Develop Reference

Can't read from buffered reader in android

I am trying to get data by using API. I get data in bufferedreader which contains multiple lines. But I am not able to extract that in a String. I do know that bufferedreader has data, i have checked by displaying it using multiple .readLine(); but the loop doesn't work.
protected String[][] doInBackground(Cursor[] cursors)
{
String list[][] = new String[cursors[0].getCount()][2];
//while(cursors[0].moveToNext())
{
String DATA="",temp;
String baseAddress="http://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY";
String apiKey="J63P";
Uri Url = Uri.parse(baseAddress)
.buildUpon()
.appendQueryParameter("symbol","SBIN")
.appendQueryParameter("interval","1min")
.appendQueryParameter("apikey",apiKey)
.build();
Log.d("built URL",Url.toString());
try
{
url= new URL(Url.toString());
urlconnection= (HttpURLConnection) url.openConnection();
urlconnection.setRequestMethod("GET");
urlconnection.connect();
InputStream inputStream = urlconnection.getInputStream();
if (inputStream==null)
{
Log.d("inputstream","empty");
return null;
}
BufferedReader reader= new BufferedReader(new InputStreamReader(inputStream));
while((temp = reader.readLine())!=null)
{
DATA.concat(temp);
}
Log.d("unedited",DATA);
}
catch(IOException e)
{
Log.e("createList", "Error in url ", e);
return null;
}
try {
String List = "Time Series (1min)";
JSONObject full = new JSONObject(DATA);
JSONArray permin = full.getJSONArray(List);
for (int i=0;i<permin.length();i++)
{
String open,high,low,close;
JSONObject current = permin.getJSONObject(i);
open = current.getString("1. open");
high = current.getString("2. high");
low = current.getString("3. low");
close = current.getString("4. close");
Log.d("Extracted ",open + " " + high + " " + low + " " + close +"\n");
}
}
catch (JSONException e)
{
Log.e("createList","Error in json",e);
}
}
return list;
}
and Log is:
04-24 14:34:52.009 3574-3619/lcukerd.com.stocknotifier D/built URL: http://www.alphavantage.co/query?function=TIME_SERIES_INTRADAY&symbol=SBIN&interval=1min&apikey=J63P
04-24 14:34:53.723 3574-3619/lcukerd.com.stocknotifier E/createList: Error in json
org.json.JSONException: End of input at character 0 of
at org.json.JSONTokener.syntaxError(JSONTokener.java:450)
at org.json.JSONTokener.nextValue(JSONTokener.java:97)
at org.json.JSONObject.<init>(JSONObject.java:156)
at org.json.JSONObject.<init>(JSONObject.java:173)
at lcukerd.com.stocknotifier.MainActivity$createList$override.doInBackground(MainActivity.java:123)
at lcukerd.com.stocknotifier.MainActivity$createList$override.access$dispatch(MainActivity.java)
at lcukerd.com.stocknotifier.MainActivity$createList.doInBackground(MainActivity.java:0)
at lcukerd.com.stocknotifier.MainActivity$createList.doInBackground(MainActivity.java:69)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Also, note that "Log" statement after inner while loop is also not working.
Pls, Help me Solve it.

You got exception in the Json data, it is very clear from the log, it says:
04-24 14:34:53.723 3574-3619/lcukerd.com.stocknotifier E/createList:
Error in json
Oh yeah:
Change this line:
DATA.concat(temp);
To
data = DATA.concat(temp);
Also in java it's better to write it this way:
data += temp;

AsyncTask DoInBackground downloading Google Spreadsheets Data Returning Null?

Here is the code:
#Override
public String doInBackground(String... params)
{
try
{
URL url = new URL("http://spreadsheets.google.com/tq?key=BLAHBLOAHBLAH");
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection(); //Cast HttpUrlConnection because URL does not contain methods available to url, creates object
httpURLConnection.setRequestMethod("GET"); //Request data from source
httpURLConnection.setDoInput(true);
httpURLConnection.connect(); //Object actually connects, connect() invoked by getInputStream() etc.
//Reads data from network stream
InputStream inputStream = httpURLConnection.getInputStream();
//Rather than read one character at a time from the network or disk, BufferedReader reads a larger block at a time
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
//Used to create mutable string e.g. append()
StringBuilder stringBuilder = new StringBuilder();
String line = "";
//Change stream data to StringBuilder data
while ((line = bufferedReader.readLine()) != null)
{
stringBuilder.append(line + "\n");
}
String result = stringBuilder.toString();
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return result;
}
catch(IOException e)
{
e.printStackTrace();
}
return null;
}
I'm basically downloading the JSON data from Google Spreadsheets, but the result returned from the doInBackground function continues to return some sort of a null object reference. What does this mean?...
EDIT*
Here is my logcat:
07-28 12:41:30.289 3796-3891/com.example.steven.app E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #2
Process: com.example.steven.app, PID: 3796
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.AlertDialog.setMessage(java.lang.CharSequence)' on a null object reference
at com.example.steven.database.DownloadGS.doInBackground(DownloadGS.java:95)
at com.example.steven.database.DownloadGS.doInBackground(DownloadGS.java:49)
at android.os.AsyncTask$2.call(AsyncTask.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588) 
at java.lang.Thread.run(Thread.java:818) 
Picture of what is actually being stored inside String result...

My problem was:
URL url = new URL("http://spreadsheets.google.com/tq?key=BLAHBLOAHBLAH");
I found out that by reading here:
URLConnection Doesn't Follow Redirect
the setFollowRedirect and setInstanceFollowRedirects only work automatically when the redirected protocol is same . ie from http to http and https to https. (Shalvika)
I changed the statement to:
URL url = new URL("https://spreadsheets.google.com/tq?key=BLAHBLOAHBLAH");

Your code looks fine, the problem is that you are not allowed to get data from that URL.
On hitting this URL "http://spreadsheets.google.com/tq?key=BLAHBLOAHBLAH"
I am getting following response, so i guess you are getting access denied from server.
google.visualization.Query.setResponse (
{
"version": "0.6",
"status": "error",
"errors": [
{
"reason": "access_denied",
"message": "Access denied",
"detailed_message": "Access denied"
}]
}
)

android- Intentional '%' in string throws IllegalArgumentException

I am making a http call to an api for a string response.
The result contains intentional % signs in a sentence like:
"This land is 95% fertail and 5% contaminated"
Android throws IllegalArgumentException: Invalid % sequence at 1756 which corresponds to the "95%" part.
EDIT: StackTrace:
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:300)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.IllegalArgumentException: Invalid % sequence at 1756: [{"address":{"addressComponen...
My httpGet method:
public String makeHttpGetRequestUtf8(String urlStr) throws IOException {
String result = "";
try {
URL url = new URL(urlStr);
BufferedReader brIn = new BufferedReader(new InputStreamReader(url.openStream(), "UTF-8"));
String line = "";
while ((line = brIn.readLine()) != null)
result += line;
}catch (Exception e){
Log.e("HTT_GET", "Failed to make httpGetRequestUtf8: " + e);
}
String afterDecode = URLDecoder.decode(result, "UTF-8");
return afterDecode;
}
Android throws IllegalArgumentException: Invalid % sequence at 1756 which corresponds to the "95%" part.
Server writes this data with this metod and so I believe the encoding should be fine?
File file = new File(path/filename.txt);
String content = writeMeToFile;
Writer out;
try{
out = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream(file), "UTF8"));
if(!file.exists()){
file.createNewFile();
}else{
FileUtils.copyFile(file, dest);
out.write(content);
out.close();
}
} catch (IOException e) {
Logger.getLogger(UpdateAds.class.getName()).log(Level.SEVERE, null, e);
}
Side question/note: Somehow characters like 'ä', 'ö', 'ü', 'õ' are fine in the browser but show up as � in android.
I don't understand at which side am I encoding the string wrong. Since the text is fine in the browser I am thinking it's android, but the httpGet method is done by the book.
Thanks!

Android API error / httpget NetworkOnMainThreadException [duplicate]

This question already has answers here:
How can I fix 'android.os.NetworkOnMainThreadException'?
(66 answers)
Closed 8 years ago.
This is my error message:
08-17 07:58:14.286 32620-32620/xxx.dk.xxx E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: xxx.dk.xxx, PID: 32620
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1239)
at java.net.InetAddress.lookupHostByName(InetAddress.java:388)
at java.net.InetAddress.getAllByNameImpl(InetAddress.java:239)
at java.net.InetAddress.getAllByName(InetAddress.java:214)
at com.android.okhttp.internal.Dns$1.getAllByName(Dns.java:28)
at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:216)
at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:122)
at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:292)
at com.android.okhttp.internal.http.HttpEngine.sendSocketRequest(HttpEngine.java:255)
at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:206)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:345)
at com.android.okhttp.internal.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:89)
at xxx.dk.xxx.DAL.JsonConnection.checkSecret(JsonConnection.java:42)
at xxx.dk.xxx.BLL.CheckCarrierData.checkSecret(CheckCarrierData.java:14)
at xxx.dk.xxx.GUI.Login.onClick(Login.java:49)
at android.view.View.performClick(View.java:4480)
at android.view.View$PerformClick.run(View.java:18686)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:157)
at android.app.ActivityThread.main(ActivityThread.java:5872)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:674)
at dalvik.system.NativeStart.main(Native Method)
Im trying to use a httpGet method, which is working on API10, but it fails when im using it on an unit with 4.4.2 -> i need the support from API10 and up.
The code:
public class JsonConnection
{
private String secretJsonStr = null;
private String nameOfCarrier = "";
public String checkSecret(String secret)
{
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
final String QueryParam = "secret";
try
{
final String httpUrl = "***SOMEURL***?";
Uri builtUri = Uri.parse(httpUrl).buildUpon().
appendQueryParameter(QueryParam, secret.toString()).build();
URL url = new URL(builtUri.toString());
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.connect();
// Read the input stream into a String
InputStream inputStream = urlConnection.getInputStream();
StringBuffer buffer = new StringBuffer();
if (inputStream == null)
{
// Nothing to do.
return null;
}
reader = new BufferedReader(new InputStreamReader(inputStream));
String line;
while ((line = reader.readLine()) != null)
{
buffer.append(line + "\n");
}
if (buffer.length() == 0)
{
// Stream was empty. No point in parsing.
return null;
}
secretJsonStr = buffer.toString();
} catch (IOException e)
{
Log.e("Login", "Error", e);
return null;
} finally
{
if (urlConnection != null)
{
urlConnection.disconnect();
}
if (reader != null)
{
try
{
reader.close();
} catch (final IOException e)
{
Log.e("Login", "Error closing stream", e);
}
}
}
try
{
JSONObject secretJson = new JSONObject(secretJsonStr);
nameOfCarrier = getCarrierInfoFromJson(secretJson);
}
catch (JSONException e)
{
e.printStackTrace();
}
return nameOfCarrier;
}
private String getCarrierInfoFromJson(JSONObject secretJson)
throws JSONException
{
final String CARRIER_NAME = "Name";
String nameOfCarrier2 = secretJson.getString(CARRIER_NAME);
return nameOfCarrier2;
}
}
Due to some protection, i cannot show you the URL, but everything is working like a charm when running in API 10 2.3.6 units..
I though there where complete backwards compatibility on all android devices.
Hope you have the knowledge to help me on, I for sure cannot see how. :-(
Kindest regards
Rasmus

The problem is that the http requests are executed on the main thread (NetworkOnMainThreadException), so you need to move the calls into a Thread. More info here.
update: actually, possible duplicate of this.

As error say you can't execute an HTTP connection on the MainThread that would froze the screen. which is not appropriate.
You can get that permission as the following:
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
But, this is not a good practice. you must run the http connection on a background thread and display a loading msg to the user.
new Thread(new Runnable() {
#Override
public void run() {
// code goes here ...
}
}).start();

As other answers are suggesting, you are getting this error because you are running network operation on main thread. I would suggest to use AsyncTask.
This link shows you structure of AsyncTask.
To call the AsyncTask, use
//getData() is name of class
new getData().execute();
More reference on Android Developer site.

NullPointerException with StringBuilder

I get a very common crash below from the code below.
I thought my try, catches will have handled that.
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:200)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
at java.lang.Thread.run(Thread.java:1102)
Caused by: java.lang.NullPointerException
at java.io.Reader.<init>(Reader.java:65)
at java.io.InputStreamReader.<init>(InputStreamReader.java:65)
at com.test.test.FinderMain.grabPlaneRoute(FinderMain.java:759)
at com.test.test.FinderMain.access$7(FinderMain.java:729)
at com.test.test.FinderMain$GetRouteTask.doInBackground(FinderMain.java:684)
at com.test.test.FinderMain$GetRouteTask.doInBackground(FinderMain.java:1)
at android.os.AsyncTask$2.call(AsyncTask.java:185)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
Line 759 is within grabPlaneRoute and is the line containing the "StringBuilder total = new StringBuilder();"
Can someone help with this, it is driving me crazy! :-)
private void grabPlaneRoute(String adshex) {
List<GeoPoint> localList = new ArrayList<GeoPoint>();
HttpURLConnection con = null;
URL url;
InputStream is=null;
try {
url = new URL("http://www.testurl.com&test=" + adshex);
con = (HttpURLConnection) url.openConnection();
con.setReadTimeout(20000 /* milliseconds */);
con.setConnectTimeout(60000 /* milliseconds */);
con.setRequestMethod("GET");
con.setDoInput(true);
// Start the query
con.connect();
is = con.getInputStream();
}catch (IOException e) {
//handle the exception !
e.printStackTrace();
return;
}
//localList = decodePoly(convertStreamToString(is));
//Log.i("HTTP DUMP", convertStreamToString(is));
BufferedReader r = new BufferedReader(new InputStreamReader(is),8024);
StringBuilder total = new StringBuilder();
String line;
try {
while ((line = r.readLine()) != null) {
String[] separated = line.split(",");
GeoPoint p = getPoint(Double.valueOf(separated[0]),Double.valueOf(separated[1]));
localList.add(p);
}
}catch (IOException e) {
//handle the exception !
e.printStackTrace();
}
drawPlaneRoute(localList);
}

Line 759 is actually the line that begins with BufferedReader r = new ....
The variable is is null.
What happens when con.GetInputStream returns a null, and doesn't throw an exception? You're not handling that case, and that's likely what's happening here.
In addition, I don't see a need for the either try/catch block at all. Just let the exception percolate up the call stack. You're hiding the IOException now, preventing anyone calling grabPlaneRoute from discovering that an error occurred.

It's fairly impossible for StringBuilder total = new StringBuilder(); to cause a NullPointerException. On the other hand, the nearest cause of the Exception is in the logtrace:
at java.io.Reader.<init>(Reader.java:65)
at java.io.InputStreamReader.<init>(InputStreamReader.java:65)
Which makes me think that it's caused by:
BufferedReader r = new BufferedReader(new InputStreamReader(is),8024);
In that case, the only thing that could be null is is.