I have problems using BufferedReader when I use readLine () it returns null value. This is my code:
How can I discover the source of the problem?
BackgroundTask_GET.java
public class BackgroundTask_GET extends AsyncTask<Void, Void, Void> {
String duongdan = MainActivity.SERVER_NAME;
TextView tvResult;
String strName, strScore;
String str;
ProgressDialog pDialog;
Context context;
public String TAG = "GG";
#Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(context);
pDialog.setMessage("Sending...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
public BackgroundTask_GET(Context context, TextView tvResult, String
strName, String strScore) {
this.tvResult = tvResult;
this.strName = strName;
this.strScore = strScore;
this.context = context;
}
#Override
protected Void doInBackground(Void... voids) {
duongdan += "?name=" + this.strName + "&score=" + this.strScore;
try {
URL url = new URL(duongdan);
HttpURLConnection urlConnection = (HttpURLConnection)
url.openConnection();
BufferedReader bfr = new BufferedReader(new
InputStreamReader(url.openStream()));
String line = "";
StringBuffer sb = new StringBuffer();
Log.d(TAG, "bfr:" + urlConnection);
while ((line = bfr.readLine()) != null) {
sb.append(line);
Log.d(TAG, "append"+sb.append(line));
}
str = sb.toString();
urlConnection.disconnect();
Log.d(TAG, "doInBackground: " + str);
} catch (MalformedURLException e) {
e.printStackTrace();
Log.d(TAG, "exception " + e);
} catch (IOException e) {
e.printStackTrace();
Log.d(TAG, "exception " + e);
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
if (pDialog.isShowing()) {
pDialog.dismiss();
}
tvResult.setText(str);
Log.d("RESULT", "khanh" + str);
}
}
`` `MainActivity
public class MainActivity extends AppCompatActivity implements
View.OnClickListener {
public static final String SERVER_NAME =
"http://192.168.1.2/AndroidNetworking_server/student_GET.php";
private EditText edtName, edtScore;
private Button btnSend;
private TextView tvResult;
String strName, strScore;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edtName = findViewById(R.id.edtName);
edtScore = findViewById(R.id.edtScore);
btnSend = findViewById(R.id.btnSend);
tvResult = findViewById(R.id.tvResult);
btnSend.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch(view.getId()) {
case R.id.btnSend:
strName = edtName.getText().toString();
strScore = edtScore.getText().toString();
BackgroundTask_GET backgroundTask = new
BackgroundTask_GET(this, tvResult, strName, strScore);
backgroundTask.execute();
break;
}
}
}
Error:
~
` 1 `
2019-07-15 14:07:58.065 24764- 28936/com.example.lab2_khanhpd02377_androidnetworkingD/GG:bfr:com.android.okhttp.internal.huc.HttpURLConnectionImpl:http://192.168.1.2/AndroidNetworking_server/student_GET.php?name=4&score=5
~
` 2 `
2019-07-15 14:07:58.066 24764- 28936/com.example.lab2_khanhpd02377_androidnetworking D/GG: doInBackground:
I can see a couple of problems with your code:
The readLine() method returns the line with the line separator removed. So
while ((line = bfr.readLine()) != null) {
sb.append(line);
}
will strip line separators while reading.
You are not checking the HTTP response code. If the response code is not a 2xx code, then getInputStream() will throw an exception.
The response code can be found using getResponseCode(). The error response body can be read using getErrorStream().
As #user207421 says, you shouldn't call urlConnection.disconnect() unless you really need to disconnect. If you don't need to, it is better to let the HTTP client library deal with disconnection. (It may be able to keep the connection open, and use it for later requests to the same server.)
You should1 close the BufferedReader, and ideally you should do it using try-with-resources.
1 - I won't say must because there are scenarios where it won't matter. However, if you don't close the stream, one way or another, you will leak file descriptors which could lead to errors later on. And, it is certainly good practice to close streams ... because you never really know if your code might be used / reused in the future in some context where the resource leak does matter.
UPDATE - I think you are saying that the real real cause for the null / empty stream was on the PHP side. Notwithstanding that, you probably ought to address the four issues that I mentioned: line separators, response code, disconnect and using try-with-resource.
Related
I am trying to make a translation application from English to Bangla using Yandex API.
It works fine in the emulator but in the real device it shows result for only one word in the text view but when writing a sentence it shows null / nothing.
I think the problem is buffer overflow but don't know how to fix it for the real device. Here are some reference pictures. In the emulator the result works fine:
In the real device it shows empty in text view:
But it works fine when a single word is used in real device.
Here is the code for my Asynctask:
public class
TranslatorBackgroundTask extends AsyncTask<String, Void, String> {
//Declare Context
Context ctx;
//Set Context
TranslatorBackgroundTask(Context ctx){
this.ctx = ctx;
}
String resultString;
#Override
protected String doInBackground(String... params) {
//String variables
String textToBeTranslated = params[0];
String languagePair = params[1];
String jsonString;
try {
//Set up the translation call URL
String yandexKey = "trnsl.1.1.20170823T130435Z.79a583874abfc8ff.61e23593359fdc92452e69a3d5ec05347fc4180b";
String yandexUrl = "https://translate.yandex.net/api/v1.5/tr.json/translate?key=" + yandexKey
+ "&text=" + textToBeTranslated + "&lang=" + languagePair;
URL yandexTranslateURL = new URL(yandexUrl);
//Set Http Conncection, Input Stream, and Buffered Reader
HttpURLConnection httpJsonConnection = (HttpURLConnection) yandexTranslateURL.openConnection();
InputStream inputStream = httpJsonConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
//Set string builder and insert retrieved JSON result into it
StringBuilder jsonStringBuilder = new StringBuilder();
while ((jsonString = bufferedReader.readLine()) != null) {
jsonStringBuilder.append(jsonString + "\n");
}
//Close and disconnect
try {
bufferedReader.close();
} catch (IOException e) {
e.printStackTrace();
}
inputStream.close();
httpJsonConnection.disconnect();
//Making result human readable
resultString = jsonStringBuilder.toString().trim();
//Getting the characters between [ and ]
resultString = resultString.substring(resultString.indexOf('[')+1);
resultString = resultString.substring(0,resultString.indexOf("]"));
//Getting the characters between " and "
resultString = resultString.substring(resultString.indexOf("\"")+1);
resultString = resultString.substring(0,resultString.indexOf("\""));
Log.d("Translation Result:", resultString);
return jsonStringBuilder.toString().trim();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
//String text = String.valueOf(resultString);
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(String result) {
MainActivity.tvTranslatedText.setText(resultString);
Toast.makeText(ctx, resultString, Toast.LENGTH_LONG).show();
super.onPostExecute(result);
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
And the code for the main activity:
public class MainActivity extends AppCompatActivity{
Context context=this;
private static final int REQUEST_CODE = 1234;
static TextView tvTranslatedText;
EditText etUserText;
Button buTranslate;
Button buSpeak;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_activity_main);
tvTranslatedText = (TextView)findViewById(R.id.tvTranslatedText);
etUserText = (EditText)findViewById(R.id.etUserText);
buTranslate = (Button)findViewById(R.id.buTranslate);
buSpeak = (Button)findViewById(R.id.buSpeak);
}
public void buTranslate(View view) {
//Default variables for translation
String textToBeTranslated = "";
textToBeTranslated= etUserText.getText().toString();
String languagePair = "en-bn"; //English to bengali ("<source_language>-<target_language>")
//Executing the translation function
Translate(textToBeTranslated,languagePair);
}
//Function for calling executing the Translator Background Task
void Translate(String textToBeTranslated, String languagePair){
TranslatorBackgroundTask translatorBackgroundTask= new TranslatorBackgroundTask(context);
String translationResult = "";
translationResult = String.valueOf(translatorBackgroundTask.execute(textToBeTranslated,languagePair)); // Returns the translated text as a String
Log.d("Translation Result",translationResult); // Logs the result in Android Monitor
}
//Speak button activities
public void buSpeak(View view) {
startVoiceRecognitionActivity();
}
private void startVoiceRecognitionActivity()
{
Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speak to translate");
startActivityForResult(intent, REQUEST_CODE);
}
/**
* Handle the results from the voice recognition activity.
*/
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
if (data != null) {
//pull all of the matches
ArrayList<String> matches = data.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
String topResult = matches.get(0);
EditText AutoText = (EditText) findViewById(R.id.etUserText);
AutoText.setText(topResult);
}
}
}
}
The error message:
Caused by: com.google.android.apps.gsa.shared.exception.GsaIOException: Error code: 393238 | Buffer overflow, no available space.
Why didn't you add a listener to your sample code?
Try adding these on onCreate in MainActivity:
buTranslate.setOnClickListener(
new View.OnClickListener() {
#Override
public void onClick(View view) {
buTranslate(view);
}
}
);
Update:
There was another issue. Emulators on android sdk 16 don't show Unicode properly. Thats why you don't see your results, as those are Unicodes. Try Log to print your resultString.
Just as a practicing exercise i'm trying to make an app that fetches a JSON from a URL.
I found the following code in other thread here in stackoverflow and it works just fine. My problem is that the URL is hardcoded, and i need it to be an input by the user. What should i change/add?
public class MainActivity extends AppCompatActivity {
Button btnHit;
TextView txtJson;
ProgressDialog pd;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnHit = (Button) findViewById(R.id.btnHit);
txtJson = (TextView) findViewById(R.id.tvJsonItem);
btnHit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new JsonTask().execute("Url address here");
}
});
}
private class JsonTask extends AsyncTask<String, String, String> {
protected void onPreExecute() {
super.onPreExecute();
pd = new ProgressDialog(MainActivity.this);
pd.setMessage("Please wait");
pd.setCancelable(false);
pd.show();
}
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 = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null) {
buffer.append(line+"\n");
Log.d("Response: ", "> " + line); //here u ll get whole response..... :-)
}
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 result) {
super.onPostExecute(result);
if (pd.isShowing()){
pd.dismiss();
}
txtJson.setText(result);
}
}
}
This is the thread where i got that code from:
Get JSON Data from URL Using Android?
Create a constructor in your async Task
private class JSONTask extends AsyncTask<String, String, String> {
String url;
public JSONTask(String url){
this.url=url;
}
use the url string in place of params[0]
And wherever you call your async task do it like this
new JSONTask(textView.getText()).execute()
This should solve it.
Else you can directly use the do in background variable params.
So the problem is that you are using a TextView. TextView does not recieve inputs.
EditText does.
Make these Changes:
TextView txtJson;
In your OnCreate change this:
txtJson = (EditText) findViewById(R.id.tvJsonItem);
btnHit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new JsonTask().execute(txtJson.getText());
}
});
Now in your xml file change the Button to EditText.
Hope this helps.
I am pretty fresh with Android Studio, and I am trying to call MVC Api service with api key and app id.
However, whenever i try the one with api key and app id, it always throws "Trust anchor for certification path not found." while it works good when i try the one without api key.
Can you give me a advice? Thank you.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = (Button)findViewById(R.id.button);
tv = (TextView)findViewById(R.id.textView);
btn.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
new JSONTask().execute("");
}
});
}
public class JSONTask extends AsyncTask<String, String, String>
{
#Override
protected String doInBackground(String... params) {
try{
StringBuilder result = new StringBuilder();
URL url2 = new URL(url);
HttpURLConnection conn = (HttpURLConnection) url2.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Apikey",key);
conn.addRequestProperty("AppID",id);
BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String line;
while ((line = rd.readLine()) != null) {
result.append(line);
}
rd.close();
return result.toString();
}
catch (IOException e)
{
Log.e("MYAPP", "exception", e);
return "error";
}
}
protected void onPostExecute(String result)
{
super.onPostExecute(result);
tv.setText(result);
}
}
This kind of exceptions mostly occur because of the misconfiguration of a web service. Check out this article. It's fully described why you are getting this exception.
So I'm trying to read a message from the server by HttpURLConnection in a AsyncTask class. The problem is, when i send the request to read the data from the server, it just keeps displaying the ProgresssDialog, like it doesn't read the data from the server:
public class MainActivity extends Activity{
EditText name, password;
Button login;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
name = (EditText) findViewById(R.id.name);
password = (EditText) findViewById(R.id.password);
login = (Button) findViewById(R.id.login);
login.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String serverURL = "http://192.168.1.1/my/text.php";
LongOperation longOperation = new LongOperation();
longOperation.execute(serverURL);
}
});
}
private class LongOperation extends AsyncTask<String, Void, Void> {
private String content;
private String error = null;
private ProgressDialog dialog = new ProgressDialog(MainActivity.this);
TextView uiUpdate = (TextView) findViewById(R.id.output);
#Override
protected void onPreExecute() {
uiUpdate.setText("Output : ");
dialog.setMessage("Downloading source..");
dialog.show();
}
#Override
protected Void doInBackground(String... urls) {
try {
URL url = new URL(urls[0]);
HttpURLConnection client = (HttpURLConnection)url.openConnection();
client.connect();
InputStream inputStream = client.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
content = bufferedReader.readLine();
bufferedReader.close();
inputStream.close();
client.disconnect();
} catch (IOException e) {
error = e.getMessage();
}
return null;
}
#Override
protected void onPostExecute(Void unused) {
dialog.dismiss();
if (error != null) {
uiUpdate.setText("Output : "+error);
} else {
uiUpdate.setText("Output : "+content);
}
}
I already tryed before the connectivity to server via HttpClient, so thats not the problem.Thanks!
Try debugging it and see if OnPostExecute() method is getting called or not.!
This seems to get stuck in your stream reader code. Also, add a connection timeout of, say, 5-10 seconds for better user experience.!
Moreover, there seems to be an issue with your return type of doInBackground() method and input parameter type of OnPostExecute() method. As per your AsyncTask definition, they both should be string, isnt it?
See this
Try remove client.connect();
try {
URL url = new URL(urls[0]);
HttpURLConnection client = (HttpURLConnection)url.openConnection();
//remove client.connect();
int response = client.getResponse();
if(response == HttpURLConnection.HTTP_OK){
InputStream inputStream = client.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
content = bufferedReader.readLine();
bufferedReader.close();
inputStream.close();
}
finally{
client.disconnect();
}
} catch (IOException e) {
error = e.getMessage();
}
return null;
Make sure your server is running. Also set request time out.
You are not always required to explicitly call the connect method to initiate the connection. Operations that depend on being connected, like getInputStream, getOutputStream will implicitly perform the connection, when necessary.
This link
Try this:
private class LongOperation extends AsyncTask<String, Void, String>
{
private String content;
private String error = null;
private ProgressDialog dialog = new ProgressDialog(MainActivity.this);
TextView uiUpdate = (TextView) findViewById(R.id.output);
#Override
protected void onPreExecute() {
uiUpdate.setText("Output : ");
dialog.setMessage("Downloading source..");
dialog.show();
}
#Override
protected Strinh doInBackground(String... urls) {
try {
URL url = new URL(urls[0]);
HttpURLConnection client = (HttpURLConnection)url.openConnection(); client.connect();
InputStream inputStream = client.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
content = bufferedReader.readLine();
bufferedReader.close();
inputStream.close();
//client.discon dialog.dismiss();
}
catch (IOException e)
{
content = e.getMessage();
}
return content ;
}
#Override
protected void onPostExecute(String returnValue) {
if (return value != null) {
uiUpdate.setText("Output : "+error);
}
else {
uiUpdate.setText("Output No Value Returned");
}
dialog.dismiss();
}
I'm having a hard time to connect the application to the internet and retrieve the html source.
Been looking all over for a solution and didn't find. Hope someone could help.
Here is my code:
public class Main extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final EditText et = (EditText) findViewById(R.id.editText1);
final Button b = (Button) findViewById(R.id.button1);
final TextView tv = (TextView) findViewById(R.id.textView1);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
try {
URL url=null;
url = new URL(et.getText().toString());
URLConnection conn = url.openConnection();
BufferedReader reader = new BufferedReader(
new InputStreamReader(conn.getInputStream()));
String line = "";
while ((line = reader.readLine()) != null) {
tv.append(line);
}
} catch (Exception e) {
}
}
});
}
I've also added INTERNET permission..
You need to move the code which connects to the internet and fetches data to an AsyncTask. This is because of the NetworkOnMainThreadException. This exception is thrown when an application attempts to perform a networking operation on its main thread.
Though there is a workaround available by using the StrictMode.ThreadPolicy, it highly advisable not to do that.
Here is a excerpt from the docs.
NetworkOnMainThreadException:-
This is only thrown for applications
targeting the Honeycomb SDK or higher. Applications targeting earlier
SDK versions are allowed to do networking on their main event loop
threads, but it's heavily discouraged.
See this question for more info.
Because you are doing this on UI therad.
Try this:
public class Main extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
final EditText et = (EditText) findViewById(R.id.editText1);
final Button b = (Button) findViewById(R.id.button1);
final TextView tv = (TextView) findViewById(R.id.textView1);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Thread th = new Thread() {
#Override
public void run() {
try {
URL url=null;
url = new URL(et.getText().toString());
URLConnection conn = url.openConnection();
BufferedReader reader = new BufferedReader(
new InputStreamReader(conn.getInputStream()));
String line = "";
while ((line = reader.readLine()) != null) {
tv.append(line);
}
} catch (Exception e) {
}
}
};
th.start();
}
});
}
i will suggest you to use AsyncTask
Do this
On ButtonClick
RequestClient reqClient = new RequestClient(ActivityName.this);
String AppResponse = null;
AppResponse = reqClient.execute().get();
RequestClient
public class RequestClient extends AsyncTask<String, Void, String> {
Context context;
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
try {
HttpClient httpclient = new DefaultHttpClient(); // Create HTTP Client
HttpGet httpget = new HttpGet("http://yoururl.com"); // Set the action you want to do
HttpResponse response = httpclient.execute(httpget); // Executeit
HttpEntity entity = response.getEntity();
InputStream is = entity.getContent(); // Create an InputStream with the response
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) // Read line by line
sb.append(line + "\n");
String resString = sb.toString(); // Result is here
is.close(); // Close the stream
} catch (Exception e) {
Log.d("ANDRO_ASYNC_ERROR", "Error is " + e.toString());
}
Log.d("ANDRO_ASYNC_RESPONSE", responseString.trim());
client.getConnectionManager().shutdown();
return responseString.trim();
}
#Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
}
}