Develop Reference

rest data getting cached android

I am using the code below to fetch data from server. When the data is updated on server, I get the old data from this method. When I use the same method in the web browser i get updated data.
Even when I stop the app and start again it reflects old data but when I have cleaned all my tasks using task manager, I get new data.
Is the data being cached on the device as i am making new request each time
String response = null;
InputStream inputStream = null;
HttpURLConnection urlConnection = null;
try {
URL url = new URL(urlString);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setReadTimeout(10000);
urlConnection.setConnectTimeout(15000);
if (method == POST) {
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.setRequestProperty("Accept", "application/json");
urlConnection.setRequestMethod("POST");
OutputStream os = urlConnection.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(params);
writer.flush();
writer.close();
os.close();
} else {
urlConnection.setRequestMethod("GET");
}
int statusCode = urlConnection.getResponseCode();
/* 200 represents HTTP OK */
if (statusCode == HttpURLConnection.HTTP_OK) {
inputStream = new BufferedInputStream(urlConnection.getInputStream());
response = convertInputStreamToString(inputStream);
return response;
}
I searched the web and found that use cache is on by default, so these two line might help
urlConnection.setUseCaches(false);
urlConnection.addRequestProperty("Cache-Control", "no-cache");

Append some random parameter i.e. current timestamp to the URL then it will treat as fresh request.
Change This
URL url = new URL(urlString);
To
URL url = new URL(urlString+new Date().getTime());

how can send a json frame to mysever hear i can reserve a json and i wnd send the data

I posted the code I used for reading the data from my server but I don't know how to send a json frame to the server.
I want to send the data string.
try {
URL url = new URL(params[0]);
con = (HttpURLConnection)url.openConnection();
con.connect();
InputStream in = con.getInputStream();
red = new BufferedReader(new InputStreamReader(in));
String line = "";
buffer = new StringBuffer();
while ((line=red.readLine())!= null){
buffer.append(line);
}
return buffer.toString();

I would assume that you are trying to post some JSON Object to a URL,
While using HttpURLConnection for connection you can set to its instance that this is a POST header request, if you are indeed posting something on that URL.
After that you can use DataOutputStream instance to write(POST) your JSON data something like this.
I have written a snippet which you can check, the code is also available on Github
private class MyTask extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
try {
/**
* Kindly change this url string with your own, where you want to post your json data
*/
URL url = new URL("");
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setDoOutput(true);
// when you are posting do make sure you assign appropriate header
// In this case POST.
httpURLConnection.setRequestMethod("POST");
httpURLConnection.connect();
// like this you can create your JOSN object which you want to send
JsonObject jsonObject = new JsonObject();
jsonObject.addProperty("email", "dddd#gmail.com"); //dummy data
jsonObject.addProperty("password", "password");// dummy data
// And this is how you will write to the URL
DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
wr.writeBytes(jsonObject.toString());
wr.flush();
wr.close();
Log.d("TAG", "" + IOUtils.toString(httpURLConnection.getInputStream()));
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
This code uses apache-common-io, to get the String from the input stream, if you would like you can change that.

HTTP url connection Android

I am having trouble getting my app to open a connection to the URL that is a JSON file online. I followed guidelines how out to get the inBackground thread to fetch the URL, though when I call .connect() on that URL it seems to return out of the inBackground function because I tested just having a String that would be modified and displayed as a Toast, and modifying the String right after httpConn.connect() caused no change at all. I made sure my permissions were right in the manifest, but perhaps there is something small I am overlooking.
protected String doInBackground(URL... urls){
InputStream in = null;
String result = "test";
int responseCode = -1;
try {
URL url = urls[0];
URLConnection urlConn = url.openConnection();
if (!(urlConn instanceof HttpURLConnection)) {
throw new IOException("URL is not an Http URL");
}
HttpURLConnection httpConn = (HttpURLConnection) urlConn;
httpConn.setRequestMethod("GET");
httpConn.setDoInput(true);
result = "get here";
httpConn.connect();
result = "don't get here";
responseCode = httpConn.getResponseCode();
if(responseCode == HttpURLConnection.HTTP_OK){
in = httpConn.getInputStream();
}
httpConn.disconnect();
result = readIt(in, 10);
return result;
}
catch (Throwable t){
t.printStackTrace();
}
return result;
}
Any ideas of what is causing there not to be any connection or how to test if I am simply overlooking or not completely understanding this? I can additional code if needed. Thank you

As I am getting ,You want to connect to a web url which returns json response .Am I right ? If yes then you need to visit this link for complete solution .

Android HTTPUrlConnection : how to set post data in http body?

I've already created my HTTPUrlConnection :
String postData = "x=val1&y=val2";
URL url = new URL(strURL);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
conn.setRequestProperty("Set-Cookie", sessionCookie);
conn.setRequestProperty("Content-Length", "" + Integer.toString(postData.getBytes().length));
// How to add postData as http body?
conn.setUseCaches(false);
conn.setDoInput(true);
conn.setDoOutput(true);
I don't know how to set postData in http body. How to do so? Would I better use HttpPost instead?
Thanks for your help.

If you want to send String only try this way:
String str = "some string goes here";
byte[] outputInBytes = str.getBytes("UTF-8");
OutputStream os = conn.getOutputStream();
os.write( outputInBytes );
os.close();
But if you want to send as Json change Content type to:
conn.setRequestProperty("Content-Type","application/json");
and now our str we can write:
String str = "{\"x\": \"val1\",\"y\":\"val2\"}";
Hope it will help,

Guruparan's link in the comment above gives a really nice answer to this question. I highly recommend looking at it. Here is the principle that makes his solution work:
From what I understand, the HttpURLConnection represents the response body as an OutputStream. So you need to call something like:
get the connection's output stream
OutputStream op = conn.getOuputStream();
write the response body
op.write( [/*your string in bit form*/] );
close the output stream
op.close();
and then carry on your merry way with the connection (which you will still need to close).

android :images not being displayed

I am making an android app in which i need to display the remote images in my app
my using following code.
but the images are not being displayed:
for(int i=0;i<stringOnTextView.length;i++){
imageUrl = "http://ondamove.it/English/images/users/";
imageUrl = imageUrl+stringOnTextView[i];
System.out.println(imageUrl);
URL myFileUrl = new URL(imageUrl);
HttpURLConnection conn= (HttpURLConnection)myFileUrl.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
bmImg = BitmapFactory.decodeStream(is);
image.setImageBitmap(bmImg);
System.out.println(bmImg.toString());
}
Can anyone tell me where is the problem. thanks

as a completion of my comment , see this three tutorials and you will find out what you should do :) :
tuto1
tuto2
tuto3