StringObjectRequestActivity.java

package com.prashant.adesara.volleyexample;

import android.annotation.TargetApi;
import android.app.ActionBar;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.android.volley.AuthFailureError;
import com.android.volley.ClientError;
import com.android.volley.NetworkError;
import com.android.volley.NoConnectionError;
import com.android.volley.ParseError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.ServerError;
import com.android.volley.TimeoutError;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import com.prashant.adesara.volleysample.ssl.SslHttpStack;

public class StringObjectRequestActivity extends Activity {

		private Button mTrigger;
		private TextView mResultView;
		private RequestQueue mVolleyQueue;
		private ProgressDialog mProgress;
		private final String TAG_REQUEST = "MY_TAG";
		

		@Override
		protected void onCreate(Bundle savedInstanceState) {
			super.onCreate(savedInstanceState);
			setContentView(R.layout.string_object_layout);
			
			actionBarSetup();
			
			// Initialise Volley Request Queue. 
			mVolleyQueue = Volley.newRequestQueue(this,new SslHttpStack(true));

			mResultView = (TextView) findViewById(R.id.result_txt);
			mTrigger = (Button) findViewById(R.id.send_http);
			mTrigger.setOnClickListener(new View.OnClickListener() {
				@Override
				public void onClick(View v) {
					showProgress();
					makeSampleHttpRequest();
				}
			});
		}
		
		@TargetApi(Build.VERSION_CODES.HONEYCOMB)
		private void actionBarSetup() {
		  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
		    ActionBar ab = getActionBar();
		    ab.setTitle("StringObjectRequest");
		  }
		}

		public void onDestroy() {
			super.onDestroy();
		}
		
		public void onStop() {
			super.onStop();
			if(mProgress != null)
				mProgress.dismiss();
			// Keep the list of requests dispatched in a List<Request<T>> mRequestList;
			/*
			 for( Request<T> req : mRequestList) {
			 	req.cancel();
			 }
			 */
			//jsonObjRequest.cancel();
			//( or )
			mVolleyQueue.cancelAll(TAG_REQUEST);
		}
		
		private void showProgress() {
			mProgress = ProgressDialog.show(this, "", "Loading...");
		}
		
		private void stopProgress() {
			mProgress.cancel();
		}
		
		private void showToast(String msg) {
			Toast.makeText(StringObjectRequestActivity.this, msg, Toast.LENGTH_LONG).show();
		}
		
		private void makeSampleHttpRequest() {
			
			String url = "http://api.openweathermap.org/data/2.5/weather?q=London,uk";
			
			StringRequest stringRequest = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
				@Override
				public void onResponse(String response) {
					mResultView.setText(response);
					stopProgress();
				}
			}, new Response.ErrorListener() {
				@Override
				public void onErrorResponse(VolleyError error) {
					// Handle your error types accordingly.For Timeout & No connection error, you can show 'retry' button.
					// For AuthFailure, you can re login with user credentials.
					// For ClientError, 400 & 401, Errors happening on client side when sending api request.
					// In this case you can check how client is forming the api and debug accordingly.
					// For ServerError 5xx, you can do retry or handle accordingly.
					if( error instanceof NetworkError) {
					} else if( error instanceof ClientError) { 
					} else if( error instanceof ServerError) {
					} else if( error instanceof AuthFailureError) {
					} else if( error instanceof ParseError) {
					} else if( error instanceof NoConnectionError) {
					} else if( error instanceof TimeoutError) {
					}

					stopProgress();
					showToast(error.getMessage());
				}
			});

			//To EXPERIMENT. Enable response caching to quickly fetch the response from cache, if set true.
			//Volley decides whether to cache the response or not, based on response headers obtained. Some of the parameters
			//to look for are Cache-control,maxAge, Expires.
			//
			//In case of weather api, the response headers has "Cache-Control: no-cache, must-revalidate" In this case, even if 
			//setShouldCache() api is set true, Volley decides not to store the response, because server has sent response headers as "must-revalidate"
			//So storing response doesn't make sense in this api. Some of these intelligences are implemented already in Volley, you need not take the burden of
			//parsing response headers.
			
			stringRequest.setShouldCache(true);
			stringRequest.setTag(TAG_REQUEST);	
			mVolleyQueue.add(stringRequest);
 	}
}