How to get the selected index of a RadioGroup in Android

No listeners required

After you've selected your RadioGroup, there's no need for an actual OnCheckedChangeListener. For instances where you just need the index of the selected radio button, just use this straightforward line:

// Why talk when you can point?
int selectedIndex = radioGroup.indexOfChild(findViewById(radioGroup.getCheckedRadioButtonId()));
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It fetches the index directly - no unnecessary listeners, or eye-rolling awkward silence.

Don’t loop, just fetch

Sometimes, you might think about looping through all those RadioButton kids inside your RadioGroup, checking their condition. Well, think again! Our little piece of code does all this for you, simplifying your code and making it easy on the eyes.

What's the chosen one saying?

Fetch the selected index, and maybe you're curious about what your radio button has to say:

// Gonna whisper in your ear
RadioButton selectedButton = (RadioButton) radioGroup.getChildAt(selectedIndex);
String selectedText = selectedButton.getText().toString();
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Now, not only do you know who was chosen, but you've got their secret message ‐ quite the spy move.

Brace for the outliers

Even with the strongest line, you won't always catch a fish. Watch out for when no radio buttons are selected:

// Did someone say "ghost"?
int radioButtonID = radioGroup.getCheckedRadioButtonId();
int selectedIndex = (radioButtonID != -1) ? radioGroup.indexOfChild(findViewById(radioButtonID)) : -1;
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Now you know how to avoid the abyss of negative indices and keep your app crash-free.

Using your newfound wisdom

To wield this knowledge like a pro coder:

• Check for negative index to prep for the radio silent times
• Select index in the right lifecycle method or event handler for accurate RadioGroup state
• Dodge unnecessary listeners while fetching index directly