src/main/java/com/google/android/libraries/feed/piet/ElementStackAdapter.java

// Copyright 2018 The Feed Authors.
//
// 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.libraries.feed.piet;

import static com.google.android.libraries.feed.piet.StyleProvider.DIMENSION_NOT_SET;

import android.content.Context;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.FrameLayout;
import com.google.android.libraries.feed.piet.AdapterFactory.SingletonKeySupplier;
import com.google.search.now.ui.piet.ElementsProto.Content;
import com.google.search.now.ui.piet.ElementsProto.Element;
import com.google.search.now.ui.piet.ElementsProto.ElementStack;
import java.util.List;

/** Container adapter that stacks its children in a FrameLayout. */
class ElementStackAdapter extends ElementContainerAdapter<FrameLayout, ElementStack> {
  private static final String TAG = "ElementStackAdapter";

  private ElementStackAdapter(Context context, AdapterParameters parameters) {
    super(context, parameters, createView(context));
  }

  @Override
  public void onBindModel(ElementStack stack, Element baseElement, FrameContext frameContext) {
    super.onBindModel(stack, baseElement, frameContext);
    for (ElementAdapter<?, ?> childAdapter : childAdapters) {
      updateChildLayoutParams(childAdapter);
    }
  }

  private void updateChildLayoutParams(ElementAdapter<? extends View, ?> adapter) {
    FrameLayout.LayoutParams childParams = new FrameLayout.LayoutParams(0, 0);

    childParams.width =
        adapter.getComputedWidthPx() == DIMENSION_NOT_SET
            ? LayoutParams.WRAP_CONTENT
            : adapter.getComputedWidthPx();
    childParams.height =
        adapter.getComputedHeightPx() == DIMENSION_NOT_SET
            ? LayoutParams.WRAP_CONTENT
            : adapter.getComputedHeightPx();

    adapter.getElementStyle().applyMargins(getContext(), childParams);

    childParams.gravity = adapter.getGravity(Gravity.CENTER);

    adapter.setLayoutParams(childParams);
  }

  @Override
  List<Content> getContentsFromModel(ElementStack model) {
    return model.getContentsList();
  }

  @Override
  ElementStack getModelFromElement(Element baseElement) {
    return baseElement.getElementStack();
  }

  private static FrameLayout createView(Context context) {
    FrameLayout view = new FrameLayout(context);
    view.setLayoutParams(
        new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
    return view;
  }

  static class KeySupplier extends SingletonKeySupplier<ElementStackAdapter, ElementStack> {
    @Override
    public String getAdapterTag() {
      return TAG;
    }

    @Override
    public ElementStackAdapter getAdapter(Context context, AdapterParameters parameters) {
      return new ElementStackAdapter(context, parameters);
    }
  }
}