In Android, a Switch is a type of button that lets the user toggle between two actions or instances. In general, a Switch is used for selecting one between two options that can be invoking any actions or functions. In this article, we are going to see how we can save the state of the Switch Button in android.Â
What we are going to build in this article?
Here is a sample video of what we are going to build in this article. Note that we will be using Java language to make this project.
Step by Step Implementation
Step 1: Create a New Project
- Open a new project.
- We will be working on Empty Activity with language as Java. Leave all other options unchanged.
- Name the application at your convenience.
- There will be two default files named activity_main.xml and MainActivity.java.
If you don’t know how to create a new project in Android Studio then you can refer to How to Create/Start a New Project in Android Studio? Â
Step 2. Working on XML files
Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file.
XML
<?xml version="1.0" encoding="utf-8"?><LinearLayout    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:padding="16dp"    android:gravity="center"    tools:context=".MainActivity">Â
    <androidx.appcompat.widget.SwitchCompat        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/switch_compat"        android:text="Switch"        android:textSize="25sp"/>       <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="20dp">               <Button            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_weight="1"            android:id="@+id/bt_next"            android:text="next"/>               <Button            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_weight="1"            android:id="@+id/bt_exit"            android:text="Exit"/>Â
    </LinearLayout>Â
</LinearLayout> |
Navigate to app > right-click < new < activity < empty activity and name it as MainActivity2. Use the following code in activity_main2.xml file-
XML
<?xml version="1.0" encoding="utf-8"?><LinearLayout    android:orientation="vertical"    android:gravity="center"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity2">         <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Second Activity"        android:textSize="30sp"/>       <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/bt_back"        android:text="back"/>Â
</LinearLayout> |
Step 3. Working on Java files
Navigate to the MainActivity.java file and use the following code in it. Comments are added to the code to have a better understanding.
Java
package com.example.savestateofswitch;Â
import androidx.appcompat.app.AppCompatActivity;import androidx.appcompat.widget.SwitchCompat;Â
import android.content.Intent;import android.content.SharedPreferences;import android.os.Bundle;import android.view.View;import android.widget.Button;Â
public class MainActivity extends AppCompatActivity {Â
    // Initialize variable    SwitchCompat switchCompat;    Button btNext,btExit;Â
    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);Â
        // Assign variable        switchCompat=findViewById(R.id.switch_compat);        btNext=findViewById(R.id.bt_next);        btExit=findViewById(R.id.bt_exit);                   // Save switch state in shared preferences        SharedPreferences sharedPreferences=getSharedPreferences("save",MODE_PRIVATE);        switchCompat.setChecked(sharedPreferences.getBoolean("value",true));Â
        switchCompat.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                if (switchCompat.isChecked())                {                    // When switch checked                    SharedPreferences.Editor editor=getSharedPreferences("save",MODE_PRIVATE).edit();                    editor.putBoolean("value",true);                    editor.apply();                    switchCompat.setChecked(true);                }                else                {                    // When switch unchecked                    SharedPreferences.Editor editor=getSharedPreferences("save",MODE_PRIVATE).edit();                    editor.putBoolean("value",false);                    editor.apply();                    switchCompat.setChecked(false);                }            }        });Â
        btNext.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                // Go to next activity                Intent intent=new Intent(MainActivity.this,MainActivity2.class);                startActivity(intent);            }        });        btExit.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                // Close the app                MainActivity.this.finishAffinity();            }        });    }} |
Navigate to the MainActivity2.java file and use the following code in it. Comments are added to the code to have a better understanding.
Java
package com.example.savestateofswitch;Â
import androidx.appcompat.app.AppCompatActivity;Â
import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;Â
public class MainActivity2 extends AppCompatActivity {Â
    // Initialize variable    Button btBack;Â
    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main2);Â
        // Assign variable        btBack=findViewById(R.id.bt_back);        btBack.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                // Go back                Intent intent=new Intent(MainActivity2.this,MainActivity.class);                startActivity(intent);            }        });    }} |
Here is the final output of our application.
Output:
