RadioGroup How to check programmatically

Question

I create a RadioGroup from XML       lt RadioGroup android id    id option           android layout width  match parent          android orientation  horizontal           android checkedButton    id block scenario off          android layout height  wrap content  gt           lt 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   gt           lt 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   gt           lt 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    gt       lt  RadioGroup gt    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

User · Answer

it will work if you put your  mOption check R id option1    into onAttachedToWindow  method or like this     view post new Runnable         public void run                     TODO Auto-generated method stub         mOption check R id option1                the reason may be that  check method will only work when the radiogroup is actually rendered

User · Answer

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

User · Answer

I prefer to use   RadioButton b    RadioButton  findViewById R id option1   b performClick      instead of using the accepted answer   RadioButton b    RadioButton  findViewById R id option1   b setChecked true     The reason is setChecked true  only changes the checked state of radio button  It does not trigger the onClick   method added to your radio button  Sometimes this might waste your time to debug why the action related to onClick   not working

User · Answer

try this     if you want your radio button to be checked based on value of some variable e g   genderStr  then you can use following code snippet      if genderStr equals  Male           genderRG check R id maleRB       else         genderRG check R id femaleRB

User · Answer

Grab the radio group and look at the children to see if any are unchecked   RadioGroup rg    RadioGroup  view  int checked   savedInstanceState getInt wrap getAttributeName      if checked    -1        RadioButton btn    RadioButton  rg getChildAt checked       btn toggle

User · Answer

Watch out  checking the radiobutton with setChecked   is not changing the state inside the RadioGroup  For example this method from the radioGroup will return a wrong result  getCheckedRadioButtonId     Check the radioGroup always with  mOption check R id option1     you ve been warned

User · Answer

Also you can use getChildAt   method  Like this   mOption    RadioGroup  findViewById R id option     RadioButton mOption getChildAt 0   setChecked true

User · Answer

You may need to declare the radio buttons in the onCreate method of your code and use them   RadioButton rb1    RadioButton  findViewById R id option1   rb1 setChecked true

User · Answer

I use this code piece while working with indexes for radio group   radioGroup check radioGroup getChildAt index  getId

User · Answer

I use this code piece while working with getId   for radio group   radiogroup check radiogroup getChildAt 0  getId       set position as per your design of RadioGroup  hope this will help you

[android] RadioGroup: How to check programmatically

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