Develop Reference

how to make one asynctask to start after the other one?

what i have is two asynctask each one call a function to parse some data ... and i want the asynctask starts after asynctasknew finish how can i do this??? here is my code ..
send.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
AsyncCallWS task = new AsyncCallWS();
try{
Intent newintent = getIntent();
mixlist=newintent.getStringArrayListExtra("listmix");
Log.e("listmix",mixlist+"");
for(int i=0;i<=mixlist.size();i++){
if(i==mixlist.size()){
Log.d("states","finished");
Item_Name="0";
Item_Price="0";
Item_Quantity="0";
Total_Price="0";
Customer_Name=name.getText().toString();
Log.e("customer_name",Customer_Name);
Customer_Number=mobile.getText().toString();
Customer_Address=addressnew.getText().toString();
//Call execute
task.execute();
}
else{
Item_Name=mixlist.get(i);
i++;
Item_Price=mixlist.get(i);
i++;
Item_Quantity=mixlist.get(i);
i++;
Total_Price=mixlist.get(i);
Customer_Name="0";
Customer_Number="0";
Customer_Address="0";
// AsyncCallWSnew tasknew = new AsyncCallWSnew();
//Call execute
AsyncCallWSnew tasknew = new AsyncCallWSnew();
tasknew.execute();
}
}
}
catch(Exception e){
e.printStackTrace();
}
}
});
}
private class AsyncCallWS extends AsyncTask<Void, Void, Void> {
protected void onPostExecute(Void result) {
//Make Progress Bar invisible
Toast.makeText(getApplicationContext(), "order has been sent + item price", Toast.LENGTH_LONG).show();
Intent intObj = new Intent(PersonalInfo.this,MainActivity.class);
startActivity(intObj);
//Error status is false
}
//Make Progress Bar visible
protected void onPreExecute() {
}
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
loginStatus = WebService.invokeLoginWS(Item_Name,Item_Price,Item_Quantity, Total_Price, Customer_Name,
Customer_Number, Customer_Address,"InsertData");
return null;
}
}
private class AsyncCallWSnew extends AsyncTask<Void, Void, Void> {
protected void onPostExecute(Void result) {
//Make Progress Bar invisible
Toast.makeText(getApplicationContext(), "order has been sent", Toast.LENGTH_LONG).show();
Intent intObj = new Intent(PersonalInfo.this,MainActivity.class);
startActivity(intObj);
//Error status is false
}
//Make Progress Bar visible
protected void onPreExecute() {
}
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
loginStatus = WebService.invokeLoginWS(Item_Name,Item_Price,Item_Quantity, Total_Price, Customer_Name,
Customer_Number, Customer_Address,"InsertData");
return null;
}
}
}
when i make a debug my code works just fine .. but in normal run .. it doesn't can any help me?

There are basically two possibilities:
Simply start the next AsyncTask from onPostExecute() of the previous one
Use AsyncTask.executeOnExecutor() with SerialExecutor and start all of them in a row.

Hi You can use AsyncTask executeonExecutor method to start the async task. But it will require minimum API version 11. Kindly refer the following code.
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
new YourFirstTask().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,params...);
new YourSecondTask().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,params...);
}else{
new YourFirstTask().execute(params...);
new YourSecondTask().execute(params...);
}
For Lower version you can call directly. automatically system will process one by one.

how to automatically invoke a method in android?

im building an android application that recive images from arduino uno in order to show them continously as a video , i write an asyncTask that reads image and show it in image view , how can i invoke this method every seconed automatically .
here is my asyncTask
I made a button that invoke the async task , but how to make it invoked continously
class myAsyncTask extends AsyncTask<Void, Void, Void>
{
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
mmInStream = tmpIn;
int byteNo;
try {
byteNo = mmInStream.read(buffer);
if (byteNo != -1) {
//ensure DATAMAXSIZE Byte is read.
int byteNo2 = byteNo;
int bufferSize = 7340;
int i = 0;
while(byteNo2 != bufferSize){
i++;
bufferSize = bufferSize - byteNo2;
byteNo2 = mmInStream.read(buffer,byteNo,bufferSize);
if(byteNo2 == -1){
break;
}
byteNo = byteNo+byteNo2;
}
}
}
catch (Exception e) {
// TODO: handle exception
}
return null;
}
protected void onPostExecute(Void result) {
super.onPostExecute(result);
bm1 = BitmapFactory.decodeByteArray(buffer, 0, buffer.length);
image.setImageBitmap(bm1);
}
}

If it's from a background thread, one possibility is to use an unbounded for loop. For example, suppose the AsyncTask currently does:
private class MyTask extends AsyncTask<T1, Void, T3>
{
protected T3 doInBackground(T1... value)
{
return longThing(value);
}
protected void onPostExecute(T3 result)
{
updateUI(result);
}
}
then rewrite it as something like:
private class MyTask extends AsyncTask<T1, T3, T3>
{
protected T3 doInBackground(T1... value)
{
for (;;)
{
T3 result = longThing(value);
publishProgress(result);
Thread.sleep(1000);
}
return null;
}
protected void onProgressUpdate(T3... progress)
{
updateUI(progress[0]);
}
}
Of course, you should have a check to break the loop (for example when the Activity is paused or destroyed).
Another option is to create a Handler instance and call postDelayed() repeatedly.

Handler h = new Handler();
h.postDelayed(r, DELAY_IN_MS);
Runnable r = new new Runnable() {
public void run() {
// Do your stuff here
h.postDelayed(this, DELAY_IN_MS);
}
}

How to perform background process in android?

I am performing some operations(uploading image to webservice) in IntentService.
Please see my code below.
Inside the activity i am calling service like this.
I am calling the below method after capturing the image i.e. inside onActivityResult. The app is getting hanged when i call this method in onActivityResult. I am able to perform the task in IntentService. But the acitivity is getting hanged.
private void callService(){
Intent intent = new Intent(this, TestIntentService.class);
intent.putExtra("imageData", imageData);
startService(intent);
}
This is my IntentService Class.
Can i perform webservice call inside callImageUploadAPI().
Am i doing anything wrong here?
public class TestIntentService extends IntentService {
public TestIntentService() {
super("com.screens.testapp");
// TODO Auto-generated constructor stub
}
//imageData passed from the activity
#Override
protected void onHandleIntent(Intent intent) {
// TODO Auto-generated method stub
if(intent != null){
Bundle extras = intent.getExtras();
imageData= extras.getString("imageData");
}
callImageUploadAPI(imageData);
}
private void callImageUploadAPI(final String imageData) {
// TODO Auto-generated method stub
try {
if (Log.checkNetworkStatus(TestIntentService.this)) {
} else {
}
} catch (Exception e) {
// TODO: handle exception
}
}
}
Thanks

If you need to do a task in background, Android provides a class called AsyncTask which you can extend and use it for doing a network operation or any other heavy operation. This is an example from Android Developer Website (AsyncTask Page):
private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
protected Long doInBackground(URL... urls) {
int count = urls.length;
long totalSize = 0;
for (int i = 0; i < count; i++) {
totalSize += Downloader.downloadFile(urls[i]);
publishProgress((int) ((i / (float) count) * 100));
// Escape early if cancel() is called
if (isCancelled()) break;
}
return totalSize;
}
protected void onProgressUpdate(Integer... progress) {
setProgressPercent(progress[0]);
}
protected void onPostExecute(Long result) {
showDialog("Downloaded " + result + " bytes");
}
}
This may be used in your code this way:
if (Log.checkNetworkStatus(TestIntentService.this)) {
new DownloadFilesTask().execute(url1, url2, url3);
} else {
}

For you to perform actions in the background use Services.
You can launch the services from your activity and you can assign a thread for the service and a handler for communication from that thread to the UIThread.
Check this: http://developer.android.com/guide/components/services.html
A little sneak peek
A Service is an application component that can perform long-running operations in the background and does not provide a user interface.

Set Progress of Dialog

I have a Async Task that does not add the percentage while it is going through the task. It always stays at 0% 0/100
Here is my code
private class getAppInfo extends AsyncTask<String, String, String> {
/** The system calls this to perform work in a worker thread and
* delivers it the parameters given to AsyncTask.execute() */
ProgressDialog dialog;
#Override
protected void onPreExecute() {
if(showLoading == true){
dialog = new ProgressDialog(SelfHelp.this);
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setMessage("Loading");
dialog.setIndeterminate(true);
dialog.setCancelable(false);
dialog.setMax(100);
dialog.setProgress(100);
dialog.show();
}
}
#Override
protected String doInBackground(String... urls) {
String xml = null;
int count = 0;
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(urls[0]);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
xml = EntityUtils.toString(httpEntity);
while(count != 100){
publishProgress(""+count);
count += 5;
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
Document doc = parser.GetDomElement(xml);
NodeList nl = doc.getElementsByTagName("topic");
getChildElements(nl);
return xml;
}
#Override
protected void onProgressUpdate(String... progress) {
Log.v("count",progress[0]);
dialog.setProgress(Integer.parseInt(progress[0]));
}
/** The system calls this to perform work in the UI thread and delivers
* the result from doInBackground() */
#Override
protected void onPostExecute(String result) {
//dialog.setProgress(100);
menuList.setAdapter(setListItems(menuItems));
menuList.setTextFilterEnabled(true);
if(showLoading == true){
dialog.dismiss();
showLoading = false;
}
}
It does go into onProgressUpdate and the count goes up by 5 but the progress bar does not change. How can I have it increment by 5 and show the progress properly?

Your issue is related to setIndeterminate(true): You should set it to false if you want to have progress update. if you setIndeterminate(true) then the ProgressDialog will work as the classic Windows Hourglass

You can try following code, It is showing progress in % ratio, here is the code,
public class ProgressBarExampleActivity extends Activity
{
ProgressThread progThread;
ProgressDialog progDialog;
Button button1, button2;
int typeBar; // Determines type progress bar: 0 = spinner, 1 = horizontal
int delay = 1000; // Milliseconds of delay in the update loop
int maxBarValue = 30; // Maximum value of horizontal progress bar
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// // Process button to start spinner progress dialog with anonymous inner class
// button1 = (Button) findViewById(R.id.Button01);
// button1.setOnClickListener(new OnClickListener()
// {
// public void onClick(View v)
// {
// typeBar = 0;
// showDialog(typeBar);
// }
// });
// Process button to start horizontal progress bar dialog with anonymous inner class
button2 = (Button) findViewById(R.id.Button02);
button2.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
typeBar = 1;
showDialog(typeBar);
}
});
}
// Method to create a progress bar dialog of either spinner or horizontal type
#Override
protected Dialog onCreateDialog(int id)
{
switch(id)
{
// case 0: // Spinner
// progDialog = new ProgressDialog(this);
// progDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
// progDialog.setMessage("Loading...");
// progThread = new ProgressThread(handler);
// progThread.start();
// return progDialog;
case 1: // Horizontal
progDialog = new ProgressDialog(this);
progDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
progDialog.setMax(maxBarValue);
progDialog.setMessage("Dollars in checking account:");
progThread = new ProgressThread(handler);
progThread.start();
return progDialog;
default:
return null;
}
}
// Handler on the main (UI) thread that will receive messages from the
// second thread and update the progress.
final Handler handler = new Handler()
{
public void handleMessage(Message msg)
{
// Get the current value of the variable total from the message data
// and update the progress bar.
int total = msg.getData().getInt("total");
progDialog.setProgress(total);
// if (total >= maxBarValue)
if (total <= 0 )
{
dismissDialog(typeBar);
progThread.setState(ProgressThread.DONE);
}
}
};
// Inner class that performs progress calculations on a second thread. Implement
// the thread by subclassing Thread and overriding its run() method. Also provide
// a setState(state) method to stop the thread gracefully.
private class ProgressThread extends Thread
{
// Class constants defining state of the thread
final static int DONE = 0;
final static int RUNNING = 1;
Handler mHandler;
int mState;
int total;
// Constructor with an argument that specifies Handler on main thread
// to which messages will be sent by this thread.
ProgressThread(Handler h)
{
mHandler = h;
}
// Override the run() method that will be invoked automatically when
// the Thread starts. Do the work required to update the progress bar on this
// thread but send a message to the Handler on the main UI thread to actually
// change the visual representation of the progress. In this example we count
// the index total down to zero, so the horizontal progress bar will start full and
// count down.
#Override
public void run()
{
mState = RUNNING;
total = maxBarValue;
while (mState == RUNNING)
{
// The method Thread.sleep throws an InterruptedException if Thread.interrupt()
// were to be issued while thread is sleeping; the exception must be caught.
try
{
// Control speed of update (but precision of delay not guaranteed)
Thread.sleep(delay);
} catch (InterruptedException e) {
Log.e("ERROR", "Thread was Interrupted");
}
// Send message (with current value of total as data) to Handler on UI thread
// so that it can update the progress bar.
Message msg = mHandler.obtainMessage();
Bundle b = new Bundle();
b.putInt("total", total);
msg.setData(b);
mHandler.sendMessage(msg);
total--; // Count down
}
}
// Set current state of thread (use state=ProgressThread.DONE to stop thread)
public void setState(int state)
{
mState = state;
}
}
}
See the output,

I will mention another aproach, because I came across this solution when I was looking for some practical way how to communicate from my Service running AsyncTask back to main UI. Lucifer's solution is not modular for Services, if you need to use your Service in more then 1 class (that was my case), you won't be able to access variable handler and as far as I know you can't even send Handler as Intent to Service (you can send it to AsyncTask tho). Solution is broadcasting.
sendBroadcast(new Intent(WORK_DONE));
in AsyncTask and
private BroadcastReceiver receiver = new BroadcastReceiver() {
public void onReceive(Context c, Intent i) { //update your UI here }
}
registerReceiver(receiver, new IntentFilter(WORK_DONE));
in your activity.
I don't like all those inner classes android developers use. I understand it's easier to create inner class and access outer class variables, but once you need to use the class again your doomed and you have to edit the code! I am realy new to Android, maybe I am wrong and you actually don't need to reuse those classes. Never did a bigger project so I have no idea but it just doesn't feel right, since on college, they tried hard to teach us how to programm reusable code.

ProgressDialog.dismiss() does not close in Async Class android

I have an inner class that downloads some images from the server. The problem is that the ProgressDialog does not dismiss() onPostExecute() method and don't understand why.
I understand that the progress dialog should be shown onPreExecute() method, and the after the code from the doInBackground() finished , in the onPostExecute() method the dialog should be dismiss. Do you have any idea what i am doing wrong here? Thank you.
/**
* Download images from server
*/
public class DownloadAsyncTask extends AsyncTask<Void, Integer, Void> {
private ProgressDialog mDialog;
// execution of result of Long time consuming operation
protected void onPostExecute(Void result) {
// progressDialog.show();
if (mDialog.isShowing()) {
mDialog.dismiss();
}
}
// Things to be done before execution of long running operation.
protected void onPreExecute() {
mDialog = ProgressDialog
.show(ImagesActivity.this, getString(R.string.pleasewait),
getString(R.string.loading));
}
// perform long running operation operation
protected Void doInBackground(Void... params) {
System.out.println("doInBackground loading.." + id);
String tempPath = FileUtils.createTempFile(id);
for (int i = 0; i < imagePaths.size(); i++) {
imagePaths.get(i).trim();
try {
Bitmap imgTemp;
imgTemp = FileUtils.downloadBitmapFromURL(id,
imagePaths.get(i), tempPath);
System.out.println("imgTemp: " + imgTemp);
if (imgTemp != null) {
// save image on sdcard.
// compress it for performance
Bitmap img = Bitmap.createScaledBitmap(imgTemp, 90, 80,
true);
imgTemp.recycle();
FileUtils.saveDataToFile(img, tempPath,
imagePaths.get(i));
} else {
continue;
}
} catch (IOException e) {
e.printStackTrace();
mDialog.dismiss();
}
}
Looper.prepare();
mDialog.dismiss();
return null;
}
/*
* Things to be done while execution of long running operation is in
* progress.
*/
protected void onProgressUpdate(Integer... values) {
if (mDialog.isShowing()) {
mDialog.dismiss();
}
}
}

actually what you are trying to do is to access the UI Thread from another thread and that is not possible , in your case you are using AsyncTask class enables proper and easy use of the UI thread without having to manipulate threads and/or handlers. use onPostExecute(Result) to access the UI Thread.
so this should work
protected void onPostExecute(Void result) {
progressDialog.show();
if (mDialog.isShowing()) {
mDialog.dismiss();
}
}

I've struggled with this same problem for quite a while. Here is how I got it solved, take a look at this part of the documentation:
A dialog is always created and displayed as a part of an Activity. You
should normally create dialogs from within your Activity's
onCreateDialog(int) callback method. When you use this callback, the
Android system automatically manages the state of each dialog and
hooks them to the Activity, effectively making it the "owner" of each
dialog
Note: If you decide to create a dialog outside of the onCreateDialog()
method, it will not be attached to an Activity. You can, however,
attach it to an Activity with setOwnerActivity(Activity).
from: http://developer.android.com/guide/topics/ui/dialogs.html#ShowingADialog
This is an example of what you have to set on your activity:
#Override
protected void onPrepareDialog(int id, Dialog dialog)
{
//This doesn't do anything
if (id == DIALOG_PROGRESS_ID) {
((ProgressDialog)dialog).setIndeterminate(true);
}
super.onPrepareDialog(id, dialog);
}
#Override
protected Dialog onCreateDialog(int id)
{
if (id == DIALOG_PROGRESS_ID) {
ProgressDialog dialog = new ProgressDialog(this);
dialog.setMessage("Loading");
dialog.setCancelable(false);
dialog.setIndeterminate(true);
return dialog;
}
return null;
}
You can then call
myActivity.showDialog(myActivity.DIALOG_PROGRESS_ID), myActivity.dismissDialog(myActivity.DIALOG_PROGRESS_ID) from any where as long as you have a reference to your activity instance.

Use a handler and onPostExecute() send the handler msg to dismiss the progress dialog.
You can get help from this link ProgressDialog dismissal in android

Your code is working fine but can you check that control are reaching in Post onPostExecute() method I have tried as
package com.alarm.activity;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
public class AlarmManagerActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//set up main content view
setContentView(R.layout.main);
new DownloadAsyncTask().execute();
}
/**
* Download images from server
*/
public class DownloadAsyncTask extends AsyncTask<Void, Integer, Void> {
private ProgressDialog mDialog;
// execution of result of Long time consuming operation
#Override
protected void onPostExecute(Void result) {
// progressDialog.show();
if (mDialog.isShowing()) {
mDialog.dismiss();
}
}
// Things to be done before execution of long running operation.
#Override
protected void onPreExecute() {
mDialog = ProgressDialog.show(AlarmManagerActivity.this, "Hello", "Test");
}
// perform long running operation operation
#Override
protected Void doInBackground(Void... params) {
//System.out.println("doInBackground loading.." + id);
/* String tempPath = FileUtils.createTempFile(id);
for (int i = 0; i < imagePaths.size(); i++) {
imagePaths.get(i).trim();
try {
Bitmap imgTemp;
imgTemp = FileUtils.downloadBitmapFromURL(id, imagePaths.get(i), tempPath);
System.out.println("imgTemp: " + imgTemp);
if (imgTemp != null) {
// save image on sdcard.
// compress it for performance
Bitmap img = Bitmap.createScaledBitmap(imgTemp, 90, 80, true);
imgTemp.recycle();
FileUtils.saveDataToFile(img, tempPath, imagePaths.get(i));
}
else {
continue;
}
}
catch (IOException e) {
e.printStackTrace();
mDialog.dismiss();
}
}
Looper.prepare();
mDialog.dismiss();*/
try {
Thread.sleep(5000);
}
catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/*
* Things to be done while execution of long running operation is in
* progress.
*/
#Override
protected void onProgressUpdate(Integer... values) {
if (mDialog.isShowing()) {
mDialog.dismiss();
}
}
}
}
I think problem in doInbackground() method. I have simply run thread for sleep 5 sec and after control reaches in post() method and dissmiss progress dialog.