In android, Switch is a two-state user interface element that 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.
By default, the android Switch will be in the 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 the XML layout file or create it in the Activity file programmatically.
Following is the sample way to define Switch control in XML layout file in the android application.
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.
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 an 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.
Generally, whenever the user clicks on Switch, we can detect whether the Switch is in ON or OFF state and we can handle the 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.
Following are the some of commonly used attributes related to Switch control in android applications.
Attribute | Description |
---|---|
android:id | It is used to uniquely identify the control |
android:checked | It is used to specify the current state of switch control |
android:gravity | It is used to specify how to align the text like left, right, center, top, etc. |
android:text | It is used to set the text. |
android:textOn | It is used to set the text when the toggle button is in the ON / Checked state. |
android:textOff | It is used to set the text when toggle button is in OFF / Unchecked state. |
android:textColor | It is used to change the color of the text. |
android:textSize | It is used to specify the size of the text. |
android:textStyle | It is used to change the style (bold, italic, bolditalic) of text. |
android:background | It is used to set the background color for toggle button control. |
android:padding | It is used to set the padding from left, right, top and bottom. |
android:drawableBottom | It’s a drawable to be drawn to the below of text. |
android:drawableRight | It’s a drawable to be drawn to the right of the text. |
android:drawableLeft | It’s drawable to be drawn to the left of the text. |
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 the 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
<?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 the 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.
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 activity, the onCreate() callback method will be called by the android framework to get the required layout for an activity.
When we run the above example using an android virtual device (AVD) we will get a result like as shown below.
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.