RadioGroup

public class RadioGroup
extends LinearLayout

java.lang.Object
   ↳ android.view.View
     ↳ android.view.ViewGroup
       ↳ android.widget.LinearLayout
         ↳ android.widget.RadioGroup


This class is used to create a multiple-exclusion scope for a set of radio buttons. Checking one radio button that belongs to a radio group unchecks any previously checked radio button within the same group.

Intially, all of the radio buttons are unchecked. While it is not possible to uncheck a particular radio button, the radio group can be cleared to remove the checked state.

The selection is identified by the unique id of the radio button as defined in the XML layout file.

XML Attributes

See RadioGroup Attributes, LinearLayout Attributes, ViewGroup Attributes, View Attributes

Also see LinearLayout.LayoutParams for layout attributes.

See also:

Summary

Nested classes

class RadioGroup.LayoutParams

This set of layout parameters defaults the width and the height of the children to ViewGroup.LayoutParams.WRAP_CONTENT when they are not specified in the XML file. 

interface RadioGroup.OnCheckedChangeListener

Interface definition for a callback to be invoked when the checked radio button changed in this group. 

XML attributes

android:checkedButton The id of the child radio button that should be checked by default within this radio group. 

Inherited XML attributes

Inherited constants

Inherited fields

Public constructors

RadioGroup(Context context)

RadioGroup(Context context, AttributeSet attrs)

Public methods

void addView(View child, int index, ViewGroup.LayoutParams params)

Adds a child view with the specified layout parameters.

void autofill(AutofillValue value)

Automatically fills the content of this view with the value.

void check(int id)

Sets the selection to the radio button whose identifier is passed in parameter.

void clearCheck()

Clears the selection.

RadioGroup.LayoutParams generateLayoutParams(AttributeSet attrs)

Returns a new set of layout parameters based on the supplied attributes set.

CharSequence getAccessibilityClassName()

Return the class name of this object to be used for accessibility purposes.

int getAutofillType()

Describes the autofill type of this view, so an AutofillService can create the proper AutofillValue when autofilling the view.

AutofillValue getAutofillValue()

Gets the View's current autofill value.

int getCheckedRadioButtonId()

Returns the identifier of the selected radio button in this group.

void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info)

Initializes an AccessibilityNodeInfo with information about this view.

void setOnCheckedChangeListener(RadioGroup.OnCheckedChangeListener listener)

Register a callback to be invoked when the checked radio button changes in this group.

void setOnHierarchyChangeListener(ViewGroup.OnHierarchyChangeListener listener)

Register a callback to be invoked when a child is added to or removed from this view.

Protected methods

boolean checkLayoutParams(ViewGroup.LayoutParams p)

LinearLayout.LayoutParams generateDefaultLayoutParams()

Returns a set of layout parameters with a width of ViewGroup.LayoutParams.MATCH_PARENT and a height of ViewGroup.LayoutParams.WRAP_CONTENT when the layout's orientation is VERTICAL.

void onFinishInflate()

Finalize inflating a view from XML.

Inherited methods

XML attributes

android:checkedButton

The id of the child radio button that should be checked by default within this radio group.

May be an integer value, such as "100".

Related methods:

Public constructors

RadioGroup

Added in API level 1
public RadioGroup (Context context)

Parameters
context Context

RadioGroup

Added in API level 1
public RadioGroup (Context context, 
                AttributeSet attrs)

Parameters
context Context

attrs AttributeSet

Public methods

addView

Added in API level 1
public void addView (View child, 
                int index, 
                ViewGroup.LayoutParams params)

Adds a child view with the specified layout parameters.

Note: do not invoke this method from View.draw(android.graphics.Canvas), View.onDraw(android.graphics.Canvas), dispatchDraw(android.graphics.Canvas) or any related method.

Parameters
child View: the child view to add

index int: the position at which to add the child or -1 to add last

params ViewGroup.LayoutParams: the layout parameters to set on the child

autofill

Added in API level 26
public void autofill (AutofillValue value)

Automatically fills the content of this view with the value.

Views support the Autofill Framework mainly by:

  • Providing the metadata defining what the view means and how it can be autofilled.
  • Implementing the methods that autofill the view.

onProvideAutofillStructure(android.view.ViewStructure, int) is responsible for the former, this method is responsible for latter.

This method does nothing by default, but when overridden it typically:

  1. Checks if the provided value matches the expected type (which is defined by getAutofillType()).
  2. Checks if the view is editable - if it isn't, it should return right away.
  3. Call the proper getter method on AutofillValue to fetch the actual value.
  4. Pass the actual value to the equivalent setter in the view.

For example, a text-field view could implement the method this way:

 @Override
 public void autofill(AutofillValue value) {
   if (!value.isText() || !this.isEditable()) {
      return;
   }
   CharSequence text = value.getTextValue();
   if (text != null) {
     this.setText(text);
   }
 }
 

If the value is updated asynchronously, the next call to AutofillManager#notifyValueChanged(View) must happen after the value was changed to the autofilled value. If not, the view will not be considered autofilled.

Note: After this method is called, the value returned by getAutofillValue() must be equal to the value passed to it, otherwise the view will not be highlighted as autofilled.

Parameters
value AutofillValue: value to be autofilled.

check

Added in API level 1
public void check (int id)

Sets the selection to the radio button whose identifier is passed in parameter. Using -1 as the selection identifier clears the selection; such an operation is equivalent to invoking clearCheck().

Parameters
id int: the unique id of the radio button to select in this group

clearCheck

Added in API level 1
public void clearCheck ()

Clears the selection. When the selection is cleared, no radio button in this group is selected and getCheckedRadioButtonId() returns null.

generateLayoutParams

Added in API level 1
public RadioGroup.LayoutParams generateLayoutParams (AttributeSet attrs)

Returns a new set of layout parameters based on the supplied attributes set.

Parameters
attrs AttributeSet: the attributes to build the layout parameters from

Returns
RadioGroup.LayoutParams an instance of ViewGroup.LayoutParams or one of its descendants

getAccessibilityClassName

Added in API level 23
public CharSequence getAccessibilityClassName ()

Return the class name of this object to be used for accessibility purposes. Subclasses should only override this if they are implementing something that should be seen as a completely new class of view when used by accessibility, unrelated to the class it is deriving from. This is used to fill in AccessibilityNodeInfo.setClassName.

Returns
CharSequence

getAutofillType

Added in API level 26
public int getAutofillType ()

Describes the autofill type of this view, so an AutofillService can create the proper AutofillValue when autofilling the view.

By default returns AUTOFILL_TYPE_NONE, but views should override it to properly support the Autofill Framework.

Returns
int Value is View.AUTOFILL_TYPE_NONE, View.AUTOFILL_TYPE_TEXT, View.AUTOFILL_TYPE_TOGGLE, View.AUTOFILL_TYPE_LIST, or View.AUTOFILL_TYPE_DATE

getAutofillValue

Added in API level 26
public AutofillValue getAutofillValue ()

Gets the View's current autofill value.

By default returns null, but subclasses should override it and return an appropriate value to properly support the Autofill Framework.

Returns
AutofillValue

getCheckedRadioButtonId

Added in API level 1
public int getCheckedRadioButtonId ()

Returns the identifier of the selected radio button in this group. Upon empty selection, the returned value is -1.

Related XML Attributes:

Returns
int the unique id of the selected radio button in this group

onInitializeAccessibilityNodeInfo

Added in API level 14
public void onInitializeAccessibilityNodeInfo (AccessibilityNodeInfo info)

Initializes an AccessibilityNodeInfo with information about this view. The base implementation sets:

Subclasses should override this method, call the super implementation, and set additional attributes.

If an AccessibilityDelegate has been specified via calling setAccessibilityDelegate(android.view.View.AccessibilityDelegate) its AccessibilityDelegate#onInitializeAccessibilityNodeInfo(View, AccessibilityNodeInfo) is responsible for handling this call.


If you override this method you must call through to the superclass implementation.

Parameters
info AccessibilityNodeInfo: The instance to initialize.

setOnCheckedChangeListener

Added in API level 1
public void setOnCheckedChangeListener (RadioGroup.OnCheckedChangeListener listener)

Register a callback to be invoked when the checked radio button changes in this group.

Parameters
listener RadioGroup.OnCheckedChangeListener: the callback to call on checked state change

setOnHierarchyChangeListener

Added in API level 1
public void setOnHierarchyChangeListener (ViewGroup.OnHierarchyChangeListener listener)

Register a callback to be invoked when a child is added to or removed from this view.

Parameters
listener ViewGroup.OnHierarchyChangeListener: the callback to invoke on hierarchy change

Protected methods

checkLayoutParams

Added in API level 1
protected boolean checkLayoutParams (ViewGroup.LayoutParams p)

Parameters
p ViewGroup.LayoutParams

Returns
boolean

generateDefaultLayoutParams

Added in API level 1
protected LinearLayout.LayoutParams generateDefaultLayoutParams ()

Returns a set of layout parameters with a width of ViewGroup.LayoutParams.MATCH_PARENT and a height of ViewGroup.LayoutParams.WRAP_CONTENT when the layout's orientation is VERTICAL. When the orientation is HORIZONTAL, the width is set to LayoutParams#WRAP_CONTENT and the height to LayoutParams#WRAP_CONTENT.

Returns
LinearLayout.LayoutParams a set of default layout parameters or null

onFinishInflate

Added in API level 1
protected void onFinishInflate ()

Finalize inflating a view from XML. This is called as the last phase of inflation, after all child views have been added.

Even if the subclass overrides onFinishInflate, they should always be sure to call the super method, so that we get called.
If you override this method you must call through to the superclass implementation.