I have a stub activity with progress bar and two labels, and another activity, that may do heavy task (initialize sqlite db from xml resources at first start).
I need start second activity after progress bar and labels are shown.
I'm trying
stubLayout.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
if (progress.getHeight() <= 0 || progress.getWidth() <= 0) return;
if (label1.getHeight() <= 0 || label1.getWidth() <= 0) return;
if (label2.getHeight() <= 0 || label2.getWidth() <= 0) return;
stubLayout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
Intent intent = new Intent();
intent.setClass(getApplicationContext(), SongListActivity.class);
startActivity(intent);
}
});
But I see empty screen while heavy activity is starting.
What am I doing wrong?
I've already found solution myself.
I've found that system create db not on get instance of db helper, but on first query.
The solution is to init db in AsyncTask and start the second activity on post execute:
AsyncTask<Void, Void, Void> initDbTask = new AsyncTask<Void, Void, Void>(){
SongDBHelper helper;
String[] artists;
#Override
protected Void doInBackground(Void... params) {
helper = SongDBHelper.getInstance(getApplicationContext(), getResources());
artists = helper.getArtistList();
return null;
}
#Override
protected void onPostExecute(Void result) {
Intent intent = new Intent();
intent.setClass(getApplicationContext(), SongListActivity.class);
startActivity(intent);
}
};
initDbTask.execute(null, null, null);
I may call your activity with progress bar SplashActivity that shows on start up. In this activity you should do your heavy task (sql initialize) in an AsyncTask. When the AsyncTask is done, just call your other activity to show.
Some stuff of code:
SplashActivity
public void onCreate(Bundle savedInstance){
super.onCreate(savedInstanceState);
setContentView(R.layout.splash_activity);
new AsyncTask<Params, Progress, Result>(){
#Override
protected Param doInBackground(Params... params) {
// DO YOUR SQL STUFF HERE
return null;
}
#Override
protected void onPostExecute(Param aParam) {
super.onPostExecute(aVoid);
// DO YOUR NEXT STEP HERE AFTER SQL TASK DONE
}
}.execute(..some parameters..);
}
Try the following:
#Override
public void onWindowFocusChanged (boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if (hasFocus ){
// start your new activity
}
}
This method is called when window receives focus and this is after all the views are shown.
Related
I have this code in my activity (LoadTask is an inner class):
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
ProgressDialog loading = new ProgressDiaolg(this);
...
}
public class LoadTask extends AsyncTask<Context, Void, Integer> {
ArrayList<HashMap<String, String>> list = new ArrayList<HashMap<String, String>>();
#Override
protected void onPreExecute() {
loading.show();
}
#Override
protected Integer doInBackground(Context... params) {
EventLoader el = new EventLoader(params[0]);
list = el.getMylist();
return el.getError();
}
protected void onPostExecute(Integer result) {
if (result == EventLoader.NO_HTTP_CONN) {
getErrorDialog(R.string.errore_caricamento, true).show();
} else if (result == EventLoader.ERR_JSON) {
getErrorDialog(R.string.errore_json, true).show();
} else if (result == EventLoader.ERR_NULL) {
getErrorDialog(R.string.errore_evento_null, true).show();
} else {
mainList=list;
Intent intent = new Intent(MainActivity.this, EventActivity.class);
intent.putExtra(Const.Tags.FULL_LIST, mainList);
loading.dismiss();
startActivity(intent);
}
}
}
the dialog works fine during the loading of the list, but here's my problem:
dismissing the dialog before startActivity(intent) will result in 2-3 seconds of no progress indicator while the new activity is created (there's a listview to be populated with a custom adapter) and before it is actually resumed, which is not very user friendly.
dismissing the dialog after startActivity(intent) will result in a rough disposal of the dialog (first goes the dimmed background, then it freezes... and so on). actually it's like not calling loading.dismiss() at all and letting it be destroyed with the activity.
Is there a smooth way for the ProgressDialog to be persistent through both the loading of the data and the creation of the new activity and eventually be dismissed when the new activity UI is ready to be shown?
If you want a smoother transition I would recommend you use fragments instead. Or you can make it slightly smoother by not populating the list view until onStart and making sure it's done on the background thread.
I am working on push notifications. The issue is when i am loading a form which is very huge and i recieve notification, before the form is completely loaded i try to click on the notification i get a blank screen after 5-6 seconds. The exception is due to dialog.dismiss.
According to my understanding, while opening notification the current activity is destroyed a new activity is created. while creating a new activity i am using asynctask to accomplish some other functionality in my app. So when the current activity is destroyed, activity context is null but the asynctask is still running also progress dialog. As soon as the activity is destroyed there is no window to show the dialog and hence window leaked exception.
Can anybody help me to get me out of this issue.I also get the blank screen when app is idle for a long time then i open the notifications.
Is there a way to stop running the asynctask as soon as the activity is destroyed.
My code is :
public class MainActivity extends Activity {
private MyProgressDialog myProgressDialog;
public LinearLayout mainPanel;
private VMobilet mobilet = null;
private String mobiletId;
private String formId ;
#Override
protected void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(mainPanel);
Intent i = getIntent();
mobiletId = i.getStringExtra("Mobilet Id");
formId = i.getStringExtra("Form ID");
VUiHelper.getInstance().setIsFinish(false);
myProgressDialog = MyProgressDialog.show(MainActivity.this,"","",true);
BackgroundTask backgroundTask = new BackgroundTask();
backgroundTask.execute(MainActivity.this);
}
#Override
protected void onPause() {
super.onPause();
if(VUiHelper.getInstance().isFinish())
{
this.finish();
}
else {
System.out.println("pausing mainactivity");
}
}
#Override
protected void onDestroy() {
super.onDestroy();
System.out.println("mainactivity ondestroy called");
if(mobilet != null)
mobilet.getForms().clear();
mobilet = null;
mainPanel = null;
VUiHelper.getInstance().clearControlCache();
VUiHelper.getInstance().MediaInput.clear();
System.gc();
}
private class BackgroundTask extends AsyncTask<Context, String, Boolean> {
#Override
public void onPreExecute() {
super.onPreExecute();
}
#Override
protected Boolean doInBackground(Context... arg0) {
if (mobiletId != null) {
** some logic **
}
return true;
}
#Override
public void onPostExecute(Boolean status){
super.onPostExecute(status);
myProgressDialog.dismiss(); //dismissing the progress dialogs
if (mobilet != null) {
** some logic **
} else {
** some logic **
}
}
}
}
}
I tried printing the activity context in onDestroy() and it is null.
You can stop running an Asynctask (as long as you have a reference to it). You might want to do something like this
when starting:
Task ref = new Task();
ref.execute()
then in onPause()
if(ref != null)
ref.cancel(true);
then inside your doInBackground() if you are doing something periodically (like downloading) have something like this:
if(isCanceled())
{
return;
}
The above snippets should allow you to gracefully exit the asynctask.
Also in your onPause
if(myProgressDialog != null)
{
if(myProgressDialog.isShowing())
{
myProgressDialog.dismiss()
}
myProgressDialog = null
}
then in your onPostExecute
if(myProgressDialog != null)
{
if(myProgressDialog.isShowing())
{
myProgessDialog.dismiss;
myProgessDialog = null;
}
}
the setting of myProgessDialog to null in onPuase should make it null in onPOstExecute()
You can cancel an AsyncTask by calling cancel(Boolean). For more usage info ctrl-f for "Cancelling a task" on that page
I think the best solution to the problem is let your asyntask check whether there is still an application running. If not simply exit. Set a flag in Activity.onPause and the let the asynctask check it before sending some output.
I have two activities. While switching to second activity by intent, it takes 3-4 seconds because it has lots of components with adapters fetching data from SQLite etc. Thus, I want to show a progress dialog while switching.
I have been digging topics for this purpose and tried many of them:
1-) Using AsyncTask on the second activity. It doesn't show the progress dialog as soon as I click on a component to switch to the second activity. It waits for 3-4 seconds and then progress dialog shows up for less then a second which is not user-friendly way.
2-) Using AsyncTask on the first activity. It shows as soon as I click on that component but the progress wheel doesn't spin. The progress dialog freezes.
3-) Using AsyncTask onStart() method on the second activity. This results as the first way.
The code below implements the second way above, using AsyncTask on the first activity.
public void toVisitRegister(Event event) { //Switching to the second activity
new startingThread().execute();
Intent toVisitRegister = new Intent(MainCalendar.this, VisitRegister.class);
startActivity(toVisitRegister);
finish();
}
And here is the AsyncTask
public class startingThread extends AsyncTask<String, String, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
startingProgress = new ProgressDialog(MainCalendar.this);
startingProgress.setTitle("Visit Register");
startingProgress.setMessage("Initializing...");
startingProgress.show();
}
#Override
protected String doInBackground(String... params) {
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if(MainCalendar.this.startingProgress != null) {
MainCalendar.this.startingProgress.dismiss();
}
}
}
I also tried to call startActivity in onPostExecute, but it didn't work. Therefore, I am waiting for your opinions and suggessions about this issue. Any help will be appreciated.
Thanks.
I also tried to call startActivity in onPostExecute,
Pass the Activity context to startingThread AsyncTask and put your start activity code in onPostExecute() of AsyncTask.
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if(MainCalendar.this.startingProgress != null) {
MainCalendar.this.startingProgress.dismiss();
Intent toVisitRegister = new Intent(MainCalendar.this, VisitRegister.class);
mContext.startActivity(toVisitRegister);
mContext.finish();
}
}
Here mContext is the Context of your current MainCalendar Activity.
Looking at your implementation, the AsyncTask wont have time to work because you will be jumping to the next Activity right away. Try calling the next activity in PostExecute().
I also tried to call startActivity in onPostExecute, but it didn't work.
Did you did it like this:
public void toVisitRegister(Event event) { //Switching to the second activity
new startingThread().execute();
}
public class startingThread extends AsyncTask<String, String, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
startingProgress = new ProgressDialog(MainCalendar.this);
startingProgress.setTitle("Visit Register");
startingProgress.setMessage("Initializing...");
startingProgress.show();
}
#Override
protected String doInBackground(String... params) {
return null;
}
#Override
protected void onPostExecute(String result) {
if(MainCalendar.this.startingProgress != null) {
MainCalendar.this.startingProgress.dismiss();
}
Intent toVisitRegister = new Intent(MainCalendar.this, VisitRegister.class);
startActivity(toVisitRegister);
finish();
}
}
In my code I load a spinner adapter by using Async Task
In My case The ProgressDialog is Not dismissing
This is My code.
I want to show the item after adapter load and the progressDialog is to dismiss
Please Help me, Thanks
private class LoadMoreVehicals extends AsyncTask<Object, Integer, Object> {
#Override
protected void onPreExecute() {
progressBar = ProgressDialog.show(RegistrationScreen.this, "",
"Loading...");
progressBar.setIndeterminate(true);
progressBar.setIndeterminateDrawable(getResources().getDrawable(
R.anim.progressbar_handler));
super.onPreExecute();
}
#Override
protected Object doInBackground(Object... params) {
String countryUrl = ConstantURL.COUNTRY_URL;
getCounty(countryUrl);
countrySpinner
.setAdapter(new MyCustomSpinnerAdapter(
RegistrationScreen.this,
R.layout.spinner_dropdown,
countyList));
return null;
}
#Override
protected void onProgressUpdate(Integer... values) {
progressBar.getProgress();
}
#Override
protected void onPostExecute(Object result) {
progressBar.dismiss();
Log.e("Im in onPostExecute", "");
super.onPostExecute(result);
}
}
While programming in Android you should remember one thing that any task which draws something on the screen should be executed on the main thread. When you set the adapter then android calls the getView() method of the adapter and draws views on the screen. So you should set the adapter in the postExecute() method instead in doInBackground() method.
Here is a small sample to clear my point:
class MyTask extends AsyncTask<Void, Void, Void> {
ProgressDialog pd = new ProgressDialog(MainActivity.this);
#Override
protected void onPreExecute ( )
{
//starting the progress dialogue
pd.show();
}
#Override
protected Void doInBackground (Void... params)
{
//fetch data here
...
...
return null;
}
#Override
protected void onPostExecute (Void result)
{
//set adapter here
...
...
//dismissing the progress dialogue
pd.dismiss();
}
}
In my experience i have so many problems with async runs and UI so now always separate the stuff trying to place the "responsibilities" in each place. So i do something like this:
Create my Async class with the process i want to do and nothing that transform the UI in it
Create a function in UI thread that modify the UI when async task finish, something like OnAsyncTaskComplete(Object response)
Keep communicated the threads
public class MyActivity extends Activity {
private static MyAsyncClass backgroundTask;
private static ProgressDialog pleaseWaitDialog;
//......activity stuff.......
#Override
public void onPause()
{
super.onPause();
//Get rid of progress dialog in the event of a screen rotation or other state change. Prevents a crash.
if (pleaseWaitDialog != null)
pleaseWaitDialog.dismiss();
}
//Function to avoid lose the async thread if the app interrupts (phone rotation, incoming call, etc) RECOMENDED TO HANDLE THIS!!
//Sets the current state after app resume
#Override
public void onResume()
{
super.onResume();
//If there is a background task set it to the new activity
if ((backgroundTask != null) && (backgroundTask.getStatus() == Status.RUNNING))
{
if (pleaseWaitDialog != null)
pleaseWaitDialog.show();
backgroundTask.setActivity(this);
}
}
}
//Logic business after the web service complete here
//Do the thing that modify the UI in a function like this
private void onTaskCompleted(Object _response)
{
//For example _response can be a new adapter
MyList.setAdapter((BaseAdapter)_response);
//or can be a list to create the new adapter
MyList.setAdapter(new MyAdapter(this, (ArrayList<String>)_response));
//or can be anything you want, just try to make here the things that you need to change the UI
}
/**
* Class that handle the async task
*/
public class MyAsyncClass extends AsyncTask<Void, Void, Object>
{
//Maintain attached activity for states change propose
private MyActivity activity;
//Keep the response of the async task
private Object _response;
//Flag that keep async task completed status
private boolean completed;
//Constructor
private MyAsyncClass(MyActivity activity) {
this.activity = activity;
}
//Pre execution actions
#Override
protected void onPreExecute() {
//Start the splash screen dialog
if (pleaseWaitDialog == null)
pleaseWaitDialog= ProgressDialog.show(activity.this,
"PLEASE WAIT",
"Getting results...",
false);
}
//Execution of the async task
protected Object doInBackground(Object...params)
{
//return the thing you want or do want you want
return new ArrayList();
}
//Post execution actions
#Override
protected void onPostExecute(Object response)
{
//Set task completed and notify the activity
completed = true;
_response = response;
notifyActivityTaskCompleted();
//Close the splash screen
if (pleaseWaitDialog != null)
{
pleaseWaitDialog.dismiss();
pleaseWaitDialog = null;
}
}
//Notify activity of async task completion
private void notifyActivityTaskCompleted()
{
if ( null != activity ) {
activity.onTaskCompleted(_response);
}
}
//for maintain attached the async task to the activity in phone states changes
//Sets the current activity to the async task
public void setActivity(MyActivity activity)
{
this.activity = activity;
if ( completed ) {
notifyActivityTaskCompleted();
}
}
}
}
Hope its help you
First of all you cannot set the adapter in the doInBackground
follow this design:
private class LoadMoreVehicals extends AsyncTask<Object, Integer, Object>
{
private ArrayList<Country> countries;
#Override
protected void onPreExecute() {
progressBar = ProgressDialog.show(RegistrationScreen.this, "","Loading...");
progressBar.setIndeterminate(true);
progressBar.setIndeterminateDrawable(getResources().getDrawable(R.anim.progressbar_handler));
super.onPreExecute();
}
#Override
protected Object doInBackground(Object... params) {
String countryUrl = ConstantURL.COUNTRY_URL;
countries = getCounty(countryUrl);
return null;
}
#Override
protected void onProgressUpdate(Integer... values) {
progressBar.getProgress();
}
#Override
protected void onPostExecute(Object result) {
countrySpinner.setAdapter(new MyCustomSpinnerAdapter(RegistrationScreen.this,R.layout.spinner_dropdown,countries));
progressBar.dismiss();
Log.e("Im in onPostExecute", "");
super.onPostExecute(result);
}
}
I have a tabgroup having multiple activities. In one of the tabs i have two activities between whom i want to place a progress dialog.For this i am using Asynk Task. Following is my AsynkTask class which i have made an inner class for AboutUs activity:
private class TheTask extends AsyncTask<Void, Void, Void>{
#Override
protected void onPreExecute() {
progDialog = ProgressDialog.show(AboutUs.this.getParent(), "Loading... ",
"please wait....", true);
}
#Override
protected Void doInBackground(Void... params) {
final Intent aboutusIntent = new Intent(getParent(), Departments.class);
final TabGroupActivity parentActivity = (TabGroupActivity)getParent();
parentActivity.startChildActivity("Departments", aboutusIntent);
return null;
}
#Override
protected void onPostExecute(Void result) {
if(progDialog.isShowing())
{
progDialog.dismiss();
}
}
}
I am calling this class in my AboutUs activity :
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.aboutus);
.
.
.
.
/* Button for going to Departments */
Button ourdepbtn = (Button) findViewById(R.id.departmentsbutton);
ourdepbtn.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
//ourDepartments();
new TheTask().execute();
return false;
}
});
}
However this does'nt start a new activity i.e. Departments. The progress dialog appears and then disappears but activity never loads.
Any suggestions..??
First, you cannot start an activity from a non GUI thread (which Async doInBackground() is). Just start directly inside your Button.onClick() (why you use onTouch?) listener.
If you want to show up a ProgressDialog for the new Activity as soon as possible, you need to create it in the new (child) Activity onCreate(), as your ProgressDialog is connected to the new (child) activity (is it?). Take care about the order of creating layouts (create the ProgressDialog after calling setContentView()).
I am not very sure why you want to show that ProgressDialog. Is there something which delays the display of the childActivity? You loading some data? Then, the Dialog should be related to that loading task (Async I guess).
private class TheTask extends AsyncTask{
Context con;
Intent aboutusIntent;
TabGroupActivity parentActivity;
private TheTask(Context context)
{
this.con=context;
}
#Override
protected void onPreExecute() {
progDialog = ProgressDialog.show(con, "Loading... ",
"please wait....", true);
}
#Override
protected Void doInBackground(Void... params) {
aboutusIntent = new Intent(con, Departments.class);
parentActivity = (TabGroupActivity)getParent();
return null;
}
#Override
protected void onPostExecute(Void result) {
if(progDialog.isShowing())
{
progDialog.dismiss();
}
parentActivity.startChildActivity("Departments", aboutusIntent);
}
}
Thanks for your suggestions Oliver :)