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.google.zxing.client.android; 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; public final class SearchBookContentsActivity extends Activity { private static final String TAG = "SearchBookContents"; private NetworkThread mNetworkThread; private String mISBN; private EditText mQueryTextView; private Button mQueryButton; private ListView mResultListView; private TextView mHeaderView; private String mUserAgent; @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) && !intent.getAction().equals(Intents.SearchBookContents.DEPRECATED_ACTION))) { finish(); return; } mISBN = intent.getStringExtra(Intents.SearchBookContents.ISBN); setTitle(getString(R.string.sbc_name) + ": ISBN " + mISBN); setContentView(R.layout.search_book_contents); mQueryTextView = (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 mQueryTextView.setText(initialQuery); } mQueryTextView.setOnKeyListener(mKeyListener); mQueryButton = (Button) findViewById(R.id.query_button); mQueryButton.setOnClickListener(mButtonListener); mResultListView = (ListView) findViewById(R.id.result_list_view); LayoutInflater factory = LayoutInflater.from(this); mHeaderView = (TextView) factory.inflate(R.layout.search_book_contents_header, mResultListView, false); mResultListView.addHeaderView(mHeaderView); mUserAgent = getString(R.string.zxing_user_agent); } @Override protected void onResume() { super.onResume(); mQueryTextView.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); } public final Handler mHandler = new Handler() { 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(); mHeaderView.setText(R.string.msg_sbc_failed); break; } } }; private void resetForNewQuery() { mNetworkThread = null; mQueryTextView.setEnabled(true); mQueryTextView.selectAll(); mQueryButton.setEnabled(true); } private final Button.OnClickListener mButtonListener = new Button.OnClickListener() { public void onClick(View view) { launchSearch(); } }; private final View.OnKeyListener mKeyListener = new View.OnKeyListener() { public boolean onKey(View view, int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_ENTER) { launchSearch(); return true; } return false; } }; private void launchSearch() { if (mNetworkThread == null) { String query = mQueryTextView.getText().toString(); if (query != null && query.length() > 0) { mNetworkThread = new NetworkThread(mISBN, query, mHandler, mUserAgent); mNetworkThread.start(); mHeaderView.setText(R.string.msg_sbc_searching_book); mResultListView.setAdapter(null); mQueryTextView.setEnabled(false); mQueryButton.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"); mHeaderView.setText("Found " + ((count == 1) ? "1 result" : count + " results")); if (count > 0) { JSONArray results = json.getJSONArray("search_results"); SearchBookContentsResult.setQuery(mQueryTextView.getText().toString()); List<SearchBookContentsResult> items = new ArrayList<SearchBookContentsResult>(count); for (int x = 0; x < count; x++) { items.add(parseResult(results.getJSONObject(x))); } mResultListView.setAdapter(new SearchBookContentsAdapter(this, items)); } else { String searchable = json.optString("searchable"); if (searchable != null && searchable.equals("false")) { mHeaderView.setText(R.string.msg_sbc_book_not_searchable); } mResultListView.setAdapter(null); } } catch (JSONException e) { Log.e(TAG, e.toString()); mResultListView.setAdapter(null); mHeaderView.setText(R.string.msg_sbc_failed); } } // Available fields: page_number, page_id, page_url, snippet_text private SearchBookContentsResult parseResult(JSONObject json) { try { 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 = snippet.replaceAll("\\<.*?\\>", ""); snippet = snippet.replaceAll("<", "<"); snippet = snippet.replaceAll(">", ">"); snippet = snippet.replaceAll("'", "'"); snippet = snippet.replaceAll(""", "\""); } else { snippet = "(" + getString(R.string.msg_sbc_snippet_unavailable) + ")"; valid = false; } return new SearchBookContentsResult(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 mISBN; private final String mQuery; private final Handler mHandler; private final String mUserAgent; public NetworkThread(String isbn, String query, Handler handler, String userAgent) { mISBN = isbn; mQuery = query; mHandler = handler; mUserAgent = userAgent; } public final 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 = new URI("http", null, "www.google.com", -1, "/books", "vid=isbn" + mISBN + "&jscmd=SearchWithinVolume2&q=" + mQuery, null); HttpUriRequest get = new HttpGet(uri); get.setHeader("cookie", getCookie(uri.toString())); client = AndroidHttpClient.newInstance(mUserAgent); 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(mHandler, 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(mHandler, R.id.search_book_contents_failed); message.sendToTarget(); } } catch (Exception e) { Log.e(TAG, e.toString()); Message message = Message.obtain(mHandler, 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 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(mUserAgent); try { HttpResponse response = client.execute(head); if (response.getStatusLine().getStatusCode() == 200) { Header[] cookies = response.getHeaders("set-cookie"); for (int x = 0; x < cookies.length; x++) { CookieManager.getInstance().setCookie(url, cookies[x].getValue()); } CookieSyncManager.getInstance().sync(); cookie = CookieManager.getInstance().getCookie(url); } } catch (IOException e) { Log.e(TAG, e.toString()); } client.close(); } return cookie; } private 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"; } } }