/**
* Copyright (c) 2013 Nokia Corporation. All rights reserved. Nokia and Nokia
* Connecting People are registered trademarks of Nokia Corporation. Oracle and
* Java are trademarks or registered trademarks of Oracle and/or its affiliates.
* Other product and company names mentioned herein may be trademarks or trade
* names of their respective owners. See LICENSE.TXT for license information.
*/
package com.nokia.example.musicexplorer.ui;
import java.util.Timer;
import java.util.TimerTask;
import java.util.Vector;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Item;
import javax.microedition.lcdui.ItemCommandListener;
import javax.microedition.lcdui.TextField;
import javax.microedition.lcdui.ItemStateListener;
import org.json.me.JSONObject;
import org.json.me.JSONArray;
import org.json.me.JSONException;
import org.tantalum.Task;
import org.tantalum.util.L;
import com.nokia.example.musicexplorer.data.QueryPager;
import com.nokia.example.musicexplorer.data.ApiCache;
import com.nokia.example.musicexplorer.data.model.GenericProductModel;
import com.nokia.example.musicexplorer.data.model.AlbumModel;
import com.nokia.example.musicexplorer.data.model.ArtistModel;
import com.nokia.example.musicexplorer.data.model.CategoryModel;
import com.nokia.example.musicexplorer.data.model.TrackModel;
/**
* Search view. The search textfield waits an amount of time before making an
* API call.
*/
public class SearchView
extends Form
implements
CommandListener,
ItemStateListener,
ItemCommandListener,
InitializableView {
public static final String VIEW_TITLE = "Search artists";
public static final String PATH_TO_ICON = "/search_icon.png";
private static final int MAX_QUERY_LENGTH_CHARS = 100;
private static final int QUERY_THROTTLE_MILLISECONDS = 1500;
private static final int SEARCH_QUERY_MIN_LENGTH = 1;
private static final int ITEMS_PER_PAGE = 20;
private final ViewManager viewManager;
private final Command backCommand;
private Vector viewModel;
private QueryPager queryPager;
private TextField searchField;
private String searchQuery;
private Timer throttle;
private LoadMoreButton loadMoreButton;
/**
* Constructor which sets the view title, adds a back command to it and adds
* the dummy text content to it.
*
* @param viewTitle Title shown in the title bar of this view
* @param viewManager View manager which will handle view switching
*/
public SearchView(ViewManager viewManager) {
super(VIEW_TITLE);
this.viewManager = viewManager;
this.backCommand = new Command("Back", Command.BACK, 1);
this.searchField = new TextField(null, null, MAX_QUERY_LENGTH_CHARS, TextField.ANY);
// Initialize the query pager.
this.queryPager = new QueryPager();
this.queryPager.setItemsPerPage(ITEMS_PER_PAGE);
this.loadMoreButton = new LoadMoreButton(this);
append(this.searchField);
addCommand(backCommand);
setCommandListener(this);
setItemStateListener(this);
}
/**
* @see com.nokia.example.musicexplorer.ui.InitializableView#initialize()
*/
public void initialize() {
}
/**
* @see javax.microedition.lcdui.CommandListener#commandAction(
* javax.microedition.lcdui.Command, javax.microedition.lcdui.Displayable)
*/
public void commandAction(Command command, Displayable displayable) {
if (backCommand.equals(command)) {
// Hardware back button was pressed
viewManager.goBack();
}
}
/**
* @see javax.microedition.lcdui.ItemCommandListener#commandAction(
* javax.microedition.lcdui.Command, javax.microedition.lcdui.Item)
*/
public void commandAction(Command c, Item item) {
if (c == loadMoreButton.getCommand()) {
// Load more triggered
performSearch(false, true); // Don't clear results. Load a new page.
}
}
/**
* Whenever the search query is changed, the state change of the textfield
* is registered here.
*
* @see javax.microedition.ItemStateListener#itemStateChanged(Item)
*/
public void itemStateChanged(Item item) {
if (item instanceof TextField) {
handleSearchField((TextField) item);
}
}
/**
* Handles the search TextField actions.
*
* @param searchField
*/
private void handleSearchField(TextField searchField) {
searchQuery = searchField.getString();
if (searchQuery.length() > SEARCH_QUERY_MIN_LENGTH) {
throttleSearch();
}
}
/**
* Delays the search and cancels a possible pending search.
*/
private void throttleSearch() {
if (throttle != null) {
// Cancel previous timer task.
throttle.cancel();
}
throttle = new Timer();
throttle.schedule(new TimerTask() {
public void run() {
performSearch(true, false); // Clear previous results. No paging.
cancel();
}
}, QUERY_THROTTLE_MILLISECONDS);
}
/**
* Performs a search API call. The method can as well handle clearing any
* previous search results (in the case of new query) and query the next
* page of a paged query.
*
* @param clearResults
* @param nextPage
*/
private void performSearch(boolean clearResults, boolean nextPage) {
String pagingQueryString;
if (nextPage) {
pagingQueryString = queryPager.getQueryStringForNextPage();
} else {
queryPager.reset();
pagingQueryString = queryPager.getCurrentQueryString();
}
if (clearResults) {
clearSearchResults();
}
ApiCache.search(
this.searchQuery,
new SearchResultHandlerTask(),
pagingQueryString);
}
private int getCategoryEnum(String category) {
category = category.toLowerCase();
if (category.indexOf("track") > -1) {
return CategoryModel.TRACK;
} else if (category.indexOf("artist") > -1) {
return CategoryModel.ARTIST;
} else if (category.indexOf("album") > -1) {
return CategoryModel.ALBUM;
} else if (category.indexOf("single") > -1) {
return CategoryModel.SINGLE;
}
return 0;
}
/**
* Parses JSON response to ListItem objects that can be appended to view.
*
* @param results
*/
private void parseResultsToViewModel(JSONArray results) {
if (viewModel != null) {
viewModel.removeAllElements();
} else {
viewModel = new Vector();
}
/*
* Response parsing
*
* Get "items" JSONArray and iterate over the JSONObjects. 1. Check
* objects "category" JSONObject 2. Decide which model to instantiate
* based on the category 3. Save models (search results) to viewModel
* vector.
*/
int loopMax = results.length();
if(loopMax > 0) {
for (int i = 0; i < loopMax; i++) {
JSONObject obj;
GenericProductModel model = null;
try {
obj = (JSONObject) results.get(i);
String category = obj.getJSONObject("category").getString("id");
switch (getCategoryEnum(category.toLowerCase())) {
case CategoryModel.SINGLE:
model = new AlbumModel(obj);
break;
case CategoryModel.ALBUM:
model = new AlbumModel(obj);
break;
case CategoryModel.ARTIST:
model = new ArtistModel(obj);
break;
case CategoryModel.TRACK:
model = new TrackModel(obj);
break;
default:
L.i("Category type not detected.", "");
break;
}
if (model != null) {
append(new ListItem(viewManager, model));
}
} catch (JSONException e) {
L.e("Failed to convert item of index " + Integer.toString(i), "", e);
}
}
} else {
append("No results.");
}
}
/**
* Clears the view.
*/
private void clearSearchResults() {
loadMoreButton.remove();
deleteAll();
append(this.searchField);
}
/**
* Appends search results to the view. If the results are paged, appends a
* load more button as well.
*/
private void appendToView() {
if (viewModel != null) {
// Avoid leaving the button between the paged results.
loadMoreButton.remove();
int loopMax = viewModel.size();
for (int i = 0; i < loopMax; i++) {
append((ListItem) viewModel.elementAt(i));
}
// Append load more button if there is paging available.
if (queryPager.hasMorePages()) {
loadMoreButton.append();
}
}
}
private class SearchResultHandlerTask extends Task {
public SearchResultHandlerTask() {
super(Task.NORMAL_PRIORITY);
}
public Object exec(Object response) {
if (response instanceof JSONObject) {
JSONArray resultsArray;
JSONObject paging;
try {
resultsArray = ((JSONObject) response).getJSONArray("items");
paging = ((JSONObject) response).getJSONObject("paging");
// Set query pager and pass results to parser.
queryPager.setPaging(paging);
parseResultsToViewModel(resultsArray);
appendToView();
} catch (JSONException ex) {
L.e("Could not parse JSON", "", ex);
}
}
return response;
}
}
}