Java tutorial
/** * Copyright (C) Azureus Software, Inc, All Rights Reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ package com.vuze.android.remote.adapter; import java.util.List; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentStatePagerAdapter; import android.support.v4.view.ViewPager; import android.support.v4.view.ViewPager.OnPageChangeListener; import android.util.Log; import android.view.ViewGroup; import com.astuetz.PagerSlidingTabStrip; import com.vuze.android.remote.AndroidUtils; import com.vuze.android.remote.SetTorrentIdListener; import com.vuze.android.remote.fragment.FragmentPagerListener; /** * PagerAdapter for a torrent. Links up {@link ViewPager}, * {@link PagerSlidingTabStrip} and adapter. * <p> * Any page Fragments that implement {@link FragmentPagerListener} will * get notified of activation/deactivation. Listener requires call to * {@link #onPause()} and {@link #onResume()} to work correcly. */ public abstract class TorrentPagerAdapter extends FragmentStatePagerAdapter { public interface PagerPosition { void setPagerPosition(int position); int getPagerPosition(); } protected static final String TAG = "TorrentPagerAdapter"; private long torrentID = -1; private ViewPager viewPager; private FragmentManager fm; private Fragment primaryItem; public TorrentPagerAdapter(final FragmentManager fragmentManager) { super(fragmentManager); this.fm = fragmentManager; } public TorrentPagerAdapter(final FragmentManager fragmentManager, ViewPager viewPager, PagerSlidingTabStrip tabs) { super(fragmentManager); this.fm = fragmentManager; init(fragmentManager, viewPager, tabs); } public void init(final FragmentManager fragmentManager, ViewPager viewPager, PagerSlidingTabStrip tabs) { this.viewPager = viewPager; // Bind the tabs to the ViewPager viewPager.setAdapter(this); tabs.setViewPager(viewPager); tabs.setOnPageChangeListener(new OnPageChangeListener() { int oldPosition = 0; @Override public void onPageSelected(int position) { if (AndroidUtils.DEBUG) { Log.d(TAG, "page selected: " + position); } Fragment oldFrag = findFragmentByPosition(fm, oldPosition); if (oldFrag instanceof FragmentPagerListener) { FragmentPagerListener l = (FragmentPagerListener) oldFrag; l.pageDeactivated(); } oldPosition = position; Fragment newFrag = findFragmentByPosition(fm, position); if (newFrag instanceof FragmentPagerListener) { FragmentPagerListener l = (FragmentPagerListener) newFrag; l.pageActivated(); } } @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageScrollStateChanged(int state) { } }); } @Override public final Fragment getItem(int position) { Fragment fragment = createItem(position); updateFragmentArgs(fragment, position); return fragment; } public abstract Fragment createItem(int position); private void updateFragmentArgs(Fragment fragment, int position) { if (fragment == null) { return; } if (fragment instanceof PagerPosition) { PagerPosition pagerPosition = (PagerPosition) fragment; pagerPosition.setPagerPosition(position); } if (fragment.getActivity() != null) { if (fragment instanceof SetTorrentIdListener) { ((SetTorrentIdListener) fragment).setTorrentID(torrentID); } if (position == viewPager.getCurrentItem()) { // Special case for first item, which never gets an onPageSelected event // Send pageActivated event. if (fragment instanceof FragmentPagerListener) { FragmentPagerListener l = (FragmentPagerListener) fragment; l.pageActivated(); } } } else { Bundle arguments = fragment.getArguments(); if (arguments == null) { arguments = new Bundle(); } arguments.putLong("torrentID", torrentID); arguments.putInt("pagerPosition", position); // Fragment will have to handle pageActivated call when it's view is // attached :( arguments.putBoolean("isActive", position == viewPager.getCurrentItem()); fragment.setArguments(arguments); } } public void setSelection(long torrentID) { this.torrentID = torrentID; } public Fragment findFragmentByPosition(FragmentManager fm, int position) { List<Fragment> fragments = fm.getFragments(); if (fragments == null) { return null; } for (Fragment fragment : fragments) { if (fragment == null || !fragment.isAdded()) { continue; } if (fragment instanceof PagerPosition) { PagerPosition pp = (PagerPosition) fragment; if (pp.getPagerPosition() == position) { return fragment; } } } return null; } public void onResume() { Fragment newFrag = findFragmentByPosition(fm, viewPager.getCurrentItem()); // newFrag will be null on first view, so position 0 will not // get pageActivated from here if (newFrag instanceof FragmentPagerListener) { FragmentPagerListener l = (FragmentPagerListener) newFrag; l.pageActivated(); } } public void onPause() { Fragment newFrag = findFragmentByPosition(fm, viewPager.getCurrentItem()); if (newFrag instanceof FragmentPagerListener) { FragmentPagerListener l = (FragmentPagerListener) newFrag; l.pageDeactivated(); } } public Fragment getCurrentFragment() { return findFragmentByPosition(fm, viewPager.getCurrentItem()); } @Override public void setPrimaryItem(ViewGroup container, int position, Object object) { if (object instanceof Fragment) { primaryItem = (Fragment) object; } super.setPrimaryItem(container, position, object); } public Fragment getPrimaryItem() { return primaryItem; } }