material-components_material-components-android/lib/java/com/google/android/material/resources/MaterialAttributes.java

/*
 * Copyright (C) 2018 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.android.material.resources;

import com.google.android.material.R;

import static androidx.annotation.RestrictTo.Scope.LIBRARY_GROUP;

import android.content.Context;
import androidx.annotation.AttrRes;
import androidx.annotation.DimenRes;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.Px;
import androidx.annotation.RestrictTo;
import android.util.TypedValue;
import android.view.View;

/**
 * Utility methods to work with attributes.
 *
 * @hide
 */
@RestrictTo(LIBRARY_GROUP)
public class MaterialAttributes {

  /**
   * Returns the {@link TypedValue} for the provided {@code attributeResId} or null if the attribute
   * is not present in the current theme.
   */
  @Nullable
  public static TypedValue resolve(@NonNull Context context, @AttrRes int attributeResId) {
    TypedValue typedValue = new TypedValue();
    if (context.getTheme().resolveAttribute(attributeResId, typedValue, true)) {
      return typedValue;
    }
    return null;
  }

  /**
   * Returns the {@link TypedValue} for the provided {@code attributeResId}.
   *
   * @throws IllegalArgumentException if the attribute is not present in the current theme.
   */
  public static int resolveOrThrow(
      @NonNull Context context,
      @AttrRes int attributeResId,
      @NonNull String errorMessageComponent) {
    TypedValue typedValue = resolve(context, attributeResId);
    if (typedValue == null) {
      String errorMessage =
          "%1$s requires a value for the %2$s attribute to be set in your app theme. "
              + "You can either set the attribute in your theme or "
              + "update your theme to inherit from Theme.MaterialComponents (or a descendant).";
      throw new IllegalArgumentException(
          String.format(
              errorMessage,
              errorMessageComponent,
              context.getResources().getResourceName(attributeResId)));
    }
    return typedValue.data;
  }

  /**
   * Returns the {@link TypedValue} for the provided {@code attributeResId}, using the context of
   * the provided {@code componentView}.
   *
   * @throws IllegalArgumentException if the attribute is not present in the current theme.
   */
  public static int resolveOrThrow(@NonNull View componentView, @AttrRes int attributeResId) {
    return resolveOrThrow(
        componentView.getContext(), attributeResId, componentView.getClass().getCanonicalName());
  }

  /**
   * Returns the boolean value for the provided {@code attributeResId}.
   *
   * @throws IllegalArgumentException if the attribute is not present in the current theme.
   */
  public static boolean resolveBooleanOrThrow(
      @NonNull Context context,
      @AttrRes int attributeResId,
      @NonNull String errorMessageComponent) {
    return resolveOrThrow(context, attributeResId, errorMessageComponent) != 0;
  }

  /**
   * Returns the boolean value for the provided {@code attributeResId} or {@code defaultValue} if
   * the attribute is not a boolean or not present in the current theme.
   */
  public static boolean resolveBoolean(
      @NonNull Context context, @AttrRes int attributeResId, boolean defaultValue) {
    TypedValue typedValue = resolve(context, attributeResId);
    return (typedValue != null && typedValue.type == TypedValue.TYPE_INT_BOOLEAN)
        ? typedValue.data != 0
        : defaultValue;
  }

  /** Returns the minimum touch target size, acceptable for accessibility, in pixels. */
  @Px
  public static int resolveMinimumAccessibleTouchTarget(@NonNull Context context) {
    return resolveDimension(context, R.attr.minTouchTargetSize, R.dimen.mtrl_min_touch_target_size);
  }

  /**
   * Returns the pixel value of the dimension specified by {@code attributeResId}. Defaults to
   * {@code defaultDimenResId} if {@code attributeResId} cannot be found or is not a dimension
   * within the given {@code context}.
   */
  @Px
  public static int resolveDimension(
      @NonNull Context context, @AttrRes int attributeResId, @DimenRes int defaultDimenResId) {
    TypedValue dimensionValue = resolve(context, attributeResId);
    if (dimensionValue == null || dimensionValue.type != TypedValue.TYPE_DIMENSION) {
      return (int) context.getResources().getDimension(defaultDimenResId);
    } else {
      return (int) dimensionValue.getDimension(context.getResources().getDisplayMetrics());
    }
  }
}