[Slider][A11y] Use arrow keys for value adjustment and TAB for navigation

Refactors Slider/RangeSlider keyboard navigation for a more intuitive and accessible experience, removing the need to press ENTER to toggle between navigation and value adjustment modes.

With this change:

- Arrow keys (+/-/=/DPAD) always adjust the value of the focused thumb.
- TAB and Shift+TAB always navigate focus between thumbs.

This simplifies event handling by ensuring `activeThumbIdx` stays synchronized with `focusedThumbIdx` during keyboard input.

Also fixes regressions in `SliderTouchTest` by preventing `onFocusChanged` logic (now conditioned on `activeThumbIdx == -1`) from incorrectly overriding thumb selection during touch events.

PiperOrigin-RevId: 816168251

Author: Material Design Team

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

@@ -3788,16 +3788,7 @@ public boolean onKeyDown(int keyCode, @NonNull KeyEvent event) {
       return super.onKeyDown(keyCode, event);
     }
 
-    // If there's only one thumb, we can select it right away.
-    if (values.size() == 1) {
-      activeThumbIdx = 0;
-    }
-
-    // If there is no active thumb, key events will be used to pick the thumb to change.
-    if (activeThumbIdx == -1) {
-      Boolean handled = onKeyDownNoActiveThumb(keyCode, event);
-      return handled != null ? handled : super.onKeyDown(keyCode, event);
-    }
+    activeThumbIdx = focusedThumbIdx;
 
     isLongPress |= event.isLongPress();
     Float increment = calculateIncrementForKey(keyCode);
@@ -3808,64 +3799,19 @@ public boolean onKeyDown(int keyCode, @NonNull KeyEvent event) {
       }
       return true;
     }
-    switch (keyCode) {
-      case KeyEvent.KEYCODE_TAB:
-        if (event.hasNoModifiers()) {
-          return moveFocus(1);
-        }
-
-        if (event.isShiftPressed()) {
-          return moveFocus(-1);
-        }
-        return false;
-      case KeyEvent.KEYCODE_DPAD_CENTER:
-      case KeyEvent.KEYCODE_ENTER:
-        activeThumbIdx = -1;
-        postInvalidate();
-        return true;
-      default:
-        // Nothing to do in this case.
-    }
-
-    return super.onKeyDown(keyCode, event);
-  }
 
-  @Nullable
-  private Boolean onKeyDownNoActiveThumb(int keyCode, @NonNull KeyEvent event) {
-    switch (keyCode) {
-      case KeyEvent.KEYCODE_TAB:
-        if (event.hasNoModifiers()) {
-          return moveFocus(1);
-        }
+    if (keyCode == KeyEvent.KEYCODE_TAB) {
+      if (event.hasNoModifiers()) {
+        return moveFocus(1);
+      }
 
-        if (event.isShiftPressed()) {
-          return moveFocus(-1);
-        }
-        return false;
-      case KeyEvent.KEYCODE_DPAD_LEFT:
-        moveFocusInAbsoluteDirection(-1);
-        return true;
-      case KeyEvent.KEYCODE_MINUS:
-        moveFocus(-1);
-        return true;
-      case KeyEvent.KEYCODE_DPAD_RIGHT:
-        moveFocusInAbsoluteDirection(1);
-        return true;
-      case KeyEvent.KEYCODE_EQUALS:
-      // Numpad Plus == Shift + Equals, at least in AVD, so fall through.
-      case KeyEvent.KEYCODE_PLUS:
-        moveFocus(1);
-        return true;
-      case KeyEvent.KEYCODE_DPAD_CENTER:
-      case KeyEvent.KEYCODE_ENTER:
-        activeThumbIdx = focusedThumbIdx;
-        postInvalidate();
-        return true;
-      default:
-        // Nothing to do in this case.
+      if (event.isShiftPressed()) {
+        return moveFocus(-1);
+      }
+      return false;
     }
 
-    return null;
+    return super.onKeyDown(keyCode, event);
   }
 
   @Override
@@ -3903,9 +3849,7 @@ private boolean moveFocus(int direction) {
       // Move focus to next or previous view.
       return false;
     }
-    if (activeThumbIdx != -1) {
-      activeThumbIdx = focusedThumbIdx;
-    }
+    activeThumbIdx = focusedThumbIdx;
     updateHaloHotspot();
     postInvalidate();
     return true;
@@ -3978,7 +3922,12 @@ protected void onFocusChanged(
       activeThumbIdx = -1;
       accessibilityHelper.clearKeyboardFocusForVirtualView(focusedThumbIdx);
     } else {
-      focusThumbOnFocusGained(direction);
+      // If activeThumbIdx != -1, a touch gesture is in progress and has already
+      // picked the thumb to focus. Don't interfere.
+      if (activeThumbIdx == -1) {
+        focusThumbOnFocusGained(direction);
+        activeThumbIdx = focusedThumbIdx;
+      }
       accessibilityHelper.requestKeyboardFocusForVirtualView(focusedThumbIdx);
     }
   }

lib/javatests/com/google/android/material/slider/SliderKeyTestCommon.java

@@ -18,7 +18,6 @@
 
 import com.google.android.material.test.R;
 
-import static com.google.android.material.slider.SliderHelper.clickDpadCenter;
 import static com.google.common.truth.Truth.assertThat;
 import static com.google.common.truth.Truth.assertWithMessage;
 
@@ -127,61 +126,6 @@ public void testMoveThumbFocus_tab_correctThumbHasFocus() {
     sendKeyEventThereAndBack(tab, shiftTab);
   }
 
-  @Test
-  public void testMoveThumbFocus_plusMinus_correctThumbHasFocus() {
-    slider.requestFocus();
-
-    KeyEventBuilder plus = new KeyEventBuilder(KeyEvent.KEYCODE_PLUS);
-    KeyEventBuilder minus = new KeyEventBuilder(KeyEvent.KEYCODE_MINUS);
-
-    sendKeyEventThereAndBack(plus, minus);
-  }
-
-  @Test
-  public void testMoveThumbFocus_equalsMinus_correctThumbHasFocus() {
-    slider.requestFocus();
-
-    // Numpad Plus == Shift + Equals, at least in AVD.
-    KeyEventBuilder equals = new KeyEventBuilder(KeyEvent.KEYCODE_EQUALS);
-    KeyEventBuilder minus = new KeyEventBuilder(KeyEvent.KEYCODE_MINUS);
-
-    sendKeyEventThereAndBack(equals, minus);
-  }
-
-  @Test
-  public void testFocusThirdThumb_clickCenterDPad_activatesThirdThumb() {
-    slider.requestFocus();
-
-    slider.setFocusedThumbIndex(2);
-
-    clickDpadCenter(slider);
-
-    assertThat(slider.getActiveThumbIndex()).isEqualTo(2);
-  }
-
-  protected void activateFocusedThumb() {
-    int focusedThumbIndex = slider.getFocusedThumbIndex();
-    if (focusedThumbIndex != -1) {
-      // Clicking D-Pad in Slider isn't idempotent. Only do it here if we're changing focused thumb.
-      if (focusedThumbIndex != slider.getActiveThumbIndex()) {
-        clickDpadCenter(slider);
-      }
-    }
-  }
-
-  @Test
-  public void testActivateThirdThumb_clickCenterDPad_deactivatesThirdThumb() {
-    slider.requestFocus();
-
-    slider.setFocusedThumbIndex(2);
-
-    activateFocusedThumb();
-
-    clickDpadCenter(slider);
-
-    assertThat(slider.getActiveThumbIndex()).isEqualTo(-1);
-  }
-
   @Test
   public void testFocusDefaultThumb_clickUpDPad_unhandled() {
     slider.requestFocus();
@@ -194,20 +138,6 @@ public void testFocusDefaultThumb_clickUpDPad_unhandled() {
     assertThat(handledUp).isFalse();
   }
 
-  @Test
-  public void testActivateDefaultThumb_clickUpDPad_unhandled() {
-    slider.requestFocus();
-
-    activateFocusedThumb();
-
-    KeyEventBuilder up = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_UP);
-    boolean handledDown = slider.dispatchKeyEvent(up.buildDown());
-    boolean handledUp = slider.dispatchKeyEvent(up.buildUp());
-
-    assertThat(handledDown).isFalse();
-    assertThat(handledUp).isFalse();
-  }
-
   @Test
   public void testFocusDefaultThumb_clickDownDPad_unhandled() {
     slider.requestFocus();
@@ -220,20 +150,6 @@ public void testFocusDefaultThumb_clickDownDPad_unhandled() {
     assertThat(handledUp).isFalse();
   }
 
-  @Test
-  public void testActivateDefaultThumb_clickDownDPad_unhandled() {
-    slider.requestFocus();
-
-    activateFocusedThumb();
-
-    KeyEventBuilder down = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_DOWN);
-    boolean handledDown = slider.dispatchKeyEvent(down.buildDown());
-    boolean handledUp = slider.dispatchKeyEvent(down.buildUp());
-
-    assertThat(handledDown).isFalse();
-    assertThat(handledUp).isFalse();
-  }
-
   @Test
   public void testFocusFirstThumb_shiftTab_unhandled() {
     slider.requestFocus();
@@ -249,23 +165,6 @@ public void testFocusFirstThumb_shiftTab_unhandled() {
     assertThat(handledUp).isFalse();
   }
 
-  @Test
-  public void testActivateFirstThumb_shiftTab_unhandled() {
-    slider.requestFocus();
-
-    slider.setFocusedThumbIndex(0);
-
-    activateFocusedThumb();
-
-    KeyEventBuilder tab = new KeyEventBuilder(KeyEvent.KEYCODE_TAB);
-    tab.meta = KeyEvent.META_SHIFT_ON;
-    boolean handledDown = slider.dispatchKeyEvent(tab.buildDown());
-    boolean handledUp = slider.dispatchKeyEvent(tab.buildUp());
-
-    assertThat(handledDown).isFalse();
-    assertThat(handledUp).isFalse();
-  }
-
   @Test
   public void testFocusLastThumb_tab_unhandled() {
     slider.requestFocus();
@@ -280,22 +179,6 @@ public void testFocusLastThumb_tab_unhandled() {
     assertThat(handledUp).isFalse();
   }
 
-  @Test
-  public void testActivateLastThumb_tab_unhandled() {
-    slider.requestFocus();
-
-    slider.setFocusedThumbIndex(countTestValues() - 1);
-
-    activateFocusedThumb();
-
-    KeyEventBuilder tab = new KeyEventBuilder(KeyEvent.KEYCODE_TAB);
-    boolean handledDown = slider.dispatchKeyEvent(tab.buildDown());
-    boolean handledUp = slider.dispatchKeyEvent(tab.buildUp());
-
-    assertThat(handledDown).isFalse();
-    assertThat(handledUp).isFalse();
-  }
-
   protected void sendKeyEventThereAndBack(KeyEventBuilder there, KeyEventBuilder back) {
     for (int i = 1; i < countTestValues(); i++) {
       there.dispatchEvent(slider);

lib/javatests/com/google/android/material/slider/SliderKeyTestLtr.java

@@ -46,23 +46,11 @@ public void testThumbFocus_focusRight_focusesFirstThumb() {
   }
 
   @Test
-  public void testMoveThumbFocus_dPad_correctThumbHasFocus() {
-    slider.requestFocus();
-
-    KeyEventBuilder right = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_RIGHT);
-    KeyEventBuilder left = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_LEFT);
-
-    sendKeyEventThereAndBack(right, left);
-  }
-
-  @Test
-  public void testActivateThirdThumb_moveRight_movesThirdThumbRight() {
+  public void testFocusThirdThumb_moveRight_movesThirdThumbRight() {
     slider.requestFocus();
 
     slider.setFocusedThumbIndex(2);
 
-    activateFocusedThumb();
-
     KeyEventBuilder right = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_RIGHT);
     for (int i = 0; i < 20; i++) {
       right.dispatchEvent(slider);
@@ -72,13 +60,11 @@ public void testActivateThirdThumb_moveRight_movesThirdThumbRight() {
   }
 
   @Test
-  public void testActivateThirdThumb_moveLeft_movesThirdThumbLeft() {
+  public void testFocusThirdThumb_moveLeft_movesThirdThumbLeft() {
     slider.requestFocus();
 
     slider.setFocusedThumbIndex(2);
 
-    activateFocusedThumb();
-
     KeyEventBuilder left = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_LEFT);
     for (int i = 0; i < 3; i++) {
       left.dispatchEvent(slider);

lib/javatests/com/google/android/material/slider/SliderKeyTestRtl.java

@@ -64,24 +64,11 @@ public void testThumbFocus_focusRight_focusesLastThumb() {
   }
 
   @Test
-  public void testMoveThumbFocus_dPad_correctThumbHasFocus() {
-    slider.requestFocus();
-
-    KeyEventBuilder left = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_LEFT);
-    KeyEventBuilder right = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_RIGHT);
-
-    // We start at far right in RTL so go left first, then go back right.
-    sendKeyEventThereAndBack(left, right);
-  }
-
-  @Test
-  public void testActivateThirdThumb_moveRight_movesThirdThumbRight() {
+  public void testFocusThirdThumb_moveRight_movesThirdThumbRight() {
     slider.requestFocus();
 
     slider.setFocusedThumbIndex(2);
 
-    activateFocusedThumb();
-
     KeyEventBuilder right = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_RIGHT);
     for (int i = 0; i < 3; i++) {
       right.dispatchEvent(slider);
@@ -92,12 +79,10 @@ public void testActivateThirdThumb_moveRight_movesThirdThumbRight() {
   }
 
   @Test
-  public void testActivateThirdThumb_moveLeft_movesThirdThumbLeft() {
+  public void testFocusThirdThumb_moveLeft_movesThirdThumbLeft() {
     slider.requestFocus();
     slider.setFocusedThumbIndex(2);
 
-    activateFocusedThumb();
-
     KeyEventBuilder left = new KeyEventBuilder(KeyEvent.KEYCODE_DPAD_LEFT);
     for (int i = 0; i < 20; i++) {
       left.dispatchEvent(slider);