ListView with predefined Layout & Array from Java

ListView is a view group that displays a list of scrollable items. The list items are automatically inserted to the list using an Adapter that pulls content from a source such as an array or database query and converts each item result into a view that’s placed into the list.

Syntax for List view

ListView listView;
ArrayAdapter arrayAdapter=new ArrayAdapter(Context(),
         layout Resource,ArrayResource);
 listView.setAdapter(arrayAdapter);

In ArrayAdapter return type is 3 arguments

1. Context
   1. Layout Resource
   1. Array Resource

Context: Interface to global information about an application environment. This is an abstract class whose implementation is provided by the Android system. It allows access to application-specific resources and classes, as well as up-calls for application-level operations such as launching activities, broadcasting and receiving intents, etc.

In Android Context we can write in 3 ways

1. SuperClassName.this
2. getApplicationContext()
3. getActivity()

(This we can use only in Fragments.)

Layout Resource: Layout Resource we can specify in 2 ways

1. Predefined layout

2. Custom Layout

Array Resource: Array Resource we can specify in 3 ways

1. Array from Java

2. Array From Xml

3. Array From Database(Server)

Will observe below with different programs with above combinations

Program: ListView with predefined Layout & Array from Java

Activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
    tools:context="androiindians.listview.MainActivity">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ListView Example"
        android:gravity="center"   />
    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/listviewex"  />
</LinearLayout>

MainActivity.java

package androiindians.listview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    ListView listView;
    String[]Course={"Android","CoreJava","Adv  Java"};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView= (ListView) findViewById(R.id.listviewex);
//predefined layout +array from Java
       ArrayAdapter arrayAdapter=new ArrayAdapter(getApplicationContext(),
                android.R.layout.simple_list_item_1,Course);
        listView.setAdapter(arrayAdapter);
  }
}