Use AsyncTask instead of Thread for cleaner async work handling

git-svn-id: https://zxing.googlecode.com/svn/trunk@2369 59b500cc-1b3d-0410-9834-0bbf25fbcc57

android/src/com/google/zxing/client/android/HttpHelper.java

@@ -16,6 +16,8 @@
 
 package com.google.zxing.client.android;
 
+import android.util.Log;
+
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -35,6 +37,8 @@ import java.util.HashSet;
  */
 public final class HttpHelper {
 
+  private static final String TAG = HttpHelper.class.getSimpleName();
+
   private static final Collection<String> REDIRECTOR_DOMAINS = new HashSet<String>(Arrays.asList(
     "amzn.to", "bit.ly", "bitly.com", "fb.me", "goo.gl", "is.gd", "j.mp", "lnkd.in", "ow.ly",
     "R.BEETAGG.COM", "r.beetagg.com", "SCN.BY", "su.pr", "t.co", "tinyurl.com", "tr.im"
@@ -75,6 +79,7 @@ public final class HttpHelper {
   }
 
   private static String downloadViaHttp(String uri, String contentTypes) throws IOException {
+    Log.i(TAG, "Downloading " + uri);
     URL url = new URL(uri);
     HttpURLConnection connection = (HttpURLConnection) url.openConnection();
     connection.setRequestProperty("Accept", contentTypes);

android/src/com/google/zxing/client/android/book/NetworkWorker.java

@@ -1,76 +0,0 @@
-/*
- * Copyright (C) 2010 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.book;
-
-import android.os.Handler;
-import android.os.Message;
-import android.util.Log;
-import com.google.zxing.client.android.HttpHelper;
-import com.google.zxing.client.android.LocaleManager;
-import com.google.zxing.client.android.R;
-import org.json.JSONException;
-import org.json.JSONObject;
-
-import java.io.IOException;
-
-final class NetworkWorker implements Runnable {
-
-  private static final String TAG = NetworkWorker.class.getSimpleName();
-
-  private final String isbn;
-  private final String query;
-  private final Handler handler;
-
-  NetworkWorker(String isbn, String query, Handler handler) {
-    this.isbn = isbn;
-    this.query = query;
-    this.handler = handler;
-  }
-
-  @Override
-  public void run() {
-    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.
-      String uri;
-      if (LocaleManager.isBookSearchUrl(isbn)) {
-        int equals = isbn.indexOf('=');
-        String volumeId = isbn.substring(equals + 1);
-        uri = "http://www.google.com/books?id=" + volumeId + "&jscmd=SearchWithinVolume2&q=" + query;
-      } else {
-        uri = "http://www.google.com/books?vid=isbn" + isbn + "&jscmd=SearchWithinVolume2&q=" + query;
-      }
-
-      try {
-        String content = HttpHelper.downloadViaHttp(uri, HttpHelper.ContentType.JSON);
-        JSONObject json = new JSONObject(content);
-        Message message = Message.obtain(handler, R.id.search_book_contents_succeeded);
-        message.obj = json;
-        message.sendToTarget();
-      } catch (IOException ioe) {
-        Message message = Message.obtain(handler, R.id.search_book_contents_failed);
-        message.sendToTarget();
-      }
-    } catch (JSONException je) {
-      Log.w(TAG, "Error accessing book search", je);
-      Message message = Message.obtain(handler, R.id.search_book_contents_failed);
-      message.sendToTarget();
-    }
-  }
-
-}

android/src/com/google/zxing/client/android/book/SearchBookContentsActivity.java

@@ -18,9 +18,8 @@ package com.google.zxing.client.android.book;
 
 import android.app.Activity;
 import android.content.Intent;
+import android.os.AsyncTask;
 import android.os.Bundle;
-import android.os.Handler;
-import android.os.Message;
 import android.util.Log;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
@@ -31,10 +30,12 @@ import android.widget.Button;
 import android.widget.EditText;
 import android.widget.ListView;
 import android.widget.TextView;
+import com.google.zxing.client.android.HttpHelper;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.regex.Pattern;
@@ -58,29 +59,12 @@ public final class SearchBookContentsActivity extends Activity {
   private static final Pattern QUOTE_ENTITY_PATTERN = Pattern.compile("'");
   private static final Pattern QUOT_ENTITY_PATTERN = Pattern.compile(""");
 
-  private Thread 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() {
     @Override
     public void onClick(View view) {
@@ -150,25 +134,57 @@ public final class SearchBookContentsActivity extends Activity {
     queryTextView.selectAll();
   }
 
-  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 Thread(new NetworkWorker(isbn, query, handler));
+      NetworkTask networkTask = new NetworkTask();
-        networkThread.start();
+      networkTask.execute(query, isbn);
       headerView.setText(R.string.msg_sbc_searching_book);
       resultListView.setAdapter(null);
       queryTextView.setEnabled(false);
       queryButton.setEnabled(false);
     }
   }
+
+  private final class NetworkTask extends AsyncTask<String,Object,JSONObject> {
+
+    @Override
+    protected JSONObject doInBackground(String... args) {
+      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.
+        String theQuery = args[0];
+        String theIsbn = args[1];
+        String uri;
+        if (LocaleManager.isBookSearchUrl(theIsbn)) {
+          int equals = theIsbn.indexOf('=');
+          String volumeId = theIsbn.substring(equals + 1);
+          uri = "http://www.google.com/books?id=" + volumeId + "&jscmd=SearchWithinVolume2&q=" + theQuery;
+        } else {
+          uri = "http://www.google.com/books?vid=isbn" + theIsbn + "&jscmd=SearchWithinVolume2&q=" + theQuery;
+        }
+        String content = HttpHelper.downloadViaHttp(uri, HttpHelper.ContentType.JSON);
+        return new JSONObject(content);
+      } catch (IOException ioe) {
+        Log.w(TAG, "Error accessing book search", ioe);
+        return null;
+      } catch (JSONException je) {
+        Log.w(TAG, "Error accessing book search", je);
+        return null;
+      }
+    }
+
+    @Override
+    protected void onPostExecute(JSONObject result) {
+      if (result == null) {
+        headerView.setText(R.string.msg_sbc_failed);
+      } else {
+        handleSearchResults(result);
+      }
+      queryTextView.setEnabled(true);
+      queryTextView.selectAll();
+      queryButton.setEnabled(true);
     }
 
     // Currently there is no way to distinguish between a query which had no results and a book
@@ -184,8 +200,8 @@ public final class SearchBookContentsActivity extends Activity {
           for (int x = 0; x < count; x++) {
             items.add(parseResult(results.getJSONObject(x)));
           }
-        resultListView.setOnItemClickListener(new BrowseBookListener(this, items));
+          resultListView.setOnItemClickListener(new BrowseBookListener(SearchBookContentsActivity.this, items));
-        resultListView.setAdapter(new SearchBookContentsAdapter(this, items));
+          resultListView.setAdapter(new SearchBookContentsAdapter(SearchBookContentsActivity.this, items));
         } else {
           String searchable = json.optString("searchable");
           if ("false".equals(searchable)) {
@@ -232,4 +248,7 @@ public final class SearchBookContentsActivity extends Activity {
       }
     }
 
+
+  }
+
 }