String json_string;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void getJSON (View view){
new BackgroundTask().execute();
}
class BackgroundTask extends AsyncTask <Void, Void, String>{
String json_url;
#Override
protected void onPreExecute() {
json_url = "http://androidtut.comli.com/json_get_data.php";
}
#Override
protected Void doInBackground(Void... voids) {
try {
URL url = new URL(json_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder stringBuilder = new StringBuilder();
while ((json_string = bufferedReader.readLine()) != null) {
stringBuilder.append(json_string + "\n");
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return stringBuilder.toString().trim();
}
catch (MalformedURLException e){
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
#Override
protected void onPostExecute(String result) {
TextView textView = (TextView) findViewById(R.id.textJSON);
textView.setText(result);
}
}
Error:(31, 5) error: MainActivity.BackgroundTask is not abstract and does not override abstract method doInBackground(Void...) in AsyncTask
Error:(39, 24) error: doInBackground(Void...) in MainActivity.BackgroundTask cannot override doInBackground(Params...) in AsyncTask
return type Void is not compatible with String
where Params,Result are type-variables:
Params extends Object declared in class AsyncTask
Result extends Object declared in class AsyncTask
Error:(38, 9) error: method does not override or implement a method from a supertype
Error:(54, 53) error: incompatible types: String cannot be converted to Void
Error:Execution failed for task ':app:compileDebugJavaWithJavac'.> Compilation failed; see the compiler error output for details.
AsyncTask <Void, Void, String>
The last type here is the return result type.
Your doInBackground is currently defined with Void, not String
Likewise, you cannot return a StringBuilder String result as a Void type.
You may find that the other Android HTTP libraries that deal with JSON are much easier to use.
AFAIK, when you define Void in AsyncTask , you should understand the meaning.
doInBackground is a function with empty argument (the first void), return a String (the last String)
protected String doInBackground()
onProgressUpdate is a function with empty argument (the 2nd void)
protected void onProgressUpdate()
onPostExecute is a function with String argument (value from step 1).
protected void onPostExecute(String)
If you can't understand the function in AsyncTask clearly,you'd better try to generate the function in AndroidStudio.
Here is the code generated by AndroidStudio.
class BackgroundTask extends AsyncTask<Void,Void,String>
{
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
#Override
protected String doInBackground(Void... params) {
return null;
}
}
Compare your code with above,I think you would kown the answer.
I found two mistakes here.
1. For task execution,
new BackgroundTask().execute(null);
2. doInBackground return type should match with Result type (i.e. String)
protected String doInBackground(Void... voids)
AsyncTask
String json_string;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void getJSON (View view){
new BackgroundTask().execute(null);
}
class BackgroundTask extends AsyncTask <Void, Void, String>{
String json_url;
#Override
protected void onPreExecute() {
json_url = "http://androidtut.comli.com/json_get_data.php";
}
#Override
protected String doInBackground(Void... voids) {
try {
URL url = new URL(json_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder stringBuilder = new StringBuilder();
while ((json_string = bufferedReader.readLine()) != null) {
stringBuilder.append(json_string + "\n");
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return stringBuilder.toString().trim();
}
catch (MalformedURLException e){
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
#Override
protected void onPostExecute(String result) {
TextView textView = (TextView) findViewById(R.id.textJSON);
textView.setText(result);
}
}
String json_string;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void getJSON (View view){
new AsynsTask(){
String json_url;
#Override
protected void onPreExecute() {
json_url = "http://androidtut.comli.com/json_get_data.php";
}
#Override
protected Void doInBackground(Void... voids) {
try {
URL url = new URL(json_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
StringBuilder stringBuilder = new StringBuilder();
while ((json_string = bufferedReader.readLine()) != null) {
stringBuilder.append(json_string + "\n");
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return stringBuilder.toString().trim();
}
catch (MalformedURLException e){
e.printStackTrace();
}
catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
#Override
protected void onPostExecute(String result) {
TextView textView = (TextView) findViewById(R.id.textJSON);
textView.setText(result);
}
}.execute();
}
Related
I want to parse JSON from the Openweather API but after many iterations and debugging, my JSON string is not updating, I do not think that there is any problem still the temperatures( minTemperature and maxTemperature) and the name of the place(mPlace) is not set, also I logged the maxtemperature but the console is showing nothing please look into my code.
public class MainActivity extends AppCompatActivity {
private EditText placeText;
private Button enterPlaceButton;
private TextView minTemperature;
private TextView maxTemperature;
private TextView mPlace;
private static final String AppID ="56a5e01eba3af36a7a9b7b210a437d09";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setTitle("Weather");
placeText = findViewById(R.id.myPlaceEditText);
enterPlaceButton = findViewById(R.id.enterPlace);
minTemperature = findViewById(R.id.minTemperature);
maxTemperature = findViewById(R.id.maxTemperature);
mPlace = findViewById(R.id.mPlace);
}
#Override
protected void onResume() {
final URL[] url = {null};
enterPlaceButton.setOnClickListener(v -> {
url[0] = makeUrl(placeText.getText().toString());
placeText.setText("");
});
if (url[0] != null) {
MyAsync myAsync = new MyAsync();
myAsync.execute(url[0]);
}
super.onResume();
}
public URL makeUrl(String place) {
Uri.Builder uriBuilder = new Uri.Builder();
uriBuilder.scheme("http");
uriBuilder.authority("api.openweathermap.org/");
uriBuilder.appendPath("data");
uriBuilder.appendPath("2.5");
uriBuilder.appendPath("weather");
uriBuilder.appendQueryParameter("q",place);
uriBuilder.appendQueryParameter("appid",AppID);
try {
return new URL(uriBuilder.build().toString());
} catch (MalformedURLException e) {
Toast.makeText(MainActivity.this, "Sorry could not able to fetch the Data", Toast.LENGTH_SHORT).show();
e.printStackTrace();
}
return null;
}
public class MyAsync extends AsyncTask<URL, Void, String> {
#Override
protected String doInBackground(URL... urls) {
StringBuilder jsonResponseBuilder = new StringBuilder();
try {
HttpURLConnection httpURLConnection = (HttpURLConnection) urls[0].openConnection();
httpURLConnection.setRequestMethod("GET");
httpURLConnection.setReadTimeout(10000);
httpURLConnection.setConnectTimeout(15000);
httpURLConnection.setDoInput(true);
httpURLConnection.setDoOutput(true);
httpURLConnection.connect();
if (httpURLConnection.getResponseCode() == 200) {
InputStreamReader inputStreamReader = new InputStreamReader(httpURLConnection.getInputStream());
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
String line = bufferedReader.readLine();
while (line != null) {
jsonResponseBuilder.append(line);
line = bufferedReader.readLine();
}
httpURLConnection.disconnect();
}
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(MainActivity.this, "Sorry could not able to fetch the Data", Toast.LENGTH_SHORT).show();
}
Log.d(MyAsync.class.getName(),jsonResponseBuilder.toString());
return jsonResponseBuilder.toString();
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(String s) {
setDataFromJSON(s);
super.onPostExecute(s);
}
public void setDataFromJSON(String s) {
try {
JSONObject jsonObject = new JSONObject(s);
JSONObject getMainObject = jsonObject.getJSONObject("main");
String maxTemp = getMainObject.getString("temp_max");
Log.i(MainActivity.class.getName(), maxTemp);
maxTemperature.setText(maxTemp);
String minTemp = getMainObject.getString("temp_min");
minTemperature.setText(minTemp);
mPlace.setText(jsonObject.getString("name"));
} catch (JSONException e) {
e.printStackTrace();
Toast.makeText(MainActivity.this, "Sorry could not able to fetch the Data", Toast.LENGTH_SHORT).show();
}
}
}
}
I tried almost all the solution but there's some problem with my Inner AsyncTask class. It seems that doInBackground() is not being executed.
onPreExecute() and onPostExecute()are working. However, doInBackground() does not read the code.
I'm really sure about getJSON() is correct 100% because i used the same code before
this is my class
public class My extends Activity implements Runnable {
public static String s = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_splash);
findViewById(android.R.id.content).postDelayed(this, 3000);
getJSON("My link ");
}
#Override
public void run() {
startActivity(new Intent(SplashActivity.this, MainActivity.class));
finish();
}
}
AsyncTask:
private void getJSON(String url) {
class GetJSON extends AsyncTask<String, Void, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
String uri = params[0];
BufferedReader bufferedReader = null;
try {
URL url = new URL(uri);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
StringBuilder sb = new StringBuilder();
bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
String json;
while((json = bufferedReader.readLine())!= null){
sb.append(json+"\n");
}
s = sb.toString().trim();
return sb.toString().trim();
} catch(Exception e){
return null;
}
}
#Override
protected void onPostExecute(String ss) {
super.onPostExecute(ss);
s = ss;
}
}
GetJSON gj = new GetJSON();
gj.execute(url);
}
Thanks
Normally I create classes for every web service call that extends with the AsyncTask and it's so hard to maintain the code. So I think to create the One class and get the OUTPUT Json string according to the parameters.
how do I return the JSON string?
UPDATE
Here what I tried
public class WebCallController extends AsyncTask<Void,Void,String>
{
String PassPeram = "";
JSONStringer JSonRequestString;
String URL;
String JSonResponseString;
public WebCallController(String PerameterPass, JSONStringer JSonRequestString, String URL) {
PassPeram = PerameterPass;
this.JSonRequestString = JSonRequestString;
this.URL = URL;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(Void... params) {
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(URL);
post.setHeader("Content-type", "application/json");
try {
StringEntity entity = new StringEntity(JSonRequestString.toString());
post.setEntity(entity);
}
catch (Exception Ex)
{
}
try {
HttpResponse response = client.execute(post);
StatusLine status = response.getStatusLine();
int statusCode = status.getStatusCode();
if(statusCode == 400)
{
Log.d("Error", "bad request");
}
else if(statusCode == 505)
{
Log.d("Error","Internal server error");
}
else
{
InputStream jsonStream = response.getEntity().getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(jsonStream));
StringBuilder builder = new StringBuilder();
String line;
while((line = reader.readLine()) != null)
{
builder.append(line);
}
JSonResponseString = builder.toString();
}
}
catch (IOException Ex)
{
}
return JSonResponseString;
}
#Override
protected void onPostExecute(String aVoid) {
super.onPostExecute(aVoid);
}
}
this may be what you are looking for(get string as result and parse it to json):
YourAsycTask yat=new YourAsycTask();
yat.execute();
String result=yat.get().toString();
I am assuming that you need to write one AsyncTask which can be reusable for every webservice call. You can do something like below example ,
Step-1: Create a abstract class
public abstract class HttpHandler {
public abstract HttpUriRequest getHttpRequestMethod();
public abstract void onResponse(String result);
public void execute(){
new AsyncHttpTask(this).execute();
}
}
2. Sterp-2: Write your AsyncTask code
public class AsyncHttpTask extends AsyncTask<String, Void, String>{
private HttpHandler httpHandler;
public AsyncHttpTask(HttpHandler httpHandler){
this.httpHandler = httpHandler;
}
#Override
protected String doInBackground(String... arg0) {
//do your task and return the result
String result = "";
return result;
}
#Override
protected void onPostExecute(String result) {
httpHandler.onResponse(result); // set it to the onResponse()
}
}
Step-3: Write your Activity code
public class MainActivity extends Activity implements OnClickListener {
private Button btnRequest;
private EditText etResponse;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnRequest = (Button) findViewById(R.id.btnRequest);
etResponse = (EditText) findViewById(R.id.etRespose);
//check isConnected()...code is on github
btnRequest.setOnClickListener(this);
}
#Override
public void onClick(View v) {
new HttpHandler() {
#Override
public HttpUriRequest getHttpRequestMethod() {
return new HttpGet("http://hmkcode.com/examples/index.php");
// return new HttpPost(url)
}
#Override
public void onResponse(String result) {
Toast.makeText(getBaseContext(), "Received!", Toast.LENGTH_LONG).show();
etResponse.setText(result);
}
}.execute();
}
// public boolean isConnected(){}
}
reference
http://hmkcode.com/android-cleaner-http-asynctask/
https://github.com/hmkcode/Android/tree/master/android-clean-http-async-task
Try out below code and put it in separate class from where it returns json string to your activity.
Only pass your url to this method and get the response in a string formate.
public static final String GetConnectionInputStream(String strUrl) {
String line = null;
String response = null;
try {
HttpParams httpParameters = new BasicHttpParams();
// Set the timeout in milliseconds until a connection is
// established.
// The default value is zero, that means the timeout is not used.
HttpConnectionParams.setConnectionTimeout(httpParameters, 30000);
// Set the default socket timeout (SO_TIMEOUT)
// in milliseconds which is the timeout for waiting for data.
HttpConnectionParams.setSoTimeout(httpParameters, 30000);
// This is the default apacheconnection.
HttpClient mHttpClient = new DefaultHttpClient(httpParameters);
// Pathe of serverside
HttpGet mHttpGet = new HttpGet(strUrl);
// get the valu from the saerverside as response.
HttpResponse mHttpResponse = mHttpClient.execute(mHttpGet);
HttpEntity mHttpEntity = mHttpResponse.getEntity();
try {
// convert response in to the string.
if (mHttpEntity.getContent() != null) {
BufferedReader mBufferedReader = new BufferedReader(
new InputStreamReader(mHttpEntity.getContent(),
HTTP.UTF_8), 8);
StringBuilder mStringBuilder = new StringBuilder();
while ((line = mBufferedReader.readLine()) != null) {
mStringBuilder.append(line + "\n");
}
response = mStringBuilder.toString();
// mInputStream.close();
}
} catch (Exception e) {
e.printStackTrace();
}
} catch (Exception e) {
e.printStackTrace();
return null;
}
return response;
}
Change your doInBackground method as below:
private class GetParsedResponse extends AsyncTask<String, Void, String> {
#Override
protected void onPreExecute() {
}
#Override
protected String doInBackground(Void... params) {
String response=null;
response=GetConnectionInputStream(URL);
return response;
}
#Override
protected void onPostExecute(String result) {
//your response parsing code.
}
}
private class MyAsyncTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
return "Executed";
}
#Override
protected String onPostExecute(String result) {
return "json String";
}
#Override
protected void onPreExecute() {}
#Override
protected void onProgressUpdate(Void... values) {}
}
I have an Async Task getting me some data from the web. Async Task works fine and I want a Progress Dialog Spinner to be displayed while the data is being procured from the web.The Progress Dialog Spinner never shows up. Here is my code:
public class JsonHttpParsingActivity extends ListActivity{
private String jsonResult;
private ArrayList nameArray;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
HttpConnection task = new HttpConnection(this);
AsyncTask<String,Void,String> taskResult = task.execute("Some URL...");
try {
jsonResult = taskResult.get();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
.
.
More Code.....
}
}
public class HttpConnection extends AsyncTask<String, Void, String> {
private ProgressDialog progressDialog;
private Activity m_activity;
protected HttpConnection(Activity activity) {
setActivity(activity);
}
public void setActivity(Activity activity) {
m_activity = activity;
progressDialog = new ProgressDialog(m_activity);
progressDialog.setMessage("Wait ...");
progressDialog.setCancelable(false);
progressDialog.setMax(100);
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.show();
}
#Override
protected String doInBackground(String... params) {
BufferedReader in = null;
String inputLine= "", finalMessage = "";
HttpURLConnection urlConnection = null;
try {
String urladdress = params[0];
URL url = new URL(urladdress);
urlConnection = (HttpURLConnection) url.openConnection();
in = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
while((inputLine = in.readLine()) != null){
finalMessage = finalMessage + inputLine;
}
in.close();
Log.v("finalmessage", ""+finalMessage);
}
catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally {
urlConnection.disconnect();
}
return finalMessage;
}
protected void onProgressUpdate(Integer... values) {
progressDialog.setProgress((int) ((values[0] / (float) values[1]) * 100));
};
#Override
protected void onPostExecute(String result){
progressDialog.hide();
}
}
Thanks!
Instead of write a separate method setActivity(activity) (Non UI Thread scope)
for starting ProgressDialog put the code in onPreExecute() (UI Thread) of AsyncTask, Because you are trying to show it in non UI thread.
Try this,
protected HttpConnection(Activity activity) {
m_activity = activity;
}
Override
protected void onPreExecute(String result){
progressDialog = new ProgressDialog(m_activity);
progressDialog.setMessage("Wait ...");
progressDialog.setCancelable(false);
progressDialog.setMax(100);
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.show();
}
Call progress bar from onPreExecute() function
The following code is working fine and tested:
public class HttpConnection extends AsyncTask<String, Void, String> {
private ProgressDialog progressDialog;
private Activity m_activity;
protected HttpConnection(Activity activity) {
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
progressDialog = new ProgressDialog(m_activity);
progressDialog.setMessage("Wait ...");
progressDialog.setCancelable(false);
progressDialog.setMax(100);
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progressDialog.show();
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
BufferedReader in = null;
String inputLine= "", finalMessage = "";
HttpURLConnection urlConnection = null;
try {
String urladdress = params[0];
URL url = new URL(urladdress);
urlConnection = (HttpURLConnection) url.openConnection();
in = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
while((inputLine = in.readLine()) != null){
finalMessage = finalMessage + inputLine;
}
in.close();
Log.v("finalmessage", ""+finalMessage);
}
catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally {
urlConnection.disconnect();
}
return finalMessage;
}
#Override
protected void onPostExecute(String result){
progressDialog.hide();
}
}
Try calling the AsyncTask from another method in the activity. My guess is that right now, you call it in the onCreate method of the activity. Since the activity is still building, this can give you exceptions. A thing I once tried when I had this issue, is starting the asynchronous task from the onPostCreate method of the activity.
I'm new to Android development and I'm trying to code a little app which allows me to grab an external JSON file and parse it. I got this to work, however it wont work if I try to execute it in the background as an AsyncTask. Eclipse gives me the error
The method findViewById(int) is undefined for the type LongOperation
in this line:
TextView txtView1 = (TextView)findViewById(R.id.TextView01);
Here is my code:
public class Main extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new LongOperation().execute();
}
}
class LongOperation extends AsyncTask<String, Void, String> {
private final Context LongOperation = null;
#Override
protected String doInBackground(String... params) {
try {
URL json = new URL("http://www.corps-marchia.de/jsontest.php");
URLConnection tc = json.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(tc.getInputStream()));
String line;
while ((line = in.readLine()) != null) {
JSONArray ja = new JSONArray(line);
JSONObject jo = (JSONObject) ja.get(0);
TextView txtView1 = (TextView)findViewById(R.id.TextView01);
txtView1.setText(jo.getString("text") + " - " + jo.getString("secondtest"));
}
} catch (MalformedURLException e) {
Toast.makeText(this.LongOperation, "Malformed URL Exception: " + e, Toast.LENGTH_LONG).show();
} catch (IOException e) {
Toast.makeText(this.LongOperation, "IO Exception: " + e, Toast.LENGTH_LONG).show();
} catch (JSONException e) {
Toast.makeText(this.LongOperation, "JSON Exception: " + e, Toast.LENGTH_LONG).show();
}
return null;
}
#Override
protected void onPostExecute(String result) {
}
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
ProgressDialog pd = new ProgressDialog(LongOperation);
pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pd.setMessage("Working...");
pd.setIndeterminate(true);
pd.setCancelable(false);
}
}
Any ideas on how to fix this?
Here is what you should do to make it work as you want. Use onPostExecude()
public class Main extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new LongOperation(this).execute();
}
}
class LongOperation extends AsyncTask<String, Void, String> {
private Main longOperationContext = null;
public LongOperation(Main context) {
longOperationContext = context;
Log.v("LongOper", "Konstuktor");
}
#Override
protected String doInBackground(String... params) {
Log.v("doInBackground", "inside");
StringBuilder sb = new StringBuilder();
try {
URL json = new URL("http://www.corps-marchia.de/jsontest.php");
URLConnection tc = json.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(tc.getInputStream()));
String line;
while ((line = in.readLine()) != null) {
JSONArray ja = new JSONArray(line);
JSONObject jo = (JSONObject) ja.get(0);
Log.v("line = ", "jo.getString() ="+jo.getString("text"));
sb.append(jo.getString("text") + " - " + jo.getString("secondtest")).append("\n");
}
} catch (MalformedURLException e) {
e.printStackTrace();
Log.v("Error", "URL exc");
} catch (IOException e) {
e.printStackTrace();
Log.v("ERROR", "IOEXECPTOIn");
} catch (JSONException e) {
e.printStackTrace();
Log.v("Error", "JsonException");
}
String result = sb.toString();
return result;
}
#Override
protected void onPostExecute(String result) {
Log.v("onPostExe", "result = "+result);
TextView txtView1 = (TextView)longOperationContext.findViewById(R.id.textView01);
txtView1.setText(result);
}
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
ProgressDialog pd = new ProgressDialog(longOperationContext);
pd.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
pd.setMessage("Working...");
pd.setIndeterminate(true);
pd.setCancelable(false);
}
}
The implementation of AsyncTask in one of the other answers is flawed. The progress dialog is being created every time within publishProgress, and the reference to the dialog is not visible outside the method. Here is my attempt:
public class Main extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
new LongOperation().execute();
}
class LongOperation extends AsyncTask<String, Void, String> {
ProgressDialog pd = null;
TextView tv = null;
#Override
protected void onPreExecute(){
tv = Main.this.findViewById(R.id.textvewid);
pd = new ProgressDialog(Main.this);
pd.setMessage("Working...");
// setup rest of progress dialog
}
#Override
protected String doInBackground(String... params) {
//perform existing background task
return result;
}
#Override
protected void onPostExecute(String result){
pd.dismiss();
tv.setText(result);
}
}
}
You are trying to do something which won't work. First of all you are inside of a class that extends AsyncTask so you won't have that method available as it is a method of the class Activity.
The second problem is that you are trying to do UI stuff in a method that is not synchronized with the UI thread. That is nothing you would want to do.
Process your JSON response in the doInBackground method and pass the result to the onPostExecute method where you will be able to handle UI stuff as it is synchronized with the UI thread.
The current setup you have will not make it easier for you to handle what you are trying to do anyway. You could make your LongOperation class a private class of your Activity class and define the TextView as a instance member. Grab it off the layout using findViewById inside of your OnCreate and modify (set text or whatever) inside the onPostExecute method of your AsyncTask.
I hope it is somewhat clear what I meant.
findViewById is method in Activity class. You should pass instance of your activity to your LongOperation when you create it. Then use that instance to call findViewById.