content: /*
   * Copyright (C) 2017 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.android.setupwizardlib.template;
  
  import androidx.annotation.NonNull;
  import androidx.annotation.Nullable;
  import android.util.Log;
  import android.widget.ScrollView;
  import com.android.setupwizardlib.template.RequireScrollMixin.ScrollHandlingDelegate;
  import com.android.setupwizardlib.view.BottomScrollView;
  import com.android.setupwizardlib.view.BottomScrollView.BottomScrollListener;
  
  /**
   * {@link ScrollHandlingDelegate} which analyzes scroll events from {@link BottomScrollView} and
   * notifies {@link RequireScrollMixin} about scrollability changes.
   */
  public class ScrollViewScrollHandlingDelegate
      implements ScrollHandlingDelegate, BottomScrollListener {
  
    private static final String TAG = "ScrollViewDelegate";
  
    @NonNull private final RequireScrollMixin requireScrollMixin;
  
    @Nullable private final BottomScrollView scrollView;
  
    public ScrollViewScrollHandlingDelegate(
        @NonNull RequireScrollMixin requireScrollMixin, @Nullable ScrollView scrollView) {
      this.requireScrollMixin = requireScrollMixin;
      if (scrollView instanceof BottomScrollView) {
        this.scrollView = (BottomScrollView) scrollView;
      } else {
        Log.w(TAG, "Cannot set non-BottomScrollView. Found=" + scrollView);
        this.scrollView = null;
      }
    }
  
    @Override
    public void onScrolledToBottom() {
      requireScrollMixin.notifyScrollabilityChange(false);
    }
  
    @Override
    public void onRequiresScroll() {
      requireScrollMixin.notifyScrollabilityChange(true);
    }
  
    @Override
    public void startListening() {
      if (scrollView != null) {
        scrollView.setBottomScrollListener(this);
      } else {
        Log.w(TAG, "Cannot require scroll. Scroll view is null.");
      }
    }
  
    @Override
    public void pageScrollDown() {
      if (scrollView != null) {
        scrollView.pageScroll(ScrollView.FOCUS_DOWN);
      }
    }
  }
  