Android radio button is a widget which can have more than option to choose from and the user can choose only one option at a time. Each option in this refers to a radio button and all the options for a topic are together referred to as Radio Group. Hence, Radio buttons are used inside a RadioGroup.
Step1: Firstly create a new Android Example. This will create an XML file “activity_main.xml” and a Java File “MainActivity.Java”. Please refer the pre-requisites to learn more about this step.
Step1: Firstly create a new Android Example. This will create an XML file “activity_main.xml” and a Java File “MainActivity.Java”. Please refer the pre-requisites to learn more about this step.
<?xml version="1.0" encoding="utf-8"?>Step2: Now, after the UI, this step will create the Backend of the App. For this, open the “MainActivity.java” file and instantiate the components made in the XML file (RadioGroup, TextView, Clear, and Submit Button) using findViewById() method. This method binds the created object to the UI Components with the help of the assigne
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Select your Subject ?"
android:textStyle="bold"
android:layout_marginLeft="10dp"
android:textSize="20dp"/>
<!-- add RadioGroup which contain the many RadioButton-->
<RadioGroup
android:layout_marginTop="50dp"
android:id="@+id/groupradio"
android:layout_marginLeft="10dp"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<!-- In RadioGroup create the 1 Radio Button-->
<!-- like this we will add some more Radio Button-->
<RadioButton
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/radia_id1"
android:text="DBMS"
android:textSize="20dp"/>
<RadioButton
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/radia_id2"
android:text="C/C++ Programing"
android:textSize="20dp"/>
<RadioButton
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/radia_id3"
android:text="Data Structure"
android:textSize="20dp"/>
<RadioButton
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/radia_id4"
android:text="Algorithms"
android:textSize="20dp"/>
</RadioGroup>
<!-- add button For Submit the Selected item-->
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Submit"
android:id="@+id/submit"
android:textStyle="bold"
android:textSize="20dp"
android:layout_marginTop="200dp"
android:layout_marginLeft="180dp"
/>
<!-- add clear button for clear the selected item-->
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Clear"
android:id="@+id/clear"
android:textSize="20dp"
android:textStyle="bold"
android:layout_marginTop="200dp"
android:layout_marginLeft="20dp"
/>
</RelativeLayout>
import android.support.v7.app.AppCompatActivity;Output:
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
// Define the object for Radio Group,
// Submit and Clear buttons
private RadioGroup radioGroup;
Button submit, clear;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Bind the components to their respective objects
// by assigning their IDs
// with the help of findViewById() method
submit = (Button)findViewById(R.id.submit);
clear = (Button)findViewById(R.id.clear);
radioGroup = (RadioGroup)findViewById(R.id.groupradio);
// Uncheck or reset the radio buttons initially
radioGroup.clearCheck();
// Add the Listener to the RadioGroup
radioGroup.setOnCheckedChangeListener(
new RadioGroup
.OnCheckedChangeListener() {
@Override
// The flow will come here when
// any of the radio buttons in the radioGroup
// has been clicked
// Check which radio button has been clicked
public void onCheckedChanged(RadioGroup group,
int checkedId)
{
// Get the selected Radio Button
RadioButton
radioButton
= (RadioButton)group
.findViewById(checkedId);
}
});
// Add the Listener to the Submit Button
submit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
// When submit button is clicked,
// Ge the Radio Button which is set
// If no Radio Button is set, -1 will be returned
int selectedId = radioGroup.getCheckedRadioButtonId();
if (selectedId == -1) {
Toast.makeText(MainActivity.this,
"No answer has been selected",
Toast.LENGTH_SHORT)
.show();
}
else {
RadioButton radioButton
= (RadioButton)radioGroup
.findViewById(selectedId);
// Now display the value of selected item
// by the Toast message
Toast.makeText(MainActivity.this,
radioButton.getText(),
Toast.LENGTH_SHORT)
.show();
}
}
});
// Add the Listener to the Submit Button
clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
// Clear RadioGroup
// i.e. reset all the Radio Buttons
radioGroup.clearCheck();
}
});
}
}
