android - How to restart an Activity

activity_main.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:id="@+id/rl"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:padding="16dp"     tools:context=".MainActivity"     android:background="#e4e3de"     >     <TextView         android:id="@+id/tv"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_centerInParent="true"         android:textSize="30sp"         android:gravity="center"         android:textColor="#000000"         android:textStyle="bold"         android:padding="25dp"         />     <Button         android:id="@+id/btn"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Restart This Activity"         />     <Button         android:id="@+id/btn2"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="Recreate This Activity"         android:layout_toRightOf="@id/btn"         /> </RelativeLayout> 

MainActivity.java

 package com.cfsuman.me.androidcodesnippets;  import android.app.Activity; import android.content.Context; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.RelativeLayout; import android.widget.TextView; import android.content.Intent;  import java.util.Random;   public class MainActivity extends AppCompatActivity {      private Context mContext;     private Activity mActivity;      private RelativeLayout mRelativeLayout;     private TextView mTextView;     private Button mButton;     private Button mButtonSecond;      private Random mRandom = new Random();       @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          // Get the application context         mContext = getApplicationContext();          // Get the activity         mActivity = MainActivity.this;          // Get the widgets reference from XML layout         mRelativeLayout = (RelativeLayout) findViewById(R.id.rl);         mTextView = (TextView) findViewById(R.id.tv);         mButton = (Button) findViewById(R.id.btn);         mButtonSecond = (Button) findViewById(R.id.btn2);          // Set the TextView text with a random generated number         mTextView.setText("Random Number : " + mRandom.nextInt(100));          // Set a click listener for the button widget         mButton.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 /*                     getIntent()                         Return the intent that started this activity.                 */                 // Get the current activity                 Intent intent = getIntent();                  /*                     public void finish ()                         Call this when your activity is done and should be closed. The ActivityResult                         is propagated back to whoever launched you via onActivityResult().                  */                 // Finish the activity                 finish();                  /*                     public void startActivity (Intent intent)                         Same as startActivity(Intent, Bundle) with no options specified.                      Parameters                         intent : Intent: The intent to start.                     Throws                         android.content.ActivityNotFoundException                 */                 // Restart the activity                 startActivity(intent);             }         });          // Set a click listener for the second button widget         mButtonSecond.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 /*                     public void recreate ()                         Cause this Activity to be recreated with a new instance. This results in                         essentially the same flow as when the Activity is created due to a                         configuration change -- the current instance will go through its lifecycle                         to onDestroy() and a new instance then created after it.                 */                 // Recreate the activity                 recreate();             }         });     } }