Java tutorial
/* * Copyright (c) 2010-2011, The MiCode Open Source Community (www.micode.net) * * This file is part of FileExplorer. * * FileExplorer 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 3 of the License, or * (at your option) any later version. * * FileExplorer 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 SwiFTP. If not, see <http://www.gnu.org/licenses/>. */ package id.ridon.fileexplorer; import android.app.ActionBar; import android.app.ActionBar.Tab; import android.app.Activity; import android.app.Fragment; import android.app.FragmentTransaction; import android.content.Context; import android.content.SharedPreferences; import android.content.res.Configuration; import android.os.Bundle; import android.preference.PreferenceManager; import android.support.v13.app.FragmentPagerAdapter; import android.support.v4.view.ViewPager; import android.view.ActionMode; import java.util.ArrayList; public class FileExplorerTabActivity extends Activity { private static final String INSTANCESTATE_TAB = "tab"; private static final int DEFAULT_OFFSCREEN_PAGES = 2; ViewPager mViewPager; TabsAdapter mTabsAdapter; ActionMode mActionMode; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.fragment_pager); mViewPager = (ViewPager) findViewById(R.id.pager); mViewPager.setOffscreenPageLimit(DEFAULT_OFFSCREEN_PAGES); final ActionBar bar = getActionBar(); bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); bar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE | ActionBar.DISPLAY_SHOW_HOME); mTabsAdapter = new TabsAdapter(this, mViewPager); mTabsAdapter.addTab(bar.newTab().setText(R.string.tab_category), FileCategoryActivity.class, null); mTabsAdapter.addTab(bar.newTab().setText(R.string.tab_sd), FileViewActivity.class, null); mTabsAdapter.addTab(bar.newTab().setText(R.string.tab_remote), ServerControlActivity.class, null); bar.setSelectedNavigationItem(PreferenceManager.getDefaultSharedPreferences(this).getInt(INSTANCESTATE_TAB, Util.CATEGORY_TAB_INDEX)); } @Override protected void onPause() { super.onPause(); SharedPreferences.Editor editor = PreferenceManager.getDefaultSharedPreferences(this).edit(); editor.putInt(INSTANCESTATE_TAB, getActionBar().getSelectedNavigationIndex()); editor.commit(); } @Override public void onConfigurationChanged(Configuration newConfig) { if (getActionBar().getSelectedNavigationIndex() == Util.CATEGORY_TAB_INDEX) { FileCategoryActivity categoryFragement = (FileCategoryActivity) mTabsAdapter .getItem(Util.CATEGORY_TAB_INDEX); if (categoryFragement.isHomePage()) { reInstantiateCategoryTab(); } else { categoryFragement.setConfigurationChanged(true); } } super.onConfigurationChanged(newConfig); } public void reInstantiateCategoryTab() { mTabsAdapter.destroyItem(mViewPager, Util.CATEGORY_TAB_INDEX, mTabsAdapter.getItem(Util.CATEGORY_TAB_INDEX)); mTabsAdapter.instantiateItem(mViewPager, Util.CATEGORY_TAB_INDEX); } @Override public void onBackPressed() { IBackPressedListener backPressedListener = (IBackPressedListener) mTabsAdapter .getItem(mViewPager.getCurrentItem()); if (!backPressedListener.onBack()) { super.onBackPressed(); } } public interface IBackPressedListener { /** * ?back * @return True: ??; False: ?? */ boolean onBack(); } public void setActionMode(ActionMode actionMode) { mActionMode = actionMode; } public ActionMode getActionMode() { return mActionMode; } public Fragment getFragment(int tabIndex) { return mTabsAdapter.getItem(tabIndex); } /** * This is a helper class that implements the management of tabs and all * details of connecting a ViewPager with associated TabHost. It relies on a * trick. Normally a tab host has a simple API for supplying a View or * Intent that each tab will show. This is not sufficient for switching * between pages. So instead we make the content part of the tab host * 0dp high (it is not shown) and the TabsAdapter supplies its own dummy * view to show as the tab content. It listens to changes in tabs, and takes * care of switch to the correct paged in the ViewPager whenever the selected * tab changes. */ public static class TabsAdapter extends FragmentPagerAdapter implements ActionBar.TabListener, ViewPager.OnPageChangeListener { private final Context mContext; private final ActionBar mActionBar; private final ViewPager mViewPager; private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>(); static final class TabInfo { private final Class<?> clss; private final Bundle args; private Fragment fragment; TabInfo(Class<?> _class, Bundle _args) { clss = _class; args = _args; } } public TabsAdapter(Activity activity, ViewPager pager) { super(activity.getFragmentManager()); mContext = activity; mActionBar = activity.getActionBar(); mViewPager = pager; mViewPager.setAdapter(this); mViewPager.setOnPageChangeListener(this); } public void addTab(ActionBar.Tab tab, Class<?> clss, Bundle args) { TabInfo info = new TabInfo(clss, args); tab.setTag(info); tab.setTabListener(this); mTabs.add(info); mActionBar.addTab(tab); notifyDataSetChanged(); } @Override public int getCount() { return mTabs.size(); } @Override public Fragment getItem(int position) { TabInfo info = mTabs.get(position); if (info.fragment == null) { info.fragment = Fragment.instantiate(mContext, info.clss.getName(), info.args); } return info.fragment; } @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override public void onPageSelected(int position) { mActionBar.setSelectedNavigationItem(position); } @Override public void onPageScrollStateChanged(int state) { } @Override public void onTabSelected(Tab tab, FragmentTransaction ft) { Object tag = tab.getTag(); for (int i = 0; i < mTabs.size(); i++) { if (mTabs.get(i) == tag) { mViewPager.setCurrentItem(i); } } if (!tab.getText().equals(mContext.getString(R.string.tab_sd))) { ActionMode actionMode = ((FileExplorerTabActivity) mContext).getActionMode(); if (actionMode != null) { actionMode.finish(); } } } @Override public void onTabUnselected(Tab tab, FragmentTransaction ft) { } @Override public void onTabReselected(Tab tab, FragmentTransaction ft) { } } }