/* * Copyright (C) 2019 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.customization.picker; import static androidx.core.view.ViewCompat.LAYOUT_DIRECTION_RTL; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import androidx.annotation.LayoutRes; import androidx.annotation.NonNull; import androidx.cardview.widget.CardView; import androidx.core.view.ViewCompat; import androidx.viewpager.widget.PagerAdapter; import com.android.customization.picker.BasePreviewAdapter.PreviewPage; import com.android.customization.widget.PreviewPager; import java.util.ArrayList; import java.util.List; /** * Base adapter for {@link PreviewPager}. * It can be used as-is by creating an extension of {@link PreviewPage} and adding pages via * {@link #addPage(PreviewPage)} * @param the type of {@link PreviewPage} that this adapter will handle. */ public class BasePreviewAdapter extends PagerAdapter { private final int mPreviewCardResId; private final Context mContext; private final LayoutInflater mInflater; protected final List mPages = new ArrayList<>(); protected BasePreviewAdapter(Context context, @LayoutRes int previewCardResId) { mContext = context; mPreviewCardResId = previewCardResId; mInflater = LayoutInflater.from(mContext); } protected void addPage(T p) { mPages.add(p); } @Override public int getCount() { return mPages.size(); } @Override public boolean isViewFromObject(@NonNull View view, @NonNull Object object) { return view == ((PreviewPage) object).card; } @NonNull @Override public Object instantiateItem(@NonNull ViewGroup container, int position) { if (ViewCompat.getLayoutDirection(container) == LAYOUT_DIRECTION_RTL) { position = mPages.size() - 1 - position; } CardView card = (CardView) mInflater.inflate(mPreviewCardResId, container, false); T page = mPages.get(position); page.setCard(card); page.bindPreviewContent(); if (card.getParent() != null) { container.removeView(card); } container.addView(card); return page; } @Override public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) { View card = ((PreviewPage) object).card; ((PreviewPage) object).card = null; if (card.getParent() == container) { container.removeView(card); } } /** * Represents a possible page in a {@link PreviewPager}, based on a CardView container. * Override {@link #bindPreviewContent()} to bind the contents of the page when instantiated. */ public static abstract class PreviewPage { protected final String title; protected CardView card; protected PreviewPage(String title) { this.title = title; } public void setCard(CardView card) { this.card = card; } public abstract void bindPreviewContent(); } }