Develop Reference

How to run process inside loop after previous process is finished? Java

Long story short, i want to upload multiple images to my server using Retrofit 2. i want to loop the process of sending single image based on the size of List image but asynchronously, so second upload only run if the first upload is succeeded. Some people tell me i should send an Array of File to my server instead and parse the array there, but i want to know if there is an error while uploading in client side or not. that way if there is an error (network problem) on first loop, second loop will stop running.
I really don't have clear idea as for how to do the task above, but here is a start.
public class UploadAllImages extends AsyncTask<Void, Void ,Void>{
#Override
protected Void doInBackground(Void... params) {
doSingleUpload(image);
return;
}
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
if(upload == succeeded){
new UploadAllImage().execute();
}
}
}

I would probably solve it like this:
public class UploadImages extends AsyncTask<Image, Integer, Boolean> {
#Override
protected Boolean doInBackground(Image... images) {
List<Image> remainingImages = new ArrayList<>(Arrays.asList(images));
while (!remainingImages.isEmpty()) {
boolean success = doSingleUpload(remainingImages.remove(0));
if (!success) {
return false;
}
}
return true;
}
#Override
protected void onPostExecute(Boolean success) {
// Handle the result of all uploads
}
}

One Service data Multiple Activity in android

Hi I make Android application for Xamarin. I have created a simple application in the Android studio. so any answer welcome either Java or C#
I have a service(GPS service) and 2 Activities.
MainActivity - GPS service are well connected with the broadcast. I hope MainActivity -> Another activity real time GPS point.(It is also okay to send from the GPS service to another activity.) but it is fail...app is dead..
MainActivity code
private void RegisterService()
{
_gpsServiceConnection = new GPSServiceConnection(_binder);
_gpsServiceIntent = new Intent(Android.App.Application.Context, typeof(GPS.GPSService));
BindService(_gpsServiceIntent, _gpsServiceConnection, Bind.AutoCreate);
}
private void RegisterBroadcastReceiver()
{
IntentFilter filter = new IntentFilter(GPSServiceReciever.LOCATION_UPDATED);
filter.AddCategory(Intent.CategoryDefault);
_receiver = new GPSServiceReciever();
RegisterReceiver(_receiver, filter);
}
private void UnRegisterBroadcastReceiver()
{
UnregisterReceiver(_receiver);
}
public void UpdateUI(Intent intent)
{
LatLng_txt.Text = intent.GetStringExtra("Location");
Lat = intent.GetDoubleExtra("Lat", 0.0);
Lng = intent.GetDoubleExtra("Lng", 0.0);
}
protected override void OnResume()
{
base.OnResume();
RegisterBroadcastReceiver();
}
protected override void OnPause()
{
base.OnPause();
UnRegisterBroadcastReceiver();
}
[BroadcastReceiver]
internal class GPSServiceReciever : BroadcastReceiver
{
public static readonly string LOCATION_UPDATED = "LOCATION_UPDATED";
public override void OnReceive(Context context, Intent intent)
{
if (intent.Action.Equals(LOCATION_UPDATED))
{
Instance.UpdateUI(intent);
}
}
}
GPS Service code
public void OnLocationChanged(Location location)
{
try
{
_currentLocation = location;
if (_currentLocation == null)
{
_location = "Unable to determine your location.";
}
else
{
_location = String.Format("{0}, {1}", _currentLocation.Latitude, _currentLocation.Longitude);
Geocoder geocoder = new Geocoder(this);
IList<Address> addressList = geocoder.GetFromLocation(_currentLocation.Latitude,
_currentLocation.Longitude, 10);
Address addressCurrent = addressList.FirstOrDefault();
if (addressCurrent != null)
{
StringBuilder deviceAddress = new StringBuilder();
for (int i = 0; i < addressCurrent.MaxAddressLineIndex; i++)
{
deviceAddress.Append(addressCurrent.GetAddressLine(i)).AppendLine(",");
}
_address = deviceAddress.ToString();
}
else
{
_address = "Unable to determine the address.";
}
IList<Address> source = geocoder.GetFromLocationName(_sourceAddress, 1);
Address addressOrigin = source.FirstOrDefault();
var coord1 = new LatLng(addressOrigin.Latitude, addressOrigin.Longitude);
var coord2 = new LatLng(addressCurrent.Latitude, addressCurrent.Longitude);
var distanceInRadius = Utils.HaversineDistance(coord1, coord2, Utils.DistanceUnit.Miles);
_remarks = string.Format("Your are {0} miles away from your original location.", distanceInRadius);
Intent intent = new Intent(this, typeof(MainActivity.GPSServiceReciever));
intent.SetAction(MainActivity.GPSServiceReciever.LOCATION_UPDATED);
intent.AddCategory(Intent.CategoryDefault);
intent.PutExtra("Location", _location);
intent.PutExtra("Lat", _currentLocation.Latitude);
intent.PutExtra("Lng", _currentLocation.Longitude);
SendBroadcast(intent);
}
}
catch
{
_address = "Unable to determine the address.";
}
}
Is not there a good way?

I understood your problem.But dont know more about GPS etc.I have faced the same problem when I was creating Music App.
Two activities were there and one service.And successfully got real time song position and song data from both activities.
My MainActivity has
ServiceConnection sc=null;
public static PlayerService ps;
And gets its value in onCreate of MainActivity
sc=new ServiceConnection(){
#Override
public void onServiceConnected(ComponentName p1, IBinder p2)
{
PlayerService.Getters getters=(PlayerService.Getters) p2;
ps=getters.getService();
}
#Override
public void onServiceDisconnected(ComponentName p1)
{
// TODO: Implement this method
}
};
Then PlayerService.Getters class is
public class Getters extends Binder
{
public PlayerService getService()
{
return PlayerService.this;
}
}
PlayerService has
#Override
public IBinder onBind(Intent p1)
{
return new Getters();
}
getService of Getters gives the object of PlayerService to my MainActivity.
Now I can get real time values of service variables and methods using static ps from multiple activities.

In order to send data or information from Service to Activity, you'll need to use Messenger API. This API will allow you to create an inter process communication (IPC) i.e. a communication link between two or more processes. In Android, Activity and Service are two separate processes, so you can use the IPC technique to establish a communication link in between them.
In the IPC technique, there are two ends, the Server end and the Client end. The Service acts as the Server and Activity acts as the Client.
Note: Service will only be able to communicate with one Activity at a time.
Messenger allows for the implementation of message-based communication across processes by help of Handlers.
Handler is a that allows you to send and process these messages.
Steps for implementing a Messenger:
Step 1. Service implements a Handler which receives the callbacks from the Activity
Step 2. The Handler then creates a Messenger object which further on creates an IBinder that the Service returns to the Activity.
Step 3. Activity then uses the IBinder to instantiate the Messenger, which the Activity uses to send messages to the Service.
Step 4. The Service receives the messages in the Handler created in the 1st step.
Lets now understand it with an example:
Create a Handler in the Service like this:
class ServiceHandler extends Handler {
#Override
public void handleMessage(Message msg) {
switch (msg.what) {
default:
super.handleMessage(msg);
}
}
}
Now, add the Messenger object along with onBind() method to the Service as mentioned in 2nd step above:
final Messenger messenger = new Messenger(new ServiceHandler());
#Override
public IBinder onBind(Intent intent) {
return messenger.getBinder();
}
In the Activity, we will create a ServiceConnection to fetch the iBinder from the Service to instantiate the Messenger object as mentioned in the 3rd step above.
Messenger messenger;
private ServiceConnection serviceConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder iBinder) {
messenger = new Messenger(iBinder);
}
public void onServiceDisconnected(ComponentName className) {
}
};
Bind the Service to the Activity by help of the ServiceConnection created above:
bindService(new Intent(this, MessengerService.class), serviceConnection,
Context.BIND_AUTO_CREATE);
To send messages to the Service from the Activity, use the send() method of the Messenger object.
If you want to receive messages from the Service in the Activity, you need to create a Messenger in the Activity along with a Handler and use the replyTo parameter of the Messenger to receive messages to the respective Handler.

Connection refused when calling endpoints from android client

My android app uses google endpoints as a scalable backend solution. However, I am having trouble calling it from the android client.
I call an async task class from an activity and in the async task class call the endpoints method. In this case the default sayHi() method is called and the message should be displayed in a toast using the onPostExecute(String result) method.
However when I run the app module in the emulator, this error appears in the toast:
failed to connect to /10.0.2.2 (port 8080) after 20000ms: isConnected failed: ECONNREFUSED (Connection refused)
Here is the code that calls the async task from the activity:
Profile profile = new Profile(firstName, lastName, birthday);
new EndpointTask(). new SaveProfileTask(profile, this).execute();
Here is the async task class:
public class EndpointTask {
public class SaveProfileTask extends AsyncTask<Void, Void, String> {
private final String LOG_TAG = SaveProfileTask.class.getSimpleName();
private MyApi mApi;
private Profile mProfile;
private Context mContext;
public SaveProfileTask(Profile profile, Context context) {
mProfile = profile;
mContext = context;
}
#Override
protected String doInBackground(Void... params) {
if (mApi == null) {
MyApi.Builder builder = new MyApi.Builder(AndroidHttp.newCompatibleTransport(),
new AndroidJsonFactory(), null)
// options for running against local devappserver
// - 10.0.2.2 is localhost's IP address in Android emulator
// - turn off compression when running against local devappserver
.setRootUrl("http://10.0.2.2:8080/_ah/api/")
.setGoogleClientRequestInitializer(new GoogleClientRequestInitializer() {
#Override
public void initialize(AbstractGoogleClientRequest<?> abstractGoogleClientRequest) throws IOException {
abstractGoogleClientRequest.setDisableGZipContent(true);
}
});
mApi = builder.build();
}
try {
return mApi.sayHi(mProfile.getFirstName()).execute().getData();
} catch (IOException e) {
return e.getMessage();
}
}
#Override
protected void onPostExecute(String result) {
Toast.makeText(mContext, result, Toast.LENGTH_LONG).show();
Log.d(LOG_TAG, "ERROR: " + result);
}
}
}
Most of this is taken from the github repo here. Which is part of the official android documentation for hooking up the client with the backend for google app engine.
Why is this error occurring and how can it be fixed?
Thanks guys, happy coding.

Google Cloud Endpoints Setup Trouble

I'm completely new to Google's Cloud Platform and I'm having trouble setting it up for my Android device. I am attempting to follow this tutorial and I'm at the point of trying to test my backend with my Android Emulator. The emulator, however, gives me this message after 20 seconds, Where instead it should say my name. Here's my code so far:
MainActivity.java
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
buildUI();
new EndpointsAsyncTask().execute(new Pair<Context, String>(this, "Solomon"));
}
EndpointsAsyncTask.java
public class EndpointsAsyncTask extends AsyncTask<Pair<Context, String>, Void, String> {
private static MyApi myApiService = null;
private Context context;
#Override
protected String doInBackground(Pair<Context, String>... params) {
if(myApiService == null) { // Only do this once
MyApi.Builder builder = new MyApi.Builder(AndroidHttp.newCompatibleTransport(),
new AndroidJsonFactory(), null)
// options for running against local devappserver
// - 10.0.2.2 is localhost's IP address in Android emulator
// - turn off compression when running against local devappserver
.setRootUrl("http://10.0.2.2:8080/_ah/api/")
.setGoogleClientRequestInitializer(new GoogleClientRequestInitializer() {
#Override
public void initialize(AbstractGoogleClientRequest<?> abstractGoogleClientRequest) throws IOException {
abstractGoogleClientRequest.setDisableGZipContent(true);
}
});
// end options for devappserver
myApiService = builder.build();
}
context = params[0].first;
String name = params[0].second;
try {
return myApiService.sayHi(name).execute().getData();
} catch (IOException e) {
return e.getMessage();
}
}
#Override
protected void onPostExecute(String result) {
Toast.makeText(context, result, Toast.LENGTH_LONG).show();
}
}
All Help is appreciated!
EDIT: Part of the problem was that I was running Endpoints Backend rather than the App Engine Servlet Backend. But now I'm now getting "connection refused" and I am running the App Engine Servlet Backend. Any Ideas?

After a tough few days, i found that the problem was that I needed to change my rootUrl from http://10.0.2.2:8080/_ah/api/ to my appspot domain. Now I'm getting the Hello World message.

How to link a Java method from JavaScript using Android DroidGap

I am developing an Android app using PhoneGap system. What I would like to do is to call a java method from javascript. This is what I tried to do:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setIntegerProperty("splashscreen", R.drawable.ldpi);
super.setStringProperty("loadingDialog", "Loading Silver Angel ...");
appView.addJavascriptInterface(this, "MainActivity");
super.setIntegerProperty("loadUrlTimeoutValue", 50000);
super.loadUrl("file:///android_asset/www/index.html",50000);
}
public String customFunctionCalled() {
return "test";
}
In my HTML:
function capturePhotoRisk() {
var testing = window.MainActivity.customFunctionCalled();
alert(testing);
}
When I click a button in the app, I want to display return that text for example. Now the problem that I keep facing is this error: Uncaught TypeError: Object [object Object] has no method 'customFunctionCalled' at file:///android_asset/www/index/html!!