What is Context on Android?

Definition

it's the context of current state of the application/object. It lets newly-created objects understand what has been going on. Typically, you call it to get information regarding another part of your program (activity and package/application). In the below program you will see that we have created a textView dynamically and passed context. This context is used to get the information about the environment.

This example demonstrates how do I display context in an android textView.

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to res/layout/activity_main.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:id="@+id/linearLayout"
   android:orientation="vertical"
   android:padding="16sp"
   tools:context=".MainActivity">
</LinearLayout>

Step 3 − Add the following code to src/MainActivity.java

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.LinearLayout;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      LinearLayout linearLayout = findViewById(R.id.linearLayout);
      TextView textViewContext = new TextView(getApplicationContext());
      textViewContext.setTextSize(30);
      textViewContext.setText("Application Context");
      textViewContext.setTextColor(Color.RED);
      TextView textViewActivityContext = new TextView(this);
      textViewActivityContext.setTextSize(30);
      textViewActivityContext.setText("Activity Context");
      linearLayout.addView(textViewContext);
      linearLayout.addView(textViewActivityContext);
   }
}

Step 4 − Add the following code to androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="app.com.sample">
   <application
      android:allowBackup="true"
      android:icon="@mipmap/ic_launcher"
      android:label="@string/app_name"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:supportsRtl="true"
      android:theme="@style/AppTheme">
      <activity android:name=".MainActivity">
         <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen –