Java tutorial
/* * Copyright (C) 2008 ZXing authors * * 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.offbye.bookmaster.android.book; import android.app.Activity; import android.content.Intent; import android.content.res.Configuration; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.KeyEvent; import android.view.LayoutInflater; import android.view.View; import android.webkit.CookieManager; import android.webkit.CookieSyncManager; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.TextView; import org.apache.http.Header; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpHead; import org.apache.http.client.methods.HttpUriRequest; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.net.URI; import java.util.ArrayList; import java.util.List; import java.util.regex.Pattern; import com.offbye.bookmaster.android.R; import com.offbye.bookmaster.android.Intents; import com.offbye.bookmaster.android.AndroidHttpClient; /** * Uses Google Book Search to find a word or phrase in the requested book. * * @author dswitkin@google.com (Daniel Switkin) */ public final class SearchBookContentsActivity extends Activity { private static final String TAG = "SearchBookContents"; private static final String USER_AGENT = "ZXing (Android)"; private static final Pattern TAG_PATTERN = Pattern.compile("\\<.*?\\>"); private static final Pattern LT_ENTITY_PATTERN = Pattern.compile("<"); private static final Pattern GT_ENTITY_PATTERN = Pattern.compile(">"); private static final Pattern QUOTE_ENTITY_PATTERN = Pattern.compile("'"); private static final Pattern QUOT_ENTITY_PATTERN = Pattern.compile("""); private NetworkThread networkThread; private String isbn; private EditText queryTextView; private Button queryButton; private ListView resultListView; private TextView headerView; private final Handler handler = new Handler() { @Override public void handleMessage(Message message) { switch (message.what) { case R.id.search_book_contents_succeeded: handleSearchResults((JSONObject) message.obj); resetForNewQuery(); break; case R.id.search_book_contents_failed: resetForNewQuery(); headerView.setText(R.string.msg_sbc_failed); break; } } }; private final Button.OnClickListener buttonListener = new Button.OnClickListener() { public void onClick(View view) { launchSearch(); } }; private final View.OnKeyListener keyListener = new View.OnKeyListener() { public boolean onKey(View view, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_ENTER) { launchSearch(); return true; } return false; } }; String getISBN() { return isbn; } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); // Make sure that expired cookies are removed on launch. CookieSyncManager.createInstance(this); CookieManager.getInstance().removeExpiredCookie(); Intent intent = getIntent(); if (intent == null || (!intent.getAction().equals(Intents.SearchBookContents.ACTION))) { finish(); return; } isbn = intent.getStringExtra(Intents.SearchBookContents.ISBN); if (isbn.startsWith("http://google.com/books?id=")) { setTitle(getString(R.string.sbc_name)); } else { setTitle(getString(R.string.sbc_name) + ": ISBN " + isbn); } setContentView(R.layout.search_book_contents); queryTextView = (EditText) findViewById(R.id.query_text_view); String initialQuery = intent.getStringExtra(Intents.SearchBookContents.QUERY); if (initialQuery != null && initialQuery.length() > 0) { // Populate the search box but don't trigger the search queryTextView.setText(initialQuery); } queryTextView.setOnKeyListener(keyListener); queryButton = (Button) findViewById(R.id.query_button); queryButton.setOnClickListener(buttonListener); resultListView = (ListView) findViewById(R.id.result_list_view); LayoutInflater factory = LayoutInflater.from(this); headerView = (TextView) factory.inflate(R.layout.search_book_contents_header, resultListView, false); resultListView.addHeaderView(headerView); } @Override protected void onResume() { super.onResume(); queryTextView.selectAll(); } @Override public void onConfigurationChanged(Configuration config) { // Do nothing, this is to prevent the activity from being restarted when the keyboard opens. super.onConfigurationChanged(config); } private void resetForNewQuery() { networkThread = null; queryTextView.setEnabled(true); queryTextView.selectAll(); queryButton.setEnabled(true); } private void launchSearch() { if (networkThread == null) { String query = queryTextView.getText().toString(); if (query != null && query.length() > 0) { networkThread = new NetworkThread(isbn, query, handler); networkThread.start(); headerView.setText(R.string.msg_sbc_searching_book); resultListView.setAdapter(null); queryTextView.setEnabled(false); queryButton.setEnabled(false); } } } // Currently there is no way to distinguish between a query which had no results and a book // which is not searchable - both return zero results. private void handleSearchResults(JSONObject json) { try { int count = json.getInt("number_of_results"); headerView.setText("Found " + (count == 1 ? "1 result" : count + " results")); if (count > 0) { JSONArray results = json.getJSONArray("search_results"); SearchBookContentsResult.setQuery(queryTextView.getText().toString()); List<SearchBookContentsResult> items = new ArrayList<SearchBookContentsResult>(count); for (int x = 0; x < count; x++) { items.add(parseResult(results.getJSONObject(x))); } resultListView.setOnItemClickListener(new BrowseBookListener(this, items)); resultListView.setAdapter(new SearchBookContentsAdapter(this, items)); } else { String searchable = json.optString("searchable"); if ("false".equals(searchable)) { headerView.setText(R.string.msg_sbc_book_not_searchable); } resultListView.setAdapter(null); } } catch (JSONException e) { Log.e(TAG, e.toString()); resultListView.setAdapter(null); headerView.setText(R.string.msg_sbc_failed); } } // Available fields: page_id, page_number, page_url, snippet_text private SearchBookContentsResult parseResult(JSONObject json) { try { String pageId = json.getString("page_id"); String pageNumber = json.getString("page_number"); if (pageNumber.length() > 0) { pageNumber = getString(R.string.msg_sbc_page) + ' ' + pageNumber; } else { // This can happen for text on the jacket, and possibly other reasons. pageNumber = getString(R.string.msg_sbc_unknown_page); } // Remove all HTML tags and encoded characters. Ideally the server would do this. String snippet = json.optString("snippet_text"); boolean valid = true; if (snippet.length() > 0) { snippet = TAG_PATTERN.matcher(snippet).replaceAll(""); snippet = LT_ENTITY_PATTERN.matcher(snippet).replaceAll("<"); snippet = GT_ENTITY_PATTERN.matcher(snippet).replaceAll(">"); snippet = QUOTE_ENTITY_PATTERN.matcher(snippet).replaceAll("'"); snippet = QUOT_ENTITY_PATTERN.matcher(snippet).replaceAll("\""); } else { snippet = '(' + getString(R.string.msg_sbc_snippet_unavailable) + ')'; valid = false; } return new SearchBookContentsResult(pageId, pageNumber, snippet, valid); } catch (JSONException e) { // Never seen in the wild, just being complete. return new SearchBookContentsResult(getString(R.string.msg_sbc_no_page_returned), "", "", false); } } private static final class NetworkThread extends Thread { private final String isbn; private final String query; private final Handler handler; NetworkThread(String isbn, String query, Handler handler) { this.isbn = isbn; this.query = query; this.handler = handler; } @Override public void run() { AndroidHttpClient client = null; try { // These return a JSON result which describes if and where the query was found. This API may // break or disappear at any time in the future. Since this is an API call rather than a // website, we don't use LocaleManager to change the TLD. URI uri; if (isbn.startsWith("http://google.com/books?id=")) { int equals = isbn.indexOf('='); String volumeId = isbn.substring(equals + 1); uri = new URI("http", null, "www.google.com", -1, "/books", "id=" + volumeId + "&jscmd=SearchWithinVolume2&q=" + query, null); } else { uri = new URI("http", null, "www.google.com", -1, "/books", "vid=isbn" + isbn + "&jscmd=SearchWithinVolume2&q=" + query, null); } HttpUriRequest get = new HttpGet(uri); get.setHeader("cookie", getCookie(uri.toString())); client = AndroidHttpClient.newInstance(USER_AGENT); HttpResponse response = client.execute(get); if (response.getStatusLine().getStatusCode() == 200) { HttpEntity entity = response.getEntity(); ByteArrayOutputStream jsonHolder = new ByteArrayOutputStream(); entity.writeTo(jsonHolder); jsonHolder.flush(); JSONObject json = new JSONObject(jsonHolder.toString(getEncoding(entity))); jsonHolder.close(); Message message = Message.obtain(handler, R.id.search_book_contents_succeeded); message.obj = json; message.sendToTarget(); } else { Log.e(TAG, "HTTP returned " + response.getStatusLine().getStatusCode() + " for " + uri); Message message = Message.obtain(handler, R.id.search_book_contents_failed); message.sendToTarget(); } } catch (Exception e) { Log.e(TAG, e.toString()); Message message = Message.obtain(handler, R.id.search_book_contents_failed); message.sendToTarget(); } finally { if (client != null) { client.close(); } } } // Book Search requires a cookie to work, which we store persistently. If the cookie does // not exist, this could be the first search or it has expired. Either way, do a quick HEAD // request to fetch it, save it via the CookieSyncManager to flash, then return it. private static String getCookie(String url) { String cookie = CookieManager.getInstance().getCookie(url); if (cookie == null || cookie.length() == 0) { //Log.v(TAG, "Book Search cookie was missing or expired"); HttpUriRequest head = new HttpHead(url); AndroidHttpClient client = AndroidHttpClient.newInstance(USER_AGENT); try { HttpResponse response = client.execute(head); if (response.getStatusLine().getStatusCode() == 200) { Header[] cookies = response.getHeaders("set-cookie"); for (Header theCookie : cookies) { CookieManager.getInstance().setCookie(url, theCookie.getValue()); } CookieSyncManager.getInstance().sync(); cookie = CookieManager.getInstance().getCookie(url); } } catch (IOException e) { Log.e(TAG, e.toString()); } client.close(); } return cookie; } private static String getEncoding(HttpEntity entity) { // FIXME: The server is returning ISO-8859-1 but the content is actually windows-1252. // Once Jeff fixes the HTTP response, remove this hardcoded value and go back to getting // the encoding dynamically. return "windows-1252"; // HeaderElement[] elements = entity.getContentType().getElements(); // if (elements != null && elements.length > 0) { // String encoding = elements[0].getParameterByName("charset").getValue(); // if (encoding != null && encoding.length() > 0) { // return encoding; // } // } // return "UTF-8"; } } }