Today i am sharing one of my analysis for image load in android for redirected url.
Our
Goal
We
need to display image from URL that itself redirected to another URL.
Hit
above URL on your browser, you will be redirected to actual URL like
below.
Problem
when using third party library like lazy loading
I
have seen many library uses HttpURLConnection class to display image
from URL.
Like
“Universal Image Loader” , “Android-Query
”
but these library can't handle URL redirection.
So,
you can also manage URL redirection using HttpURLConnection class
itself.
Please
read below explanation to get more idea and What is best approach.
Now,
We have below Http clients which are used to download image from
specified URL.
- HttpURLConnection / HttpsURLConnection
3.
DefaultHttpClient
/ HttpClient
- This class does not support URL redirection automatically.
- We need to write extra code to handle URL redirection.
- You need to take care manually to close the connection of client.
- It will handle HTTP to HTTPS URL redirection and vice versa.
- It will handle only 1 URL redirection.
- HttpURLConnection
- This class does not support URL redirection automatically.
- We need to write some code by setting property setInstanceFollowRedirects = false to handle URL redirection properly.
- You need to take care manually to close the connection of client.
- It will handle HTTP to HTTPS URL redirection and vice versa.
- This class handles up to 5 redirection.
- DefaultHttpClient / HttpClient
- This class by default support URL redirection automatically.
- We need not to write any code.
- No need to close the connection.
- It will handle HTTP to HTTPS URL redirection and vice versa.
- This class handles greater than five redirection. I am not able to find maximum limit.
Conclusion
From
above explanation, Winner is DefaultHttpClient. We must use
DefaultHttpClient class. This class also handles Cookie forward
mechanism very well if we use singleton pattern in cookie based
authentication process in project.
Now below are code for above example.
Below is my main Activity class.
public class MainActivity extends Activity implements OnClickListener{
private static String TAG = MainActivity.class.getSimpleName();
private Button btnAndroidHttpClient, btnDownloadHttpURLConnection, btnDownloadDefaultHttpClient;
private ImageView imgView;
private DefaultHttpClient client = null;
/**
* put your URL that itself redirected to another url that is the actual url to download image
*/
private static final String URL_AndroidHttp = "http://graph.facebook.com/xxxxxxxxxxxx/picture/";
private static final String URL_HttpUrlConnection = "http://wired.ivvy.com/image/display/account/14/file/119806";
private static final String URL_DefaultHttp = "http://graph.facebook.com/xxxxxxxxxxxx/picture/";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnAndroidHttpClient = (Button) findViewById(R.id.btnDownloadAndroidHttpClient);
btnAndroidHttpClient.setOnClickListener(this);
btnDownloadHttpURLConnection = (Button)findViewById(R.id.btnDownloadHttpURLConnection);
btnDownloadHttpURLConnection.setOnClickListener(this);
btnDownloadDefaultHttpClient = (Button) findViewById(R.id.btnDownloadDefaultHttpClient);
btnDownloadDefaultHttpClient.setOnClickListener(this);
imgView = (ImageView)findViewById(R.id.imgView);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnDownloadAndroidHttpClient:
if(Utils.isNetworkAvailable(MainActivity.this))
{
if(URL_AndroidHttp != null || !URL_AndroidHttp.equalsIgnoreCase(""))
{
new DownloadImageViaAndroidHttpClientTask().execute(URL_AndroidHttp,imgView);
}
else
{
Toast.makeText(MainActivity.this, "Please provide image url.", Toast.LENGTH_SHORT).show();
}
}
else
{
Toast.makeText(MainActivity.this, "Please check your internet connectivity.", Toast.LENGTH_SHORT).show();
}
break;
case R.id.btnDownloadHttpURLConnection:
if(Utils.isNetworkAvailable(MainActivity.this))
{
if(URL_HttpUrlConnection != null || !URL_HttpUrlConnection.equalsIgnoreCase(""))
{
new DownloadImageViaHttpURLConnectionTask().execute(URL_HttpUrlConnection,imgView);
}
else
{
Toast.makeText(MainActivity.this, "Please provide image url.", Toast.LENGTH_SHORT).show();
}
}
else
{
Toast.makeText(MainActivity.this, "Please check your internet connectivity.", Toast.LENGTH_SHORT).show();
}
break;
case R.id.btnDownloadDefaultHttpClient:
if(Utils.isNetworkAvailable(MainActivity.this))
{
if(URL_DefaultHttp != null || !URL_DefaultHttp.equalsIgnoreCase(""))
{
new DownloadImageViaDefaultHttpClientTask().execute(URL_DefaultHttp,imgView);
}
else
{
Toast.makeText(MainActivity.this, "Please provide image url.", Toast.LENGTH_SHORT).show();
}
}
else
{
Toast.makeText(MainActivity.this, "Please check your internet connectivity.", Toast.LENGTH_SHORT).show();
}
break;
}
}
class DownloadImageViaAndroidHttpClientTask extends AsyncTask<Object, Void, Drawable>
{
private ImageView imgView;
private ProgressDialog dialog;
private AndroidHttpClient androidHttpClient = AndroidHttpClient.newInstance("Android");
@Override
protected void onPreExecute() {
dialog = new ProgressDialog(MainActivity.this);
dialog.setMessage("Please wait...");
dialog.show();
}
@Override
protected Drawable doInBackground(Object... params) {
imgView = (ImageView) params[1];
try {
HttpGet httpGet=new HttpGet((String)params[0]);
HttpResponse httpResponse=androidHttpClient.execute(httpGet);
androidHttpClient.close();
final int statusCode = httpResponse.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Header[] headers = httpResponse.getHeaders("Location");
if (headers != null && headers.length != 0) {
String newUrl = headers[headers.length - 1].getValue();
AppLog.i(TAG, "newUrl=>"+newUrl);
/**
* call again with new URL to get image
*/
return downloadImage(newUrl);
} else {
return null;
}
}
}
catch (Exception ex)
{
AppLog.e(TAG, "DownloadImageTask doInBackground() Exception=>"+ex);
}
return null;
}
@Override
protected void onPostExecute(Drawable drawable) {
if (dialog.isShowing()) {
dialog.dismiss();
}
if(drawable != null)
{
imgView.setImageDrawable(drawable);
}
}
}
class DownloadImageViaHttpURLConnectionTask extends AsyncTask<Object, Void, Drawable>
{
private ImageView imgView;
private ProgressDialog dialog;
private HttpURLConnection con = null;
@Override
protected void onPreExecute() {
dialog = new ProgressDialog(MainActivity.this);
dialog.setMessage("Please wait...");
dialog.show();
}
@Override
protected Drawable doInBackground(Object... params) {
imgView = (ImageView) params[1];
try {
con = (HttpURLConnection)(new URL((String)params[0]).openConnection());
con.disconnect();
con.setInstanceFollowRedirects(false);
con.connect();
final int responseCode = con.getResponseCode();
AppLog.i(TAG, "responseCode=>"+responseCode);
if (responseCode != HttpStatus.SC_OK) {
String newUrl = con.getHeaderField("Location");;
AppLog.i(TAG, "newUrl=>"+newUrl);
return downloadImage(newUrl);
}
}
catch (Exception ex)
{
AppLog.e(TAG, "DownloadImageTask doInBackground() Exception=>"+ex);
}
finally
{
if(con != null)
{
con.disconnect();
con= null;
}
}
return null;
}
@Override
protected void onPostExecute(Drawable drawable) {
if (dialog.isShowing()) {
dialog.dismiss();
}
if(drawable != null)
{
imgView.setImageDrawable(drawable);
}
}
}
class DownloadImageViaDefaultHttpClientTask extends AsyncTask<Object, Void, Drawable>
{
private ImageView imgView;
private ProgressDialog dialog;
@Override
protected void onPreExecute() {
dialog = new ProgressDialog(MainActivity.this);
dialog.setMessage("Please wait...");
dialog.show();
}
@Override
protected Drawable doInBackground(Object... params) {
imgView = (ImageView) params[1];
try {
/**
* check for whether client os initialized or not. first time it is null, after first request
* it will not create client. it will use existing initialized client to reduce memory consumption and improve performance.
* It will also used to cookie based implementation if we are using only one instance of client to redirect cookie to further request.
*/
if(client==null)
{
createClient();
}
HttpParams httpParams = client.getParams();
httpParams.setIntParameter("http.connection.timeout", 30000); // 30 SECONDS
httpParams.setIntParameter("http.socket.timeout", 30000); // 30 SECONDS
HttpGet httpGet=new HttpGet((String)params[0]);
HttpResponse httpResponse=client.execute(httpGet);
InputStream is=httpResponse.getEntity().getContent();
Drawable d = Drawable.createFromStream(is, "src name");
is.close();
return d;
}
catch (Exception ex)
{
AppLog.e(TAG, "DownloadImageTask doInBackground() Exception=>"+ex);
}
return null;
}
@Override
protected void onPostExecute(Drawable drawable) {
if (dialog.isShowing()) {
dialog.dismiss();
}
if(drawable != null)
{
imgView.setImageDrawable(drawable);
}
}
}
private static Drawable downloadImage(String stringUrl) {
URL url = null;
HttpURLConnection connection = null;
InputStream inputStream = null;
try {
url = new URL(stringUrl);
connection = (HttpURLConnection) url.openConnection();
connection.setUseCaches(true);
inputStream = connection.getInputStream();
Drawable d = Drawable.createFromStream(inputStream, "src name");
inputStream.close();
return d;
} catch (Exception e) {
AppLog.e(TAG, "Error while retrieving bitmap from " + e);
} finally {
if (connection != null) {
connection.disconnect();
}
}
return null;
}
public void createClient() {
BasicHttpParams params = new BasicHttpParams();
SchemeRegistry schemeRegistry = new SchemeRegistry();
schemeRegistry.register( new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
schemeRegistry.register( new Scheme("https", SSLSocketFactory.getSocketFactory(), 443));
ClientConnectionManager ccm = new ThreadSafeClientConnManager( params, schemeRegistry);
client = new DefaultHttpClient( ccm, params);
}
}
----------------------------------------------------------------------------------------------------------
public class AppLog {
private static boolean sFlagDebug= true;
private static boolean sFlagInfo= true;
private static boolean sFlagErr= true;
/**
* THis will print in Blue
* @param tag
* @param message
*/
public static void d(String tag, String message){
if(sFlagDebug)
{
Log.d(tag,message);
}
}
/**
* This will print in Green
* @param tag
* @param message
*/
public static void i(String tag, String message){
if(sFlagInfo)
{
Log.i(tag,message);
}
}
/**
* This will print in Error
* @param tag
* @param message
*/
public static void e(String tag, String message){
if(sFlagErr)
{
Log.e(tag,message);
}
}
}
---------------------------------------------------------------------------------------------------------
public class Utils {
private static final String TAG = Utils.class.getSimpleName();
/**
* Check Internet connection flag.
* @param context
* @return
*/
public static boolean isNetworkAvailable(Context context) {
ConnectivityManager connectivityManager = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkInfo networkInfo = connectivityManager
.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnectedOrConnecting()) {
return true;
}
return false;
}
}
