1d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd/* 2d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * Copyright (C) 2015 The Android Open Source Project 3d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * 4d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * Licensed under the Apache License, Version 2.0 (the "License"); 5d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * you may not use this file except in compliance with the License. 6d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * You may obtain a copy of the License at 7d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * 8d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * http://www.apache.org/licenses/LICENSE-2.0 9d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * 10d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * Unless required by applicable law or agreed to in writing, software 11d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * distributed under the License is distributed on an "AS IS" BASIS, 12d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * See the License for the specific language governing permissions and 14d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * limitations under the License. 15d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd */ 16d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddpackage com.android.messaging.ui; 17d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 18d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport android.os.Bundle; 19d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport android.os.Parcelable; 20d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport android.support.v4.view.PagerAdapter; 21d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport android.view.View; 22d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport android.view.ViewGroup; 23d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 24d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport com.android.messaging.Factory; 25d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport com.android.messaging.util.Assert; 26d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport com.android.messaging.util.UiUtils; 27d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddimport com.google.common.annotations.VisibleForTesting; 28d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 29d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd/** 30d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * A PagerAdapter that provides a fixed number of paged Views provided by a fixed set of 31d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * {@link PagerViewHolder}'s. This allows us to put a fixed number of Views, instead of fragments, 32d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd * into a given ViewPager. 33d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd */ 34d3b009ae55651f1e60950342468e3c37fdeb0796Mike Doddpublic class FixedViewPagerAdapter<T extends PagerViewHolder> extends PagerAdapter { 35d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd private final T[] mViewHolders; 36d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 37d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public FixedViewPagerAdapter(final T[] viewHolders) { 38d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd Assert.notNull(viewHolders); 39d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd mViewHolders = viewHolders; 40d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 41d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 42d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd @Override 43d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public Object instantiateItem(final ViewGroup container, final int position) { 44d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final PagerViewHolder viewHolder = getViewHolder(position); 45d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final View view = viewHolder.getView(container); 46d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd if (view == null) { 47d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return null; 48d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 49d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd view.setTag(viewHolder); 50d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd container.addView(view); 51d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return viewHolder; 52d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 53d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 54d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd @Override 55d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public void destroyItem(final ViewGroup container, final int position, final Object object) { 56d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final PagerViewHolder viewHolder = getViewHolder(position); 57d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final View destroyedView = viewHolder.destroyView(); 58d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd if (destroyedView != null) { 59d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd container.removeView(destroyedView); 60d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 61d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 62d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 63d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd @Override 64d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public int getCount() { 65d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return mViewHolders.length; 66d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 67d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 68d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd @Override 69d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public boolean isViewFromObject(final View view, final Object object) { 70d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return view.getTag() == object; 71d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 72d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 73d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public T getViewHolder(final int i) { 74d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return getViewHolder(i, true /* rtlAware */); 75d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 76d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 77d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd @VisibleForTesting 78d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public T getViewHolder(final int i, final boolean rtlAware) { 79d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return mViewHolders[rtlAware ? getRtlPosition(i) : i]; 80d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 81d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 82d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd @Override 83d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public Parcelable saveState() { 84d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // The paged views in the view pager gets created and destroyed as the user scrolls through 85d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // them. By default, only the pages to the immediate left and right of the current visible 86d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // page are realized. Moreover, if the activity gets destroyed and recreated, the pages are 87d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // automatically destroyed. Therefore, in order to preserve transient page UI states that 88d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // are not persisted in the DB we'd like to store them in a Bundle when views get 89d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // destroyed. When the views get recreated, we rehydrate them by passing them the saved 90d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // data. When the activity gets destroyed, it invokes saveState() on this adapter to 91d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd // add this saved Bundle to the overall saved instance state. 92d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final Bundle savedViewHolderState = new Bundle(Factory.get().getApplicationContext() 93d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd .getClassLoader()); 94d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd for (int i = 0; i < mViewHolders.length; i++) { 95d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final Parcelable pageState = getViewHolder(i).saveState(); 96d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd savedViewHolderState.putParcelable(getInstanceStateKeyForPage(i), pageState); 97d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 98d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return savedViewHolderState; 99d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 100d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 101d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd @Override 102d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public void restoreState(final Parcelable state, final ClassLoader loader) { 103d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd if (state instanceof Bundle) { 104d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final Bundle restoredViewHolderState = (Bundle) state; 105d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd ((Bundle) state).setClassLoader(Factory.get().getApplicationContext().getClassLoader()); 106d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd for (int i = 0; i < mViewHolders.length; i++) { 107d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd final Parcelable pageState = restoredViewHolderState 108d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd .getParcelable(getInstanceStateKeyForPage(i)); 109d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd getViewHolder(i).restoreState(pageState); 110d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 111d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } else { 112d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd super.restoreState(state, loader); 113d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 114d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 115d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 116d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd public void resetState() { 117d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd for (int i = 0; i < mViewHolders.length; i++) { 118d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd getViewHolder(i).resetState(); 119d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 120d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 121d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 122d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd private String getInstanceStateKeyForPage(final int i) { 123d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return getViewHolder(i).getClass().getCanonicalName() + "_savedstate_" + i; 124d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 125d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd 126d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd protected int getRtlPosition(final int position) { 127d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd if (UiUtils.isRtlMode()) { 128d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return mViewHolders.length - 1 - position; 129d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 130d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd return position; 131d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd } 132d3b009ae55651f1e60950342468e3c37fdeb0796Mike Dodd} 133