[MaterialDatePicker][a11y] Improve date input validation feedback

Resolves #2223

Add `TextInputLayout.setErrorAccessibilityLiveRegion` and `TextInputLayout.getErrorAccessibilityLiveRegion` to allow controlling the way the TextInputLayout error is announced.

Example:

```
textInputLayout.setErrorAccessibilityLiveRegion(ViewCompat.ACCESSIBILITY_LIVE_REGION_NONE);
```

PiperOrigin-RevId: 497323465
(cherry picked from commit e1688f3)

lib/java/com/google/android/material/datepicker/DateSelector.java

@@ -100,6 +100,9 @@ public interface DateSelector<S> extends Parcelable {
   @NonNull
   String getSelectionContentDescription(@NonNull Context context);
 
+  @Nullable
+  String getError();
+
   @StringRes
   int getDefaultTitleResId();
 

lib/java/com/google/android/material/datepicker/MaterialDatePicker.java

@@ -52,9 +52,11 @@
 import androidx.annotation.StyleRes;
 import androidx.annotation.VisibleForTesting;
 import androidx.core.util.Pair;
+import androidx.core.view.AccessibilityDelegateCompat;
 import androidx.core.view.OnApplyWindowInsetsListener;
 import androidx.core.view.ViewCompat;
 import androidx.core.view.WindowInsetsCompat;
+import androidx.core.view.accessibility.AccessibilityNodeInfoCompat;
 import com.google.android.material.dialog.InsetDialogOnTouchListener;
 import com.google.android.material.internal.CheckableImageButton;
 import com.google.android.material.internal.EdgeToEdgeUtils;
@@ -296,6 +298,16 @@ public void onClick(View v) {
             dismiss();
           }
         });
+    ViewCompat.setAccessibilityDelegate(
+        confirmButton,
+        new AccessibilityDelegateCompat() {
+          @Override
+          public void onInitializeAccessibilityNodeInfo(
+              @NonNull View host, @NonNull AccessibilityNodeInfoCompat info) {
+            super.onInitializeAccessibilityNodeInfo(host, info);
+            info.setContentDescription(getDateSelector().getError());
+          }
+        });
 
     Button cancelButton = root.findViewById(R.id.cancel_button);
     cancelButton.setTag(CANCEL_BUTTON_TAG);

lib/java/com/google/android/material/datepicker/RangeDateSelector.java

@@ -23,6 +23,7 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.text.InputType;
+import android.text.TextUtils;
 import android.util.DisplayMetrics;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -34,6 +35,7 @@
 import androidx.annotation.RestrictTo.Scope;
 import androidx.core.util.Pair;
 import androidx.core.util.Preconditions;
+import androidx.core.view.ViewCompat;
 import com.google.android.material.internal.ManufacturerUtils;
 import com.google.android.material.resources.MaterialAttributes;
 import com.google.android.material.textfield.TextInputLayout;
@@ -50,6 +52,7 @@
 @RestrictTo(Scope.LIBRARY_GROUP)
 public class RangeDateSelector implements DateSelector<Pair<Long, Long>> {
 
+  @Nullable private CharSequence error;
   private String invalidRangeStartError;
   // "" is not considered an error
   private final String invalidRangeEndError = " ";
@@ -176,6 +179,12 @@ public String getSelectionContentDescription(@NonNull Context context) {
         R.string.mtrl_picker_announce_current_range_selection, startPlaceholder, endPlaceholder);
   }
 
+  @Nullable
+  @Override
+  public String getError() {
+    return TextUtils.isEmpty(error) ? null : error.toString();
+  }
+
   @Override
   public int getDefaultTitleResId() {
     return R.string.mtrl_picker_range_header_title;
@@ -199,6 +208,8 @@ public View onCreateTextInputView(
     final TextInputLayout startTextInput =
         root.findViewById(R.id.mtrl_picker_text_input_range_start);
     final TextInputLayout endTextInput = root.findViewById(R.id.mtrl_picker_text_input_range_end);
+    startTextInput.setErrorAccessibilityLiveRegion(ViewCompat.ACCESSIBILITY_LIVE_REGION_NONE);
+    endTextInput.setErrorAccessibilityLiveRegion(ViewCompat.ACCESSIBILITY_LIVE_REGION_NONE);
     EditText startEditText = startTextInput.getEditText();
     EditText endEditText = endTextInput.getEditText();
     if (ManufacturerUtils.isDateInputKeyboardMissingSeparatorCharacters()) {
@@ -278,16 +289,25 @@ private void updateIfValidTextProposal(
     if (proposedTextStart == null || proposedTextEnd == null) {
       clearInvalidRange(startTextInput, endTextInput);
       listener.onIncompleteSelectionChanged();
-      return;
-    }
-    if (isValidRange(proposedTextStart, proposedTextEnd)) {
+    } else if (isValidRange(proposedTextStart, proposedTextEnd)) {
       selectedStartItem = proposedTextStart;
       selectedEndItem = proposedTextEnd;
       listener.onSelectionChanged(getSelection());
     } else {
       setInvalidRange(startTextInput, endTextInput);
       listener.onIncompleteSelectionChanged();
     }
+    updateError(startTextInput, endTextInput);
+  }
+
+  private void updateError(@NonNull TextInputLayout start, @NonNull TextInputLayout end) {
+    if (!TextUtils.isEmpty(start.getError())) {
+      error = start.getError();
+    } else if (!TextUtils.isEmpty(end.getError())) {
+      error = end.getError();
+    } else {
+      error = null;
+    }
   }
 
   private void clearInvalidRange(@NonNull TextInputLayout start, @NonNull TextInputLayout end) {

lib/java/com/google/android/material/datepicker/SingleDateSelector.java

@@ -23,6 +23,7 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.text.InputType;
+import android.text.TextUtils;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
@@ -32,6 +33,7 @@
 import androidx.annotation.RestrictTo;
 import androidx.annotation.RestrictTo.Scope;
 import androidx.core.util.Pair;
+import androidx.core.view.ViewCompat;
 import com.google.android.material.internal.ManufacturerUtils;
 import com.google.android.material.resources.MaterialAttributes;
 import com.google.android.material.textfield.TextInputLayout;
@@ -47,6 +49,7 @@
 @RestrictTo(Scope.LIBRARY_GROUP)
 public class SingleDateSelector implements DateSelector<Long> {
 
+  @Nullable private CharSequence error;
   @Nullable private Long selectedItem;
   @Nullable private SimpleDateFormat textInputFormat;
 
@@ -106,6 +109,7 @@ public View onCreateTextInputView(
     View root = layoutInflater.inflate(R.layout.mtrl_picker_text_input_date, viewGroup, false);
 
     TextInputLayout dateTextInput = root.findViewById(R.id.mtrl_picker_text_input_date);
+    dateTextInput.setErrorAccessibilityLiveRegion(ViewCompat.ACCESSIBILITY_LIVE_REGION_NONE);
     EditText dateEditText = dateTextInput.getEditText();
     if (ManufacturerUtils.isDateInputKeyboardMissingSeparatorCharacters()) {
       // Using the URI variation places the '/' and '.' in more prominent positions
@@ -135,11 +139,13 @@ void onValidDate(@Nullable Long day) {
             } else {
               select(day);
             }
+            error = null;
             listener.onSelectionChanged(getSelection());
           }
 
           @Override
           void onInvalidDate() {
+            error = dateTextInput.getError();
             listener.onIncompleteSelectionChanged();
           }
         });
@@ -177,6 +183,12 @@ public String getSelectionContentDescription(@NonNull Context context) {
     return res.getString(R.string.mtrl_picker_announce_current_selection, placeholder);
   }
 
+  @Nullable
+  @Override
+  public String getError() {
+    return TextUtils.isEmpty(error) ? null : error.toString();
+  }
+
   @Override
   public int getDefaultTitleResId() {
     return R.string.mtrl_picker_date_header_title;

lib/java/com/google/android/material/textfield/IndicatorViewController.java

@@ -119,6 +119,7 @@ final class IndicatorViewController {
   private boolean errorEnabled;
   @Nullable private TextView errorView;
   @Nullable private CharSequence errorViewContentDescription;
+  private int errorViewAccessibilityLiveRegion;
   private int errorTextAppearance;
   @Nullable private ColorStateList errorViewTextColor;
 
@@ -501,8 +502,8 @@ void setErrorEnabled(boolean enabled) {
       setErrorTextAppearance(errorTextAppearance);
       setErrorViewTextColor(errorViewTextColor);
       setErrorContentDescription(errorViewContentDescription);
+      setErrorAccessibilityLiveRegion(errorViewAccessibilityLiveRegion);
       errorView.setVisibility(View.INVISIBLE);
-      ViewCompat.setAccessibilityLiveRegion(errorView, ViewCompat.ACCESSIBILITY_LIVE_REGION_POLITE);
       addIndicator(errorView, ERROR_INDEX);
     } else {
       hideError();
@@ -658,11 +659,22 @@ void setErrorContentDescription(@Nullable final CharSequence errorContentDescrip
     }
   }
 
+  void setErrorAccessibilityLiveRegion(final int accessibilityLiveRegion) {
+    this.errorViewAccessibilityLiveRegion = accessibilityLiveRegion;
+    if (errorView != null) {
+      ViewCompat.setAccessibilityLiveRegion(errorView, accessibilityLiveRegion);
+    }
+  }
+
   @Nullable
   CharSequence getErrorContentDescription() {
     return errorViewContentDescription;
   }
 
+  int getErrorAccessibilityLiveRegion() {
+    return errorViewAccessibilityLiveRegion;
+  }
+
   @ColorInt
   int getHelperTextViewCurrentTextColor() {
     return helperTextView != null ? helperTextView.getCurrentTextColor() : -1;

lib/java/com/google/android/material/textfield/TextInputLayout.java

@@ -614,6 +614,10 @@ public TextInputLayout(@NonNull Context context, @Nullable AttributeSet attrs, i
         a.getResourceId(R.styleable.TextInputLayout_errorTextAppearance, 0);
     final CharSequence errorContentDescription =
         a.getText(R.styleable.TextInputLayout_errorContentDescription);
+    final int errorAccessibilityLiveRegion =
+        a.getInt(
+            R.styleable.TextInputLayout_errorAccessibilityLiveRegion,
+            ViewCompat.ACCESSIBILITY_LIVE_REGION_POLITE);
     final boolean errorEnabled = a.getBoolean(R.styleable.TextInputLayout_errorEnabled, false);
 
     final int helperTextTextAppearance =
@@ -636,6 +640,7 @@ public TextInputLayout(@NonNull Context context, @Nullable AttributeSet attrs, i
         a.getInt(R.styleable.TextInputLayout_boxBackgroundMode, BOX_BACKGROUND_NONE));
 
     setErrorContentDescription(errorContentDescription);
+    setErrorAccessibilityLiveRegion(errorAccessibilityLiveRegion);
 
     setCounterOverflowTextAppearance(counterOverflowTextAppearance);
     setHelperTextTextAppearance(helperTextTextAppearance);
@@ -2071,6 +2076,25 @@ public CharSequence getErrorContentDescription() {
     return indicatorViewController.getErrorContentDescription();
   }
 
+  /**
+   * Sets an accessibility live region for the error message.
+   *
+   * @param errorAccessibilityLiveRegion Accessibility live region to set
+   * @attr ref com.google.android.material.R.styleable#TextInputLayout_errorAccessibilityLiveRegion
+   */
+  public void setErrorAccessibilityLiveRegion(final int errorAccessibilityLiveRegion) {
+    indicatorViewController.setErrorAccessibilityLiveRegion(errorAccessibilityLiveRegion);
+  }
+
+  /**
+   * Returns the accessibility live region of the error message.
+   *
+   * @see #setErrorAccessibilityLiveRegion(int)
+   */
+  public int getErrorAccessibilityLiveRegion() {
+    return indicatorViewController.getErrorAccessibilityLiveRegion();
+  }
+
   /**
    * Sets an error message that will be displayed below our {@link EditText}. If the {@code error}
    * is {@code null}, the error message will be cleared.

lib/java/com/google/android/material/textfield/res-public/values/public.xml

@@ -53,6 +53,7 @@
   <public name="errorTextAppearance" type="attr"/>
   <public name="errorTextColor" type="attr"/>
   <public name="errorContentDescription" type="attr"/>
+  <public name="errorAccessibilityLiveRegion" type="attr"/>
   <public name="errorIconDrawable" type="attr"/>
   <public name="errorIconTint" type="attr"/>
   <public name="errorIconTintMode" type="attr"/>

lib/java/com/google/android/material/textfield/res/values/attrs.xml

@@ -92,6 +92,8 @@
          Should be set when the error message has special characters that a
          screen reader is not able to announce properly. -->
     <attr name="errorContentDescription" format="string"/>
+    <!-- AccessibilityLiveRegion of any error message displayed. -->
+    <attr name="errorAccessibilityLiveRegion" format="integer"/>
     <!-- End icon to be shown when an error is displayed. -->
     <attr name="errorIconDrawable" format="reference"/>
     <!-- Tint color to use for the error icon. -->

lib/javatests/com/google/android/material/datepicker/RangeDateSelectorTest.java

@@ -305,6 +305,55 @@ public void getSelectionContentDescription_startNotEmpty_endNotEmpty_returnsStar
     assertThat(contentDescription).isEqualTo(expected);
   }
 
+  @Test
+  public void getError_emptyDates_isNull() {
+    assertThat(rangeDateSelector.getError()).isNull();
+  }
+
+  @Test
+  public void getError_validStartDate_isNull() {
+    View root = getRootView();
+    TextInputLayout startTextInput = root.findViewById(R.id.mtrl_picker_text_input_range_start);
+    activity.setContentView(root);
+    startTextInput.getEditText().setText("1/1/11");
+    ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
+
+    assertThat(rangeDateSelector.getError()).isNull();
+  }
+
+  @Test
+  public void getError_validEndDate_isNull() {
+    View root = getRootView();
+    TextInputLayout endTextInput = root.findViewById(R.id.mtrl_picker_text_input_range_end);
+    activity.setContentView(root);
+    endTextInput.getEditText().setText("1/1/11");
+    ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
+
+    assertThat(rangeDateSelector.getError()).isNull();
+  }
+
+  @Test
+  public void getError_invalidStartDate_isNotEmpty() {
+    View root = getRootView();
+    TextInputLayout startTextInput = root.findViewById(R.id.mtrl_picker_text_input_range_start);
+    activity.setContentView(root);
+    startTextInput.getEditText().setText("1/1/");
+    ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
+
+    assertThat(rangeDateSelector.getError()).isNotEmpty();
+  }
+
+  @Test
+  public void getError_invalidEndDate_isNotEmpty() {
+    View root = getRootView();
+    TextInputLayout endTextInput = root.findViewById(R.id.mtrl_picker_text_input_range_end);
+    activity.setContentView(root);
+    endTextInput.getEditText().setText("1/1/");
+    ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
+
+    assertThat(rangeDateSelector.getError()).isNotEmpty();
+  }
+
   @Test
   public void getSelectedRanges_fullRange() {
     Calendar setToStart = UtcDates.getUtcCalendar();

lib/javatests/com/google/android/material/datepicker/SingleDateSelectorTest.java

@@ -37,6 +37,7 @@
 import org.junit.runner.RunWith;
 import org.robolectric.Robolectric;
 import org.robolectric.RobolectricTestRunner;
+import org.robolectric.shadows.ShadowLooper;
 
 @RunWith(RobolectricTestRunner.class)
 public class SingleDateSelectorTest {
@@ -128,6 +129,33 @@ public void getSelectionContentDescription_notEmpty_returnsDate() {
     assertThat(contentDescription).isEqualTo(expected);
   }
 
+  @Test
+  public void getError_emptyDate_isNull() {
+    assertThat(singleDateSelector.getError()).isNull();
+  }
+
+  @Test
+  public void getError_validDate_isNull() {
+    View root = getRootView();
+    ((ViewGroup) activity.findViewById(android.R.id.content)).addView(root);
+    TextInputLayout textInputLayout = root.findViewById(R.id.mtrl_picker_text_input_date);
+    textInputLayout.getEditText().setText("1/1/11");
+    ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
+
+    assertThat(singleDateSelector.getError()).isNull();
+  }
+
+  @Test
+  public void getError_invalidDate_isNotEmpty() {
+    View root = getRootView();
+    ((ViewGroup) activity.findViewById(android.R.id.content)).addView(root);
+    TextInputLayout textInputLayout = root.findViewById(R.id.mtrl_picker_text_input_date);
+    textInputLayout.getEditText().setText("1/1/");
+    ShadowLooper.runUiThreadTasksIncludingDelayedTasks();
+
+    assertThat(singleDateSelector.getError()).isNotEmpty();
+  }
+
   @Test
   public void getSelectedRanges_isEmpty() {
     Calendar calendar = UtcDates.getUtcCalendar();