[Slider] Use a uniform way to update labels

Resolves #4093

GIT_ORIGIN_REV_ID=7db4936713bd31a070d4bb1d9743d99222840184
PiperOrigin-RevId: 614741678

(cherry picked from commit 3bc6612)

Author: pubiqq

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

@@ -348,25 +348,7 @@ abstract class BaseSlider<
 
   @NonNull
   private final ViewTreeObserver.OnScrollChangedListener onScrollChangedListener =
-      () -> {
-        if (shouldAlwaysShowLabel() && isEnabled()) {
-          Rect contentViewBounds = new Rect();
-          ViewUtils.getContentView(this).getHitRect(contentViewBounds);
-          boolean isSliderVisibleOnScreen = getLocalVisibleRect(contentViewBounds);
-          for (int i = 0; i < labels.size(); i++) {
-            TooltipDrawable label = labels.get(i);
-            // Get associated value for label
-            if (i < values.size()) {
-              positionLabel(label, values.get(i));
-            }
-            if (isSliderVisibleOnScreen) {
-              ViewUtils.getContentViewOverlay(this).add(label);
-            } else {
-              ViewUtils.getContentViewOverlay(this).remove(label);
-            }
-          }
-        }
-      };
+      this::updateLabels;
 
   /**
    * Determines the behavior of the label which can be any of the following.
@@ -2029,12 +2011,7 @@ protected void onDraw(@NonNull Canvas canvas) {
       maybeDrawCompatHalo(canvas, trackWidth, yCenter);
     }
 
-    // Draw labels if there is an active thumb or the labels are always visible.
-    if ((activeThumbIdx != -1 || shouldAlwaysShowLabel()) && isEnabled()) {
-      ensureLabelsAdded();
-    } else {
-      ensureLabelsRemoved();
-    }
+    updateLabels();
 
     drawThumbs(canvas, trackWidth, yCenter);
   }
@@ -2660,6 +2637,37 @@ public void onAnimationUpdate(ValueAnimator animation) {
     return animator;
   }
 
+  private void updateLabels() {
+    switch (labelBehavior) {
+      case LABEL_GONE:
+        ensureLabelsRemoved();
+        break;
+      case LABEL_VISIBLE:
+        if (isEnabled() && isSliderVisibleOnScreen()) {
+          ensureLabelsAdded();
+        } else {
+          ensureLabelsRemoved();
+        }
+        break;
+      case LABEL_FLOATING:
+      case LABEL_WITHIN_BOUNDS:
+        if (activeThumbIdx != -1 && isEnabled()) {
+          ensureLabelsAdded();
+        } else {
+          ensureLabelsRemoved();
+        }
+        break;
+      default:
+        throw new IllegalArgumentException("Unexpected labelBehavior: " + labelBehavior);
+    }
+  }
+
+  private boolean isSliderVisibleOnScreen() {
+    final Rect contentViewBounds = new Rect();
+    ViewUtils.getContentView(this).getHitRect(contentViewBounds);
+    return getLocalVisibleRect(contentViewBounds);
+  }
+
   private void ensureLabelsRemoved() {
     // If the labels are animated in or in the process of animating in, create and start a new
     // animator to animate out the labels and remove them once the animation ends.
@@ -2683,11 +2691,6 @@ public void onAnimationEnd(Animator animation) {
   }
 
   private void ensureLabelsAdded() {
-    if (labelBehavior == LABEL_GONE) {
-      // If the label shouldn't be drawn we can skip this.
-      return;
-    }
-
     // If the labels are not animating in, start an animator to show them. ensureLabelsAdded will
     // be called multiple times by BaseSlider's draw method, making this check necessary to avoid
     // creating and starting an animator for each draw call.