I put together an RSS reader that works as-is but, I want to setup the connection to the RSS URL using HttpUrlConnection method. When I tried it, the program locked up after I clicked Read Rss button:
private class getRssFeedTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
try {
URL rssUrl = new URL(params[0]);
HttpURLConnection urlIn = (HttpURLConnection) rssUrl.openConnection();
InputStream in = new BufferedInputStream(urlIn.getInputStream());
String line;
feed = "";
while ((line = in.toString()) != null) {
feed += line;
}
in.close();
return feed;
} catch (MalformedURLException ue) {
System.out.println("Malformed URL");
} catch (IOException ioe) {
System.out.println("The URL is unreachable");
}
return null;
}
}
This is the connection method I am stuck using which works:
private class getRssFeedTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
try {
URL rssUrl = new URL(params[0]);
BufferedReader in = new BufferedReader(new InputStreamReader(rssUrl.openStream()));
String line;
feed = "";
while ((line = in.readLine()) != null) {
feed += line;
}
in.close();
return feed;
} catch (MalformedURLException ue) {
System.out.println("Malformed URL");
} catch (IOException ioe) {
System.out.println("The URL is unreachable");
}
return null;
}
}
Thanks for any help you can provide!
What you need to do is put it into a string I called it results. I have attached my code for the doInBackground. By adding it to a string it has a place to store the feed. And it works for the rss reader.
public String doInBackground(String... urls){
String result = "";
try{
URL url = new URL(urls[0]);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
InputStream in = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
String line = "";
while((line = reader.readLine()) != null){
result = result + line;
}
conn.disconnect();
}
catch(Exception e){
Log.e("ERROR Fetching ", e.toString());
}
return result;
}
Related
I am passing the url https://www.reddit.com/r/wallpapers/top/.json into my method for getting the JSON array of a subreddit. However, it only returns the JSON array for the hot category rather than the top or new categories. I have checked the URL and code thoroughly and have tried other different formats of the URL to only get the same results. For some reason all JSON gets all return only the hot page or default subreddit URL. But when I visit the URL in my browser that I've linked, it displays the correct JSON array for the top category. (Android Studio)
Here's the beginning of my JSON task that returns the array:
private class JsonTask extends AsyncTask<String, String, String> {
protected void onPreExecute() {
super.onPreExecute();
}
protected String doInBackground(String... params) {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = null;
try {
stream = connection.getInputStream();
} catch (Exception e) {
Log.e("Subreddit Closed", urlString);
connection.disconnect();
return null; //if can't retrieve JSON file
}
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
}
return buffer.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally {
if (connection != null) {
connection.disconnect();
}
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
Update: This was an issue with Reddit's API, it is now working as expected. Take caution of URL formats as */hot/.json is equivalent to */.json
I'm trying to make a mobile app that downloads info from the openweathermap.org apis. For example, if you feed that app this link: http://api.openweathermap.org/data/2.5/weather?q=Boston,us&appid=fed33a8f8fd54814d7cbe8515a5c25d7 you will get the information about the weather in Boston, MA. My code seems to work up to the point where I have to convert the input stream to a string variable. When I do that, I get garbage. Is there a particular way to do this seemingly simple task in a proper way? Here is my code so far...
private class DownloadWebpageTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
// params comes from the execute() call: params[0] is the url.
try {
return downloadUrl(urls[0]);
} catch (IOException e) {
return null;
}
}
// onPostExecute displays the results of the AsyncTask.
#Override
protected void onPostExecute(String result) {
TextView test = (TextView) findViewById(R.id.test);
if(result!=null) test.setText(result);
else{
Log.i(DEBUG_TAG, "returned result is null");}
}
}
private String downloadUrl(String myurl) throws IOException {
InputStream is = null;
try {
URL url = new URL(myurl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(10000 /* milliseconds */);
conn.setConnectTimeout(15000 /* milliseconds */);
conn.setRequestMethod("GET");
conn.setDoInput(true);
// Starts the query
conn.connect();
int response = conn.getResponseCode();
Log.i(DEBUG_TAG, "The response is: " + response);
is = conn.getInputStream();
String text = getStringFromInputStream(is);
//JSONObject json = new JSONObject(text);
//try (Scanner scanner = new Scanner(is, StandardCharsets.UTF_8.name())) {
//text = scanner.useDelimiter("\\A").next();
//}
//Bitmap bitmap = BitmapFactory.decodeStream(is);
return text;
}catch(Exception e) {
Log.i(DEBUG_TAG, e.toString());
}finally {
if (is != null) {
is.close();
}
}
return null;
}
private static String getStringFromInputStream(InputStream is) {
BufferedReader br = null;
StringBuilder sb = new StringBuilder();
String line;
try {
br = new BufferedReader(new InputStreamReader(is));
while ((line = br.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return sb.toString();
}
Check this library . Is An asynchronous callback-based Http client for Android built on top of Apache’s HttpClient libraries.
I have got problem with read output form request.
public JSONArray listLights()
{
try
{
URL adres = new URL("https://api.lifx.com/v1/lights/all");
HttpURLConnection polaczenie = (HttpURLConnection) adres.openConnection();
polaczenie.setRequestProperty("Authorization", "Bearer " + apiKey);
polaczenie.setRequestMethod("GET");
BufferedReader wejscie = new BufferedReader(new InputStreamReader((polaczenie.getInputStream())));
StringBuilder odpowiedz = new StringBuilder();
String json;
while ((json = wejscie.readLine()) != null)
odpowiedz.append(json);
wejscie.close();
return new JSONArray(odpowiedz.toString());
}
catch (Exception wyjatek)
{
wyjatek.printStackTrace();
}
return new JSONArray();
}
StackTrace
I added to AndroidManifest Internet access too.
Welcome to leave any comments. :P
EDIT:
I google internet and found partial solution. Added AsyncTask, but now I'm receiving '429' response code.
public class JSONTask extends AsyncTask<String, String, String>
{
String apiKey = "blah_blah_blah";
String txtresult;
#Override
protected String doInBackground(String... params) {
HttpsURLConnection connection = null;
BufferedReader reader = null;
try
{
URL adres = new URL(params[0]);
HttpsURLConnection polaczenie = (HttpsURLConnection) adres.openConnection();
polaczenie.setRequestProperty("Authorization", "Bearer " + apiKey);
polaczenie.setRequestMethod("GET");
System.out.println(polaczenie.getResponseCode());
InputStream stream = polaczenie.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null)
{
buffer.append(line);
}
return buffer.toString();
}
catch (MalformedURLException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
finally {
if (connection != null)
connection.disconnect();
try
{
if (reader != null)
reader.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
return null;
}
#Override
protected void onPostExecute(String s)
{
super.onPostExecute(s);
widok.setText(s);
}
}
My current StackTrace
EDIT2:
New day, new surprise. I figure out that I'm making connection with Bulb once/twice on every 10 attempts. Any ideas?
HTTP Status code 429 means too many requests in a given an amount of time. So how many requests exactly are you doing?
android.os.NetworkOnMainThreadException it means, that You have to make a htttp request from another threat than UIthread. Why are you using async task ?
Edit: You can also try make a call from postman and maybe You will see the problem.
In the end, everything is working. Problem was on the side of bulb or Lifx Cloud.
i would like to write data in an external mysql database with my android app.
this class works for that:
public class SendingData extends AppCompatActivity {
Intent intent = null;
private class LoadingDataURL extends AsyncTask<String, String, JSONArray> {
#Override
protected JSONArray doInBackground(String... params) {
URL url;
HttpURLConnection urlConnection = null;
JSONArray response = new JSONArray();
try {
url = new URL(params[0]);
urlConnection = (HttpURLConnection) url.openConnection();
int responseCode = urlConnection.getResponseCode();
String responseString = readStream(urlConnection.getInputStream());
intent = new Intent(SendingData.this, Overview.class);
startActivity(intent);
response = new JSONArray(responseString);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (urlConnection != null)
urlConnection.disconnect();
}
return response;
}
private String readStream(InputStream in) {
BufferedReader reader = null;
StringBuffer response = new StringBuffer();
try {
reader = new BufferedReader(new InputStreamReader(in, "UTF-8"));
String line = "";
while ((line = reader.readLine()) != null) {
response.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return response.toString();
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loading_data);
String firstname = "Max";
String secondname= "Mustermann";
LoadingDataURL client = new LoadingDataURL();
client.execute("https://domain.com/index.php?"+
"fristname="+fristname+
"&secondname="+secondname);
}
}
My Problem is, that if in my strings (fristname, secondname) is an & or ? or any special characters, the entry will not be save correctly.
any ideas? :)
Use the URLEncoder class.
Try this please
String fn = URLEncoder.encode(fristname, "utf-8");
String sn = URLEncoder.encode(secondname, "utf-8");
LoadingDataURL client = new LoadingDataURL();
client.execute("https://domain.com/index.php?"+
"fristname=" + fn + "&secondname=" + sn);
Note: Don't encode the full url, just the parameter values.
The code pasted below was taken from Javadocs on HttpURLConnection.
I get the following error:
readStream(in)
...as there is no such method.
I see this same thing in the Class Overview for URLConnection at
URLConnection.getInputStream
Where is readStream? The code snippet is provided below:
URL url = new URL("http://www.android.com/");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
try
{
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
readStream(in); <-----NO SUCH METHOD
}
finally
{
urlConnection.disconnect();
}
Try with this code:
InputStream in = address.openStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(in));
StringBuilder result = new StringBuilder();
String line;
while((line = reader.readLine()) != null) {
result.append(line);
}
System.out.println(result.toString());
It looks like the documentation is just using readStream() to mean:
Ok, we've shown you how to get the InputStream, now your code goes in readStream()
So you should either write your own readStream() method which does whatever you wanted to do with the data in the first place.
Spring has an util class for that:
import org.springframework.util.FileCopyUtils;
InputStream is = connection.getInputStream();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
FileCopyUtils.copy(is, bos);
String data = new String(bos.toByteArray());
try this code
String data = "";
InputStream iStream = httpEntity.getContent();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream, "utf8"));
StringBuffer sb = new StringBuffer();
String line = "";
while ((line = br.readLine()) != null) {
sb.append(line);
}
data = sb.toString();
System.out.println(data);
a complete code for reading from a webservice in two ways
public void buttonclick(View view) {
// the name of your webservice where reactance is your method
new GetMethodDemo().execute("http://wervicename.nl/service.asmx/reactance");
}
public class GetMethodDemo extends AsyncTask<String, Void, String> {
//see also:
// https://developer.android.com/reference/java/net/HttpURLConnection.html
//writing to see: https://docs.oracle.com/javase/tutorial/networking/urls/readingWriting.html
String server_response;
#Override
protected String doInBackground(String... strings) {
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL(strings[0]);
urlConnection = (HttpURLConnection) url.openConnection();
int responseCode = urlConnection.getResponseCode();
if (responseCode == HttpURLConnection.HTTP_OK) {
server_response = readStream(urlConnection.getInputStream());
Log.v("CatalogClient", server_response);
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
url = new URL(strings[0]);
urlConnection = (HttpURLConnection) url.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(
urlConnection.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null)
System.out.println(inputLine);
in.close();
Log.v("bufferv ", server_response);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
Log.e("Response", "" + server_response);
//assume there is a field with id editText
EditText editText = (EditText) findViewById(R.id.editText);
editText.setText(server_response);
}
}