[Slider][A11y] Prevent duplicate accessibility announcements

PiperOrigin-RevId: 762520075

Author: Material Design Team

lib/java/com/google/android/material/slider/BaseSlider.java

@@ -80,6 +80,7 @@
 import android.view.ViewTreeObserver;
 import android.view.accessibility.AccessibilityEvent;
 import android.view.accessibility.AccessibilityManager;
+import android.view.accessibility.AccessibilityNodeInfo;
 import android.widget.SeekBar;
 import androidx.annotation.ColorInt;
 import androidx.annotation.ColorRes;
@@ -3484,6 +3485,14 @@ private boolean isThisAndAncestorsVisible() {
     return (VERSION.SDK_INT >= VERSION_CODES.N) ? thisAndAncestorsVisible : isShown();
   }
 
+  @Override
+  public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
+    super.onInitializeAccessibilityNodeInfo(info);
+    // Setting content description to null prevents duplicate announcements by making only our
+    // virtual view accessible, not the parent container.
+    info.setContentDescription(null);
+  }
+
   @Override
   public void onVisibilityAggregated(boolean isVisible) {
     super.onVisibilityAggregated(isVisible);