Android Change Activity By Intent

Change Activity By Intent:

To change an activity is normally done by making use of an Intent (which simply means Intention).

Intent is an object containing a description of a task to be performed, and is used to initiate an activity, pass data between activities or do other operations within the boundaries of an Android application.

Example:

                                    
                                        // activity_change_by_intent_example.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"
        tools:context=".ChangeActivityByIntentExample"
        android:padding="16dp"
        android:gravity="center"
        android:orientation="vertical"
        android:background="@color/colorAccent"
        >
   
       <Button
           android:id="@+id/second"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:text="Second Activity"
           android:textColor="@color/colorWhite"
           android:background="@color/colorOrange"/>
   
</LinearLayout>

// activity_second.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"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        tools:context=".SecondActivity"
        android:padding="16dp"
        android:gravity="center"
        android:orientation="vertical"
        android:background="@color/colorBrown"    >
   
           <Button
               android:id="@+id/first"
               android:layout_width="match_parent"
               android:layout_height="wrap_content"
               android:text="First Activity"
               android:textColor="@color/colorWhite"
               android:background="@color/colorAccent"/>
   
</LinearLayout>

                                    
                                        // ChangeActivityByIntentExample.java

package com.example.widgets;
    
import android.content.Intent;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
    
public class ChangeActivityByIntentExample extends AppCompatActivity {
   
    Button button;
   
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_change_by_intent_example);
   
        button=(Button)findViewById(R.id.second);
   
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(getApplicationContext(),SecondActivity.class);
                startActivity(intent);
            }
        });
   
    }
}
   

// SecondActivity.java


package com.example.widgets;
    
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
    
public class SecondActivity extends AppCompatActivity {
    
    Button button;
   
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
   
   
        button=(Button)findViewById(R.id.first);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });
    }

}

                                    
                                        // ChangeActivityByIntentExample.kt
package com.example.widgets

import android.content.Intent
import android.os.Bundle
import android.view.View
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity

class ChangeActivityByIntentExample : AppCompatActivity() {

    private lateinit var button: Button

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_change_by_intent_example)

        button = findViewById(R.id.second)

        button.setOnClickListener {
            val intent = Intent(applicationContext, SecondActivity::class.java)
            startActivity(intent)
        }
    }
}

// SecondActivity.kt
package com.example.widgets

import android.os.Bundle
import android.view.View
import android.widget.Button
import androidx.appcompat.app.AppCompatActivity

class SecondActivity : AppCompatActivity() {

    private lateinit var button: Button

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_second)

        button = findViewById(R.id.first)
        button.setOnClickListener {
            finish()
        }
    }
}

Output