I defined an AsyncTask in a button's onclicklistener, and once user clicks the button, ideally progress dialog shows while asynctask downloading.
However, progress dialog just flashes in and disappears before the results returned, and the button gets focused while the asynctask works in the background.
Can someone help me figure out what I did wrong here? Code snippet:
final ProgressDialog progressDialog = new ProgressDialog(context);
progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
((Button)findViewById(R.id.buttonLoginActivity)).setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
AsyncTask<Void, Void, Void> downloadTask= new AsyncTask<Void, Void, Void>(){
#Override
protected Void doInBackground(Void... params) {
String data = Service.getSomeData();
context.getContentResolver.notifyChange("content://some_url");
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
if(progressDialog== null) return;
if(progressDialog!=null) {
progressDialog.dismiss();
progressDialog = null;
}
}
};
progressDialog.show();
downloadTask.execute();
try{
downloadTask.get();
}catch(Exception e){
e.printStackTrace();
return;
}
}
});
Don't use get()
downloadTask.get();
this is a blocking call. From the Docs
Waits if necessary for the computation to complete, and then retrieves its result.
Just use execute() as you are then do what you need with the results in onPostExecute()
show the progressDialog on the onPreExecute which need to be writen, and it will run on the UI thread, not in background ( android 4 )
also I would call the async task on a new Handler().post(myAsynctaskcaller)
#Override
protected void onPreExecute() {
super.onPreExecute();
progressDialog.show();
}
Related
I need to show simple progress bar dialog while some method not finish.
I Try to call it like
ProgressDialog progressDialog = ProgressDialog.show(Activity.this, "", "Please wait");
SyncCity()
SyncStreet()
progressDialog.dismiss();
But than app is blocked while method not finish,after that i get progress dialog,and in next second dissapear, sometimes i not See it at all.
All calling is going on button click...
Where is catch?
Thank You.
That's because you're blocking the UI thread. Try using AsyncTask, like this:
ProgressDialog progressDialog;
new AsyncTask<Void, Void, Void>() {
#Override
protected void onPreExecute() {
progressDialog = ProgressDialog.show(Activity.this, "", "Please wait");
}
#Override
protected Void doInBackground(Void... params) {
SyncCity()
SyncStreet()
return null;
}
#Override
protected void onPostExecute(Void args) {
progressDialog.dismiss();
}
}.execute();
You should use an AsyncTask to do such processes. You shouldn't do any process in the UI thread.
Here is a good example on how to use AsyncTask:
http://www.vogella.com/tutorials/AndroidBackgroundProcessing/article.html
I have a progress bar and I do not want to incorporate a numerical value to show the loading of some content. I just want that the ProgressBar should appear, animate and then go away.
I used:
public void buttonClick(View v){
ProgressBar mProgress=(ProgressBar)findViewById(R.id.my_progress);
mProgress.setVisibility(VISIBLE); //line 1..
//loading data from web... takes time
mProgress.setVisibility(INVISIBLE); //line 2..
}
but when I run this code, both line 1 and line 2 executes, but the UI changes afterwards, which is not desired. I want that when the button is clicked, the progress bar should appear and when the data is downloaded from the web the progress bar should disappear.
I tried setting the visibility from another thread, but it didn't work as UI changes are not allowed in other threads.
You download your data in AsyncTask right? Put this code
private class DownloadData extends AsyncTask<Void, Void, Void>{
#Override
protected void onPreExecute() {
super.onPreExecute();
mProgress.setVisibility(View.VISIBLE);
}
#Override
protected Void doInBackground(Void... params) {
// download your data here
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
mProgress.setVisibility(View.GONE);
}
}
The best way implement it by using an AsyncTask
MyTask.java
class MyTask extends AsyncTask<Void, Void, Void> {
ProgressDialog dialog;
Context context;
MyTask(Context context){
this.context=context;
}
#Override
protected void onPreExecute() {
dialog=new ProgressDialog(context);
dialog.setMessage("Please wait...");
dialog.setIndeterminate(true);
dialog.setCancelable(false);
dialog.show();
}
#Override
protected Void doInBackground(Void... params) {
//do your task here
}
#Override
protected void onPostExecute(Void result) {
if(dialog.isShowing()){
dialog.dismiss();
}
}
}
You can start the task like this:
public void buttonClick(View v){
new MyTask(YourActivity.this).execute();
}
You can modify the AsyncTask accordingly to retrieve the result.
Hope it helps. :)
I am new in android. I am trying to display ProgressDialog when click on button .
This is my code:
// set listener
btn_Login.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
//progress.show();
MyAsynch asynch = new MyAsynch();
asynch.execute();
}
In this code progress dialog too much late appear when i am comment on Asynctask object then progress dialog appear normally.
I am puting my progress dialog in
AsynchTask method
onPreExecute() but same out put dialog display late .
How to solve my problem..??
I am also read stack answers following link but not solve my problem .
async task progress dialog show too late
ProgressDialog appears too late and dissapears too fast
here is my Asynctask code
private class MyAsynch extends AsyncTask<String, Void, String> {
ProgressDialog progress;
String login_stat;
String stat;
#Override
protected void onPreExecute() {
progress = new ProgressDialog(this);
progress.setTitle(" User Login ");
progress.setMessage("Please Wait!!");
progress.setCancelable(false);
progress.setIndeterminate(true);
progress.setProgressStyle(ProgressDialog.STYLE_SPINNER);
progress.show();
}
#Override
protected String doInBackground(String... urls) {
try {
login_stat = s_ApiHandling.doLogin(m_Et_Username.getText()
.toString().trim(), m_Et_Password.getText()
.toString().trim());
} catch (Exception e) {
System.out.println("internet connection loss ");
stat = "ERORR";
e.printStackTrace();
}
return stat;
}
#Override
protected void onPostExecute(String status) {
progress.dismiss();
}
}
You are probably doing too much in onPreExecute
Remove progress.cancel() from your doInBackground method and put it in to a onPostExecute method in your AsyncTask (like the second link you posted)
You shouldn't have anything talking to the UI in a background thread - that should all be done in pre/post execution.
you code should look like this:
AsyncTask<String, Void, String>()
{
private ProgressDialog progressDialog = ProgressDialog.show(this, "", "Loading...");
#Override
protected void onPostExecute(String result)
{
progressDialog.dismiss();
}
#Override
protected String[] doInBackground(String... params)
{
//ALL CODE GOES HERE.
}
}
When you call the asynctask you must not use the get() method or the progress dialog won't work correctly.
I have problem in my app with progress dialog in AsyncTask:
my AsyncTask is doing some geting data from internet in doInBackGround(), I am starting progress dialog in onPreExecute(), finish dialog in onPostExecute().
I execute this asyncTask when click on Button. 1st time When I click this button (long operation takes place) progress dialog is not shown. But next times Progress dialog is shown normaly.
What can be the problem that 1st time of running AsyncTask, progress dialog isnt shown ?
this is onClick method:
public void onClickFind(View view){
new Task_Search().execute();
}
This is task Task_Search:
private class Task_Search extends AsyncTask<Void, Void, Void> {
#SuppressWarnings("deprecation")
protected void onPreExecute() {
showDialog(DIALOG_TASKING);
}
protected Void doInBackground(Void... unused) {
//some geting of web content here
}
#SuppressWarnings("deprecation")
protected void onPostExecute(Void unused) {
dismissDialog(DIALOG_TASKING);
}
}
progress dialog defined in MainActivity:
#SuppressWarnings("deprecation")
#Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_TASKING:
mSearchDialog = new ProgressDialog(this);
mSearchDialog.setMessage("Searching for field number..");
mSearchDialog.setCancelable(true);
return mSearchDialog;
}
return super.onCreateDialog(id);
}
Before of using AsyncTask I used separate Thread for downloading data instead: in onClick, I started first progressDialog then Thread, when Thread finished also progressDialog was stoped,
Behaviour was same:
1st time of click on Button dialog wasnt shown, next times its shown.
Anybody who can help ?
I cant see you calling show() on the dialog.
Replace
#SuppressWarnings("deprecation")
protected void onPreExecute() {
showDialog(DIALOG_TASKING);
}
with
#SuppressWarnings("deprecation")
protected void onPreExecute() {
showDialog(DIALOG_TASKING).show();
}
Do not call showDialog insode onPreExecute().
AsyncTask provides publishProgress() method which can be invoked from doInBackground() to publish updates on the UI thread.
Okay,
I created in MainActivity my own methods:
public void showProgressDialog() {
if (mProgressDialog == null) {
mProgressDialog = new ProgressDialog(this);
mProgressDialog.setMessage("Searching for field number..");
mProgressDialog.show();
return;
}else{
mProgressDialog.setMessage("Searching for field number..");
mProgressDialog.show();
return;
}
}
also:
public void closeProgressDialog() {
if (mProgressDialog != null) {
mProgressDialog.dismiss();
}
return;
}
I changed AsyncTask following:
private class Task_Search extends AsyncTask<Void, Void, Void> {
protected void onPreExecute() {
// showDialog(DIALOG_TASKING);
showProgressDialog();
}
protected Void doInBackground(Void... unused) {
//Some long duration stuff here
}
protected void onPostExecute(Void unused) {
//dismissDialog(DIALOG_TASKING);
closeProgressDialog();
}
}
mProgressDialog is a private member of MainActivity
private ProgressDialog mProgressDialog;
Situation is same: wheck onClick on button: 1st time ProgressDialog stuck, next times it works perfect
I have an AsyncTask that is supposed to show a progress bar while it uploads some stuff via Internet. Sometimes it works like a charm and sometimes it does not show any progress bar. Here is the code:
public class Upload extends AsyncTask<Void, Void, Void> {
private ProgressDialog dialog = new ProgressDialog(Activity.this);
protected void onPreExecute() {
dialog = ProgressDialog.show(Activity.this, "wait...", "", true, true);
}
#Override
protected Void doInBackground(Void... params) {
//upload stuff
return null;
}
protected void onPostExecute(Void result) {
try {
if (dialog.isShowing())
dialog.dismiss();
dialog = null;
} catch (Exception e) {
// nothing
}
Intent next = new Intent(getApplicationContext(), SecondActivity.class);
startActivity(next);
}
}
}
The doInBackground and onPostExecute work always, and sometimes altogether it works like a charm. But sometimes, there is no progress bar while it is uploading. Is this a race condition? I do not think so, but I cannot find any explanation.
You're creating the object twice in the class. The ProgressDialog.show already returns a created ProgressDialog object, but you have instantiated it first at the top. The ProgressDialog should be instantiated once, so try removing the instantiation at the top and try again, like so:
private ProgressDialog dialog;
protected void onPreExecute() {
dialog = ProgressDialog.show(Activity.this, "wait...", "", true, true);
}
Maybe it is because void parameter that causes that problem. Just try to use Integer as your parameters.:
public class Upload extends AsyncTask<Integer, Integer, Integer>