What I want: I want to show a progress dialog while adding views dynamically to my ViewFlipper.
What I have: I have used an AsyncTask to achieve this. The ViewFlipper is declared in my Main Activity, I am adding views to ViewFlipper in the doInBackground() of AsyncTask.
What is the problem: I am getting an exception on the viewFlipper.addView() statement and the exception is " Main has leaked window com.android.internal.policy.impl ..... that was originally added here. " , something like this.
Here is the code:
public class Main extends Activity
{
private ViewFlipper viewFlipper;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main_flipper);
viewFlipper = (ViewFlipper)findViewById(R.id.id_vf_main);
new LoadData().execute();
// Some other tasks.
}
class LoadData extends AsyncTask<Object, Void, String>
{
protected ProgressDialog progressDialog;
#Override
protected void onPreExecute()
{
super.onPreExecute();
progressDialog = ProgressDialog.show(Main.this,"Loading", "Loading Data...", true, false);
}
#Override
protected String doInBackground(Object... parametros)
{
for (int i = 0; i < Login.data_Channel_Name.size(); i++)
{
LayoutInflater inflater = getLayoutInflater();
RelativeLayout rl_main = (RelativeLayout) inflater.inflate(R.layout.main,null);
TextView tv_channelNumber = (TextView)rl_main.findViewById(R.id.id_tv_ChannelNumber);
if(tv_channelNumber != null)
{
tv_channelNumber.setText("Some Number");
}
TextView tv_channelName = (TextView)rl_main.findViewById(R.id.id_tv_ChannelName);
if(tv_channelName != null)
{
tv_channelName.setText("Some name");
}
viewFlipper.addView(rl_main);
}
return null;
}
#Override
protected void onPostExecute(String result)
{
super.onPostExecute(result);
progressDialog.dismiss();
}
}
}
You are trying to interact with the UI from the background thread which isn't allowed. You are allowed to mess with the UI in your onPostExecute() and onPreExecute() methods. There is another method; onProgressUpdate() you can use like so:
protected void onProgressUpdate(Integer... progress) {
// on UI thread!
viewFlipper.addView(rl_main);
}
Obviously you'll need to handle passing the view to this method by creating a field or something. You can call this within your doInBackground() with the following:
publishProgress(0);
The function is typically used for updating the percentage on a loading bar or similar (hence passing the integer) but should work fine your your purposes.
Related
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);
}
}
My expected result is in the first launch there will display a progress dialog to wait for the background thread loading the content. The dialog dismisses after worker thread is done the job. I did search and got this solution How to display progress dialog before starting an activity in Android?
This is my complete code:
private ManagerApplication app;
private ImageAdapter adapter;
private GridView gridview;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
setupView();
}
private void setupView() {
gridview = (GridView) findViewById(R.id.gridview);
app = (ManagerApplication) getApplication();
ProgressDialog progress = new ProgressDialog(this);
progress.setMessage("Loading...");
new LoadImageTask(progress, this).execute();
}
private class LoadImageTask extends AsyncTask<Void, Void, Void> {
private ProgressDialog progress;
private Context context;
public LoadImageTask(ProgressDialog progress, Context context) {
this.progress = progress;
this.context = context;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
progress.show();
}
#Override
protected Void doInBackground(Void... params) {
adapter = new ImageAdapter(app.getShoes(), context);
gridview.setAdapter(adapter);
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
progress.dismiss();
}
}
However, my application crashes with the reason that "Only the original thread that created a view hierarchy can touch its views". I suppose there are something blocked the main UI thread, but its still very unclear. So could anyone point me to the problem ? Thanks
Funnily enough there's an article entitled Painless Threading that you should read. You shouldn't try to manipulate views in doInBackground. In your case, you can call app.getShoes() but don't do the adapter setup in there.
doinBackground is non UI Thread ,So never update any UI(View) in this
method...
and use OnPostExecute or OnProgressUpdate for update UI
#Override
protected Void doInBackground(Void... params) {
//here just background task ,
//its non UI Thread so dont set ant view here set it in OnPostExecute,...
return null;
}
call asynctask from setupview
private void setupView() {
gridview = (GridView) findViewById(R.id.gridview);
app = (ManagerApplication) getApplication();
new LoadImageTask(progress, this).execute();
}
and create ProgressDilog in OnPreExecute method
ProgressDialog progress;
#Override
protected void onPreExecute() {
super.onPreExecute();
progress = new ProgressDialog(this);
progress.setMessage("Loading...");
progress.show();
}
and in onPostExecute dismiss it
In one of my app, I have a scenario where I need to do some background task. For doing that I am using Async Task. Also I am using custom progress dialog. Below is the layout of the custom progress dialog
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/layout_root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center_vertical|center_horizontal"
android:orientation="vertical" >
<ProgressBar
android:layout_width="60dp"
android:layout_height="60dp"
android:indeterminateDrawable="#drawable/progressloader"
android:layout_gravity="center"/>
<TextView
android:id="#+id/progressMessage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#color/black"
android:textSize="18sp"
android:text="Please wait...." />
</LinearLayout>
Everything works fine but when I try to set text to TextView then I am getting java NullPointerException.
AsyncTask code
private class InitialSetup extends AsyncTask<String, Integer, Long> {
ProgressDialog dialog = new ProgressDialog(getParent(),R.style.progressdialog);
#Override
protected void onPreExecute() {
dialog.show();
dialog.setContentView(R.layout.progressbar);
}
#Override
protected Long doInBackground(String... urls) {
// txtView.setText("Testing"); here I am getting the error
fetchDetails();
return 0;
}
#Override
protected void onPostExecute(Long result) {
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
populateUI(getApplicationContext());
}
}
MainActivity
public class SummaryActivity extends Activity {
final TextView txtView = (TextView)findbyid(R.id.progressMessage);
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.accountsummary);
new InitialSetup().execute("");
}
}
If I understand correctly, your TextView of which you want to set the text can be found in the xml file progressbar.xml (i.e. R.layout.progressbar). This TextView can be obtained once the content view has been set (using setContentView()). In your code you set it before this call is been and the code of mussharapp, he is calling it to early. Namely, he calls it after the setContentView(R.layout.accountsummary) call which does not contain the TextView. Consequently, the variable txtView will be NULL and you will get a NullPointerException.
What you should do is the following:
Set the variable txtView in onPreExecute, after setContentView is called.
Based on Paresh Mayani's explanation: Use the runOnUiThread method.
For the code look down below:
private class InitialSetup extends AsyncTask<String, Integer, Long> {
ProgressDialog dialog = new ProgressDialog(getParent(),R.style.progressdialog);
// The variable is moved here, we only need it here while displaying the
// progress dialog.
TextView txtView;
#Override
protected void onPreExecute() {
dialog.show();
dialog.setContentView(R.layout.progressbar);
// Set the variable txtView here, after setContentView on the dialog
// has been called! use dialog.findViewById().
txtView = dialog.findViewById(R.id.progressMessage);
}
#Override
protected Long doInBackground(String... urls) {
// Already suggested by Paresh Mayani:
// Use the runOnUiThread method.
// See his explanation.
runOnUiThread(new Runnable() {
#Override
public void run() {
txtView.setText("Testing");
}
});
fetchDetails();
return 0;
}
#Override
protected void onPostExecute(Long result) {
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
populateUI(getApplicationContext());
}
}
Yes, because you are trying to set the TextView inside the doInBackground() method, and this is not allowed,
Why not allowed? Because There is a only one Thread running which is UI Main Thread, and it doesn't allowed to update UI from thread process. read more info here: Painless Threading
So there is a solution if you want to set the TextView inside the doInBackground() method, do the UI updating operations inside the runOnUiThread method.
Otherwise, suggestion is to do all the UI display/update related operations inside the onPostExecute() method instead of doInBackground() method of your AsyncTask class.
(TextView)findViewByid(R.id.progressMessage);
should only be executed after the command setContentView().
TextView txtView;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.accountsummary);
**txtView = (TextView)findbyid(R.id.progressMessage);**
new InitialSetup().execute("");
}
Also you can only change UI elements in the main UI thread. doInBackground() is not in the main UI thread. Make UI changes in onPostExecute
public class InitialSetup extends AsyncTask<String, Integer, Long> {
private Activity activity;
ProgressDialog progressDialog;
public InitialSetup(Activity activity) {
this.activity = activity;
}
#Override
protected void onPreExecute() {
progressDialog = new ProgressDialog(activity);
progressDialog.setMessage("Starting task....");
progressDialog.show();
}
#Override
protected Long doInBackground(String... urls) {
// do something
//
return 0;
}
#Override
protected void onPostExecute(Long result) {
progressDialog.dismiss();
//Perform all UI changes here
**textView.setText("Text#2");**
}
}
The explanations are correct: You are not to make UI changes in any thread except the thread which create the UI. But AsyncTask has a method called
onProgressUpdate()
which always will run in the UI Thread. So based on the modifications by dennisg your code should look like this:
private class InitialSetup extends AsyncTask<String, String, Long> {
ProgressDialog dialog = new ProgressDialog(getParent(),R.style.progressdialog);
// The variable is moved here, we only need it here while displaying the
// progress dialog.
TextView txtView;
#Override
protected void onPreExecute() {
dialog.show();
dialog.setContentView(R.layout.progressbar);
// Set the variable txtView here, after setContentView on the dialog
// has been called! use dialog.findViewById().
txtView = dialog.findViewById(R.id.progressMessage);
}
#Override
protected Long doInBackground(String... urls) {
publishProgress("Testing");
fetchDetails();
return 0;
}
#Override
protected void onPostExecute(Long result) {
if (this.dialog.isShowing()) {
this.dialog.dismiss();
}
populateUI(getApplicationContext());
}
#Override
protected void onProgressUpdate(String... update) {
if (update.length > 0)
txtView.setText(update[0]);
}
}
Note that the type of the parameter of onProgressUpdate is the second type given in AsyncTask!
Extra: To make your code more robust you should check if the progress dialog still exists before setting the text.
I'm using "include" on my main layout. Each one of them is a RelativeLayout which needs an OnClick listener to be attached, and update some information related.
So I've tried to do it simply by:
setContentView(R.layout.allobjects);
ObjectListeners objectListeners = new ObjectListeners(objects);
for(int i=0;i<1;i++)
{
RelativeLayout objectBoxRelativeLayout = (RelativeLayout)findViewById(R.id.object1 + i);
objectBoxRelativeLayout.setOnClickListener(objectListeners.GetObjectListener(i));
SomeObject currentObject = this.objects.get(i);
Object viewObject = findViewById(R.id.object1 + i);
this.setObjectView(viewObject, currentObject);
}
The issue is that it takes too long after the "setContentView(R.layout.allobjects);" command, and the application shows black screen until it finish loading.
In addition, I use "setContentView(R.layout.allobjects);" after I perform the above commands. All of these commands have to be written after "setContentView(R.layout.allobjects);".
How can I handle that kind of situation ? Do I have to use onPreExecute and implement AsyncTask ?
Yes, AsyncTask is good solution to show loading dialog while these commands being executed.
UPDATE:
Add this class under your onCreate() function:
private class MyTask extends AsyncTask<Void, Void, Void> {
private ProgressDialog dialog;
private Context context;
public MyTask(Activity activity) {
context = activity;
dialog = new ProgressDialog(context);
}
protected void onPreExecute() {
dialog.setTitle("Loading...");
dialog.setMessage("Loading...");
dialog.show();
}
#Override
protected Void doInBackground(Void... params) {
//do your code here in background
protected void onPostExecute(Void res) {
dialog.dismiss();
}
}
then use the task inside onCreate() like this:
MyTask mt = new MyTask(this);
mt.execute();
I'm using a ListView on my Activity and it takes a while to load from a SQLite DB, so I wanted to show a ProgressDialog to the user to let them know something is loading. I tried to run the task on a separate thread but I'm getting a CalledFromWrongThreadException. Here's my main Activity code:
#Override
public void onCreate(Bundle savedInstanceState)
{
try
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
setContentView(R.layout.open_issues);
getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.custom_title);
//Set Window title.
final TextView title = (TextView) findViewById(R.id.customTitle);
if (title != null)
title.setText("Open Issues");
//Call Async Task to run in the background.
new LoadIssuesTask().execute();
}
catch (Exception e)
{
Errors.LogError(e);
}
}
And the LoadIssuesTask code:
private class LoadIssuesTask extends AsyncTask<Void, Void, Cursor> {
ProgressDialog pdDialog = null;
protected void onPreExecute()
{
try
{
pdDialog = new ProgressDialog(OpenIssues.this);
pdDialog.setMessage("Loading Issues and Activities, please wait...");
pdDialog.show();
}
catch (Exception e)
{
Errors.LogError(e);
}
}
#Override
protected Cursor doInBackground(Void... params) {
LoadIssues();
return null;
}
#Override
protected void onPostExecute(Cursor c) {
pdDialog.dismiss();
pdDialog = null;
}
}
And the LoadIssues code:
private void LoadIssues(){
//Set listview of Issues.
ListView lvIssues = (ListView)findViewById(R.id.lvIssues);
lvIssues.setOnItemClickListener(viewIssuesListener);
IssueCreator = new IssueInfoCreator(this, Integer.parseInt(AppPreferences.mDBVersion));
IssueCreator.open();
lvIssues.setAdapter(new IssueInfoAdapter(this, IssueCreator.queryAll()));
IssueCreator.close();
}
Constructor for IssueInfoAdapter:
public IssueInfoAdapter(Context c, List<IssueInfo> list){
mListIssueInfo = list;
//create layout inflater.
mInflater = LayoutInflater.from(c);
}
It's throwing the error on the .setAdapter method inside LoadIssues().
ERROR:
03-12 10:41:23.174: E/AndroidRuntime(11379): Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException:
Only the original thread that created a view hierarchy can touch its views.
You're trying to access the views in the doInBackground method that doesn't run on the main UI thread. You'll have to set your adapter in the method onPostExecute that runs on the UI thread:
#Override
protected void onPostExecute(List<IsueInfo> items) {
pdDialog.dismiss();
ListView lvIssues = (ListView)findViewById(R.id.lvIssues);
lvIssues.setOnItemClickListener(viewIssuesListener);
lvIssues.setAdapter(new IssueInfoAdapter(this, items));
}
and in your doInBackground method:
#Override
protected List<IssueInfo> doInBackground(Void... params) {
IssueCreator = new IssueInfoCreator(this, Integer.parseInt(AppPreferences.mDBVersion));
IssueCreator.open();
IssueCreator.close();
return IssueCreator.queryAll();
}
Also your AsyncTask should be:
private class LoadIssuesTask extends AsyncTask<Void, Void, List<IssueInfo>>
In private void LoadIssues method call handler.setMessage(0) and create a private Handler instance to call setAdapter method
Use Handler instead of Asynctask.