How can you call a method within an AsyncTask? In my asynctask,which is an inner class in my java file 'xyz', when the user clicks a button, it should call a method within 'xyz' which also happens to be an alertDialog, i know it calls it, but when it reaches the method, the app crashes and gives a runtime exception, which says 'Can't create handler inside thread that has not called Looper.prepare()'. I looked up examples here but it threw the same runtime exception. How can i make it work? isn't calling an outer method from within the asynctask a possibility?
this is the snippet to call the method:
private class DownloadFilesTask extends AsyncTask<Void,Void,Void> {
private LoginActivity loginActivity;
public DownloadFilesTask(LoginActivity loginActivity){
this.loginActivity=loginActivity;
}
#Override
protected Void doInBackground(Void... voids) {
long start=System.currentTimeMillis();
in=null;
try {
website=new URI(URL);
request.setURI(website);
} catch (URISyntaxException e) {
e.printStackTrace();
}
HttpPost httpPost=new HttpPost(URL);
List<NameValuePair>nameValuePairs=new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("name",name));
nameValuePairs.add(new BasicNameValuePair("pwd",pwd));
try {
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
try {
response=httpClient.execute(request);
} catch (IOException e) {
e.printStackTrace();
}
try {
in=new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
} catch (IOException e) {
e.printStackTrace();
}
try {
String line=in.readLine();
long end=System.currentTimeMillis();
long times=end-start;
String time=String.valueOf(times);
System.out.println(name);
System.out.println(NAME_PATTERN);
System.out.println(pwd);
System.out.println(PWD_PATTERN);
if (name.equals(NAME_PATTERN) && (pwd.equals(PWD_PATTERN))) {
bloggedIn=true;
System.out.println("Youre right");
}else
{
bloggedIn=false;
System.out.println(line);
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
private void onPostExecute(String line, String time) {
if(bloggedIn=true){
navigateToMainActivity(time);
}else{ if (bloggedIn=false){
newp(line,time);
}
}
}
}
and this is the method called:
public void navigateToMainActivity(String timetoo) {
al=new AlertDialog.Builder(LoginActivity.this);
al.setTitle("Welcome");
al.setMessage("Hey there");
al.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
startActivity(new Intent(LoginActivity.this, Main.class));
}
});
al.show();
}
It looks like you need doInBackground to return true or false when it's finsished. You need doInBackground to return the boolean. Try this:
#Override
protected Boolean doInBackground(Void... arg0)
{
// your stuff
return bloggedIn; // instead of null or return the boolean where you are setting it true or false
}
Then your onPostExecute should look like this:
#Override
protected void onPostExecute(Boolean result)
{
super.onPostExecute(result);
if(result){
navigateToMainActivity(time);
}else{
newp(line,time);
}
}
Related
I have two activities, When I will move from activity A to B, B keeps restarting or "refreshing", when i go back from B to A, it also keeps restarting. The code is very big, here I am posting area where I think problem causes :
Thread t = new Thread(new Runnable() {
#Override
public void run() {
while (true) {
deviceStatus();
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
t.start();
this is deviceStatus();
public void deviceStatus(){
try {
RequestQueue requestQueue = Volley.newRequestQueue(InActivate.this);
String URL = "http://gickuwait-dev.com/electionapi/api/DeviceStatus";
JSONObject jsonBody = new JSONObject();
jsonBody.put("device_PK", device_ID2);
final String requestBody = jsonBody.toString();
StringRequest stringRequest = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
if(response.equals("true")){
Intent intent = new Intent(InActivate.this, Vote.class);
startActivity(intent);
finish();
}else if(response.equals("false")) {
}
// Toast.makeText(getApplicationContext(), response.toString(), Toast.LENGTH_SHORT).show();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("VOLLEY", error.toString());
}
}) {
#Override
public String getBodyContentType() {
return "application/json; charset=utf-8";
}
#Override
public byte[] getBody() throws AuthFailureError {
try {
return requestBody == null ? null : requestBody.getBytes("utf-8");
} catch (UnsupportedEncodingException uee) {
VolleyLog.wtf("Unsupported Encoding while trying to get the bytes of %s using %s", requestBody, "utf-8");
return null;
}
}
#Override
protected Response<String> parseNetworkResponse(NetworkResponse response) {
String responseString;
String json = null;
try {
json = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
responseString = String.valueOf(json).trim();
ArrayList<DeviceStatusResponse> list = new ArrayList<DeviceStatusResponse>();
Type listType = new TypeToken<List<DeviceStatusResponse>>() {}.getType();
list = new Gson().fromJson(responseString, listType);
device_Status = list.get(0).getIsActive().toString();
// Toast.makeText(getApplicationContext(), ""+device_Status+" null ", Toast.LENGTH_LONG).show();
return Response.success(device_Status, HttpHeaderParser.parseCacheHeaders(response));
}
};
requestQueue.add(stringRequest);
} catch (JSONException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
}
in Activity B, i have the same code to check the device status from the database, any help would be appreciated
You can use Handle to check the repeated task.
private Handler delayHandler = new Handler();
private Runnable runnable = new Runnable() {
#Override
public void run() {
deviceStatus();
driverDelayHandler.postDelayed(runnable, 1000);
}
};
Don't forgot to cancel on onStop method.
delayHandler.removeCallbacks(runnable);
I have push Notification and I want to update realm objects when the phone gets a notification but when I try launch this:
RealmModelActiveUser actUser= realm.where(RealmModelActiveUser.class).equalTo("id",1).findFirst();
int myid= actUser.getUser().getUser_id();
new ServerBackgroundDownloadConversations(getApplicationContext()) {
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (!result.equals("Error")) {
Log.i("Conversation", "UPDATED");
}
}
}.execute(myid);
The program jumps into the constructor ServerBackgroundDownloadConversations(getApplicationContext()) but doesn't call doInBackground and I don't know why.
My AsyncTask:
public class ServerBackgroundCreateConversation extends AsyncTask<RealmModelConversations,Void,String> {
Context context;
Handler handler;
String out= "";
#SuppressLint("HandlerLeak")
public ServerBackgroundCreateConversation(Context context) {
this.context = context;
handler = new Handler() {
#Override
public void handleMessage(Message msg) {
Bundle bundle= msg.getData();
if (bundle!=null){
out = (String) bundle.get("response");
} else {
out= "Error";
}
}
};
}
#Override
protected String doInBackground(RealmModelConversations... params) {
RealmModelConversations newConv = params[0];
UploadImageApacheHttp uploadTask = new UploadImageApacheHttp();
uploadTask.doFileUpload(newConv.getWork(newConv.getIntWork()), newConv, handler);
while (out.equals("")){
try {
Thread.sleep(50);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return out;
}
#Override
protected void onPreExecute() {
}
#Override
protected void onPostExecute(String result) {
if (!result.equals("]") || !result.equals("")){
/// prihlási nového user aj do active (login/register)
CreateNewConversation(result);
} else {
result="Error";
}
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
private void CreateNewConversation(String result){
Realm realm= Realm.getDefaultInstance();
try {
Gson gson = new Gson();
Type typeConv = new TypeToken<JsonSablonaConversations>() {
}.getType();
JSONObject pom;
JSONArray parentArray = new JSONArray(result);
JSONObject finalObject = parentArray.getJSONObject(0);
JsonSablonaConversations conversation = gson.fromJson(finalObject.toString(), typeConv);
final RealmModelConversations NewUserConv = new RealmModelConversations();
NewUserConv.setId_dialog(conversation.getId_dialog());
NewUserConv.setDate(conversation.getDate());
NewUserConv.setKey(conversation.getKey());
NewUserConv.setId_user(conversation.getId_user());
NewUserConv.setId_user2(conversation.getId_user2());
NewUserConv.setMeno(conversation.getMeno());
NewUserConv.setMeno2(conversation.getMeno2());
realm.executeTransaction(new Realm.Transaction() {
#Override
public void execute(Realm realm) {
try {
realm.copyToRealmOrUpdate(NewUserConv);
} catch (Exception e) {
int pom=4;
}
RealmResults<RealmModelConversations> ru= realm.where(RealmModelConversations.class).findAll();
}
});
}
catch (Exception e) {
int ppp=4;
ppp++;
}finally {
realm.close();
}
}
}
I try calling this ↑ from an external thread which is called from a Service, but my AsyncTask has handler and handler needs to be in runOnUIthread and in Thread. I can't get Activity because the thread is called from a Service which doesn't have access to Activity.
I solved my problem with this code
public String postData(int myUserId) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.gallopshop.eu/OFY/getConversations.php");
try {
// Add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("id", Integer.toString(myUserId)));
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
String responseStr = EntityUtils.toString(response.getEntity());
return responseStr;
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
} catch (IOException e) {
// TODO Auto-generated catch block
}
return null;
}
I will try to put this method & after this method into simply thread, But maybe it's not needed because it's in a service.
Question - Do I put this into Thread or do you think it'll affect the performance of the app?
Other class:
SpotifyTask st = new SpotifyTask(new Closure<JSONObject>() {
#Override
public void executeOnSuccess(JSONObject result) {
track.setJson(result);
}
});
st.execute("asd");
Being SpotifyTask:
public class SpotifyTask extends AsyncTask<Object, Void, JSONObject> {
private final Closure<JSONObject> closure;
public SpotifyTask(Closure<JSONObject> closure) {
this.closure = closure;
}
public static void getTrack(Closure<JSONObject> closure) {
new SpotifyTask(closure).execute("asd");
}
#Override
protected JSONObject doInBackground(Object... params) {
JSONObject result = null;
SpotifyCall spcall = new SpotifyCall();
try {
result = spcall.getTrack();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return result;
}
#Override
protected void onPostExecute(JSONObject result) {
System.out.println("ASD: on post execute "+result);
closure.executeOnSuccess(result);
}
}
So... doInBackground is running OK, and and returning a JSONObject all right; I know because Im debbuging it and "result" IS a JSONObject.
But onPostExecute is never executed, the debugger never gets there and "ASD: on postexecute "+result is never logged.
Any suggestions?
Thanks in advance!
The problem was that I was "holding" the UI Thread:
this.status = "loading";
final Track track = new Track();
SpotifyTask.getTrack(new Closure<JSONObject>() {
#Override
public void executeOnSuccess(JSONObject result) {
track.setJson(result);
}
});
while (this.status.equals("loading")) {
if (track.getJson() != null) {
this.trackUno = track.getJson();
this.status = "ready";
} else {
try {
System.out.println("Not ready, waiting.");
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
As soon I removed the while block, it worked perfectly.
I would have to find another way to "wait" for the call to be complete.
Thanks for your time fellas!
I coded a class which starts a http connection for getting the text of e.g. website.
I used AsyncTask but I got NetworkOnMainException. May u help me?
The class
public class getXMLData extends AsyncTask<String, Void, String> {
TextView _textview;
public getXMLData(TextView textview) {
_textview = textview;
}
protected String doInBackground(String... url)
{
String _text = "";
try {
try {
URL _url = new URL(url[0]);
HttpURLConnection con = (HttpURLConnection) _url.openConnection();
_text = readStream(con.getInputStream());
}
catch (Exception e) {
e.printStackTrace();
}
}
catch (Exception e) {
e.printStackTrace();
}
return _text;
}
protected void onPostExecute(String result)
{
_textview.setText(result.toCharArray(), 0, result.length());
}
private String readStream(java.io.InputStream in) {
java.io.BufferedReader reader = null;
String result = "";
reader = new BufferedReader(new InputStreamReader(in));
try {
while ((reader.readLine() != null)) {
result = result + reader.readLine();
}
}
catch (java.io.IOException i)
{
}
finally
{
try {
reader.close();
}
catch (java.io.IOException e) {
e.printStackTrace();
}
}
return result;
}
Here how I start the AsyncTask:
bu_aktualize.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
_getXMLData.doInBackground("http://www.google.de");
}
});
Thanks for your help.
You do not call doInBackground() yourself. Instead, you call execute() or executeOnExecutor() to start the AsyncTask.
You may wish to review the documentation for AsyncTask, which shows an example of setting up an AsyncTask, including a call to execute().
Hi Please Can someone help me look at this code? Don't know what am doing wrong,But the try block doesn't run. instead it goes to the catch block.
public void onClick(View arg0) {
//Toast.makeText(getBaseContext(), "connecting",Toast.LENGTH_SHORT).show();
// TODO Auto-generated method stub
httpclient = new DefaultHttpClient();
htpost = new HttpPost("http://10.0.2.2/fanaticmobile/log_in.php");
uname= username.getText().toString();
pass= password.getText().toString();
try {
namearray = new ArrayList<NameValuePair>();
namearray.add(new BasicNameValuePair("username", uname));
namearray.add(new BasicNameValuePair("password", pass));
htpost.setEntity(new UrlEncodedFormEntity(namearray));
response= httpclient.execute(htpost);
if(response.getStatusLine().getStatusCode()==200){
entity= response.getEntity();
if(entity != null){
InputStream stream = entity.getContent();
JSONObject jresponse = new JSONObject(ConvertInput(stream));
String logged= jresponse.getString("logged");
login_err.setText(""+logged);
if(logged.equals("true")){
Toast.makeText(getBaseContext(), "Successfull",Toast.LENGTH_SHORT).show();
//String retname= jresponse.getString("name");
//String retmail= jresponse.getString("email");
}else if(logged.equals("false")){
String message=jresponse.getString("message");
Toast.makeText(getBaseContext(), message,Toast.LENGTH_SHORT).show();
}
}
}else{
}
}
catch (Exception e) {
e.printStackTrace();
Toast.makeText(getBaseContext(), "Poor Connection",Toast.LENGTH_SHORT).show();
}
}//
This is the function to read the json object
private static String ConvertInput(InputStream is){
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line ="";
try {
while((line = reader.readLine())!= null){
sb.append("\n");
}
} catch (IOException e) {
e.printStackTrace();
}finally{
try {
is.close();
} catch (IOException e) {
// TODO: handle exception
e.printStackTrace();
}
}
return sb.toString();
}// end of convert function
Please am new to this and i followed a tutorial to this point,but mine is not working. Have set permission(internet) in the manifest file
I have a suggestion Try to Use AsyncHttpclient for getting responses from server no need of this long codes.
http://loopj.com/android-async-http/
AsyncHttpClient asyncHttpClient=new AsyncHttpClient();
RequestParams params=new RequestParams();
params.put("username", uname);
params.put("password", pass);
asyncHttpClient.post("http://10.0.2.2/fanaticmobile/log_in.php", params,new AsyncHttpResponseHandler(){
#Override
public void onFailure(Throwable arg0, String arg1) {
// TODO Auto-generated method stub
super.onFailure(arg0, arg1);
}
#Override
public void onSuccess(String arg0) {
// TODO Auto-generated method stub
super.onSuccess(arg0);
}
});
Just include the jar file in your project it will be simple to use.
Like already been stated in the comments, you're running a network operation in your main thread (the UI thread). This is not only discouraged (lengthy operations should never use the Main Thread), but also forbidden in the case of networking.
response= httpclient.execute(htpost)
^ this fails.
Read how to move that code to an AsyncTask and do it the right way in the official google reference. Googling AsyncTask will help too.
A Pseudo Code version would be:
public class YourTask extends AsyncTask<Void, Void, Void>{
YourListener mListener;
public YourTask(final YourListener listener) {
mListener = listener;
}
#Override
protected Void doInBackground(final Void... params) {
// do your lengthy operation here
return null;
}
#Override
protected void onPostExecute(Void result) {
mListener.onVeryLongTaskDone();
}
public interface YourListener {
public void onVeryLongTaskDone();
}
}
Then make your activity implement that "YourListener" interface and the method onVeryLongTaskDone() will be called.
How do you start the task?
in your onClick method:
(new YourTask(YourActivityName.this)).execute();