My previous article Customized ListView with Image and Text gives you a good overview of customizing a list view which contains a thumbnail image and few text fields. All the list data will be downloaded by making a network calls. The main challenge in that tutorial is downloading the images asynchronously and caching them. Because of lack of good tools I used a third party library (it is a good library though) to download the listview data and caching the images.
Today I am going to explain the same, but this time with a different approach by using an another library called volley. By using volley you can see decent improvement in listview performance without much effort.
Final Output
The list view we are going to build contains list of movies information where each list row defines single movie. The row layout is customized that contains movie poster as thumbnail image on the left and the movie title, rating, genre and release date on the right. Below is the final output.
1. Example JSON
I am going to use this example json to load the list data. This json contains array of objects where the each object contains information like movie name, rating, genre and release date.
JSON Url: http://api.androidhive.info/json/movies.json
[
{
"title": "Dawn of the Planet of the Apes",
"image": "http://api.androidhive.info/json/movies/1.jpg",
"rating": 8.3,
"releaseYear": 2014,
"genre": ["Action", "Drama", "Sci-Fi"]
},
....
....
]
2. Downloading Volley Library (volley.jar)
If you are coming across volley for the first time, I would suggest you go through my previous article Android working with Volley Library which gives you enough knowledge about volley and other things like building the volley library to generate volley.jar. It is up to you that you want to generate volley.jar on your own or just download the the volley.jar
3. Planning The Layout Design
To achieve this customized layout I choose the RelativeLayout as parent element. All the child elements are aligned using relative properties like align below, align right, align parent bottom etc.,
Now let’s start by creating a new project.
4. Creating New Project
1. In Eclipse create a new project by navigating to File ⇒ New ⇒ Android Application Project and fill required details. I gave my project package name as
info.androidhive.customlistviewvolley
2. Once the project is created paste the volley.jar in libs folder.
3. I am creating required packages first just to keep the project organised. This step is optional but it is recommended. Create four packages named adapter, app, model and util. So after creating packages my project contains following.
info.androidhive.customlistviewvolley.adater
info.androidhive.customlistviewvolley.app
info.androidhive.customlistviewvolley.model
info.androidhive.customlistviewvolley.util
4. Open colors.xml under res ⇒ values and add below colors. If you don’t see colors.xml file, create a new file and add these color values.
<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="genre">#666666</color>
<color name="year">#888888</color>
<color name="list_divider">#d9d9d9</color>
<color name="list_row_start_color">#ffffff</color>
<color name="list_row_end_color">#ffffff</color>
<color name="list_row_hover_start_color">#ebeef0</color>
<color name="list_row_hover_end_color">#ebeef0</color>
</resources>
5. Also add below dimensions in dimens.xml file located under res ⇒ values.
<resources>
<dimen name="title">17dp</dimen>
<dimen name="rating">15dip</dimen>
<dimen name="genre">13dip</dimen>
<dimen name="year">12dip</dimen>
</resources>
6. Before start writing java code, I would like to complete the UI part first. Create list_row_bg.xml, list_row_bg_hover.xml and list_row_selector.xml with below respective codes under res ⇒ drawable folder. If you don’t see drawable folder under res, create a new folder and name it as drawable.
list_row_bg.xml – Default style for list view row.
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<gradient
android:startColor="@color/list_row_start_color"
android:endColor="@color/list_row_end_color"
android:angle="270" />
</shape>
list_row_bg_hover.xml – Style for list view row when row is selected
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<gradient
android:angle="270"
android:endColor="@color/list_row_hover_end_color"
android:startColor="@color/list_row_hover_start_color" />
</shape>
list_row_selector.xml – Selector file to toggle the row states.
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/list_row_bg" android:state_pressed="false" android:state_selected="false"/>
<item android:drawable="@drawable/list_row_bg_hover" android:state_pressed="true"/>
<item android:drawable="@drawable/list_row_bg_hover" android:state_pressed="false" android:state_selected="true"/>
</selector>
7. Now open your layout file of main activity(in my case activity_main.xml) and add a ListView element.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<ListView
android:id="@+id/list"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:divider="@color/list_divider"
android:dividerHeight="1dp"
android:listSelector="@drawable/list_row_selector" />
</RelativeLayout>
8. We need to create another layout file for list view row. This is the main design component in this project as we define actual custom list design here. I am naming this file as list_row.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@drawable/list_row_selector"
android:padding="8dp" >
<!-- Thumbnail Image -->
<com.android.volley.toolbox.NetworkImageView
android:id="@+id/thumbnail"
android:layout_width="80dp"
android:layout_height="80dp"
android:layout_alignParentLeft="true"
android:layout_marginRight="8dp" />
<!-- Movie Title -->
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="@+id/thumbnail"
android:layout_toRightOf="@+id/thumbnail"
android:textSize="@dimen/title"
android:textStyle="bold" />
<!-- Rating -->
<TextView
android:id="@+id/rating"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@id/title"
android:layout_marginTop="1dip"
android:layout_toRightOf="@+id/thumbnail"
android:textSize="@dimen/rating" />
<!-- Genre -->
<TextView
android:id="@+id/genre"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_below="@id/rating"
android:layout_marginTop="5dp"
android:layout_toRightOf="@+id/thumbnail"
android:textColor="@color/genre"
android:textSize="@dimen/genre" />
<!-- Release Year -->
<TextView
android:id="@+id/releaseYear"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:textColor="@color/year"
android:textSize="@dimen/year" />
</RelativeLayout>
Here we completed the design part. Let’s move to java part.
9. Create LruBitmapCache.java under util package. This class takes care of caching images on disk.
package info.androidhive.customlistviewvolley.util;
import com.android.volley.toolbox.ImageLoader.ImageCache;
import android.graphics.Bitmap;
import android.support.v4.util.LruCache;
public class LruBitmapCache extends LruCache<String, Bitmap> implements
ImageCache {
public static int getDefaultLruCacheSize() {
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
final int cacheSize = maxMemory / 8;
return cacheSize;
}
public LruBitmapCache() {
this(getDefaultLruCacheSize());
}
public LruBitmapCache(int sizeInKiloBytes) {
super(sizeInKiloBytes);
}
@Override
protected int sizeOf(String key, Bitmap value) {
return value.getRowBytes() * value.getHeight() / 1024;
}
@Override
public Bitmap getBitmap(String url) {
return get(url);
}
@Override
public void putBitmap(String url, Bitmap bitmap) {
put(url, bitmap);
}
}
10. Create AppController.java under app package. This class is a singleton class which initializes core objects of volley library.
package info.androidhive.customlistviewvolley.app;
import info.androidhive.customlistviewvolley.util.LruBitmapCache;
import android.app.Application;
import android.text.TextUtils;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.Volley;
public class AppController extends Application {
public static final String TAG = AppController.class.getSimpleName();
private RequestQueue mRequestQueue;
private ImageLoader mImageLoader;
private static AppController mInstance;
@Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized AppController getInstance() {
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
public ImageLoader getImageLoader() {
getRequestQueue();
if (mImageLoader == null) {
mImageLoader = new ImageLoader(this.mRequestQueue,
new LruBitmapCache());
}
return this.mImageLoader;
}
public <T> void addToRequestQueue(Request<T> req, String tag) {
// set the default tag if tag is empty
req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
getRequestQueue().add(req);
}
public <T> void addToRequestQueue(Request<T> req) {
req.setTag(TAG);
getRequestQueue().add(req);
}
public void cancelPendingRequests(Object tag) {
if (mRequestQueue != null) {
mRequestQueue.cancelAll(tag);
}
}
}
11. Now add the AppController.java class in AndroidManifest.xml to your <application> tag using name property to execute this class on application start. Also add INTERNET permission as we are going to make network calls.
<application
android:name="info.androidhive.customlistviewvolley.app.AppController" ../>
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="info.androidhive.customlistviewvolley"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:name="info.androidhive.customlistviewvolley.app.AppController"
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="info.androidhive.customlistviewvolley.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
12. Now create Movie.java under model package. This model class will be used to provide movie objects data to list view after parsing the json.
package info.androidhive.customlistviewvolley.model;
import java.util.ArrayList;
public class Movie {
private String title, thumbnailUrl;
private int year;
private double rating;
private ArrayList<String> genre;
public Movie() {
}
public Movie(String name, String thumbnailUrl, int year, double rating,
ArrayList<String> genre) {
this.title = name;
this.thumbnailUrl = thumbnailUrl;
this.year = year;
this.rating = rating;
this.genre = genre;
}
public String getTitle() {
return title;
}
public void setTitle(String name) {
this.title = name;
}
public String getThumbnailUrl() {
return thumbnailUrl;
}
public void setThumbnailUrl(String thumbnailUrl) {
this.thumbnailUrl = thumbnailUrl;
}
public int getYear() {
return year;
}
public void setYear(int year) {
this.year = year;
}
public double getRating() {
return rating;
}
public void setRating(double rating) {
this.rating = rating;
}
public ArrayList<String> getGenre() {
return genre;
}
public void setGenre(ArrayList<String> genre) {
this.genre = genre;
}
}
13. Create a class named CustomListAdapter.java with below code. This is a custom list adapter class which provides data to list view. In other words it renders the layout_row.xml in list by pre-filling appropriate information.
package info.androidhive.customlistviewvolley.adater;
import info.androidhive.customlistviewvolley.R;
import info.androidhive.customlistviewvolley.app.AppController;
import info.androidhive.customlistviewvolley.model.Movie;
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import com.android.volley.toolbox.ImageLoader;
import com.android.volley.toolbox.NetworkImageView;
public class CustomListAdapter extends BaseAdapter {
private Activity activity;
private LayoutInflater inflater;
private List<Movie> movieItems;
ImageLoader imageLoader = AppController.getInstance().getImageLoader();
public CustomListAdapter(Activity activity, List<Movie> movieItems) {
this.activity = activity;
this.movieItems = movieItems;
}
@Override
public int getCount() {
return movieItems.size();
}
@Override
public Object getItem(int location) {
return movieItems.get(location);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (inflater == null)
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null)
convertView = inflater.inflate(R.layout.list_row, null);
if (imageLoader == null)
imageLoader = AppController.getInstance().getImageLoader();
NetworkImageView thumbNail = (NetworkImageView) convertView
.findViewById(R.id.thumbnail);
TextView title = (TextView) convertView.findViewById(R.id.title);
TextView rating = (TextView) convertView.findViewById(R.id.rating);
TextView genre = (TextView) convertView.findViewById(R.id.genre);
TextView year = (TextView) convertView.findViewById(R.id.releaseYear);
// getting movie data for the row
Movie m = movieItems.get(position);
// thumbnail image
thumbNail.setImageUrl(m.getThumbnailUrl(), imageLoader);
// title
title.setText(m.getTitle());
// rating
rating.setText("Rating: " + String.valueOf(m.getRating()));
// genre
String genreStr = "";
for (String str : m.getGenre()) {
genreStr += str + ", ";
}
genreStr = genreStr.length() > 0 ? genreStr.substring(0,
genreStr.length() - 2) : genreStr;
genre.setText(genreStr);
// release year
year.setText(String.valueOf(m.getYear()));
return convertView;
}
}
14. Now open your main activity class (MainActivity.java) and do the below changes. Here I created volley’s JsonArrayRequest to get the json from url. Upon parsing the json, I stored all the json data into an ArrayList as Movie objects. Finally I called notifyDataSetChanged() on CustomListAdapter instance to render the list view with updated information.
package info.androidhive.customlistviewvolley;
import info.androidhive.customlistviewvolley.adater.CustomListAdapter;
import info.androidhive.customlistviewvolley.app.AppController;
import info.androidhive.customlistviewvolley.model.Movie;
import java.util.ArrayList;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.widget.ListView;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.VolleyLog;
import com.android.volley.toolbox.JsonArrayRequest;
public class MainActivity extends Activity {
// Log tag
private static final String TAG = MainActivity.class.getSimpleName();
// Movies json url
private static final String url = "http://api.androidhive.info/json/movies.json";
private ProgressDialog pDialog;
private List<Movie> movieList = new ArrayList<Movie>();
private ListView listView;
private CustomListAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) findViewById(R.id.list);
adapter = new CustomListAdapter(this, movieList);
listView.setAdapter(adapter);
pDialog = new ProgressDialog(this);
// Showing progress dialog before making http request
pDialog.setMessage("Loading...");
pDialog.show();
// changing action bar color
getActionBar().setBackgroundDrawable(
new ColorDrawable(Color.parseColor("#1b1b1b")));
// Creating volley request obj
JsonArrayRequest movieReq = new JsonArrayRequest(url,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
Log.d(TAG, response.toString());
hidePDialog();
// Parsing json
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
Movie movie = new Movie();
movie.setTitle(obj.getString("title"));
movie.setThumbnailUrl(obj.getString("image"));
movie.setRating(((Number) obj.get("rating"))
.doubleValue());
movie.setYear(obj.getInt("releaseYear"));
// Genre is json array
JSONArray genreArry = obj.getJSONArray("genre");
ArrayList<String> genre = new ArrayList<String>();
for (int j = 0; j < genreArry.length(); j++) {
genre.add((String) genreArry.get(j));
}
movie.setGenre(genre);
// adding movie to movies array
movieList.add(movie);
} catch (JSONException e) {
e.printStackTrace();
}
}
// notifying list adapter about data changes
// so that it renders the list view with updated data
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d(TAG, "Error: " + error.getMessage());
hidePDialog();
}
});
// Adding request to request queue
AppController.getInstance().addToRequestQueue(movieReq);
}
@Override
public void onDestroy() {
super.onDestroy();
hidePDialog();
}
private void hidePDialog() {
if (pDialog != null) {
pDialog.dismiss();
pDialog = null;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Now run the project and test it once. Please do comment below if you ran into any issue.
