Question

From my understanding, to determine if a checkbox is “clicked” and find if it’s checked or not, code such as the following can be used:

cb=(CheckBox)findViewById(R.id.chkBox1);
        cb.setOnCheckedChangeListener(this);

public void onCheckedChanged(CompoundButton buttonView, 
    boolean isChecked) { 
        if (isChecked) { 
            cb.setText("This checkbox is: checked"); 
        } 
        else { 
            cb.setText("This checkbox is: unchecked"); 
        } 
    }

However, I am unable to work out the logic on how to do the above for a radiogroup.

Here is the xml for my RadioGroup:

<RadioGroup android:id="@+id/radioGroup1" 
android:layout_width="wrap_content" 
android:layout_height="wrap_content">
    <RadioButton android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/radio1" android:checked="true" 
    android:text="RadioButton1">
    </RadioButton>
    <RadioButton android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/radio2" android:text="RadioButton2" android:checked="true">
    </RadioButton>
    <RadioButton android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/radio3" android:text="RadioButton3">
    </RadioButton>
</RadioGroup>

Question: Do i need to setup another listener, or will the listener already there also “register” this group?

Also, should the listener be set up on the RadioGroup or the RadioButton?

Answer 1

This is how you get the checked radiobutton:

// This will get the radiogroup
RadioGroup rGroup = (RadioGroup)findViewById(r.id.radioGroup1);
// This will get the radiobutton in the radiogroup that is checked
RadioButton checkedRadioButton = (RadioButton)rGroup.findViewById(rGroup.getCheckedRadioButtonId());

To use the listener, you do this:

// This overrides the radiogroup onCheckListener
rGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener()
{
    public void onCheckedChanged(RadioGroup group, int checkedId)
    {
        // This will get the radiobutton that has changed in its check state
        RadioButton checkedRadioButton = (RadioButton)group.findViewById(checkedId);
        // This puts the value (true/false) into the variable
        boolean isChecked = checkedRadioButton.isChecked();
        // If the radiobutton that has changed in check state is now checked...
        if (isChecked)
        {
            // Changes the textview's text to "Checked: example radiobutton text"
            tv.setText("Checked:" + checkedRadioButton.getText());
        }
    }
});