GridView Using Custom ArrayAdapter in Android with Example

Last Updated : 12 Aug, 2024

This article will be building an application to demonstrate the use of CustomArrayAdapters in GridView. GridViews are view containers that display views in two-dimensional (rows and columns) they are used in my android applications one simple example would be the gallery app. The adapter connects the UI elements with the data source, It helps populate data with us taking care of it. e.g when the user is scrolling through a gallery app the GridView is automatically populated without specifying anything.

There are different Adapters to name a few:

ArrayAdapter
BaseAdapter
Custom ArrayAdapter

This article will be covering the Custom ArrayAdapter.

Why use a Custom ArrayAdapter?

Android already provides the implementation for an ArrayAdapter, which can be used with just a single line demonstrated below. They are used when Whenever we have a list of single items we can use ArrayAdapter. For instance, a list of phone contacts, countries, or names. Below is the syntax of the ArrayAdapter used for displaying text data.

Syntax:

ArrayAdapter(Context context, int resource, int textViewResourceId, T[] objects)

Parameters:

Context: is the application context being used
resource: The second parameter is the resource id used to set the layout(xml file).
textViewResourceId: Id of the TextView element where the data will be displayed
objects: are the data elements stored in an array.

The problem with or limitation of this method is we cannot use complex layouts eg. Imagine we were building an app like Netflix or prime where each element is made up of many elements eg an ImageView, TextView, etc. Such complex views are not possible with the simple implementation of the ArrayAdapter for this we need to create our custom Adapter by extending the ArrayAdapter class. The following code shows the structure of the Custom ArrayAdapter.

Java

import android.content.Context; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import java.util.List;  public class CustomAdapter extends ArrayAdapter {     public CustomAdapter(Context context, int resource,                          List objects)     {         super(context, resource, objects);     }      @Override public int getCount()     {         return super.getCount();     }      @Override     public View getView(int position, View convertView,                         ViewGroup parent)     {         return super.getView(position, convertView, parent);     } }

Kotlin

import android.content.Context import android.view.View import android.view.ViewGroup import android.widget.ArrayAdapter  class CustomAdapter(context: Context?, resource: Int, objects: List<*>?) : ArrayAdapter<Any?>(context!!, resource, objects!!) {          override fun getCount(): Int {         return super.getCount()     }      override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {         return super.getView(position, convertView, parent)     } }

The two important methods used are:

getCount(): returns the number of data elements present in the List.
getView(): this is the important method where will be initializing and returning the custom view.

Example

A sample GIF is given below to get an idea about what we are going to do in this article. We are going to implement this project using both Java and Kotlin Programming Language for Android.

Step by Step Implementation

Step 1: Create a New Project in Android Studio

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. The code for that has been given in both Java and Kotlin Programming Language for Android.

Step 2: Working with the XML Files

Next, go to the activity_main.xml file, which represents the UI of the project. Below is the code for the activity_main.xml file. Comments are added inside the code to understand the code in more detail.

XML

<?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"     tools:context=".MainActivity">      <GridView         android:id="@+id/grid_view"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:horizontalSpacing="10dp"         android:numColumns="auto_fit"         android:verticalSpacing="10dp"         app:layout_constraintBottom_toBottomOf="parent"         app:layout_constraintEnd_toEndOf="parent"         app:layout_constraintStart_toStartOf="parent"         app:layout_constraintTop_toTopOf="parent" />  </androidx.constraintlayout.widget.ConstraintLayout>

Creating a new layout XML file

Creating a new file named custom_view.xml in the same folder as the activity_main.xml file. This Custom View will host an ImageView and a TextView.

XML

<?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">      <ImageView         android:id="@+id/imageView"         android:layout_width="match_parent"         android:layout_height="wrap_content"         tools:srcCompat="@tools:sample/avatars" />      <TextView         android:id="@+id/textView"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="TextView"         android:textAlignment="center" /> </LinearLayout>

Step 3: Working with the Java/Kotlin Files

Now to hold the info of our custom view we need to create a getter setter class. We can do things without this just using two arrays one for images and the other for text but what if we want to modify your view to add a Button? Then will again need a third array. Hence a class that holds the custom view is a more flexible option. Create the class In the same folder as the MainActivity create a new class called items. Below is the code for the items file.

Java

public class items {      private int image_id;     private String text;      public int getImage_id() {         return image_id;     }      public void setImage_id(int image_id) {         this.image_id = image_id;     }      public String getText() {         return text;     }      public void setText(String text) {         this.text = text;     }      items(int img, String text) {         image_id = img;         this.text = text;     } }

Kotlin

class items internal constructor(private var image_id: Int, private var text: String) {     fun getImage_id(): Int {         return image_id     }      fun setImage_id(image_id: Int) {         this.image_id = image_id     }      fun getText(): String {         return text     }      fun setText(text: String) {         this.text = text     }      fun items(img: Int, text: String) {         image_id = img         this.text = text     } }

Note: For an image, we store the id of the image and not the image.

Step 4: Implementing the CustomAdapter class

Create a new class classed as CustomAdapter in the same folder as items. The main method of the Adapter is the getView().

Java

import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ImageView; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.annotation.Nullable;  @NonNull @Override public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {      View v = convertView;      if (v == null) {         // getting reference to the main layout and initializing         LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);         v = inflater.inflate(custom_layout_id, null);     }      // initializing the imageview and textview and setting data     ImageView imageView = v.findViewById(R.id.imageView);     TextView textView = v.findViewById(R.id.textView);      // get the item using the  position param     items item = items_list.get(position);      imageView.setImageResource(item.getImage_id());     textView.setText(item.getText());     return v; }

Kotlin

import android.content.Context import android.view.LayoutInflater import android.view.View import android.view.ViewGroup import android.widget.ImageView import android.widget.TextView  fun getView(position: Int, convertView: View?, parent: ViewGroup): View {              var v = convertView              if (v == null) {         // getting reference to the main layout and initializing         val inflater = getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater         v = inflater.inflate(custom_layout_id, null)     }      // initializing the imageview and textview and setting data     val imageView = v!!.findViewById<ImageView>(R.id.imageView)     val textView = v.findViewById<TextView>(R.id.textView)      // get the item using the  position param     val item: items = items_list.get(position)     imageView.setImageResource(item.getImage_id())     textView.setText(item.getText())     return v }

public View inflate (int resource,ViewGroup root)

Inflate a new view hierarchy from the specified xml resource. Throws InflateException if there is an error.

resource  int: ID for an XML layout resource to load (e.g., R.layout.main_page)

root ViewGroup: Optional view to be the parent of the generated hierarchy. This value may be null.

This method first parses out the custom_view.xml file using the inflate() method. This method is quite computationally expensive and should be used only when needed eg. when the adapter has to populate new items when the user reaches the end of the screen. After getting the reference of the view we then initialize the image view and text view from the custom_view.xml file set the data and return the view. Below is the complete code for the CustomAdapter file. 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.ImageView; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.annotation.Nullable;  public class CustomAdapter extends ArrayAdapter<items> {      List<items> items_list;     int custom_layout_id;      public CustomAdapter(@NonNull Context context, int resource, @NonNull List<items> objects) {         super(context, resource, objects);         items_list = objects;         custom_layout_id = resource;     }      @Override public int getCount() {         return items_list.size();     }      @NonNull     @Override     public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {         View v = convertView;         if (v == null) {             // getting reference to the main layout and initializing             LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);             v = inflater.inflate(custom_layout_id, null);         }          // initializing the imageview and textview and setting data         ImageView imageView = v.findViewById(R.id.imageView);         TextView textView = v.findViewById(R.id.textView);          // get the item using the  position param         items item = items_list.get(position);          imageView.setImageResource(item.getImage_id());         textView.setText(item.getText());         return v;     } }

Kotlin

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  class CustomAdapter(context: Context, resource: Int, objects: List<items>) : ArrayAdapter<items?>(context, resource, objects) {      init {         items_list = objects         custom_layout_id = resource     }          private var items_list: List<items>     private var custom_layout_id: Int          override fun getCount(): Int {         return items_list.size     }      fun getView(position: Int, convertView: View?, parent: ViewGroup): View {         var v = convertView         if (v == null) {             // getting reference to the main layout and initializing             val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater             v = inflater.inflate(custom_layout_id, null)         }          // initializing the imageview and textview and setting data         val imageView = v!!.findViewById<ImageView>(R.id.imageView)         val textView = v.findViewById<TextView>(R.id.textView)          // get the item using the  position param         val item: items = items_list[position]         imageView.setImageResource(item.getImage_id())         textView.setText(item.getText())         return v     } }

Step 5: Working with the MainActivity File

Go to the MainActivity File and refer to the following code. Below is the code for the MainActivity File. Comments are added inside the code to understand the code in more detail. For the images, here we have used android studio icons. The images are present in the res/drawable folder. Should look like this

Java

import android.os.Bundle; import android.widget.GridView; import androidx.appcompat.app.AppCompatActivity; import java.util.ArrayList;  public class MainActivity extends AppCompatActivity {      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          List<items> itemsList = new ArrayList<>();         itemsList.add(new items(R.drawable.android_1, "image_1"));         itemsList.add(new items(R.drawable.android_2, "image_2"));         itemsList.add(new items(R.drawable.android_3, "image_3"));         itemsList.add(new items(R.drawable.android_4, "image_4"));         itemsList.add(new items(R.drawable.android_5, "image_5"));         itemsList.add(new items(R.drawable.android_1, "image_6"));         itemsList.add(new items(R.drawable.android_2, "image_7"));         itemsList.add(new items(R.drawable.android_3, "image_8"));         itemsList.add(new items(R.drawable.android_4, "image_9"));         itemsList.add(new items(R.drawable.android_5, "image_10"));          GridView gridView = findViewById(R.id.grid_view);         CustomAdapter customAdapter = new CustomAdapter(this, R.layout.custom_view, itemsList);         gridView.setAdapter(customAdapter);     } }

Kotlin

import android.os.Bundle import android.widget.GridView import androidx.appcompat.app.AppCompatActivity  class MainActivity : AppCompatActivity() {     override fun onCreate(savedInstanceState: Bundle?) {         super.onCreate(savedInstanceState)         setContentView(R.layout.activity_main)                  val itemsList: List<items> = ArrayList<Any>()         itemsList.add(items(R.drawable.android_1, "image_1"))         itemsList.add(items(R.drawable.android_2, "image_2"))         itemsList.add(items(R.drawable.android_3, "image_3"))         itemsList.add(items(R.drawable.android_4, "image_4"))         itemsList.add(items(R.drawable.android_5, "image_5"))         itemsList.add(items(R.drawable.android_1, "image_6"))         itemsList.add(items(R.drawable.android_2, "image_7"))         itemsList.add(items(R.drawable.android_3, "image_8"))         itemsList.add(items(R.drawable.android_4, "image_9"))         itemsList.add(items(R.drawable.android_5, "image_10"))                  val gridView = findViewById<GridView>(R.id.grid_view)         val customAdapter = CustomAdapter(this, R.layout.custom_view, itemsList)         gridView.adapter = customAdapter     } }

Final Project Structure

Output:

GridView Using Custom ArrayAdapter in Android with Example

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Java

GridView Using Custom ArrayAdapter in Android with Example

There are different Adapters to name a few:

This article will be covering the Custom ArrayAdapter.

Why use a Custom ArrayAdapter?

Syntax:

Parameters:

The two important methods used are:

Example

Step by Step Implementation

Step 1: Create a New Project in Android Studio

Step 2: Working with the XML Files

Creating a new layout XML file

Step 3: Working with the Java/Kotlin Files

Step 4: Implementing the CustomAdapter class

Step 5: Working with the MainActivity File

Final Project Structure

Output:

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