Java tutorial
/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*- * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ package org.mozilla.gecko.home; import java.util.EnumSet; import org.mozilla.gecko.GeckoProfile; import org.mozilla.gecko.R; import org.mozilla.gecko.ReaderModeUtils; import org.mozilla.gecko.Telemetry; import org.mozilla.gecko.TelemetryContract; import org.mozilla.gecko.db.BrowserContract.ReadingListItems; import org.mozilla.gecko.db.BrowserContract.URLColumns; import org.mozilla.gecko.db.BrowserDB; import org.mozilla.gecko.db.ReadingListAccessor; import org.mozilla.gecko.home.HomeContextMenuInfo.RemoveItemType; import org.mozilla.gecko.home.HomePager.OnUrlOpenListener; import org.mozilla.gecko.util.HardwareUtils; import android.content.Context; import android.database.Cursor; import android.os.Bundle; import android.support.v4.content.Loader; import android.support.v4.widget.CursorAdapter; import android.text.SpannableStringBuilder; import android.text.Spanned; import android.text.style.ImageSpan; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.view.ViewStub; import android.widget.AdapterView; import android.widget.TextView; /** * Fragment that displays reading list contents in a ListView. */ public class ReadingListPanel extends HomeFragment { // Cursor loader ID for reading list private static final int LOADER_ID_READING_LIST = 0; // Formatted string in hint text to be replaced with an icon. private final String MATCH_STRING = "%I"; // Adapter for the list of reading list items private ReadingListAdapter mAdapter; // The view shown by the fragment private HomeListView mList; // Reference to the View to display when there are no results. private View mEmptyView; // Reference to top view. private View mTopView; // Callbacks used for the reading list and favicon cursor loaders private CursorLoaderCallbacks mCursorLoaderCallbacks; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.home_reading_list_panel, container, false); } @Override public void onViewCreated(View view, Bundle savedInstanceState) { super.onViewCreated(view, savedInstanceState); mTopView = view; mList = (HomeListView) view.findViewById(R.id.list); mList.setTag(HomePager.LIST_TAG_READING_LIST); mList.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { final Cursor c = mAdapter.getCursor(); if (c == null || !c.moveToPosition(position)) { return; } String url = c.getString(c.getColumnIndexOrThrow(URLColumns.URL)); url = ReaderModeUtils.getAboutReaderForUrl(url); Telemetry.sendUIEvent(TelemetryContract.Event.LOAD_URL, TelemetryContract.Method.LIST_ITEM); // This item is a TwoLinePageRow, so we allow switch-to-tab. mUrlOpenListener.onUrlOpen(url, EnumSet.of(OnUrlOpenListener.Flags.ALLOW_SWITCH_TO_TAB)); } }); mList.setContextMenuInfoFactory(new HomeContextMenuInfo.Factory() { @Override public HomeContextMenuInfo makeInfoForCursor(View view, int position, long id, Cursor cursor) { final HomeContextMenuInfo info = new HomeContextMenuInfo(view, position, id); info.url = cursor.getString(cursor.getColumnIndexOrThrow(ReadingListItems.URL)); info.title = cursor.getString(cursor.getColumnIndexOrThrow(ReadingListItems.TITLE)); info.readingListItemId = cursor.getInt(cursor.getColumnIndexOrThrow(ReadingListItems._ID)); info.itemType = RemoveItemType.READING_LIST; return info; } }); registerForContextMenu(mList); } @Override public void onDestroyView() { super.onDestroyView(); mList = null; mTopView = null; mEmptyView = null; } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); mAdapter = new ReadingListAdapter(getActivity(), null); mList.setAdapter(mAdapter); // Create callbacks before the initial loader is started. mCursorLoaderCallbacks = new CursorLoaderCallbacks(); loadIfVisible(); } @Override protected void load() { getLoaderManager().initLoader(LOADER_ID_READING_LIST, null, mCursorLoaderCallbacks); } private void updateUiFromCursor(Cursor c) { // We delay setting the empty view until the cursor is actually empty. // This avoids image flashing. if ((c == null || c.getCount() == 0) && mEmptyView == null) { final ViewStub emptyViewStub = (ViewStub) mTopView.findViewById(R.id.home_empty_view_stub); mEmptyView = emptyViewStub.inflate(); final TextView emptyHint = (TextView) mEmptyView.findViewById(R.id.home_empty_hint); if (HardwareUtils.isLowMemoryPlatform()) { emptyHint.setVisibility(View.GONE); } else { String readingListHint = emptyHint.getText().toString(); // Use an ImageSpan to include the reader icon in the "Tip". int imageSpanIndex = readingListHint.indexOf(MATCH_STRING); if (imageSpanIndex != -1) { final ImageSpan readingListIcon = new ImageSpan(getActivity(), R.drawable.reader_cropped, ImageSpan.ALIGN_BOTTOM); final SpannableStringBuilder hintBuilder = new SpannableStringBuilder(readingListHint); // Add additional spacing. hintBuilder.insert(imageSpanIndex + MATCH_STRING.length(), " "); hintBuilder.insert(imageSpanIndex, " "); // Add icon. hintBuilder.setSpan(readingListIcon, imageSpanIndex + 1, imageSpanIndex + MATCH_STRING.length() + 1, Spanned.SPAN_INCLUSIVE_INCLUSIVE); emptyHint.setText(hintBuilder, TextView.BufferType.SPANNABLE); } } mList.setEmptyView(mEmptyView); } } /** * Cursor loader for the list of reading list items. */ private static class ReadingListLoader extends SimpleCursorLoader { private final ReadingListAccessor accessor; public ReadingListLoader(Context context) { super(context); accessor = GeckoProfile.get(context).getDB().getReadingListAccessor(); } @Override public Cursor loadCursor() { return accessor.getReadingList(getContext().getContentResolver()); } } /** * Cursor adapter for the list of reading list items. */ private class ReadingListAdapter extends CursorAdapter { public ReadingListAdapter(Context context, Cursor cursor) { super(context, cursor, 0); } @Override public void bindView(View view, Context context, Cursor cursor) { final ReadingListRow row = (ReadingListRow) view; row.updateFromCursor(cursor); } @Override public View newView(Context context, Cursor cursor, ViewGroup parent) { return LayoutInflater.from(parent.getContext()).inflate(R.layout.reading_list_item_row, parent, false); } } /** * LoaderCallbacks implementation that interacts with the LoaderManager. */ private class CursorLoaderCallbacks extends TransitionAwareCursorLoaderCallbacks { @Override public Loader<Cursor> onCreateLoader(int id, Bundle args) { return new ReadingListLoader(getActivity()); } @Override public void onLoadFinishedAfterTransitions(Loader<Cursor> loader, Cursor c) { mAdapter.swapCursor(c); updateUiFromCursor(c); } @Override public void onLoaderReset(Loader<Cursor> loader) { super.onLoaderReset(loader); mAdapter.swapCursor(null); } } }