Java tutorial
/* * Copyright (c) 2017. Faruk Cankaya * * 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.farukcankaya.rtlviewpager; import android.database.DataSetObservable; import android.database.DataSetObserver; import android.os.Parcelable; import android.support.annotation.NonNull; import android.support.v4.view.PagerAdapter; import android.view.View; import android.view.ViewGroup; /** * PagerAdapter decorator. */ class PagerAdapterWrapper extends PagerAdapter { private final DataSetObservable dataSetObservable = new DataSetObservable(); @NonNull private final PagerAdapter adapter; protected PagerAdapterWrapper(@NonNull PagerAdapter adapter) { this.adapter = adapter; this.adapter.registerDataSetObserver(new DataSetObserver() { @Override public void onChanged() { PagerAdapterWrapper.super.notifyDataSetChanged(); dataSetObservable.notifyChanged(); } @Override public void onInvalidated() { dataSetObservable.notifyInvalidated(); } }); } @NonNull public PagerAdapter getInnerAdapter() { return adapter; } @Override public int getCount() { return adapter.getCount(); } @Override public boolean isViewFromObject(View view, Object object) { return adapter.isViewFromObject(view, object); } @Override public CharSequence getPageTitle(int position) { return adapter.getPageTitle(position); } @Override public float getPageWidth(int position) { return adapter.getPageWidth(position); } @Override public int getItemPosition(Object object) { return adapter.getItemPosition(object); } @Override public Object instantiateItem(ViewGroup container, int position) { return adapter.instantiateItem(container, position); } @Override public void destroyItem(ViewGroup container, int position, Object object) { adapter.destroyItem(container, position, object); } @Override public void setPrimaryItem(ViewGroup container, int position, Object object) { adapter.setPrimaryItem(container, position, object); } @Override public void notifyDataSetChanged() { adapter.notifyDataSetChanged(); } @Override public void registerDataSetObserver(DataSetObserver observer) { dataSetObservable.registerObserver(observer); } @Override public void unregisterDataSetObserver(DataSetObserver observer) { dataSetObservable.unregisterObserver(observer); } @Override public Parcelable saveState() { return adapter.saveState(); } @Override public void restoreState(Parcelable state, ClassLoader loader) { adapter.restoreState(state, loader); } @Override public void startUpdate(ViewGroup container) { adapter.startUpdate(container); } @Override public void finishUpdate(ViewGroup container) { adapter.finishUpdate(container); } }