How to set radio button checked as default in radiogroup?

Question

I have created RadioGroup and RadioButton dynamically as following:

RadioGroup radioGroup = new RadioGroup(context);
                    RadioButton radioBtn1 = new RadioButton(context);
                    RadioButton radioBtn2 = new RadioButton(context);
                    RadioButton radioBtn3 = new RadioButton(context);

                    radioBtn1.setText("Less");
                    radioBtn2.setText("Normal");
                    radioBtn3.setText("More");

                    radioBtn2.setChecked(true);

                    radioGroup.addView(radioBtn1);
                    radioGroup.addView(radioBtn2);
                    radioGroup.addView(radioBtn3);

Here step radioBtn2.setChecked(true); causes radioBtn2 always checked. That means I cannot uncheck radioBtn2 by checking other two radio buttons (radioBtn1,radioBtn3). I want to make that RadioGroup can check only one radio button at a time (Now it can check two radiobutton at a time).

How can I solve this problem?

Guillema

is there you need dynamically??? – Tmesis

Answer 1

you should check the radiobutton in the radiogroup like this:

radiogroup.check(IdOfYourButton)

Of course you first have to set an Id to your radiobuttons

EDIT: i forgot, radioButton.getId() works as well, thx Ramesh

EDIT2:

android:checkedButton="@+id/my_radiobtn"

works in radiogroup xml

Unmistakable

or if you don't want to id your RadioButton and you know the index you can use ((RadioButton)radioGroup.getChildAt(INDEX)).setChecked(true); – Rycca

You shouldn't do that. That will cause the "setChecked" problem described in this question. Of course there are ways to do that without ids of your buttons, but please not by using setChecked() One way would be radiogroup.check(((RadioButton)radioGroup.getChildAt(INDEX)).getId()) or something like that – Unmistakable

good to not forget to add the radio button to the radio button group before calling group.check(button.getId()) – Susannasusannah

I had to do it this way: radioGroup.Check(radioGroup.GetChildAt(0).Id); for Xamarin.Android users – Mount

Answer 2

In case for xml attribute its android:checkedButton which takes the id of the RadioButton to be checked.

<RadioGroup
...
...
android:checkedButton="@+id/IdOfTheRadioButtonInsideThatTobeChecked"
... >....</RadioGroup>

Pudendas

Answer 3

In the XML file set the android:checkedButton field in your RadioGroup, with the id of your default RadioButton:

<RadioGroup
    ....
    android:checkedButton="@+id/button_1">

    <RadioButton
        android:id="@+id/button_1"
        ...../>

    <RadioButton
        android:id="@+id/button_2"
        ...../>

    <RadioButton
        android:id="@+id/button_3"
        ...../>
</RadioGroup>

Shamblin

Answer 4

    RadioGroup radioGroup = new RadioGroup(WvActivity.this);
    RadioButton radioBtn1 = new RadioButton(this);
    RadioButton radioBtn2 = new RadioButton(this);
    RadioButton radioBtn3 = new RadioButton(this);

    radioBtn1.setText("Less");
    radioBtn2.setText("Normal");
    radioBtn3.setText("More");


    radioGroup.addView(radioBtn1);
    radioGroup.addView(radioBtn2);
    radioGroup.addView(radioBtn3);

    radioGroup.check(radioBtn2.getId());

Freiburg

Answer 5

RadioGroup radioGroup = new RadioGroup(context);
RadioButton radioBtn1 = new RadioButton(context);
RadioButton radioBtn2 = new RadioButton(context);
RadioButton radioBtn3 = new RadioButton(context);

radioBtn1.setText("Less");
radioBtn2.setText("Normal");
radioBtn3.setText("More");

radioGroup.addView(radioBtn1);
radioGroup.addView(radioBtn2);
radioGroup.addView(radioBtn3);
radioBtn2.setChecked(true);

Kenogenesis

The important thing is to use setChecked() after all radio buttons have been added to the radio group. Then, radioGroup.check(radioBtn2.getId()) is not neccessary – Histoplasmosis

Answer 6

There was same problem in my Colleague's code. This sounds as your Radio Group is not properly set with your Radio Buttons. This is the reason you can multi-select the radio buttons. I tried many things, finally i did a trick which is wrong actually, but works fine.

for ( int i = 0 ; i < myCount ; i++ )
{
    if ( i != k )
    {
        System.out.println ( "i = " + i );
        radio1[i].setChecked(false);
    }
}

Here I set one for loop, which checks for the available radio buttons and de-selects every one except the new clicked one. try it.

Gewgaw

Answer 7

It's a bug of RadioGroup

RadioButton radioBtn2 = new RadioButton(context);

radioBtn2 without viewId, and generateViewId is in onChildViewAdded()

public void onChildViewAdded(View parent, View child) {
    if (parent == RadioGroup.this && child instanceof RadioButton) {
        int id = child.getId();
        // generates an id if it's missing
        if (id == View.NO_ID) {
            id = View.generateViewId();
            child.setId(id);
        }
        ((RadioButton) child).setOnCheckedChangeWidgetListener(
                mChildOnCheckedChangeListener);
    }

    if (mOnHierarchyChangeListener != null) {
        mOnHierarchyChangeListener.onChildViewAdded(parent, child);
    }
}

so, first radioGroup.addView(radioBtn2), then radioBtn2.setChecked(true);

Like this:

RadioGroup radioGroup = new RadioGroup(context);
RadioButton radioBtn1 = new RadioButton(context);
RadioButton radioBtn2 = new RadioButton(context);
RadioButton radioBtn3 = new RadioButton(context);

radioBtn1.setText("Less");
radioBtn2.setText("Normal");
radioBtn3.setText("More");

radioGroup.addView(radioBtn1);
radioGroup.addView(radioBtn2);
radioGroup.addView(radioBtn3);

radioBtn2.setChecked(true);

Tatianna

Answer 8

Add android:checked = "true" in your activity.xml

Interrogatory

This should be added to <RadioButton> tag, since this is an important detail! – Antineutron