Saturday, October 5, 2019

Android Switch (ON / OFF) Button with Examples

In android, Switch is a two-state user interface element which is used to display ON (Checked) or OFF (Unchecked) states as a button with thumb slider. By using thumb, the user may drag back and forth to choose an option either ON or OFF.

The Switch element is useful for the users to change the settings between two states either ON or OFF. We can add a Switch to our application layout by using Switch object.

Following is the pictorial representation of using Switch in android applications.

Android Switches Example Diagram

By default, the android Switch will be in OFF (Unchecked) state. We can change the default state of Switch by using android:checked attribute.

In case, if we want to change the state of Switch to ON (Checked), then we need to set android:checked = “true” in our XML layout file.

In android, we can create Switch control in two ways either in XML layout file or create it in Activity file programmatically.

Create Switch in XML Layout File

Following is the sample way to define Switch control in XML layout file in android application.

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    
android:layout_width="match_parent" android:layout_height="match_parent">
<
Switch
    
android:id="@+id/switch1"
    
android:layout_width="wrap_content"
    
android:layout_height="wrap_content"
    
android:switchMinWidth="56dp"
    
android:layout_marginLeft="100dp"
    
android:layout_marginTop="120dp"
    
android:text="Switch1:"
    
android:checked="true"
    
android:textOff="OFF"
    
android:textOn="ON"/>
</
RelativeLayout>
If you observe above code snippet, here we defined Switch control and setting Switch state ON using android:checked attribute and textOff / textOn attributes are used to set the text to represent Switch state in xml layout file.

Create Switch Control in Activity File

In android, we can create Switch control programmatically in activity file based on our requirements. 

Following is the example of creating Switch control dynamically in activity file.

RelativeLayout layout = (RelativeLayout)findViewById(R.id.r_layout);
Switch sb = 
new Switch(this);
sb.setTextOff(
"OFF");
sb.setTextOn(
"ON");
sb.setChecked(
true);
layout.addView(sb);
This is how we can define Switch in XML layout file or programmatically in activity file based on our requirements.

Handle Switch Click Events

Generally, whenever the user clicks on Switch, we can detect whether the Switch is in ON or OFF state and we can handle Switch click event in activity file using setOnCheckedChangeListener like as shown below.

Switch sw = (Switch) findViewById(R.id.switch1);
sw.setOnCheckedChangeListener(
new CompoundButton.OnCheckedChangeListener() {
    
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
        
if (isChecked) {
            
// The toggle is enabled
        
else {
            
// The toggle is disabled
        
}
    }
});
This is how we can handle Switch click events in android applications based on our requirements.

Android Switch Control Attributes

Following are the some of commonly used attributes related to Switch control in android applications.

AttributeDescription
android:idIt is used to uniquely identify the control
android:checkedIt is used to specify the current state of switch control
android:gravityIt is used to specify how to align the text like left, right, center, top, etc.
android:textIt is used to set the text.
android:textOnIt is used to set the text when toggle button is in ON / Checked state.
android:textOffIt is used to set the text when toggle button is in OFF / Unchecked state.
android:textColorIt is used to change the color of text.
android:textSizeIt is used to specify the size of text.
android:textStyleIt is used to change the style (bold, italic, bolditalic) of text.
android:backgroundIt is used to set the background color for toggle button control.
android:paddingIt is used to set the padding from left, right, top and bottom.
android:drawableBottomIt’s a drawable to be drawn to the below of text.
android:drawableRightIt’s a drawable to be drawn to the right of text.
android:drawableLeftIt’s a drawable to be drawn to the left of text.

Android Switch Control Example

Following is the example of defining a two Switch controls and one Button control in RelativeLayout to get the state of Switch controls when we click on Button control in android application.

Create a new android application using android studio and give names as SwitchExample. In case if you are not aware of creating an app in android studio check this article Android Hello World App.

Now open an activity_main.xml file from \res\layout path and write the code like as shown below

activity_main.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    
android:layout_width="match_parent" android:layout_height="match_parent">
    <
Switch
        
android:id="@+id/switch1"
        
android:layout_width="wrap_content"
        
android:layout_height="wrap_content"
        
android:switchMinWidth="56dp"
        
android:layout_marginLeft="100dp"
        
android:layout_marginTop="120dp"
        
android:text="Switch1:"
        
android:checked="true"
        
android:textOff="OFF"
        
android:textOn="ON"/>
    <
Switch
        
android:id="@+id/switch2"
        
android:layout_width="wrap_content"
        
android:layout_height="wrap_content"
        
android:switchMinWidth="56dp"
        
android:layout_below="@+id/switch1"
        
android:layout_alignLeft="@+id/switch1"
        
android:text="Switch2:"
        
android:textOff="OFF"
        
android:textOn ="ON"/>
    <
Button
        
android:id="@+id/getBtn"
        
android:layout_width="wrap_content"
        
android:layout_height="wrap_content"
        
android:layout_marginLeft="150dp"
        
android:layout_marginTop="200dp"
        
android:text="Get" />
</
RelativeLayout>
If you observe above code we defined a two Switch controls and one Button control in RelativeLayout to get the state of Switch controls when we click on Button control in XML layout file.

Once we are done with creation of layout with required controls, we need to load the XML layout resource from our activity onCreate() callback method, for that open main activity file MainActivity.java from \java\com.tutlane.switchexample path and write the code like as shown below.

MainActivity.java

package com.tutlane.switchexample;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.Switch;import android.widget.Toast;
public class MainActivity extends AppCompatActivity {private Switch sw1,sw2;
    
private  Button btnGet;
    
@Override
    
protected void onCreate(Bundle savedInstanceState) {
        
super.onCreate(savedInstanceState);
        setContentView(R.layout.
activity_main);
        
sw1 = (Switch)findViewById(R.id.switch1);
        
sw2 = (Switch)findViewById(R.id.switch2);
        
btnGet = (Button)findViewById(R.id.getBtn);
        
btnGet.setOnClickListener(new View.OnClickListener() {
            
@Override
            
public void onClick(View v) {
                String str1, str2;
                
if (sw1.isChecked())
                    str1 = 
sw1.getTextOn().toString();
                
else
                    
str1 = sw1.getTextOff().toString();
                
if (sw2.isChecked())
                    str2 = 
sw2.getTextOn().toString();
                
else
                    
str2 = sw2.getTextOff().toString();
                Toast.makeText(getApplicationContext(), 
"Switch1 -  " + str1 + \n"Switch2 - " + str2,Toast.LENGTH_SHORT).show();
            }
        });
    }
}
If you observe above code we are calling our layout using setContentView method in the form of R.layout.layout_file_name in our activity file. Here our xml file name is activity_main.xml so we used file name activity_main and we are trying to get the state of two Switch controls on Button click.

Generally, during the launch of our activityonCreate() callback method will be called by android framework to get the required layout for an activity.

Output of Android Switch Example

When we run above example using android virtual device (AVD) we will get a result like as shown below.

Android Switch Control Example Result

This is how we can use Switch control in android applications to switch the settings between two states either ON or OFF based on our requirements.

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