Android Application Development Cookbook: 93 Recipes for Building Winning Apps

Figure 2-5 
www.it-ebooks.info

---

48
❘
ChAPter 2
using Views to design the user interFAce
The following code snippet shows how to determine whether a radio button is checked:
package net.learn2develop.radiobuttons;
import android.app.Activity;
import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//---RadioButton---
RadioGroup radioGroup = (RadioGroup) findViewById(R.id.rdbGp1);
radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener()
{
public void onCheckedChanged(RadioGroup group, int checkedId) {
RadioButton rb1 = (RadioButton) findViewById(R.id.rdb1);
if (rb1.isChecked()) {
Toast.makeText(getBaseContext(), 
"Option 1 checked!", 
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getBaseContext(), 
"Option 2 checked!", 
Toast.LENGTH_LONG).show();
}
}
});
}
}
You can determine whether a radio button is checked by listening to the 
onCheckedChanged
event 
on of the 
RadioGroup
element. This event is fired whenever a radio button contained within it is 
checked or unchecked. To determine the state of a radio button, examine its 
isChecked()
method. 
Figure 2-6 shows the 
Toast
class displaying a message when a radio button is clicked on the 
emulator. 
www.it-ebooks.info

---