RadioGroup: How to check programmatically

Question

I create a RadioGroup from XML

    <RadioGroup android:id="@+id/option"          android:layout_width="match_parent"         android:orientation="horizontal"          android:checkedButton="@+id/block_scenario_off"         android:layout_height="wrap_content">         <RadioButton              android:layout_width="0dip"             android:layout_weight="1"              android:text="@string/option1"              android:layout_height="wrap_content"              android:id="@+id/option1"             android:layout_gravity="center|left"              android:onClick="@string/on_click"/>         <RadioButton              android:layout_width="0dip"             android:layout_weight="1"              android:text="@string/option2"              android:onClick="@string/on_click"             android:layout_height="wrap_content"             android:layout_gravity="center"              android:id="@+id/option2"/>         <RadioButton              android:layout_width="0dip"             android:layout_weight="1"              android:text="@string/option3"             android:onClick="@string/on_click"              android:layout_height="wrap_content"             android:layout_gravity="center|right"              android:id="@+id/option3" />     </RadioGroup> 

In Java code, I programmatically check the first one on activity creation (onCreate()) as following:

    mOption = (RadioGroup) findViewById(R.id.option);     mOption.check(R.id.option1); 

But when the activity is shown, no radio button is checked. Any help?

Answer 1

In your layout you can add android:checked="true" to CheckBox you want to be selected.

Or programmatically, you can use the setChecked method defined in the checkable interface:

RadioButton b = (RadioButton) findViewById(R.id.option1); b.setChecked(true);