEdt.getText().toString();
                courseDescription = courseDescriptionEdt.getText().toString();
                courseDuration = courseDurationEdt.getText().toString();

                // validating the text fields if empty or not.
                if (TextUtils.isEmpty(courseName)) {
                    courseNameEdt.setError("Please enter Course Name");
                } else if (TextUtils.isEmpty(courseDescription)) {
                    courseDescriptionEdt.setError("Please enter Course Description");
                } else if (TextUtils.isEmpty(courseDuration)) {
                    courseDurationEdt.setError("Please enter Course Duration");
                } else {
                    // calling method to add data to Firebase Firestore.
                    addDataToDatabase(courseName, courseDescription, courseDuration);
                }
            }
        });
    }

    private void addDataToDatabase(String courseName, String courseDescription, String courseDuration) {

        // Configure Query
        ParseObject courseList = new ParseObject("courses");

        // on below line we are adding our data with their key value in our object.
        courseList.put("courseName", courseName);
        courseList.put("courseDescription", courseDescription);
        courseList.put("courseDuration", courseDuration);

        // after adding all data we are calling a
        // method to save our data in background.
        courseList.saveInBackground(new SaveCallback() {
            @Override
            public void done(ParseException e) {
                // inside on done method we are checking
                // if the error is null or not.
                if (e == null) {

                    // if the error is null we are displaying a simple toast message.
                    Toast.makeText(MainActivity.this, "Data has been successfully added to Database", Toast.LENGTH_SHORT).show();

                    // on below line we are setting our edit text fields to empty value.
                    courseNameEdt.setText("");
                    courseDescriptionEdt.setText("");
                    courseDurationEdt.setText("");
                } else {
                    // if the error is not null we will be
                    // displaying an error message to our user.
                    Toast.makeText(getApplicationContext(), e.getMessage().toString(), Toast.LENGTH_LONG).show();
                }
            }
        });
    }
}