I have an activity which starts a (intent)service. Both access the same DB and potentially write to the same table. What design pattern would you recommand to avoid concurrency?
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A new question about android and services. Currently I'm developing a App that should send images to a server. It should also be possible to send more images parallel. I made a service that creates for every image a new image. The activity can bind to that service and gather information about the progress. I want to show the current status for every image in a notification (and when the user clicks a notification, an activity with the progress for that image should be shown). But I get several problems with that approach. There are errors with binding, the notification pending event starts the activity completely new, so I lose information about currently sending images and so on. How I could design in a appropriate way.
View 1 Replies View RelatedI'm an android noob that is looking for some advice on how to properly use a service in Android. I am building an app that will connect to a server on the Internet to get a data stream via TCP. That data then needs to get send out to another device that is connected via a bluetooth serial port. I want this to continue to function in the background while the user looks at a different activity. The app will be a NTRIP client, which pulls real time RTK correction data from the Internet and sends it to a RTK GPS receiver that I connect to via bluetooth. The data rate will be about 500 bytes/second. The user interface is a single button to connect or disconnect the data stream and some text to show status of the GPS receiver. There are also a few settings that will need to be configured by the user such as the IP/port of the server to connect to and the bluetooth device to communicate with.I think I need to have the main activity spawn a local service, and then have the service spawn a thread for the TCP stream and another thread for the bluetooth connection. Does this sound right? What is the best model for the service in this scenario?-Start(bind) the service every time the activity starts, and have the connect/disconnect button send commands to the service to start/stop the threads. If I go this route, the service will continue to run after the user disconnects and goes to another app. The service would need an inactivity timer to terminate itself.-Start and stop the service when the user presses the connect/disconnect button. The service only runs when data is moving. If I do this, the activity will need to see if the service is running when the activity starts, in order to know if it should bind to the service or tell the user that the link is disconnected.
View 2 Replies View RelatedIn short, I am writing an Android application that I want to have pull data from a remote database. I was looking into .NET web services, but this http://stackoverflow.com/questions/297586/how-to-call-web-service-with-android question pointed me away from that direction.
Is REST as simple as writing some short PHP to handle something like https://www.example.com/data.php?employee=michael and have it return relevant XML or JSON data? That to me seems like what has been described to me by various sites and videos. Also, is this the best way to do this kind of operation over the internet for mobile devices, desktop applications, etc?
I'm designing an android app which will need to do the following steps:
1. User pushes a button or otherwise indicates to "sync data".
2. Sync process will use rest web services to move data to and from the server.
3. The data will be stored locally in a sqlite database.
4. The sync process should provide status updates/messages to the UI
5. The user should not be allowed to wander off to other parts of the application and do more work during the sync process.
The first time the sync process runs, it may take 10-20 minutes. After the initial sync, less data will be transferred and stored and I expect the process to take 1-2 minutes or less. I've been doing a lot of reading about android's AsychTask and various examples of using a Service. But I don't fully understand the design considerations and trade-offs of choosing one design over the other. I currently have my demo project stubbed out using an AsychTask. After watching (most of) Developing Android REST client applications:
http://code.google.com/events/io/2010/sessions/developing-RESTful-and...
I'm left confused the design patterns described here feel overly complex, perhaps because I just "don't get it" yet.
I am developing an app for android mobiles that communicates with a json/rest web service. I need to make certain kinds of calls periodically to the server to check for some information. Within that context I might need also to query the GPS for the current position. I'm quite undecided to use a Local Service, since I don't know very well how to deal with them, in fact I need to retrieve those data periodically and refresh a MapView accordingly. I heard that I can use PendingIntents,in the service, associate this data as a payload and send them to a broadcast receiver which unpack the data and refresh the UI, I heard also that this is a bad design approach because of what broadcast receiver are intended to be used for.
View 1 Replies View RelatedI have a service running that grabs the users attention with a notification. What i would like to happen when the user clicks on the notification is for it to launch a dialog box. The "proper" thing to do is to launch an activity in this way, so is there a way to get an activity to launch with out filling the screen? So it looks like a dialog box?
View 5 Replies View RelatedI have a simple question. I am trying to design a simple Android app, which based on keywords searches something and shows a listing view of results. Currently it merely searches SMSes in the cellphone.Here are some of the things I am faced with: I have a simple first page with a textbox and a submit button. It's rendered by "Activity" inherited class call SMS Finder.once I have the results present with me, I want them to be binded to a list view. Showing preview text to limited characters, say 20 chars. Clicking on the same should "ideally" open the inbox (or outbox or whatever) and open the SMS, however that meant I cannot come back to my app easily. So I would rather open the whole SMS in my own app. So clicking on the app should open the SMS in a new screen with complete message, sender info etc. Few questions here, For generic Android phone apps, what are the best practices to make UI as compliant to as many phones? Like what kind of views should I use?
View 1 Replies View RelatedAre any <uses-permission> clauses needed in the manifest for: 1. Writing to a file using the Activity.openFileOutput() mechanism; 2. Writing to the SD card using FileOutputStreams; 3. Sending email using the Activity.startActivity( Intent.create Chooser (...)) mechanism
http://developer.android.com/guide/topics/security/security.html and didn't see anything that seemed relevant. My app works on my ADP1 without any <uses-permission> clauses when installed with "adb install xyz.apk" but I was worried that it may have problems on a "real" consumer device.
This question is related to an existing question I asked. I though I'll ask a new question instead of replying back to the other question. Cannot "comment" on my previous question because of a word limit. Marc wrote - I've more than one Handlers in an Activity." Why? If you do not want a complicated handleMessage() method, then use post() (on Handler or View) to break the logic up into individual Runnable. Multiple Handlers makes me nervous. I'm new to Android. Is having multiple handlers in a single activity a bad design ?
I'm new to Android.My question is - is having multiple handlers in a single activity a bad design ? Here is the sketch of my current implementation. I've a mapActivity that creates a data thread (a UDP socket that listens for data).
My first handler is responsible for sending data from the data thread to the activity. On the map I've a bunch of "dynamic" markers that are refreshed frequently. Some of these markers are video markers i.e., if the user clicks a video marker, I add a ViewView that extends a android.opengl.GLSurfaceView to my map activity and display video on this new vide.
I use my second handler to send information about the marker that the user tapped on ItemizedOverlay onTap(int index) method.The user can close the video view by tapping on the video view. I use my third handler for this. I would appreciate if people can tell me what's wrong with this approach and suggest better ways to implement this.
Should I create a Listener within a BaseAdapter or should I pass it in? I have 4 classes that inherit from a base class. I pass the Adapter a list objects.
The Adapter is eventually used with a ListActivity I want to create a View based on the derived class and I want them to launch an Activity based on the type of a View. Currently I create the intent and Listener in the BaseAdapter. Is what I'm doing a good pratice?
I know that Android provides some useful methods to be overridden in order to define a menu:
CODE:..............................
I would like to have this menu shared by each Activity and ListActivity of my Android application. This is for having a standard menu in each (List) Activity that lets the user jump to every part of the application within a click.
Right now, the easiest way to achieve this is to copy-and-paste both methods in every (List) Activity of the application. I don't like this redundancy of code written.
Is sub-classing a reasonable choice? I've already seen that sub-classing one of my ListActivity does not work very well (threads that retrieve objects from a database are giving problems). Are there other ways to share a menu though Activities?
Whenever the memory needs to be reclaimed, the process is being killed by Activity Manager Service in killPidsForProcess. I have a back button in my activity window on right corner of the title bar.
I want to kill the activity completely on clicking the close button. Can I reuse the same function and will it have any major effect? Please help me out in this.
I need to made an activity (without layout) that on start check if a service is running. if it is true it starts Activity2, if it false it starts Activity1.
I tried with this code:
CODE:............
Enter code here
But when I check, in the onCreate method, if serviceConnect!=null I receive sometime a NullPointerExcption.
I tried also to insert the operation in the method onCreate in an Async Task:
CODE:............
Is there an equivalent view structure to the iPhone default table cell? The default table cell formats an image (icon) and text in a nice looking way. Are there suggested equivalents for Android? Is there a sample somewhere?
At a certain point in my program, when I'm completely done with my service, my activity executes unbindService() and stopService() -- yet the process persists. I can tell that it persists because I run "ps" in "adb -e shell":
CODE:.............
"adb logcat", I can show you the sequence of events:
ACTIVITY: context.unbindService(serviceConnection);
SERVICE: onUnbind();
ACTIVITY: stopService(serviceIntent); & returns true!
SERVICE: onDestroy();
First, my activity calls unbindService(serviceConnection). According to the documentation, unbindService() will "Disconnect from an application service. You will no longer receive calls as the service is restarted, and the service is now allowed to stop at any time." So that is fine, and it is happening.
Appropriately, we see the onUnbind() call happen on the service side. According to the documentation, onUnbind() is called when "all clients have disconnected from a particular interface published by the service." So this confirms the correct service connection is being passed, and that the service is responding accordingly.
Next, my activity calls stopService(serviceIntent), and returns true. According to the documentation, stopService() does the following: "If there is a service matching the given Intent that is already running, then it is stopped and true is returned; else false is returned." Again, this is happening and returning true.
In response, the service's onDestroy() method is called. According to the documentation, onDestroy() is "Called by the system to notify a Service that it is no longer used and is being removed. The service should clean up any resources it holds (threads, registered receivers, etc) at this point. Upon return, there will be no more calls in to this Service object and it is effectively dead."
At this point I expect the process to disappear from the process table. Yet it remains indefinitely. But why?
Also, the process is so persistent that I can bind to it again, and I see that it is the same exact process responding because the PID (process ID) is the same!
I want to create say 5 different types of cells in table along with identifiers and load them appropriately as per the given data depending upon the type?
Creating TableRow inside TableLayout seems to be one of the options but how to dynamically create the tableRows depending upon the type?
Here is my screen description: It is a TableLayout and it contains multiple Rows. I have set TableRow as clickable, as I want to go to next screen on click of a tableRow. Everything I am doing through Java programming (instead of XML layout, because number of TableRows changes each time) On next screen, I wanted to display all the views of that particular clicked TableRow. Here the problem i am facing is how to capture particular tableRow on onclick() even and how do I get all the textviews of that particular Row. I tried to set id at runtime, and tried to get id of view, but it's not working, giving error resourcenotfoundexception.
View 2 Replies View RelatedThe table "credentials" does show up in the adb shell.
I've checked logcat and it doesn't seem to report a problem...
CODE:........
I've been pouring over this and I bet its some silly syntax typo! Or, at least I hope it is something trivial.
I have a table layout with a few predefined rows in it. Each row has only two columns.
Now I need to dynamically add additional rows in it.
I have two problems:
1) When programmatically inflating, I cannot set the index of the newly created row (I want it in place 'n') 2) After inflation, the inserted (actually appended) row doesn't listen to parent table's stretch column property.
So here are my questions:
q1) Can I set the place where to insert the inflated row programatically ?
q2) Why doesn't the new row inflate properly (the second column is not shown because the first column doesn't contains a TextView with fill_parent.
In the end I need the first column to occupy 80% of the screen width, and the second column remaining 20%.
q3) is that doable with programmatic row insertions ?
When a button is clicked, the following method is run:
public void createTableRow(View v) {
TableLayout tl = (TableLayout) findViewById(R.id.spreadsheet);
TableRow tr = new TableRow(this);
LayoutParams lp = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
tr.setLayoutParams(lp);
TextView tvLeft = new TextView(this);
tvLeft.setLayoutParams(lp);......................
R.id.spreadsheet is an xml TableLayout. I can see from debugging that the method is being accessed, but nothing is drawn to the screen. What gives? Do I need to reset the Content View somehow?
Alice has to answer three questions. After she answered the questions she gets a dialog that lists the question and answers and there's a button to save the answers to a database.
At the moment I think that the design should be three classes: Master, Question, Summary.
Master calls Question with an intent that includes the question text of question 1.
After Alice inputs her answer the Question returns the answer to master via an intent.
Repeat two times.
Then Master does processing of the questions and calls Summary via an intent.
Is this kind of design recommendable in Android? Is it possible to have such an Master activity. If so, how can I allow a running master activity to listen to intents?
I am going to develop an Android Application but before developing it i needs to have MockUp for the Android Application,so is there any way to design MockUp/GUI Design tool for the Android Application?
I know about DroidDraw tool , but i think it is not the exact way to prepare Mockup for the android application.
I have already referred this SO Question , but overthere i just found all the tools for the I-Phone only. So please feel free to share with me if you have/found any !
Suppose I have an Activity that's a list. It calls a Service when this Activity starts.The Service will do background stuff download, parse, and fill the list.My question is this: How can the Service communicate with the Activity?How can I call a method in the Activity, from the Service? (I'm new to OOP)
View 2 Replies View RelatedIn Virgil Dobjanschi's talk, "Developing Android REST client applications" (link here), he said a few things that took me by surprise. Including:
Don't run http queries in threads spawned by your activities. Instead, communicate with a service to do them, and store the information in a ContentProvider.
Use a ContentObserver to be notified of changes.
Always perform long running tasks in a Service, never in your Activity.
Stop your Service when you're done with it.
I understand that he was talking about a REST API, but I'm trying to make it fit with some other ideas I've had for apps. One of APIs I've been using uses long-polling for their chat interface. There is a loop http queries, most of which will time out. This means that, as long as the app hasn't been killed by the OS, or the user hasn't specifically turned off the chat feature, I'll never be done with the Service, and it will stay open forever. This seems less than optimal.
Long question short:
For a chat application that uses long polling to simulate push and immediate response, is it still best practice to use a Service to perform the HTTP queries, and store the information in a ContentProvider?
Our application will expose a Service that can be called by Activities in other people's applications.In many cases, the parent applications calling Activity may be paused before our Service completes. I am looking for the best way for a Service to communicate back to the calling Activity that may have been paused.These are the known options:
(1) Require calling Activities to have a registerReceiver() with a custom action and broadcast to that from our Service. The only way to secure this registerReceiver() is with a signature-based permission.As our Service communicates with any number of unknown 3rd party apps,we can't sign our Service's parent app with all these unknown certificates. These apps would therefore be exposing an unsecured registerReceiver() on their Activity. Would ideally like to avoid requiring this.
(2) Create a PendingIntent to send results back to the activity and give it to our Service. Our Service would send data to calling Activity's onActivityResult(). Each time the result is delivered, the calling Activity will go through onPause() and onResume() but this should be OK.
(3) The calling Activities could create a Handler. The Activity would then create a Messenger pointing to that Handler and send it to our service. Our Service can then use the Messenger to deliver our message back to the calling Activity.
I have a launcher activity which gets activated everytime i start the application and a service which complements it. Now as i press the return key from my main activity .Its Ondestroy gets called.Now i have nullify the pointer of the my launcher activity there. now i am listening through the service any event happening on the network after closing the launcher activity thread and if any event occurs i have to relaunch my launcher activity. i have tried intent but doesnot seems to get though it .
View 4 Replies View RelatedI have a service (input method) and from within that service I want to start and activity which was declared in the same manifest. The activity maybe running but in the background.
How do i check its presence and bring it to front, or optionally start this.
From what I can gather from other posts, this is about what I need to do:
CODE:..............
I don't knwo which of thest flags pertain to what I need to do. The docs are quite merky, and my random attempt at making this work failed.
My application has a background process which continuously waits on a socket for receiving messages and it should be started only once and at the time of application starting.Thus i want to do that background job in a service.
The service should not be started from the activity ,it should be started at the application starting.
How can i define the service,which will be started at the time of application starting?
If at all the service is started from activity.The activity can be destroyed and restarted.when this happens the service also be restarted .
How can I start a service from an Activity ?
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