[TextInputLayout] Updated cursor color on error for APIs >= 29.

Resolves #2719

PiperOrigin-RevId: 472535969

lib/java/com/google/android/material/color/MaterialColors.java

@@ -29,6 +29,7 @@
 import androidx.annotation.FloatRange;
 import androidx.annotation.IntRange;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.core.content.ContextCompat;
 import androidx.core.graphics.ColorUtils;
 import com.google.android.material.resources.MaterialAttributes;
@@ -129,6 +130,24 @@ public static ColorStateList getColorStateList(
     return resolvedColor == null ? defaultValue : resolvedColor;
   }
 
+  /**
+   * Returns the color state list for the provided theme color attribute, or null if the attribute
+   * is not set in the current theme.
+   */
+  @Nullable
+  public static ColorStateList getColorStateListOrNull(
+      @NonNull Context context, @AttrRes int colorAttributeResId) {
+    TypedValue typedValue = MaterialAttributes.resolve(context, colorAttributeResId);
+    if (typedValue == null) {
+      return null;
+    } else if (typedValue.resourceId != 0) {
+      return ContextCompat.getColorStateList(context, typedValue.resourceId);
+    } else if (typedValue.data != 0) {
+      return ColorStateList.valueOf(typedValue.data);
+    }
+    return null;
+  }
+
   private static int resolveColor(@NonNull Context context, @NonNull TypedValue typedValue) {
     if (typedValue.resourceId != 0) {
       // Color State List

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

@@ -4206,6 +4206,7 @@ void updateTextInputBoxState() {
 
     final boolean hasFocus = isFocused() || (editText != null && editText.hasFocus());
     final boolean isHovered = isHovered() || (editText != null && editText.isHovered());
+    final boolean isOnError = shouldShowError() || (counterView != null && counterOverflowed);
 
     // Update the text box's stroke color based on the current state.
     if (!isEnabled()) {
@@ -4230,6 +4231,10 @@ void updateTextInputBoxState() {
       boxStrokeColor = defaultStrokeColor;
     }
 
+    if (VERSION.SDK_INT >= VERSION_CODES.Q) {
+      updateCursorColor(isOnError);
+    }
+
     endLayout.onTextInputBoxStateUpdated();
 
     refreshStartIconDrawableState();
@@ -4286,6 +4291,25 @@ private void updateStrokeErrorColor(boolean hasFocus, boolean isHovered) {
     }
   }
 
+  @TargetApi(VERSION_CODES.Q)
+  private void updateCursorColor(boolean isOnError) {
+    ColorStateList cursorColor =
+        MaterialColors.getColorStateListOrNull(getContext(), R.attr.colorControlActivated);
+    if (editText == null || editText.getTextCursorDrawable() == null || cursorColor == null) {
+      // If there's no cursor or if its color is null, return.
+      return;
+    }
+
+    Drawable cursorDrawable = editText.getTextCursorDrawable();
+    if (isOnError) {
+      // Use the stroke error color for the cursor error color, or the box stroke color if
+      // strokeErrorColor is null.
+      cursorColor =
+          strokeErrorColor != null ? strokeErrorColor : ColorStateList.valueOf(boxStrokeColor);
+    }
+    DrawableCompat.setTintList(cursorDrawable, cursorColor);
+  }
+
   private void expandHint(boolean animate) {
     if (animator != null && animator.isRunning()) {
       animator.cancel();