Develop Reference

Downloading a file by using a service

To download some files on lots of activities, I thought it will be much better to integrate all the same codes into one activity like (DownloadFiles.class), but here is the problem. I have to get a progress value into my main activity (SetupActivity.class), it is impossible to do that using AsyncTask. The original code was:
private class DownloadFiles extends AsyncTask<String, Integer, String> {
private Context context;
private PowerManager.WakeLock mWakeLock;
public DownloadFiles(Context context) {
this.context = context;
}
#Override
protected String doInBackground(String... input_value) {
InputStream input = null;
OutputStream output = null;
HttpURLConnection connection = null;
try {
URL url = new URL(input_value[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
int fileLength = connection.getContentLength();
input = connection.getInputStream();
output = new FileOutputStream(new File(input_value[1]));
byte data[] = new byte[4096];
long total = 0;
int count;
while ((count = input.read(data)) != -1) {
if (isCancelled()) {
input.close();
return null;
}
total += count;
if (fileLength > 0)
publishProgress((int) (total * 100 / fileLength));
output.write(data, 0, count);
}
} catch (Exception e) {
return e.toString();
} finally {
try {
if (output != null) output.close();
if (input != null) input.close();
} catch (IOException ignored){
ignored.printStackTrace();
}
return "Download Complete.";
}
}
#Override
protected void onPreExecute() {
super.onPreExecute();
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
mWakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
getClass().getName());
mWakeLock.acquire();
}
#Override
protected void onProgressUpdate(Integer... progress) {
super.onProgressUpdate(progress);
}
#Override
protected void onPostExecute(String result) {
mWakeLock.release();
if (!result.equals("Download Complete.")) {
} else {
}
}
}
It was unable to use onProgressUpdate to handle other activities' progressbar. The reason why I am not using ProgressDialog is since it is deprecated, it is much better to use the Progressbar which doesn't prevent user from interacting with user interfaces.
I heard that using services is one of the answers, but there are no ways to update progressbar with my knowledge.

You can also pass a callback value to the AsyncTask like this:
private class DownloadFiles extends AsyncTask<String, Integer, String> {
private Context context;
private PowerManager.WakeLock mWakeLock;
private ProgressCallback mProgressCallback
public DownloadFiles(Context context, ProgressCallback callback) {
this.context = context;
mProgressCallback = callback
}
Then you create an interface like this:
public interface ProgressCallback{
void onProgressUpdate(int percentComplete);
Have every activity or fragment which needs to show the progress implement this interface and then you can call from onProgressupdate in the asyncTask:
#Override
protected void onProgressUpdate(Integer... progress) {
super.onProgressUpdate(progress);
mProgressCallback.onProgressUpdate(progress[0])
}
You can tweak the interface and method whichever way you like.

See, as you might know, services runs on the background thread hence there is no chance for you to update the progressbar.
But, as an alternative you can use the progressbar on the Notification section, like how youtube does when reviewing offline videos or downloading any videos.
On the other hand, your idea of using one DownloadFiles.class is excellent. So, why not call when the activities open and show progress bar, update views etc etc.
There will be no need of service too.

How to load new values of JSON after every 10 seconds

Hi people I am getting problem in getting my latest JSON value after every 10 seconds. I have developed this code and now I am stucked in this. When I run this code it shows the value after second and did not get updated the second time. I have implemented the handler but it is also not working here.
public class MainActivity extends AppCompatActivity {
TextView a,b,c,d,e,f,g,h;
String result = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
a=(TextView) findViewById(R.id.a);
b=(TextView) findViewById(R.id.b);
c=(TextView) findViewById(R.id.c);
DownloadTask task = new DownloadTask();
task.execute("https://api.thingspeak.com/channels/12345/feeds.json?results=1");
}
public class DownloadTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL(urls[0]);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while (data != -1) {
char current = (char) data;
result += current;
data = reader.read();
}
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(final String result) {
super.onPostExecute(result);
new Handler().postDelayed(new Runnable() {
public void run() {
search(result);
}
}, 10000);
}
public void search(String result){
try {
JSONObject jsonObject = new JSONObject(result);
JSONArray weatherInfo = jsonObject.getJSONArray("feeds");
JSONObject legsobject = weatherInfo.getJSONObject(0);
a.setText(legsobject.getString("field1"));
b.setText(legsobject.getString("field2"));
c.setText(legsobject.getString("field3"));
}catch (JSONException e) {
e.printStackTrace();
}
}
}
}
I want to get my value refreshed after every 10 seconds and it is not doing it.
Can any one guide me that how can I make it possible.

Try this code ..
private final int INTERVAL_MILLI = 60000; // define your time..
Handler mHandler;
#Override
protected void onDestroy() {
super.onDestroy();
mHandler.removeCallbacks(SyncData);
}
Runnable SyncData = new Runnable() {
#Override
public void run() {
// call your code here..
Log.e(TAG, "SyncData1: " + new java.sql.Date(System.currentTimeMillis()).toString());
final String Token = AppSetting.getStringSharedPref(mContext, Constants.USER_KEY_TOKEN, "");
if (!TextUtils.isEmpty(Token) && !CommonUtils.isServiceRunning(mContext)) {
Log.e(TAG, "SyncData2: " + new java.sql.Date(System.currentTimeMillis()).toString());
startService(new Intent(mContext, SyncService.class));
}
callSyncData();
}
};
public void callSyncData()
{
mHandler.postDelayed(SyncData, INTERVAL_MILLI);
}
and callSyncData() method called in activity onCreate method and run method.

To begin with, I don't like the idea of hammering the server with a request every 10s even nothing changes really. If you can move to a solution with notification from the server it will be better.
If you still need to do that you can use three common solutions to fire a repeating task with a period:
1- Use Timer & TimerTask
For this solution you need to declare your timer task to run:
final TimerTask repeatedTask = new TimerTask() {
#Override
public void run() {
//you stuff here
}
};
Then you need to schedule your task using a timer like below:
final Timer timer = new Timer();
timer.scheduleAtFixedRate(repeatedTask,0, 10 * 1000);
==> Don't forget to call timer.cancel(); when your are done (or activity pause, stop, ...)
2- Use ScheduledThreadPoolExecutor
This is basically a replacing for Timer task starting android 5.0. The setup is more easy and straightforward like below:
ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
executor.scheduleAtFixedRate(new Runnable() {
#Override
public void run() {
//you stuff here
}
}, 0, 10, TimeUnit.SECONDS);
==> don't forget to shutdown your executor when you are done by calling : executor.shutdown();
3- Use Handler
The tip here is to repost the runnable after downloading your json like mentionned in the previous answer.

You can use TimerTask and Timer. If you need to update UI components you should run it on UI thread.
final TimerTask yourRepeatedTask = new TimerTask() {
#Override
public void run() {
runOnUiThread(new Runnable() {
#Override
public void run() {
//your code here
}
});
}
};
And the Timer which schedules your task in a given interval. In your case, it is 10s. Make sure to give the interval in milliseconds.
final Timer timer = new Timer();
timer.scheduleAtFixedRate(yourRepeatedTask ,0, 10 * 1000);
At last call timer.cancel() to stop the timer.
#Override
protected void onPause() {
if (timer != null) {
timer.cancel();
}
super.onPause();
}

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);
}
}

ProgressDialog is not showing when .3gp file converting to a .zip

I am working on Android app.
I need to show a progress dialog box when I click on button.
In that button I am converting video file to .zip file and calculating that file size.
In this process I need to show a ProgressDialog, but it is not showing.
Screen get struck while calculating and after calculation it shows ProgressDialog and then screen navigating to the next screen.
My Code:
save.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
MediaCheck.this.runOnUiThread(new Runnable() {
public void run() {
pd = ProgressDialog.show(MediaCheck.this, "",
"Checking the video compatability. Please wait", true);
}
});
video_Path= makeZip(video_Path);
if (video_Path.equalsIgnoreCase("File size is too large")) {
pd.dismiss();
Toast.makeText(getApplicationContext(),
"Large video", Toast.LENGTH_LONG)
.show();
return;
}
pd.dismiss();
// Doing screen navigation here.
}
});
Code to make a zip and know the size
private static String makeZip(String videoPath) {
byte[] buffer = new byte[1024];
String[] videoFileName = videoPath.split("/");
File directory = null;
try {
ContextWrapper cw = new ContextWrapper(context_this);
// path to /data/data/yourapp/app_data/imageDir
directory = cw.getDir("imageDir", Context.MODE_PRIVATE);
FileOutputStream fos = new FileOutputStream(directory
+ "/IRCMS_Video.zip");
ZipOutputStream zos = new ZipOutputStream(fos);
ZipEntry ze = null;
ze = new ZipEntry(videoFileName[5]);
zos.putNextEntry(ze);
FileInputStream in = new FileInputStream(videoPath);
int len;
while ((len = in.read(buffer)) > 0) {
zos.write(buffer, 0, len);
}
File videoZip = new File(directory + "/IRCMS_Video.zip");
videoLength = videoZip.length() / (1024 * 1024);
if (videoLength > 3)
return "File size is too large";
in.close();
zos.closeEntry();
// remember close it
zos.close();
System.out.println("Done");
} catch (IOException ex) {
ex.printStackTrace();
}
return directory.toString() + "/IRCMS_Video.zip";
}
}
Please help...

then you should try ASYNCTASK to easily perform your operation and reduce the complexity of using threads
private class Converter extends AsyncTask<String, Void, Void> { //Converter is class name
protected String doInBackground(String... urls) {
//THIS METHOD WILL BE CALLED AFTER ONPREEXECUTE
//YOUR NETWORK OPERATION HERE
return null;
}
protected void onPreExecute() {
super.onPreExecute();
//THIS METHOD WILL BE CALLED FIRST
//DO OPERATION LIKE SHOWING PROGRESS DIALOG PRIOR TO BEGIN NETWORK OPERATION
}
protected void onPostExecute(String result) {
super.onPostExecute();
//TNIS METHOD WILL BE CALLED AT LAST AFTER DOINBACKGROUND
//DO OPERATION LIKE UPDATING UI HERE
}
}

You are doing calculation on UI thread therfore it hangs your app. Do calculation on background thread. You can resolve this by-
save.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
pd = ProgressDialog.show(MediaCheck.this, "",
"Checking the video compatability. Please wait", true);
Thread background = new Thread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
video_Path= makeZip(video_Path);
MediaCheck.this.runOnUiThread(new Runnable()
{
public void run()
{
if (video_Path.equalsIgnoreCase("File size is too large")) {
pd.dismiss();
Toast.makeText(getApplicationContext(),
"Large video", Toast.LENGTH_LONG)
.show();
pd.dismiss();
return;
}
}
});
}
});
background.start();
// Doing screen navigation here.
}
});

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.