A ListView is a type of AdapterView that displays a vertical list of scroll-able views and each view is placed one below the other. Using adapter, items are inserted into the list from an array or database. For displaying the items in the list method setAdaptor()
is used. setAdaptor()
method conjoins an adapter with the list.
Android ListView is a ViewGroup that is used to display the list of items in multiple rows and contains an adapter that automatically inserts the items into the list.
The main purpose of the adapter is to fetch data from an array or database and insert each item that placed into the list for the desired result. So, it is the main source to pull data from strings.xml file which contains all the required strings in Java or XML files.
XML Attributes of ListView
Attribute | Description |
---|
android:divider | A color or drawable to separate list items. |
android:dividerHeight | Divider’s height. |
android:entries | Reference to an array resource that will populate the ListView. |
android:footerDividersEnabled | When set to false, the ListView will not draw the divider before each footer view. |
android:headerDividersEnabled | When set to false, the ListView will not draw the divider before each header view. |
How to add a ListView in an Android App
Now let’s understand how to use a listview in an android application with an example. In the example, let’s create an android application that will display a list of tutorials available in GeeksforGeeks portal.
Step 1: Create a new project
- Click on File, then New => New Project.
- Choose “Empty Activity” for the project template.
- Select language as Java.
- Select the minimum SDK as per your need.
Step 2: Modify activity_main.xml file
Add a ListView in the activity_main.xml
file.
activity_main.xml
<? xml version = "1.0" encoding = "utf-8" ?>
< LinearLayout
android:layout_width = "match_parent"
android:layout_height = "match_parent"
tools:context = ".MainActivity" >
< ListView
android:id = "@+id/list"
android:layout_width = "match_parent"
android:layout_height = "match_parent" />
</ LinearLayout >
|
Step 3: Modify MainActivity.java file
In this section, let’s design the backend of the application. Go to MainActivity.java
. Now in the java file create a string array and store the values you want to display in the list. Also, create an object of ListView class. In onCreate()
method find Listview by id using findViewById()
method. Create an object of ArrayAdapter using a new keyword followed by a constructor call. The ArrayAdaptor public constructor description is below:
public ArrayAdapter (Context context, int Resource, T[ ] objects)
Parameter | Description |
---|
context | current context |
Resource | the resource ID for a layout file |
objects | objects to display in the ListView |
According to this pass the argument in ArrayAdapter Constructor and create an object. At last, conjoin the adapter with the list using setAdapter()
method.
MainActivity.java
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class MainActivity extends AppCompatActivity {
ListView l;
String tutorials[]
= { "Algorithms" , "Data Structures" ,
"Languages" , "Interview Corner" ,
"GATE" , "ISRO CS" ,
"UGC NET CS" , "CS Subjects" ,
"Web Technologies" };
@Override
protected void onCreate(Bundle savedInstanceState)
{
super .onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
l = findViewById(R.id.list);
ArrayAdapter<String> arr;
arr
= new ArrayAdapter<String>(
this ,
R.layout.support_simple_spinner_dropdown_item,
tutorials);
l.setAdapter(arr);
}
}
|
Output
