Develop Reference

Android currency converter application

I'm working on a big program for Android and I'm trying to get the currency converter part of the program to work. For full disclosure: I found it from http://firstamong.com/building-android-currency-converter/, and it's a tutorial on how to build a real-time currency converter. I'll post the code in question followed by the logcat. The error that occurs is when I try to convert from one currency to another, the application says it was forced to stop. However, the "Invalid" portion works (the case where both currency fields are the same.) Any help would truly be appreciated:
Code:
public class currency_converter extends Activity {
public int to;
public int from;
public String [] val;
public String s;
public Handler handler;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_currency_converter);
Spinner s1 = (Spinner) findViewById(R.id.spinner1);
Spinner s2 = (Spinner) findViewById(R.id.spinner2);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this, R.array.name, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice);
val = getResources().getStringArray(R.array.value);
s1.setAdapter(adapter);
s2.setAdapter(adapter);
s1.setOnItemSelectedListener(new spinOne(1));
s2.setOnItemSelectedListener(new spinOne(2));
Button b = (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
TextView t = (TextView) findViewById(R.id.textView4);
if(from == to)
{
Toast.makeText(getApplicationContext(), "Invalid", 4000).show();
}
else
{
try {
s = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22"+val[from]+val[to]+"%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");
JSONObject jObj;
jObj = new JSONObject(s);
String exResult = jObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");
t.setText(exResult);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
});
}
public String getJson(String url)throws ClientProtocolException, IOException {
StringBuilder build = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
HttpResponse response = client.execute(httpGet);
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(content));
String con;
while ((con = reader.readLine()) != null) {
build.append(con);
}
return build.toString();
}
private class spinOne implements OnItemSelectedListener
{
int ide;
spinOne(int i)
{
ide =i;
}
public void onItemSelected(AdapterView<?> parent, View view,
int index, long id) {
if(ide == 1)
from = index;
else if(ide == 2)
to = index;
}
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
class GetResponseData extends AsyncTask<String, String, String> {
private ProgressDialog dialog;
private ArrayList<String> titleList;
private TextView textView;
public GetResponseData(TextView textView) {
this.textView = textView;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
dialog = ProgressDialog.show(currency_converter.this, "", "Loading",
false);
}
#Override
protected String doInBackground(String... params) {
try {
String s = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22" + val[from] + val[to] + "%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");
JSONObject jObj;
jObj = new JSONObject(s);
String exResult = jObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");
return exResult;
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (dialog != null)
dialog.dismiss();
if (result != null) {
textView.setText(result);
}
}
}
}
}
Logcat:
10-30 00:59:48.164 20591-20591/com.example.travelapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1128)
at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:365)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:587)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:511)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:489)
at com.example.travelapplication.currency_converter.getJson(currency_converter.java:93)
at com.example.travelapplication.currency_converter$1.onClick(currency_converter.java:68)
at android.view.View.performClick(View.java:4222)
at android.view.View$PerformClick.run(View.java:17620)
at android.os.Handler.handleCallback(Handler.java:800)
at android.os.Handler.dispatchMessage(Handler.java:100)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5391)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:525)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)

Try this,,
Your performing a networking operation on its main thread. That why your getting NetworkOnMainThreadException
b.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
TextView t = (TextView) findViewById(R.id.textView4);
if(from == to)
{
Toast.makeText(getApplicationContext(), "Invalid", 4000).show();
}
else
{
GetResponseData abcd = GetResponseData(t);
abcd.execute();
}
}
});

You are getting:
NetworkOnMainThreadException
Issue is that you are calling your function getJson() in your Activity.
Use AsyncTask:
public class ProcessTask extends AsyncTask<Void, Integer, String>{
public ProcessTask() {
// TODO Auto-generated constructor stub
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
}
#Override
protected String doInBackground(Void... params) {
// TODO Auto-generated method stub
//your code of parsing
StringBuilder build = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url); //your yahooapi url goes here
HttpResponse response = client.execute(httpGet);
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(content));
String con;
while ((con = reader.readLine()) != null) {
build.append(con);
}
return build.toString();
}
#Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
}
}

It looks like you have strict mode on in your android manifest. Strict mode will complain when you are doing network calls on you main thread. You can just disable strict mode or a better approach is to put your network call into an async task. The network call in question is
HttpResponse response = client.execute(httpGet);
inside public String getJson(String url)
The async task you need is already there you just need to use it
Change this else statement
else
{
try {
s = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22"+val[from]+val[to]+"%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");
JSONObject jObj;
jObj = new JSONObject(s);
String exResult = jObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");
t.setText(exResult);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
To this
else {
new GetResponseData().execute("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22"+val[from]+val[to]+"%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");
}

It will help use this :
public class CurrencyConverter extends Fragment {
public CurrencyConverter() {
}
TextView t;
public int to;
public int from;
public String[] val;
public String s;
String exResult;
public Handler handler;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.currency_converter, container, false);
t= (TextView) rootView.findViewById(R.id.textView4);
Spinner s1 = (Spinner) rootView.findViewById(R.id.spinner1);
Spinner s2 = (Spinner) rootView.findViewById(R.id.spinner2);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
this.getActivity(), R.array.name, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice);
val = getResources().getStringArray(R.array.value);
s1.setAdapter(adapter);
s2.setAdapter(adapter);
s1.setOnItemSelectedListener(new spinOne(1));
s2.setOnItemSelectedListener(new spinOne(2));
Button b = (Button) rootView.findViewById(R.id.button1);
b.setOnClickListener(new View.OnClickListener() {
public void onClick(View View) {
if (from == to) {
Toast.makeText(getActivity().getApplicationContext(), "Invalid", 4000).show();
} else {
new calculate().execute();
}
}
});
return rootView;
}
public class calculate extends AsyncTask<String, String, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... args) {
try {
s = getJson("http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20yahoo.finance.xchange%20where%20pair%20in%20(%22"+val[from]+val[to]+"%22)&format=json&diagnostics=true&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=");
JSONObject jObj;
jObj = new JSONObject(s);
exResult = jObj.getJSONObject("query").getJSONObject("results").getJSONObject("rate").getString("Rate");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return exResult;
}
#Override
protected void onPostExecute(String exResult) {
t.setText(exResult);
}
}
public String getJson(String url)throws IOException {
StringBuilder build = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
HttpResponse response = client.execute(httpGet);
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(content));
String con;
while ((con = reader.readLine()) != null) {
build.append(con);
}
return build.toString();
}
public class spinOne implements AdapterView.OnItemSelectedListener
{
int ide;
spinOne(int i)
{
ide =i;
}
public void onItemSelected(AdapterView<?> parent, View view,
int index, long id) {
if(ide == 1)
from = index;
else if(ide == 2)
to = index;
}
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
}
}

Check if URL exists or not on Server

This is my code which I am using to verify, URL exists or not on Server, but always getting not exist however link is alive
Where I am doing mistake in my code, why I am always getting "doesnot exist !"
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String customURL = "http://www.desicomments.com/dc3/08/273858/273858.jpg";
boolean bResponse = exists(customURL);
if (bResponse==true)
{
Toast.makeText(MainActivity.this, "File exists!", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(MainActivity.this, "File does not exist!", Toast.LENGTH_SHORT).show();
}
}
public static boolean exists(String URLName){
try {
HttpURLConnection.setFollowRedirects(false);
HttpURLConnection con = (HttpURLConnection) new URL(URLName).openConnection();
con.setRequestMethod("HEAD");
return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
}
catch (Exception e) {
e.printStackTrace();
return false;
}
}
}

You will get Network On Main Thread Exception
Look at NetworkOnMainThreadException
so your method always returns false because of:
catch (Exception e) {
e.printStackTrace();
return false;
}
quick fix:
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String customURL = "http://www.desicomments.com/dc3/08/273858/273858.jpg";
MyTask task = new MyTask();
task.execute(customURL);
}
private class MyTask extends AsyncTask<String, Void, Boolean> {
#Override
protected void onPreExecute() {
}
#Override
protected Boolean doInBackground(String... params) {
try {
HttpURLConnection.setFollowRedirects(false);
HttpURLConnection con = (HttpURLConnection) new URL(params[0]).openConnection();
con.setRequestMethod("HEAD");
System.out.println(con.getResponseCode());
return (con.getResponseCode() == HttpURLConnection.HTTP_OK);
}
catch (Exception e) {
e.printStackTrace();
return false;
}
}
#Override
protected void onPostExecute(Boolean result) {
boolean bResponse = result;
if (bResponse==true)
{
Toast.makeText(MainActivity.this, "File exists!", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(MainActivity.this, "File does not exist!", Toast.LENGTH_SHORT).show();
}
}
}
}
With a ScheduledThreadPoolExecutor:
but remember to shut down it!!
public class MainActivity extends Activity {
String customURL;
String msg = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
customURL = "http://www.desicomments.com/dc3/08/273858/273858.jpg";
final ScheduledThreadPoolExecutor myTimer = new ScheduledThreadPoolExecutor(1);
myTimer.scheduleAtFixedRate(new Runnable() {
#Override
public void run() {
try {
HttpURLConnection.setFollowRedirects(false);
HttpURLConnection con = (HttpURLConnection) new URL(customURL).openConnection();
con.setRequestMethod("HEAD");
System.out.println(con.getResponseCode());
if(con.getResponseCode() == HttpURLConnection.HTTP_OK){
msg = "File exist!";
}else{
msg = "File does not exist!";
}
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(MainActivity.this, msg, Toast.LENGTH_SHORT).show();
}
});
}
catch (Exception e) {
e.printStackTrace();
return;
}
}
}, 0,10000, TimeUnit.MILLISECONDS);
}

Change your exists() to this
public boolean exists(String url){
HttpURLConnection huc = ( HttpURLConnection ) url.openConnection ();
huc.setRequestMethod ("GET"); //OR huc.setRequestMethod ("HEAD");
huc.connect () ;
int code = huc.getResponseCode() ;
System.out.println(code);
if(code==200)
return true;
else
return false;
}

Use if(bResponse) instead of if(bResponse==true)

you can use the follow code to try.
final String customURL = "http://www.desicomments.com/dc3/08/273858/273858.jpg";
new Thread(){
#Override
public void run() {
// TODO Auto-generated method stub
super.run();
try {
URL url = new URL(customURL);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("HEAD");
con.connect();
Log.i(TAG, "con.getResponseCode() IS : " + con.getResponseCode());
if(con.getResponseCode() == HttpURLConnection.HTTP_OK){
Log.i(TAG, "Sucess");
}
} catch (Exception e) {
e.printStackTrace();
Log.i(TAG, "fail");
}
}
}.start();
Reason: After android 2.3, you can't perform a networking operation on its main thread,
if you do so, there will be can exception and you can't get the right result.
So if you want the application to perform a networking operation, you can use another Thread to do it.

I use this code to verify url alive. I have tested this code with image url
Example:
url = "https://ima.vn/wp-content/uploads/2017/11/ima-sofa-titan-trungkinh-1-of-3.jpg"
message = "Image url";
public void assertUrlalive(String url, String message) {
try {
URL myUrl = new URL(url);
HttpURLConnection huc = (HttpURLConnection) myUrl.openConnection();
assertEquals(huc.getResponseCode(), 200, message);
} catch (IOException e) {
e.printStackTrace();
logger.error("Connection Err: " + e.getMessage());
}
}

UDP holepunching: PC-to-Android UDP connection does not work with nonlocal addresses

I wrote a simple UDP transfer between an Android App and Python Server. I know that the system is working because when I try to connect on a local ip address (192.168.X.X), the correct message is sent and recieved. However, this does not work when I try to use a public IP address. Does anyone know why and how I can try to fix this?
I am trying to implement UDP holepunching, having the server act as the target client of the Android one, but I cannot get the 2nd client's UDP packet to the Android one, it never gets picked up on the Android's side. Would having a 2nd machine act as the 2nd client fix this, or is my code incomplete?
Does my provider (T-Mobile) matter for UDP packet communication?
Client (Android):
public class CustomizeGatewayActivity extends ActionBarActivity {
AsyncUDPReceiver aReceive = null;
static TextView recieve = null;
public static class PlaceholderFragment extends Fragment {
EditText addressText, portText, messageText;
Button udpsend, tcpsend;
Socket socket = null;
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(
R.layout.fragment_customize_gateway, container, false);
recieve = (TextView) rootView.findViewById(R.id.textView1);
addressText = (EditText) rootView.findViewById(R.id.editText1);
messageText = (EditText) rootView.findViewById(R.id.editText3);
udpsend = (Button) rootView.findViewById(R.id.UDP);
udpsend.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
AsyncUDPSend aSend = new AsyncUDPSend(addressText.getText().toString(), messageText.getText().toString());
aSend.execute();
}
});
public class AsyncUDPSend extends AsyncTask<Void, Void, Void> {
String address = "";
String message = "";
String response = "";
AsyncUDPSend(String addr, String mes) {
address = addr;
message = mes;
}
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
DatagramSocket dsocket = null;
try {
dsocket = new DatagramSocket();
dsocket.setSoTimeout(10000);
InetAddress dest = InetAddress.getByName(address);
DatagramPacket packet = new DatagramPacket(message.getBytes(), message.length(), dest, 5001);
dsocket.send(packet);
System.out.println("Sent");
byte[] resp = new byte[1024];
DatagramPacket recv = new DatagramPacket(resp, resp.length);
System.out.println("Waitng for Response");
dsocket.receive(recv);
System.out.println("Received");
response = new String(recv.getData());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
response = "IOException: " + e.toString();
System.out.println(response);
} finally {
if (dsocket != null) {
dsocket.close();
}
}
return null;
}
#Override
protected void onPostExecute(Void result) {
recieve.setText(response);
super.onPostExecute(result);
}
}
#Override
protected void onResume() {
super.onResume();
aReceive = new AsyncUDPReceiver();
aReceive.start();
}
#Override
protected void onPause() {
super.onPause();
aReceive.kill();
}
public class AsyncUDPReceiver extends Thread {
boolean keepRunning = true;
String response = "";
Runnable updateText = new Runnable(){
public void run() {
if(aReceive == null && recieve == null)
return;
recieve.setText(response);
}
};
public void run() {
android.os.Debug.waitForDebugger();
System.out.println("running");
DatagramSocket dsock = null;
byte[] message = new byte[1024];
DatagramPacket dpack = new DatagramPacket(message, message.length);
try {
dsock = new DatagramSocket(5002);
System.out.println(dsock.toString());
while(keepRunning) {
dsock.receive(dpack);
response = new String(dpack.getData());
System.out.println(response);
runOnUiThread(updateText);
}
} catch (SocketException e) {
// TODO Auto-generated catch block
response = "SocketException: " + e.toString();
System.out.println(response);
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
response = "IOException: " + e.toString();
System.out.println(response);
e.printStackTrace();
} finally {
if(dsock != null)
dsock.close();
}
}
public void kill() {
keepRunning = false;
}
}
}
Server (Python):
class ThreadedUDPRequestHandler(socketserver.BaseRequestHandler):
def handle(self):
data = self.request[0].strip().decode("utf-8")
print("{} Recieved: ".format(self.client_address) + data)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
response = data.upper()
sock.sendto(bytes(response, "utf-8"), self.client_address)
print("{} Sent: {}".format(self.client_address,response))
class ThreadedUDPServer(socketserver.ThreadingMixIn, socketserver.UDPServer):
pass
if __name__ == "__main__":
# Port 0 means to select an arbitrary unused port
HOST, PORT = "", 5000
udpserver = ThreadedUDPServer((HOST,PORT+1), ThreadedUDPRequestHandler)
udp_thread = threading.Thread(target=udpserver.serve_forever)
udp_thread.daemon = True
udp_thread.start()
print("UDP serving at port", PORT+1)
while True:
pass
udpserver.shutdown()

Are you supplying the expected value to InetAddress.getByName(address);
Also since you are trying to do something in background,it will be better if you run a service with wake lock so that you eliminate errors caused due to killing of process.

Start timer after button click

I want to start timer after clicking on Button and poll for every 3 secs.
I am using following code.
private EditText url;
private Button submit;
private TextView error;
String some_URL;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_live);
loadviews();
handler=new Handler();
submit.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
some_URL="http://"+url.getText().toString();
getStatus();
}
}
});
private void getStatus() {
// TODO Auto-generated method stub
handler.postDelayed(new Runnable(){
#Override
public void run() {
// TODO Auto-generated method stub
new Class_Poll().execute(some_URL);
error.setText("ID:"+ID+"\n"+
"Name:"+name+"\n" +
"Type:"+type+"\n"+
"Status:"+Status+"\n"+
"Content:"+Content);
}
}, 3000);
}
}
private void loadviews() {
// TODO Auto-generated method stub
url=(EditText)findViewById(R.id.url);
submit=(Button)findViewById(R.id.Submit);
error=(TextView)findViewById(R.id.log);
error.setMovementMethod(new ScrollingMovementMethod());
}
private class Class_Poll extends AsyncTask<String, Void, Void>{
private final HttpClient Client = new DefaultHttpClient();
#Override
protected Void doInBackground(String... arg0) {
// TODO Auto-generated method stub
Content=executeHttpRequest(some_URL);
return null;
}
#Override
protected void onPostExecute(Void unused) {
JSONObject jsonResponse;
try {
jsonResponse = new JSONObject(Content);
ID=jsonResponse.optString("ID").toString();
name=jsonResponse.optString("Name").toString();
type=jsonResponse.optString("Type").toString();
Status=jsonResponse.optString("Status").toString();
error.setText("ID:"+ID+"\n"+
"Name:"+name+"\n" +
"Type:"+type+"\n"+
"Status:"+Status+"\n"+
"Content:"+Content);
} catch (JSONException e) {
error.setText(e.toString());
}
//Toast.makeText(getApplicationContext(), "ID:"+ID+" Name:"+name+" Type:"+type+" Status:"+Status, Toast.LENGTH_LONG).show();
}
}
public static String executeHttpRequest(String url)
{
HttpURLConnection urlConnection = null;
try
{
URL httpUrl = new URL(url);
urlConnection = (HttpURLConnection) httpUrl.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.addRequestProperty("Accept", "text/html,text/xhtml,application/xhtml+xml,application/xml;");
urlConnection.setConnectTimeout(10000);
InputStream in = null;
try
{
in = urlConnection.getInputStream();
} catch (NullPointerException e)
{
Log.e("Check", "Request Failed, Check the url");
return null;
}
if (in != null)
{
in = new BufferedInputStream(in);
String response = readStream(in);
Log.e("Check", response + "");
if (response != null && !response.isEmpty())
{
// statusTrace.print(TAG, "Operation executed : " +
// isSuccess(response));
return response;
}
else
{
Log.e("Check", "Request Failed");
}
} else
;//statusTrace.print(TAG, "Request Failed");
} catch (IOException e)
{
Log.e("Check", "Error : " + e.toString());
//statusTrace.print("Error", "Network Error. Check connection and Tuxedo IP");
}
return null;
}
public static String readStream(InputStream in)throws IOException {
// TODO Auto-generated method stub
InputStreamReader is = new InputStreamReader(in);
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(is);
String read = br.readLine();
while (read != null)
{
sb.append(read);
read = br.readLine();
}
return sb.toString();
}
error is TextView in which I am displaying some Text.
And I am invoking web service in Asyntask. So it is not executing asynchtask for delay of 3 seconds after button click.
I don't know where know what is the problem exactly. It should execute actually, my textview is not getting updated for each 3 seconds.

Timer runs on a different thread you should not invoke AsyncTask from a background thread.
Please read Threading rules #
http://developer.android.com/reference/android/os/AsyncTask.html
public void scheduleAtFixedRate (TimerTask task, long delay, long period)
Added in API level 1
Schedule a task for repeated fixed-rate execution after a specific delay has passed.
Parameters
task the task to schedule.
delay amount of time in milliseconds before first execution.
period amount of time in milliseconds between subsequent executions.
Throws
IllegalArgumentException if delay < 0 or period <= 0.
IllegalStateException if the Timer has been canceled, or if the task has been scheduled or canceled.
Your delay is 0. See this }, 0, 3000);
can you suggest me an alternative to this so that I can execute
AsynchTask at after 3 secs of delay??
I assume you want to invoke asynctask after a 3 sec delay
You can use a Handler
Handler handler = new Handler():
handler.postDelayed(new Runnable(){
#Override
public void run() {
// run something after 3 sec delay
}
}, 3000);
Edit:
public class MainActivity extends Activity
{
private EditText url;
private Button submit;
private TextView error;
String Content;
String some_URL;
Handler handler;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_live);
loadviews();
handler=new Handler();
submit.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
some_URL="http://"+url.getText().toString();
getStatus();
}
});
}
private void getStatus() {
// TODO Auto-generated method stub
handler.postDelayed(new Runnable(){
#Override
public void run() {
new Class_Poll().execute(some_URL);
}
}, 3000);
}
private void loadviews() {
// TODO Auto-generated method stub
url=(EditText)findViewById(R.id.url);
submit=(Button)findViewById(R.id.Submit);
error=(TextView)findViewById(R.id.log);
error.setMovementMethod(new ScrollingMovementMethod());
}
private class Class_Poll extends AsyncTask<String, Void, String>{
#Override
protected String doInBackground(String... arg0) {
String _response;
try
{
HttpClient httpclient = new DefaultHttpClient();
HttpGet request = new HttpGet(arg0[0]);
HttpResponse response = httpclient.execute(request);
HttpEntity resEntity = response.getEntity();
}catch(Exception e)
{
e.printStackTrace();
}
return _response;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
JSONObject jsonResponse;
try {
jsonResponse = new JSONObject(result);
String ID=jsonResponse.optString("ID").toString();
String name=jsonResponse.optString("Name").toString();
String type=jsonResponse.optString("Type").toString();
String Status=jsonResponse.optString("Status").toString();
error.setText("ID:"+ID+"\n"+
"Name:"+name+"\n" +
"Type:"+type+"\n"+
"Status:"+Status+"\n"+
"Content:"+Content);
} catch (JSONException e) {
error.setText(e.toString());
}
}
}
}

Fetching and setting images in listView via HTTP

I am making an app that loads images via internet to a ListView. It is built on sdk 15 with an minimum of 8. Everything works fine if i run it on an emulator with version 8, but if i run it on anything with an sdk of 11 and up the app fails to set the images in the ListView and it then only displays an empty list. Logcat doesn't give anything on this.
I haven't had any succes finding an article addressing this issue, but i think it most be something with the HTTP that is suppose to get the images from the internet, but i don't understand why they don't work on the newer versions of android.
My code looks like this.
EDIT UPDATED CODE:
public class MainActivity extends Activity {
static ArrayList<Tumblr> tumblrs;
ListView listView;
TextView footer;
int offset = 0;
ProgressDialog pDialog;
View v;
String responseBody;
HttpResponse r;
HttpEntity e;
String searchUrl;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
}
final ConnectivityManager conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkInfo activeNetwork = conMgr.getActiveNetworkInfo();
if (activeNetwork != null && activeNetwork.isConnected()) {
setContentView(R.layout.main);
try {
tumblrs = getTumblrs();
listView = (ListView) findViewById(R.id.list);
View v = getLayoutInflater().inflate(R.layout.footer_layout,
null);
footer = (TextView) v.findViewById(R.id.tvFoot);
listView.addFooterView(v);
listView.setAdapter(new UserItemAdapter(this, R.layout.listitem));
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
new GetChicks().execute();
footer.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new loadMoreListView().execute();
}
});
} else {
setContentView(R.layout.nonet);
}
}
public class UserItemAdapter extends ArrayAdapter<Tumblr> {
public UserItemAdapter(Context context, int imageViewResourceId) {
super(context, imageViewResourceId, tumblrs);
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
v = convertView;
if (v == null) {
LayoutInflater vi = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v = vi.inflate(R.layout.listitem, null);
}
Tumblr tumblr = tumblrs.get(position);
if (tumblr != null) {
ImageView image = (ImageView) v.findViewById(R.id.avatar);
if (image != null) {
image.setImageBitmap(GetImage_usingURl(urls[position]));
}
}
return v;
}
}
String[] urls = new String[] { "url1", "url2", "url2" };
public Bitmap GetImage_usingURl(String BitmapUrl) {
try {
Log.d("Image Download State", " Open Stream For : " + BitmapUrl);
InputStream in = new java.net.URL(BitmapUrl).openStream();
Log.d("Image Download State", " Start Decode");
return BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", "" + e.getMessage());
return null;
}
}
public ArrayList<Tumblr> getTumblrs() throws ClientProtocolException,
IOException, JSONException {
searchUrl = "http://api.tumblr.com/v2/blog/factsandchicks.com/posts?api_key=rTZsymOWtMudbb5tql2U20qQ5ooYLPYVNnL3COPpO2qBHDxJUu&limit=2&offset=0";
ArrayList<Tumblr> tumblrs = new ArrayList<Tumblr>();
return tumblrs;
}
private class GetChicks extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
// Showing progress dialog before sending http request
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Chicks coming up..");
pDialog.setIndeterminate(true);
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... unused) {
// TODO Auto-generated method stub
HttpParams params = new BasicHttpParams();
params.setParameter(CoreProtocolPNames.PROTOCOL_VERSION,
HttpVersion.HTTP_1_1);
HttpClient client = new DefaultHttpClient(params);
HttpGet get = new HttpGet(searchUrl);
HttpResponse r = null;
try {
r = client.execute(get);
int status = r.getStatusLine().getStatusCode();
if (status == 200) {
e = r.getEntity();
responseBody = EntityUtils.toString(e);
}
} catch (ClientProtocolException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
JSONObject jsonObject;
try {
jsonObject = new JSONObject(responseBody);
JSONArray posts = jsonObject.getJSONObject("response")
.getJSONArray("posts");
for (int i = 0; i < posts.length(); i++) {
JSONArray photos = posts.getJSONObject(i).getJSONArray(
"photos");
for (int j = 0; j < photos.length(); j++) {
JSONObject photo = photos.getJSONObject(j);
String url = photo.getJSONArray("alt_sizes")
.getJSONObject(0).getString("url");
Tumblr tumblr = new Tumblr(url);
tumblrs.add(tumblr);
}
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void unused) {
// Setting new scroll position
listView.setSelectionFromTop(0, 0);
pDialog.dismiss();
}
}
public class Tumblr {
public String image_url;
public Tumblr(String url) {
this.image_url = url;
}
}
private class loadMoreListView extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
// Showing progress dialog before sending http request
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("More chicks coming up..");
pDialog.setIndeterminate(true);
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... unused) {
// TODO Auto-generated method stub
// increment current page
offset += 2;
// Next page request
tumblrs.clear();
String searchUrl = "http://api.tumblr.com/v2/blog/factsandchicks.com/posts?api_key=rTZsymOWtMudbb5tql2U20qQ5ooYLPYVNnL3COPpO2qBHDxJUu&limit=2&offset="
+ offset;
HttpParams params = new BasicHttpParams();
params.setParameter(CoreProtocolPNames.PROTOCOL_VERSION,
HttpVersion.HTTP_1_1);
HttpClient client = new DefaultHttpClient();
HttpGet get = new HttpGet(searchUrl);
HttpResponse r = null;
try {
r = client.execute(get);
int status = r.getStatusLine().getStatusCode();
if (status == 200) {
HttpEntity e = r.getEntity();
responseBody = EntityUtils.toString(e);
}
} catch (ClientProtocolException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
JSONObject jsonObject;
try {
jsonObject = new JSONObject(responseBody);
JSONArray posts = jsonObject.getJSONObject("response")
.getJSONArray("posts");
for (int i = 0; i < posts.length(); i++) {
JSONArray photos = posts.getJSONObject(i).getJSONArray(
"photos");
for (int j = 0; j < photos.length(); j++) {
JSONObject photo = photos.getJSONObject(j);
String url = photo.getJSONArray("alt_sizes")
.getJSONObject(0).getString("url");
Tumblr tumblr = new Tumblr(url);
tumblrs.add(tumblr);
}
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Void unused) {
// Setting new scroll position
listView.setSelectionFromTop(0, 0);
pDialog.dismiss();
}
}
#Override
public boolean onCreateOptionsMenu(android.view.Menu menu) {
// TODO Auto-generated method stub
super.onCreateOptionsMenu(menu);
MenuInflater blowUp = getMenuInflater();
blowUp.inflate(R.menu.cool_menu, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// TODO Auto-generated method stub
switch (item.getItemId()) {
case R.id.aboutUs:
Intent i = new Intent("com.example.example.ABOUT");
startActivity(i);
break;
case R.id.refresh:
Intent f = new Intent(MainActivity.this, MainActivity.class);
startActivity(f);
finish();
break;
case R.id.exit:
finish();
break;
}
return false;
}
}
LOG
10-09 13:21:57.923: D/Image Download State(888): Open Stream For : url1
10-09 13:21:57.923: E/Error(888): Protocol not found: url1
10-09 13:21:58.013: D/Image Download State(888): Open Stream For : url2
10-09 13:21:58.033: E/Error(888): Protocol not found: url2
10-09 13:21:58.113: D/Image Download State(888): Open Stream For : url1
10-09 13:21:58.123: E/Error(888): Protocol not found: url1
10-09 13:21:58.153: D/Image Download State(888): Open Stream For : url2
10-09 13:21:58.153: E/Error(888): Protocol not found: url2

For Images From internet Try this Could Help you:
if you want to download when you create adapter .
String[] urls=new String[]{"url1","url2","url2"}
public Bitmap GetImage_usingURl(String url){
try {
Log.d("Image Download State", " Open Stream For : "
+ url);
InputStream in = new java.net.URL(url).openStream();
Log.d("Image Download State", " Start Decode");
return BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.e("Error", e.getMessage());
return null;
e.printStackTrace();
}
}
And When You Create Adapet Just Use :
image.setImageBitmap(GetImage_usingURl(urls[position]);
Important Thing For Your Project You Have To Get Policy When You using HTTP its Only For API 9 or higher so i check VERSION.SDK_INT First .
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
}
if you don't set StrictMode you program maybe crash.
Set This Code Before Everything .
Your Errors Its :
In getView You Try To Check img!=null but you forget its create now and its already null
so compiler never get in and set your images , This is first thing .