Android activity to authenticate using Instagram client side auth.

InstagramOAuthActivity.java

/**
 * 
 */
package com.bwuit.app.activities;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import org.apache.http.HttpStatus;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;

import com.bwuit.app.R;
import com.bwuit.app.models.User;
import com.bwuit.app.utils.API;
import com.bwuit.app.utils.APIResponse;
import com.bwuit.app.utils.Utils;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.NavUtils;
import android.util.Log;
import android.view.MenuItem;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.Toast;

/**
 * @author jars
 *
 */
public class InstagramOAuthActivity extends Activity {
	
	private static final String TAG = InstagramOAuthActivity.class.getName();
	
	private static final String CLIENT_ID       = "<client id here>";
	private static final String REDIRECT_URI    = "http://bwuit.com/auth/instagram/callback";
	private static final String FAILURE_URL     = "http://bwuit.com/auth/failure";
	private static final String AUTH_URI        = "https://instagram.com/oauth/authorize/?client_id="
	+ CLIENT_ID + "&redirect_uri=" + REDIRECT_URI + "&response_type=token";
	
	private ProgressDialog linking;

	/** */
	public InstagramOAuthActivity() {
		// TODO Auto-generated constructor stub
	}
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
        getActionBar().setDisplayHomeAsUpEnabled(true);		
		
		WebView wb = new WebView(this);		
		setContentView(wb);
		setClient(this, wb);
		
		wb.loadUrl(AUTH_URI);
	}
	
	private AsyncTask<String, Void, APIResponse> getConnectInstagramTask() {
		final Activity self = this;
		return new AsyncTask<String, Void, APIResponse>() {
			
			@Override
			protected void onPreExecute() {
				String message = String.format(self.getString(R.string.linking_account), "instagram");			
				linking = ProgressDialog.show(self, "Bwuit", message);
			}
	
			@Override
			protected APIResponse doInBackground(String... params) {
				String accessToken = params[0];
				
				// get user info
				try {
					URL url = new URL("https://api.instagram.com/v1/users/self?access_token="
						+ accessToken);
					HttpURLConnection conn = (HttpURLConnection) url.openConnection();
					
					conn.setRequestMethod("GET");
					conn.setDoInput(true);
					conn.connect();
					
					int response = conn.getResponseCode();
					String message = conn.getResponseMessage();
					Log.d(TAG, "The API response is: " + response + ", message: " + message);
					if (response == HttpStatus.SC_OK) {
						BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
						StringBuilder sb = new StringBuilder();
						String line;
						while ((line = br.readLine()) != null) {
						    sb.append(line + "\n");
						}
						br.close();
						JSONObject data = new JSONObject(sb.toString());
						// update user
						String userName = data.getJSONObject("data").getString("username");
						Log.d(TAG, "Instagram username: " + userName);
						
		    			User u = User.load();
		    			API api = new API(self);
		    			APIResponse apiResponse = null;
		    			if (u.exist()) {
		    				// register instagram
		    				apiResponse = api.post(
		    					"users/" + u.id + "/add/instagram",  
		    					new BasicNameValuePair("token", accessToken),
		    					new BasicNameValuePair("bwuit_token", u.bwuitToken)
		    				);
		    			} else {
		    				// add instagram
		    				apiResponse = api.post(
		    					"users/register/instagram", 
		    					new BasicNameValuePair("token", accessToken)
		    				);
		    				if (apiResponse.isOk()) {
		    					u.updateFromServer(apiResponse.content);
		    					u.sendDeviceTokenToBackendAndSaveIt(self);
		    				}
		    			}
		    			if (apiResponse.isOk()) {
		    				// save accessToken client
		    				try {
								u.instagramUserName = userName;
			    				u.instagramAccessToken = accessToken;
			    				u.searchInInstagram = "1";
			    				u.save();
							} catch (Exception e) {
								Utils.notify(e);
							}
		    			}
		    			return apiResponse;
					} else {
						// TODO: Error, pending to do something
						return new APIResponse(500, null);
					}
									
				} catch (Exception e) {
					// TODO: Error, pending to do something
					Log.e(TAG, e.getMessage());
				}
				
				return null;
			}
			
			@Override
			protected void onPostExecute(APIResponse result) {
				super.onPostExecute(result);
				linking.dismiss();
				APIResponse response = (APIResponse) result;
				if (response != null && !response.isOk()) {
					String m = String.format(self.getString(
							R.string.error_linking_account), "instagram");
					Utils.errorAlert(self, m + ", error: "
						+ response.responseCode + " - " + response.content, new DialogInterface.OnClickListener() {
							@Override
							public void onClick(DialogInterface arg0, int arg1) {
								finish();
							}
						
					});
				} else {
			        AlertDialog.Builder builder = new AlertDialog.Builder(self);
			        String msg = String.format(self.getString(
			        	R.string.message_we_will_organize_info_of), "Instagram");
			        builder.setMessage(msg)
		               .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
		                   public void onClick(DialogInterface dialog, int id) {
		                	   finish();
		                   }
		               });
			        builder.create().show();
				}
			}
			
		};	
	}
	
	private void setClient(final Activity act, WebView webView) {
		webView.setWebViewClient(new WebViewClient() {
			@Override
			public boolean shouldOverrideUrlLoading(WebView view, String url) {
				Log.d(TAG, "URL : " + url);
				if (url.startsWith(REDIRECT_URI)) {
					if (url.contains("access_token")) {
						String accessToken = url.split("#access_token=")[1];
						Log.d(TAG, "Instagram TOKEN: " + accessToken);
						getConnectInstagramTask().execute(accessToken);
					} else if (url.contains("error_reason")) {
						String error = url.contains("user_denied") ? "User denied access" : "Authentication failed";
						Utils.notify(new RuntimeException(error + " at " + TAG));
						Toast.makeText(act, String.format(getString(R.string.account_denied), "Instagram"),
							Toast.LENGTH_SHORT).show();
						finish();
					}
					return true;
				} else if (url.startsWith(FAILURE_URL)) {
					// TODO: Alert unknown error
					finish();
					return true;
				}
				return super.shouldOverrideUrlLoading(view, url);
			}
		});
	}	
	
	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		switch (item.getItemId()) {
		case android.R.id.home:
			NavUtils.navigateUpFromSameTask(this);
			return true;
		}
		return super.onOptionsItemSelected(item);
	}
}

Hello.,
where can i find APIResponse,Navutils etc classes?
thanks in advance