Java tutorial
/* * Copyright (C) 2011 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.xbrowser; import android.app.ActionBar; import android.app.Activity; import android.app.Fragment; import android.app.FragmentTransaction; import android.content.Context; import android.content.Intent; import android.net.Uri; import android.os.Bundle; import android.support.v13.app.FragmentPagerAdapter; import android.support.v4.view.ViewPager; import android.view.Menu; import android.view.MenuItem; import com.android.xbrowser.UI.ComboViews; import java.util.ArrayList; public class ComboViewActivity extends Activity implements CombinedBookmarksCallbacks { private static final String STATE_SELECTED_TAB = "tab"; public static final String EXTRA_COMBO_ARGS = "combo_args"; public static final String EXTRA_INITIAL_VIEW = "initial_view"; public static final String EXTRA_OPEN_SNAPSHOT = "snapshot_id"; public static final String EXTRA_OPEN_ALL = "open_all"; public static final String EXTRA_CURRENT_URL = "url"; private ViewPager mViewPager; private TabsAdapter mTabsAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setResult(RESULT_CANCELED); Bundle extras = getIntent().getExtras(); Bundle args = extras.getBundle(EXTRA_COMBO_ARGS); String svStr = extras.getString(EXTRA_INITIAL_VIEW, null); ComboViews startingView = svStr != null ? ComboViews.valueOf(svStr) : ComboViews.Bookmarks; mViewPager = new ViewPager(this); mViewPager.setId(R.id.tab_view); setContentView(mViewPager); final ActionBar bar = getActionBar(); bar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); if (BrowserActivity.isTablet(this)) { bar.setDisplayOptions(ActionBar.DISPLAY_SHOW_HOME | ActionBar.DISPLAY_USE_LOGO); } else { bar.setDisplayOptions(0); } mTabsAdapter = new TabsAdapter(this, mViewPager); mTabsAdapter.addTab(bar.newTab().setText(R.string.tab_bookmarks), BrowserBookmarksPage.class, args); mTabsAdapter.addTab(bar.newTab().setText(R.string.tab_history), BrowserHistoryPage.class, args); mTabsAdapter.addTab(bar.newTab().setText(R.string.tab_snapshots), BrowserSnapshotPage.class, args); if (savedInstanceState != null) { bar.setSelectedNavigationItem(savedInstanceState.getInt(STATE_SELECTED_TAB, 0)); } else { switch (startingView) { case Bookmarks: mViewPager.setCurrentItem(0); break; case History: mViewPager.setCurrentItem(1); break; case Snapshots: mViewPager.setCurrentItem(2); break; } } } @Override protected void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(STATE_SELECTED_TAB, getActionBar().getSelectedNavigationIndex()); } @Override public void openUrl(String url) { Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(url)); setResult(RESULT_OK, i); finish(); } @Override public void openInNewTab(String... urls) { Intent i = new Intent(); i.putExtra(EXTRA_OPEN_ALL, urls); setResult(RESULT_OK, i); finish(); } @Override public void close() { finish(); } @Override public void openSnapshot(long id) { Intent i = new Intent(); i.putExtra(EXTRA_OPEN_SNAPSHOT, id); setResult(RESULT_OK, i); finish(); } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.combined, menu); return super.onCreateOptionsMenu(menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { if (item.getItemId() == android.R.id.home) { finish(); return true; } else if (item.getItemId() == R.id.preferences_menu_id) { String url = getIntent().getStringExtra(EXTRA_CURRENT_URL); Intent intent = new Intent(this, BrowserPreferencesPage.class); intent.putExtra(BrowserPreferencesPage.CURRENT_PAGE, url); startActivityForResult(intent, Controller.PREFERENCES_PAGE); return true; } return super.onOptionsItemSelected(item); } /** * 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 page 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; 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); return Fragment.instantiate(mContext, info.clss.getName(), info.args); } @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(android.app.ActionBar.Tab tab, FragmentTransaction ft) { Object tag = tab.getTag(); for (int i = 0; i < mTabs.size(); i++) { if (mTabs.get(i) == tag) { mViewPager.setCurrentItem(i); } } } @Override public void onTabUnselected(android.app.ActionBar.Tab tab, FragmentTransaction ft) { } @Override public void onTabReselected(android.app.ActionBar.Tab tab, FragmentTransaction ft) { } } private static String makeFragmentName(int viewId, int index) { return "android:switcher:" + viewId + ":" + index; } }