material-components_material-components-android/lib/java/com/google/android/material/appbar/ViewUtilsLollipop.java

/*
 * Copyright (C) 2015 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.appbar;

import com.google.android.material.R;

import android.animation.AnimatorInflater;
import android.animation.ObjectAnimator;
import android.animation.StateListAnimator;
import android.content.Context;
import android.content.res.TypedArray;
import androidx.annotation.RequiresApi;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewOutlineProvider;
import com.google.android.material.internal.ThemeEnforcement;

@RequiresApi(21)
class ViewUtilsLollipop {

  private static final int[] STATE_LIST_ANIM_ATTRS = new int[] {android.R.attr.stateListAnimator};

  static void setBoundsViewOutlineProvider(View view) {
    view.setOutlineProvider(ViewOutlineProvider.BOUNDS);
  }

  static void setStateListAnimatorFromAttrs(
      View view, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    final Context context = view.getContext();
    final TypedArray a =
        ThemeEnforcement.obtainStyledAttributes(
            context, attrs, STATE_LIST_ANIM_ATTRS, defStyleAttr, defStyleRes);
    try {
      if (a.hasValue(0)) {
        StateListAnimator sla =
            AnimatorInflater.loadStateListAnimator(context, a.getResourceId(0, 0));
        view.setStateListAnimator(sla);
      }
    } finally {
      a.recycle();
    }
  }

  /** Creates and sets a {@link StateListAnimator} with a custom elevation value */
  static void setDefaultAppBarLayoutStateListAnimator(final View view, final float elevation) {
    final int dur = view.getResources().getInteger(R.integer.app_bar_elevation_anim_duration);

    final StateListAnimator sla = new StateListAnimator();

    // Enabled and liftable, but not lifted means not elevated
    sla.addState(
        new int[] {android.R.attr.enabled, R.attr.state_liftable, -R.attr.state_lifted},
        ObjectAnimator.ofFloat(view, "elevation", 0f).setDuration(dur));

    // Default enabled state
    sla.addState(
        new int[] {android.R.attr.enabled},
        ObjectAnimator.ofFloat(view, "elevation", elevation).setDuration(dur));

    // Disabled state
    sla.addState(new int[0], ObjectAnimator.ofFloat(view, "elevation", 0).setDuration(0));

    view.setStateListAnimator(sla);
  }
}