How to Create Dynamic ListView in Android using Firebase Firestore? - GeeksforGeeks

17 Jan, 2021
ListView is one of the most used UI components in Android which you can find across various apps. So we have seen listview in many different apps. In the previous article, we have seen implementing ListView in Android using Firebase Realtime Database. Now in this article, we will take a look at the implementation of ListView using Firebase Firestore in Android. Now, let’s move towards the implementation of this project. 
We will be building a simple ListView application in which we will be displaying a list of courses along with images in our ListView. We will fetch all the data inside our ListView from Firebase Firestore. A sample GIF is given below to get an idea about what we are going to do in this article. Note that we are going to implement this project using the Java language. 
Step 1: Create a new Project
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Java as the programming language.  
Step 2: Connect your app to Firebase 
After creating a new project navigate to the Tools option on the top bar. Inside that click on Firebase. After clicking on Firebase, you can get to see the right column mentioned below in the screenshot.
Inside that column Navigate to Firebase Cloud Firestore. Click on that option and you will get to see two options on Connect app to Firebase and Add Cloud Firestore to your app. Click on Connect now option and your app will be connected to Firebase. After that click on the second option and now your App is connected to Firebase. After connecting your app to Firebase you will get to see the below screen.  
After that verify that dependency for the Firebase Firestore database has been added to our Gradle file. Navigate to the app > Gradle Scripts inside that file to check whether the below dependency is added or not. If the below dependency is not present in your build.gradle file. Add the below dependency in the dependencies section.
implementation ‘com.google.firebase:firebase-firestore:22.0.1’
After adding this dependency sync your project and now we are ready for creating our app. If you want to know more about connecting your app to Firebase. Refer to this article to get in detail about How to add Firebase to Android App.  
Step 3: Working with the AndroidManifest.xml file
For adding data to Firebase we should have to give permissions for accessing the internet. For adding these permissions navigate to the app > AndroidManifest.xml and Inside that file add the below permissions to it.  
XML
<!--Permissions for internet--><uses-permission android:name="android.permission.INTERNET" /><uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 Step 4: Working with the activity_main.xml file
Go to the activity_main.xml file and refer to the following code. Below is the code for the activity_main.xml file.
XML
<?xml version="1.0" encoding="utf-8"?><RelativeLayout     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">      <ListView        android:id="@+id/idLVCourses"        android:layout_width="match_parent"        android:layout_height="match_parent" />  </RelativeLayout>
Step 5: Now we will create a new Java class for storing our data  
For reading data from the Firebase Firestore database, we have to create an Object class and we will read data inside this class. For creating an object class, navigate to the app > java > your app’s package name > Right-click on it and click on New > Java Class > Give a name to your class. Here we have given the name as DataModal and add the below code to it.  
Java
public class DataModal {      // variables for storing our image and name.    private String name;    private String imgUrl;      public DataModal() {        // empty constructor required for firebase.    }      // constructor for our object class.    public DataModal(String name, String imgUrl) {        this.name = name;        this.imgUrl = imgUrl;    }      // getter and setter methods    public String getName() {        return name;    }      public void setName(String name) {        this.name = name;    }      public String getImgUrl() {        return imgUrl;    }      public void setImgUrl(String imgUrl) {        this.imgUrl = imgUrl;    }}
Step 6: Create a layout file for our item of ListView
Navigate to the app > res > layout > Right-click on it and click on New > Layout Resource File and give a name to that file. After creating that file add the below code to it. Here we have given the name as image_lv_item and add the below code to it.  
XML
<?xml version="1.0" encoding="utf-8"?><androidx.cardview.widget.CardView     xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:layout_margin="4dp"    android:padding="2dp"    app:cardElevation="3dp">      <RelativeLayout        android:layout_width="match_parent"        android:layout_height="wrap_content">          <!--Image view for displaying our image-->        <ImageView            android:id="@+id/idIVimage"            android:layout_width="100dp"            android:layout_height="100dp"            android:layout_margin="8dp"            android:background="@color/white"            android:backgroundTint="@color/white"            android:padding="3dp" />          <!--Text view for displaying our text -->        <TextView            android:id="@+id/idTVtext"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_marginStart="10dp"            android:layout_marginTop="40dp"            android:layout_toEndOf="@id/idIVimage"            android:padding="3dp"            android:text="Category Text"            android:textAlignment="center"            android:textColor="@color/black" />      </RelativeLayout>  </androidx.cardview.widget.CardView>
Step 7: Now create an Adapter class for our ListView
For creating a new Adapter class navigate to the app > java > your app’s package name > Right-click on it and Click on New > Java class and name your java class as CoursesLVAdapter and add the below code to it. Comments are added inside the code to understand the code in more detail.
Java
import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;  import androidx.annotation.NonNull;import androidx.annotation.Nullable;  import com.squareup.picasso.Picasso;  import java.util.ArrayList;  public class CoursesLVAdapter extends ArrayAdapter<DataModal> {      // constructor for our list view adapter.    public CoursesLVAdapter(@NonNull Context context, ArrayList<DataModal> dataModalArrayList) {        super(context, 0, dataModalArrayList);    }      @NonNull    @Override    public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {        // below line is use to inflate the         // layout for our item of list view.        View listitemView = convertView;        if (listitemView == null) {            listitemView = LayoutInflater.from(getContext()).inflate(R.layout.image_lv_item, parent, false);        }                  // after inflating an item of listview item        // we are getting data from array list inside         // our modal class.        DataModal dataModal = getItem(position);                  // initializing our UI components of list view item.        TextView nameTV = listitemView.findViewById(R.id.idTVtext);        ImageView courseIV = listitemView.findViewById(R.id.idIVimage);                  // after initializing our items we are         // setting data to our view.        // below line is use to set data to our text view.        nameTV.setText(dataModal.getName());                  // in below line we are using Picasso to         // load image from URL in our Image VIew.        Picasso.get().load(dataModal.getImgUrl()).into(courseIV);          // below line is use to add item click listener        // for our item of list view.        listitemView.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                // on the item click on our list view.                // we are displaying a toast message.                Toast.makeText(getContext(), "Item clicked is : " + dataModal.getName(), Toast.LENGTH_SHORT).show();            }        });        return listitemView;    }}
Step 8: Working with the MainActivity.java file
Go to the MainActivity.java file and refer to the following code. Below is the code for the MainActivity.java file. Comments are added inside the code to understand the code in more detail.
Java
import android.os.Bundle;import android.widget.ListView;import android.widget.Toast;  import androidx.annotation.NonNull;import androidx.appcompat.app.AppCompatActivity;  import com.google.android.gms.tasks.OnFailureListener;import com.google.android.gms.tasks.OnSuccessListener;import com.google.firebase.firestore.DocumentSnapshot;import com.google.firebase.firestore.FirebaseFirestore;import com.google.firebase.firestore.QuerySnapshot;  import java.util.ArrayList;import java.util.List;  public class MainActivity extends AppCompatActivity {      // creating a variable for our list view,     // arraylist and firebase Firestore.    ListView coursesLV;    ArrayList<DataModal> dataModalArrayList;    FirebaseFirestore db;      @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                  // below line is use to initialize our variables        coursesLV = findViewById(R.id.idLVCourses);        dataModalArrayList = new ArrayList<>();          // initializing our variable for firebase         // firestore and getting its instance.        db = FirebaseFirestore.getInstance();                  // here we are calling a method        // to load data in our list view.        loadDatainListview();    }      private void loadDatainListview() {        // below line is use to get data from Firebase        // firestore using collection in android.        db.collection("Data").get()                .addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {                    @Override                    public void onSuccess(QuerySnapshot queryDocumentSnapshots) {                        // after getting the data we are calling on success method                        // and inside this method we are checking if the received                        // query snapshot is empty or not.                        if (!queryDocumentSnapshots.isEmpty()) {                            // if the snapshot is not empty we are hiding                             // our progress bar and adding our data in a list.                            List<DocumentSnapshot> list = queryDocumentSnapshots.getDocuments();                            for (DocumentSnapshot d : list) {                                // after getting this list we are passing                                 // that list to our object class.                                DataModal dataModal = d.toObject(DataModal.class);                                                                  // after getting data from Firebase we are                                // storing that data in our array list                                dataModalArrayList.add(dataModal);                            }                            // after that we are passing our array list to our adapter class.                            CoursesLVAdapter adapter = new CoursesLVAdapter(MainActivity.this, dataModalArrayList);                                                          // after passing this array list to our adapter                             // class we are setting our adapter to our list view.                            coursesLV.setAdapter(adapter);                        } else {                            // if the snapshot is empty we are displaying a toast message.                            Toast.makeText(MainActivity.this, "No data found in Database", Toast.LENGTH_SHORT).show();                        }                    }                }).addOnFailureListener(new OnFailureListener() {            @Override            public void onFailure(@NonNull Exception e) {                // we are displaying a toast message                // when we get any error from Firebase.                Toast.makeText(MainActivity.this, "Fail to load data..", Toast.LENGTH_SHORT).show();            }        });    }}
After adding the above code add the data to Firebase Firestore in Android. 
Step 9: Adding the data to Firebase Firestore in Android
Search for Firebase in your browser and go to that website and you will get to see the below screen.  
After clicking on Go to Console option. Click on your project which is shown below.
After clicking on your project you will get to see the below screen. After clicking on this project you will get to see the below screen.  
After clicking on the Create Database option you will get to see the below screen.  
Inside this screen, we have to select the Start in test mode option. We are using test mode because we are not setting authentication inside our app. So we are selecting Start in test mode. After selecting on test mode click on the Next option and you will get to see the below screen.  
Inside this screen, we just have to click on the Enable button to enable our Firebase Firestore database. After completing this process we have to add the data inside our Firebase Console. For adding data to our Firebase Console. 
You have to click on Start Collection Option and give the collection name as Data. After creating a collection you have to click on Autoid option for creating the first document. Then create two fields, one filed for “name” and one filed for “imgUrl” and enter the corresponding values for them. Note that specify the image URL link in the value for the imgUrl filed. And click on the Save button. Your first image to the Data has been added. 
Similarly, add more images by clicking on the “Add document” button. 
After adding these images run your app and you will get to see the output on the below screen. 
android
Technical Scripter 2020
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Android
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