So my code seems to run just fine until it hits this line
adapter.notifyDataSetChanged();
The error that pops up in the logcat is CalledFromWrongThreadException. The debug also shows the handler being run in the Background thread. How do I get the handler to bind to the main thread, and not the background one? I thought I just had to create the handler in the main thread, but I guess I am wrong, quite possible I am new to andriod. How do I fix this?
//Imports are included
public class DirectoryActivity extends ListActivity {
private ProgressDialog ProgressDialog = null;
private ArrayList<DirectoryListing> listing = null;
private DirectoryAdapter adapter;
private Runnable viewOrders;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.directory);
final Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
if (listing != null && listing.size() > 0) {
adapter.notifyDataSetChanged();
for (int i = 0; i < listing.size(); i++)
adapter.add(listing.get(i));
Log.e("log_tag", "\nStill running\n");
}
ProgressDialog.dismiss();
adapter.notifyDataSetChanged();
}
};
listing = new ArrayList<DirectoryListing>();
adapter = new DirectoryAdapter(this, R.layout.rows, listing);
setListAdapter(adapter);
ProgressDialog = ProgressDialog.show(DirectoryActivity.this, "Please wait...", "Retrieving data ...", true);
viewOrders = new Runnable() {
#Override
public void run() {
listing = PreparePage.getArrayList();
handler.handleMessage(null);
}
};
Thread thread = new Thread(null, viewOrders, "Background");
thread.start();
}
private static class PreparePage {
protected static ArrayList<DirectoryListing> getArrayList() {
ArrayList<DirectoryListing> listings = new ArrayList<DirectoryListing>();
JSONObject information = GetPageData.getJSONFromURL(url);
Iterator key = information.keys();
while (key.hasNext()) {
String id = (String) key.next();
JSONObject info = null;
try {
info = information.getJSONObject(id);
} catch (JSONException e) {
e.printStackTrace();
}
String name = "", title = "", photo = "";
try {
name = info.get("firstName") + " " + info.get("lastName");
title = info.getJSONObject("position").getString("name");
photo = info.optString("photoPath", "none");
} catch (JSONException e) {
e.printStackTrace();
}
listings.add(new DirectoryListing(name, title, photo));
}
return listings;
}
}
}
Try calling handler.sendEmptyMessage(0); instead of handler.handleMessage(null);
I don't know why this would cause the errors you are seeing, but this is how I have it set up when I use handler and thread instead of AsyncTask. And I have have never seen that error doing it this way.
#Nguyen is right though AsyncTask is the preferred way to handle these types of things now. And it actually makes it much easier to do.
AsyncTask docs
AsyncTask Example
In my experience, you should create your own class that extends AsyncTask class to do something at background. This is a simpler and more effectively than using thread + handler.
Related
I am using OkHttpClient to get the Staff List (in JSON form) as response using AsyncTask Function. After getting the response in AsyncTask funtion, while inserting staff list in database, I want to show the count on the screen. but it gives following error. I tried many solutions, but couldn't resolve.
Following is the synchronizeStaffList Activity that calls SenkronizeEt Funtion using handler.
public class synchronizeStaffList extends AppCompatActivity {
DatabaseHelper gksDatabase;
TextView txtrecordValue;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_synchronize_staff_list);
gksDatabase = new DatabaseHelper(this);
txtrecordValue = (TextView) findViewById(R.id.txtrecordValue);
final Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
//Do something after 100ms
SenkronizeEt();
}
}, 500);
final Handler handler2 = new Handler();
handler2.postDelayed(new Runnable() {
#Override
public void run() {
//Do something after 100ms
AlertDialog.Builder builder;
builder = new AlertDialog.Builder(synchronizeStaffList.this);
builder.setCancelable(false);
if (progressStaffListInfo == 0) {
builder.setMessage("Sunucu ile iletişim yok");
} else if (progressStaffListInfo == 1) {
builder.setMessage("Sicil/Personel listesi güncellendi");
}
builder.setPositiveButton("Tamam", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
// if user pressed "MINIMIZE", cancel this dialog & minimize the application
// while attendance process will keep working in the back
// finish();
startActivity(new Intent(synchronizeStaffList.this, synchronize.class));
finish();
}
});
AlertDialog alert = builder.create();
alert.show();
}
}, 5000);
}
I uses second handler to show an alertbox.
Following the SenkronizeEt Function that call OkHttpHandler AsyncTask function to get the okHttpResponse/result
public int progressStaffListInfo = 0; // 0: List no updated, 1: List updated,
private void SenkronizeEt() {
progressStaffListInfo = 0;
// Updating Staff List in device by calling webservices
HashMap<String, String> Parametre = gksDatabase.GetParameter();
final String urlStaffList = "http://127.0.0.1:8080/JAXRSJsonCRUDExample/rest/employees/" + Parametre.get("DeviceNo");
OkHttpHandler handler = new OkHttpHandler();
String jsonEmployeesList = null;
try {
jsonEmployeesList = handler.execute(urlStaffList).get();
} catch (Exception e) {
//tv.setText("sorry, something went wrong !");
}
if (progressStaffListInfo == 0) {
Toast.makeText(synchronizeStaffList.this, "List Not Updated", Toast.LENGTH_SHORT).show();
} else if (progressStaffListInfo == 1) {
Toast.makeText(synchronizeStaffList.this, "List updated in database", Toast.LENGTH_SHORT).show();
}
}
Here is the OkHttpHandler AsyncTask function that call the URL to get the response and then update it in database.
public class OkHttpHandler extends AsyncTask<String, Integer, String> {
OkHttpClient client = new OkHttpClient();
#Override
protected String doInBackground(String... params) {
Request.Builder builder = new Request.Builder();
builder.url(params[0]);
Request request = builder.build();
try {
Response response = client.newCall(request).execute();
// return response.body().string();
String jsonData = response.body().string();
//JSONObject Jobject = new JSONObject(jsonData);
//JSONArray Jarray = Jobject.getJSONArray("employees");
JSONArray Jarray = new JSONArray(jsonData);
//get the length of the json array
int limit = Jarray.length();
if (limit != 0) {
gksDatabase.PersonsDelete();
progressStaffListInfo = 1; // Staff List updated
}
for (int i = 0; i < limit; i++) {
JSONObject object = Jarray.getJSONObject(i);
//store the data into database
// SId:StaffID SNo:StaffNumber SN:StaffName CNo:CardNumber
gksDatabase.PersonsSave(Integer.parseInt(object.getString("sid")), object.getString("sno"), object.getString("sn"),
object.getString("cno")
);
publishProgress((int) (((i+1) / (float) limit) * 100));
}
return jsonData;
} catch (JSONException e) {
progressStaffListInfo = 0;
} catch (Exception e) {
e.printStackTrace();
progressStaffListInfo = 0;
}
return null;
}
#Override
protected void onProgressUpdate(Integer... progress) {
setProgressPercent(progress[0]);
}
}
private void setProgressPercent(int progValue){
txtrecordValue.setText(progValue);
}
In above AsyncTask function, it gives error when it try to display the count of entries inserted in database.
Actually, not only this. if I set any thing (Like progressbar or count) on different thread, even then it stops till the asyncTask finishes its work. As an example AlertDialog handler also starts when AsyncTask function finishes all its work.
Following are the logs:
E/AndroidRuntime: FATAL EXCEPTION: main android.content.res.Resources$NotFoundException: String resource ID #0x0
at android.content.res.Resources.getText(Resources.java:249)
at android.support.v7.widget.ResourcesWrapper.getText(ResourcesWrapper.java:52)
at android.widget.TextView.setText(TextView.java:3796)
at com.emiturk.gsk.synchronizeStaffList.setProgressPercent(synchronizeStaffList.java:172)
at com.emiturk.gsk.synchronizeStaffList.access$100(synchronizeStaffList.java:25)
at com.emiturk.gsk.synchronizeStaffList$OkHttpHandler.onProgressUpdate(synchronizeStaffList.java:167)
at com.emiturk.gsk.synchronizeStaffList$OkHttpHandler.onProgressUpdate(synchronizeStaffList.java:116)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:647)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4810)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:556)
at dalvik.system.NativeStart.main(Native Method
Kindly help me out.
You cannot set int value on textView so it should be a String object so do it like
private void setProgressPercent(int progValue){
txtrecordValue.setText(""+progValue);
}
""+ will implicitly convert your progValue to String as if first parameter is a string (which it is empty string "") along with + then other will be promoted to string
I got a weird problem with an android activity : I re-used one of my previous activity that works well, but this time all I got is "Can't create handler inside thread that has not called Looper.prepare()"
I tried to debug, and everything in the async task is performing well but when I reach then end of onPostExecute() the error is raised.
So I tried to disable my process about the process dialog, the only change is that it's crashing on line upper.
Here is the code :
public class DateActivity extends ActionBarActivity{
ProgressDialog mProgressDialog;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_date);
ActionBar actionBar = this.getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setTitle(getResources().getString(R.string.actionbar_titre_date));
if (VerifConnexion.isOnline(this)) {
this.mProgressDialog = ProgressDialog.show(this, getResources().getString(R.string.loading),
getResources().getString(R.string.loading), true);
new QueryForDateTask().execute(this.mProgressDialog, this, this.getApplicationContext());
} else {
...
}
});
alertDialog.show();
}
}
private class QueryForDateTask extends
AsyncTask<Object, Void, ArrayList<String>> {
private ProgressDialog mProgressDialog;
private Activity act;
private Context context;
protected ArrayList<String> doInBackground(Object... o) {
this.mProgressDialog = (ProgressDialog) o[0];
this.act = (Activity) o[1];
this.context = (Context) o[2];
ArrayList<String> listeDate = this.parseJSON(this.startQuerying());
return listeDate;
}
public JSONObject startQuerying() {
JSONRequest jr = new JSONRequest();
String from = getResources().getString(R.string.api_param_from);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd", Locale.FRANCE);
from += "=" + sdf.format(new Date());
String url = getResources().getString(
R.string.api_dates_json);
JSONObject jo = jr.getJSONFromUrl(url + "?" + from);
return jo;
}
public ArrayList<String> parseJSON(JSONObject jsonObject) {
ArrayList<String> l = new ArrayList<String>();
try {
JSONArray array = jsonObject.getJSONArray("dates");
if (array != null) {
for (int i = 0; i < array.length(); i++) {
String type = array.getString(i);
l.add(type);
} // fin parcours JSONArray
}
} catch (Exception _e) {
}
return l;
}
protected void onProgressUpdate(Integer... progress) {
// setProgressPercent(progress[0]);
}
protected void onPostExecute(ArrayList<String> lDate) {
// Create items for the ListView
DateAdapter adapter = new DateAdapter(this.context, R.layout.searchitem_date, lDate, this.act);
// specify the list adaptor
((ListView)findViewById(R.id.list)).setAdapter(adapter);
this.mProgressDialog.dismiss();
}
} // fin async
}
I tried this to replace the call to the AsyncTask :
runOnUiThread(new Runnable() {
public void run() {
QueryForDateTask task = new QueryForDateTask();
task.execute(DateActivity.this.mProgressDialog, DateActivity.this, DateActivity.this.getApplicationContext());
}
});
(like explained in Asynctask causes exception 'Can't create handler inside thread that has not called Looper.prepare()' as far as I understood), but the result is exactly the same.
So I can't understand why it is not working in this activity despite all is ok for the other ones of the project.
Any clue ?
Thank a lot for all ideas :)
Just a post to mark the trouble as resolved :
the adapter i used was buggy in parsing parameters and throwed a NullPointerException.
I just fixed it, the AsyncTask is now running without problem.
Could you help me to change piece of code to show progresDialog or some information during database creation. I have tried to do this with Thread with no success. When I put most of code to thread I get error, when only db.createDataBase() "text" is set before database is created.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myCalendar = new MyCalendar();
menu = (TextView) findViewById(R.id.poleMenu);
text = (TextView) findViewById(R.id.glownePoleTekstowe);
menu.setText(kalendarz.setCurrentDateOnView());
value = menu.getText().toString();
db = new DatabaseHandler(this);
try {
// separate class to load database
// MOST IMPORTANT
db.createDataBase();
} catch (IOException ioe) {
throw new Error("nie można utworzyć bazy danych");
}
dane = db.getDataFromDate(value);
db.close();
try {
log = dane.getTekst();
}catch(Exception e) {System.out.println(e);}
text.setText(log);
}
Update, with thread and handler:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
kalendarz = new Kalendarz();
menu = (TextView) findViewById(R.id.poleMenu);
text = (TextView) findViewById(R.id.glownePoleTekstowe);
menu.setText(kalendarz.setCurrentDateOnView());
value = menu.getText().toString();
db = new DatabaseHandler(this);
// thread
ladujDane();
dane = db.getDaneFromDate(value);
db.close();
try {
log = dane.getTekst();
}catch(Exception e) {System.out.println(e);}
text.setText(log);
}
//------------------------------------------
public void ladujDane() {
mLoadDBHandler = new Handler()
{
#Override
public void handleMessage(Message msg)
{
progressDialog.dismiss();
}
};
progressDialog = ProgressDialog.show(
this,
"Ładowanie danych", "Proszę chwilkę poczekać",
true,
false);
Thread t = new Thread(new LoadDBThread());
t.start();
}
//----------------------------------------
private class LoadDBThread implements Runnable
{
public void run()
{
try {
db.createDataBase();
} catch (IOException ioe) {
throw new Error("nie można utworzyć bazy danych");
}
mLoadDBHandler.sendEmptyMessage(0);
}
}
Your problem is that you are trying to do UI operations on another thread than the main thread.
You could use a handler for that. First declare a handler:
Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
// do UI stuff
}
};
Then from your thread that creates DB you call: handler.sendEmptyMessage(0);
Just use AsyncTask you can safetly mage progress bar from it's onProgress.
You can't change UI elements from thread other than UI thread, on the other hand you can't do long lasting operations in UI thread. AsyncTask is your answer.
Please help with this error .... In the following code the get info function works correctly but it gives an error saying the thread caught an exception at exiting.... I am trying to use a tab host and the first tab page is the following... In this i show a progress dialog until i get my data and then show it in a list view
public class History extends Activity implements OnItemClickListener
{
/** Called when the activity is first created. */
ListView list;
//LIST OF ARRAY STRINGS WHICH WILL SERVE AS LIST ITEMS
ArrayList<String> listItems;
//DEFINING STRING ADAPTER WHICH WILL HANDLE DATA OF LISTVIEW
ArrayAdapter<String> adapter;
private String resDriver,resPassenger,ID;
private ProgressDialog dialog;
ArrayList<HashMap<String, Object>> listInfo = new ArrayList<HashMap<String, Object>>();
HashMap<String, Object> item;
JSONObject jDriver;
//JSONObject jPassenger;
// Make strings for logging
private final String TAG = this.getClass().getSimpleName();
private final String RESTORE = ", can restore state";
private final String state = "Home Screen taking care of all the tabs";
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
Intent loginIntent = getIntent();
ID = loginIntent.getStringExtra("ID");
listItems = new ArrayList<String>();
Log.i(TAG, "Started view active rides");
setContentView(R.layout.searchresults);
list = (ListView)findViewById(R.id.ListView01);
list.setOnItemClickListener(this);
adapter=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,listItems);
list.setAdapter(adapter);
getInfo();
}
The function getInfo is used to start a thread which shows a dialog box and starts a http request to get some data ...
public void getInfo(){
GetInfoThread checkUpdate = new GetInfoThread();
checkUpdate.start();
dialog = ProgressDialog.show(History.this, "Retrieving Info","Please Wait ...", true);
}
private class GetInfoThread extends Thread
{
public void run() {
jDriver = new JSONObject();
try {
jDriver.put("ID", ID);
jDriver.put("task", "GET DATES");
} catch (JSONException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
listItems = new ArrayList<String>();
Log.i(TAG,"Sending data for the driver rides");
resDriver = HTTPPoster.sendJson(jDriver,"http://dsadsada"); // Any Server URL
JSONObject driver;
try {
driver = new JSONObject(resDriver);
Log.i(TAG,"Recieved Driver details");
listItems.add(array[0]);
handler.sendEmptyMessage(0);
}
}
} catch (JSONException e) {
// TODO Auto-generated catch block
listItems.add("No driver rides created");
handler.sendEmptyMessage(0);
}
}
private Handler handler = new Handler() {
#Override
public void handleMessage(Message msg) {
dialog.dismiss();
Log.i(TAG,"hello 123");
adapter.notifyDataSetChanged();
}
};
}
I am not sure exactly what is causing your error but I suspect it has to do with UI changes not running on the actual UI thread. In Android there is a class called AsyncTask that will do the threading for you and handle the passing of data between the background thread an the UI thread. I would suggest rewriting your code to utilize the AsyncTask class.
I never got this working in a straightforward manner. Sorry if I'm being a little vague. I'll try to elaborate on what I'm trying to do. I am trying to build a listview that grabs its data from a webservice. Once I initialize a listview, I want to keep polling the webserver periodically and update the contents of the listview. For this I am doing something like this:
public class SampleAutoUpdateList extends Activity {
//Autoupdate handler
private Handler handler = new Handler();
private Runnable updater = new Runnable() {
public void run() {
/*
* Update the list
*/
try {
Log.i("UPDATE", "Handler called");
searchAdapter = getFeed(URL);
searchAdapter.notifyDataSetChanged();
handler.postDelayed(this, Configuration.REFRESH_INTERVAL);
} catch(Exception e) {
Log.e("UPDATE ERROR", e.getMessage());
}
}
};
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.linearmode);
this.context = this;
searchAdapter = getFeed(URL);
LinearLayout l2 = (LinearLayout) findViewById(R.id.secondaryLayout);
ListView list = new ListView(context);
l2.addView(list);
// display UI
UpdateDisplay(list);
updater.run();
}
private SearchAdapter getFeed(String URL) {
try
{
SearchHandler handler = new SearchHandler();
URL url = new URL(URL);
String data = convertStreamToString(url.openStream());
data = data.substring(data.indexOf('['), data.length()-1);
handler.parseJSON(data);
return handler.getFeed();
}
catch (Exception ee)
{
// if we have a problem, simply return null
Log.e("getFeed", ee.getMessage());
return null;
}
}
private void UpdateDisplay(View searchView) {
// TODO Auto-generated method stub
// TODO Auto-generated method stub
searchList = (ListView) searchView;
myProgressDialog = ProgressDialog.show(this,
"Please wait...", "Loading search....", true);
new Thread() {
public void run() {
try{
Thread.sleep(2000);
} catch (Exception e) { }
runOnUiThread(new Runnable() {
#Override
public void run() {
if (searchAdapter == null)
{
Log.e("ERROR", "No Feed Available");
return;
}
searchAdapter.setContext(context);
searchList.setAdapter(searchAdapter);
searchList.setSelection(0);
}
});
// Dismiss the Dialog
myProgressDialog.dismiss();
}
}.start();
}
}
And the SearchHandler class is simple:
public class SearchHandler extends DefaultHandler {
SearchAdapter _adapter;
SearchItem _item;
public SearchHandler()
{
}
public SearchAdapter getFeed()
{
return _adapter;
}
public void parseJSON(String data) {
// TODO Auto-generated method stub
_adapter = new SearchAdapter();
JSONArray parseArray;
try {
parseArray = new JSONArray(data);
for (int i=0; i < parseArray.length(); i++) {
SearchItem item = new SearchItem();
JSONObject jsonUser = parseArray.getJSONObject(i);
item.set_from(jsonUser.getString ("from"));
item.set_msg(jsonUser.getString("msg"));
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
No matter what I do, the handler gets called and the new items are fetched, but the list is never refreshed... Any ideas on what could be going wrong?
Well, it is a little bit difficult to follow your code, since you only have a fragment of it, and few of the really relevant bits. For example, based on your available code, your list should be forever empty, since you never associate the searchAdapter with a ListView...at least in the code you have shown.
That being said, the following lines seem particularly odd:
searchAdapter = getFeed(URL);
searchAdapter.notifyDataSetChanged();
I am going to assume that getFeed() (not shown) creates a new ListAdapter of some sort. If getFeed() is creating a new ListAdapter, there is no need to call notifyDataSetChanged() on it, as its data set hasn't changed -- it's brand new. Moreover, unless you are associating this new ListAdapter to your ListView, the new ListAdapter will have no effect.
If I'm barking up the wrong tree, consider adding lines to your sample showing the implementation of getFeed() and where you are using searchAdapter.