diff --git a/core/java/android/widget/RadioButton.java b/core/java/android/widget/RadioButton.java
index d44fbd7c6f8e8..3e26f63697471 100644
--- a/core/java/android/widget/RadioButton.java
+++ b/core/java/android/widget/RadioButton.java
@@ -18,6 +18,7 @@ package android.widget;
 
 import android.content.Context;
 import android.util.AttributeSet;
+import android.view.accessibility.AccessibilityNodeInfo;
 
 
 /**
@@ -38,19 +39,19 @@ import android.util.AttributeSet;
  * guide.</p>
  *
  * <p><strong>XML attributes</strong></p>
- * <p> 
- * See {@link android.R.styleable#CompoundButton CompoundButton Attributes}, 
- * {@link android.R.styleable#Button Button Attributes}, 
- * {@link android.R.styleable#TextView TextView Attributes}, 
+ * <p>
+ * See {@link android.R.styleable#CompoundButton CompoundButton Attributes},
+ * {@link android.R.styleable#Button Button Attributes},
+ * {@link android.R.styleable#TextView TextView Attributes},
  * {@link android.R.styleable#View View Attributes}
  * </p>
  */
 public class RadioButton extends CompoundButton {
-    
+
     public RadioButton(Context context) {
         this(context, null);
     }
-    
+
     public RadioButton(Context context, AttributeSet attrs) {
         this(context, attrs, com.android.internal.R.attr.radioButtonStyle);
     }
@@ -81,4 +82,20 @@ public class RadioButton extends CompoundButton {
     public CharSequence getAccessibilityClassName() {
         return RadioButton.class.getName();
     }
+
+    @Override
+    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+        super.onInitializeAccessibilityNodeInfo(info);
+        if (getParent() instanceof RadioGroup) {
+            RadioGroup radioGroup = (RadioGroup) getParent();
+            if (radioGroup.getOrientation() == LinearLayout.HORIZONTAL) {
+                info.setCollectionItemInfo(AccessibilityNodeInfo.CollectionItemInfo.obtain(0, 1,
+                        radioGroup.getIndexWithinVisibleButtons(this), 1, false, isChecked()));
+            } else {
+                info.setCollectionItemInfo(AccessibilityNodeInfo.CollectionItemInfo.obtain(
+                        radioGroup.getIndexWithinVisibleButtons(this), 1, 0, 1,
+                        false, isChecked()));
+            }
+        }
+    }
 }
diff --git a/core/java/android/widget/RadioGroup.java b/core/java/android/widget/RadioGroup.java
index c62c16c7e719a..90bc0a3ee7b22 100644
--- a/core/java/android/widget/RadioGroup.java
+++ b/core/java/android/widget/RadioGroup.java
@@ -18,6 +18,7 @@ package android.widget;
 
 import android.annotation.IdRes;
 import android.annotation.NonNull;
+import android.annotation.Nullable;
 import android.annotation.UnsupportedAppUsage;
 import android.content.Context;
 import android.content.res.TypedArray;
@@ -26,6 +27,7 @@ import android.util.Log;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewStructure;
+import android.view.accessibility.AccessibilityNodeInfo;
 import android.view.autofill.AutofillManager;
 import android.view.autofill.AutofillValue;
 
@@ -93,6 +95,7 @@ public class RadioGroup extends LinearLayout {
         if (getImportantForAutofill() == IMPORTANT_FOR_AUTOFILL_AUTO) {
             setImportantForAutofill(IMPORTANT_FOR_AUTOFILL_YES);
         }
+        setImportantForAccessibility(IMPORTANT_FOR_ACCESSIBILITY_YES);
 
         // retrieve selected radio button as requested by the user in the
         // XML layout file
@@ -475,4 +478,50 @@ public class RadioGroup extends LinearLayout {
         }
         return null;
     }
-}
+
+    @Override
+    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+        super.onInitializeAccessibilityNodeInfo(info);
+        if (this.getOrientation() == HORIZONTAL) {
+            info.setCollectionInfo(AccessibilityNodeInfo.CollectionInfo.obtain(1,
+                    getVisibleChildCount(), false,
+                    AccessibilityNodeInfo.CollectionInfo.SELECTION_MODE_SINGLE));
+        } else {
+            info.setCollectionInfo(
+                    AccessibilityNodeInfo.CollectionInfo.obtain(getVisibleChildCount(),
+                    1, false,
+                    AccessibilityNodeInfo.CollectionInfo.SELECTION_MODE_SINGLE));
+        }
+    }
+
+    private int getVisibleChildCount() {
+        int count = 0;
+        for (int i = 0; i < getChildCount(); i++) {
+            if (this.getChildAt(i) instanceof RadioButton) {
+                if (((RadioButton) this.getChildAt(i)).getVisibility() == VISIBLE) {
+                    count++;
+                }
+            }
+        }
+        return count;
+    }
+
+    int getIndexWithinVisibleButtons(@Nullable View child) {
+        if (!(child instanceof RadioButton)) {
+            return -1;
+        }
+        int index = 0;
+        for (int i = 0; i < getChildCount(); i++) {
+            if (this.getChildAt(i) instanceof RadioButton) {
+                RadioButton radioButton = (RadioButton) this.getChildAt(i);
+                if (radioButton == child) {
+                    return index;
+                }
+                if (radioButton.getVisibility() == VISIBLE) {
+                    index++;
+                }
+            }
+        }
+        return -1;
+    }
+}
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