Android :: How Does BaseAdapter Communicate With Its ListView?
Sep 6, 2009
How does BaseAdapter communicate with its ListView? I was wondering how the BaseAdapter.notifyDataSetChanged() method notifies the attached View that the underlying data has been changed and it should refresh itself? When creating a BaseAdapter you attach it to the View with.So the ListView then knows it's adapter to get list elements. But you never tell the BaseAdapter what ListView it is attached to. So when you call BaseAdapter.notifyDataSetChanged() how does it reach the View to tell it to refresh itself?
View 3 Replies
Feb 16, 2010
I'm trying to get my first Android app stable enough for the marketplace, and I've hit a brick wall with one exception that I don't understand. Probably I'm doing something stupid, but I can't tell what, and after several hours googling and experimenting, I thought I'd see if I can get some help. My Activity extends ListActivity, and the parts I think are most important are extracted below:
GroupedListAdapter is a simple class that extends BasedAdapter to provide headings for sections of the list (not unlike the Fancy ListView tutorials that are floating around).
I create this in onCreate, and it works fine. Inside onListItemClick, I do some actions which will create a different set of list contents. I "clear" the adapter, which empties the contents, and call reload, which repopulates it. Then I call notifyDataSetChanged.
Most often, this seems to work, but also fairly often, I get the exception following the code snippets below - this seems to indicate the ListView is not in sync with my changes. Lately this crash happens 100% of the time under the simulator.
CODE:.........................
View 8 Replies
View Related
Nov 19, 2009
For Google about BaseAdapter class
In Android 1.6 and 2.0 the BaseAdapter class has apparently been modified to throw an exception when it sees the Adapter.getCount() method return a number different than what it picked up when BaseAdapter.notifyDataSetChanged() was called (at least I did not observe this behavior in pre 1.6).
So now the question is, when should one call notifyDataSetChanged() or more importantly, when can the count in the Adapter be safely changed?
Consider the case of an app with a background thread delivering data to a BaseAdapter at a rate faster than the ListView responds to notifyDataSetChanged(). Because notifyDataSetChanged() is a synchronous call and the ListView updates are taking place sometime in the indeterminate future on the UI thread, how can an app know when it is safe to change the adapter count?
If the app changes the count while the ListView is updating itself the exception will be thrown (and there is no way to catch the exception).
Is there a way to know when it is safe to change the count in the BaseAdapter?
View 10 Replies
View Related
Mar 9, 2010
I am using BaseAdapter for displaying the list. This list is fetched by calling a Web Service. At a time only 20 records are returned. Now, when the scroll of the BaseAdapter reaches the last record then the application should fetch more records from the server.
So, what I want to know is how to know the scroll position or some other way of knowing that the last record has been reached so fetch more records from the server. I don't want to implement the next and previous button on the screen.and so am trying to implement it in this manner.
View 2 Replies
View Related
Nov 22, 2010
In my android application I have custom listview with an image and textview. In extended BaseAdapter under getView method click events of textview and image are associated with onClick method using setOnClickListener as shown in code below
CODE:.............
And
CODE:...................
When clicking on image it acutally deletes that entry from List which works fine, but on clicking textview i would like to return the text of clicked textview to main activity but I am unable to achieve this, although I can do this from setOnItemClickListener of this custom listview acitivity.
View 1 Replies
View Related
Oct 12, 2010
I have Parsed the Json Response and Now I want to use the BaseAdapter Class in my Application. I have a rough Idea about the BaseAdapter Class but not very clear about the same. what exactly the Base Class does.
Also do I need to use the Getter and Setter Methods if I am using the BaseAdapter Class in my Application?
View 1 Replies
View Related
Feb 22, 2009
In a list, is it possible to have different kind of views, inflated from different layout XML?
I started with the sample in the API Demo, using the Efficient Adapter, and it starts like this Code...
View 3 Replies
View Related
Dec 17, 2009
I custom the BaseAdapter to show image array with full-screen mode. I want the user can flick the images so I use the gallery class.When a image displays on the screen, a correlative sentence should be showed as well. The issue is the position param in getView function jump abnormally, especially when I flick into more one picture at a time. Therefore the string is showed incorrectly, I don't know why the image still displays normally. Here is my code...
View 4 Replies
View Related
Jun 26, 2009
I've tried to describe this problem a few times, but I'll try again.I have a thread (not spawned from the adapter) which updates items in a List that a BaseAdapter child uses to populate its view. I am not adding things in the List from the thread, just modifying content. In any case, I have 6 rows visible at first on the screen. The thread pulls data from the network and updates them in 0, 1, 2, 3, 4, 5 order. However, when 0 is updated, 5 mirrors its data on the screen briefly, then 1 is updated, 4 mirrors it, 3 is updated, then 4 is reloaded correctly, then 5, then 6. I am using the view holder/ convertView pattern correctly, as far as I can tell.How many views are created by default for an adapter? My guess is 3 based on what I see. Then, when getView() gets to index 4, 5, or 6, it correctly creates more Views and populates the right data. Anyone ever seen anything like this?
View 17 Replies
View Related
Jul 29, 2010
I have a little problem. I have class
CODE:..............
When I do that, method convertView.setBackgroundColor(Color.RED) work great, what I need Image is there:
dl.dropbox.com/u/866867/stack/device2.png
But when I want to remove that item, I can't do it. I add there convertView.setVisibility(View.GONE); , but have empty item, beside hide it. I read that parameter View.INVISIBLE won't hide layout, but View.GONE have, but in my code, doesn't.
And that image: http://dl.dropbox.com/u/866867/stack/device.png
View 1 Replies
View Related
Mar 23, 2010
Data being pulled from a local DB, then mapped using a cursor. Custom Adapter displays data similar to a ListView. As items are added/deleted from the DB, the adapter is supposed to refresh. The solution attempted below crashes the application at launch.
CODE:................
Errors:
CODE:.........................
View 3 Replies
View Related
Mar 19, 2010
How to invoke the getView method in the baseAdapter in Android from another WebService Bean?
The adapter in my code as follows, I extends the base adapter code...
View 1 Replies
View Related
Feb 27, 2009
I am using a TabHost one tab with a list and another to show the details of a specific item selected in the list. Does anyone know how I can communicate between tabs?
View 2 Replies
View Related
Mar 25, 2009
I am trying to send AT commands via Ril from LocationManager as there is only one AT port I can use. But it seems like that there is no ways to call the function refer to Ril. Can I just new a commandsinterface and to call ril's functions via it?
View 2 Replies
View Related
Apr 22, 2009
I have read 'http://developer.android.com/guide/tutorials/notepad/notepad-ex2.html', specifically step 4 ahow can I return a different result to the 'calling activity', in this example, it always return ACTIVITY_CREATE. What if the 'activity being launcher' has a 'okay' and a 'cancel' button. How can the 'calling activity' knows which button user presses in the 'activity being launcher'.
View 3 Replies
View Related
Nov 24, 2010
my machine is running window 7.i want to communicate bw two android emulators running on same machine.Emulator 1 is listening on some ip 10.0.2.15 when emulator two tries to create Socket socket = new Socket ("10.0.2.15",8080);it gives exception, unable to connect to 10.0.2.15.does any know how to solve this problem??
View 1 Replies
View Related
Apr 9, 2012
I want to control my pc with an app on my android device over usb. Is this possible.
View 1 Replies
View Related
Feb 17, 2010
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 Related
May 12, 2010
I'm loading up a webview with some locally generated html and javascript.It makes calls to app methods just fine.But what's the right way to get data from Javascript back to the application? It's simple to have javascript call app methods, but any parameters specified in the call on the javascript side don't survive the trip (I just get null in the app).Gross hacks seem obvious (open a url and encode the data in the url), but that can't be right.You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscribe@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
View 3 Replies
View Related
Jul 2, 2010
I am working on a app that will eventually need to communicate with an external device over the phone USB port. Are there any USB drivers and hooks in the Android OS for such applications.
View 4 Replies
View Related
Jan 30, 2010
In my current project I have a full screen TabActivity. Each tab content is handled by two instances of same ListActivity. Now, I put an extra int in intent to know which data should be displayed.So in onCreate method of my ListActivity, I check the int in extra and I build my query to obtain a SQLLiteCursor.I would like to dynamycally give to this two instances of ListActivity the list of item that should be displayed.I do not know what is the best way to do this. Any idea ?
View 1 Replies
View Related
Aug 25, 2009
i have some problem to communicate with a service from an Android application.The service is in a first package "package com.myService" and the application in another on "package com.myApplication".My service work and start well but my next step is to add an AIDL interface to external applications.I have tried to follow the recomandation described here : http://developer.android.com/guide/developing/tools/aidl.html, but i have still the following error (given in the log service):W/ActivityManager( 568): Unable to start service Intent { action=com.MyApplication.IBootstrapService }: not found
View 2 Replies
View Related
May 19, 2010
I'm wondering which is the best way to communicate between a Service and an activity..
Broadcast intent
Callback
others?...
View 1 Replies
View Related
Sep 30, 2009
i have an app widget that has a couple of buttons on it, and in my onUpdate() call, I am hooking up the buttons to do something when you press them
RemoteViews remoteViews = new RemoteViews(context.getPackageName (), R.layout.appwidget); remoteViews.setOnClickPendingIntent(R.id.Button1, button1PendingIntent); remoteViews.setOnClickPendingIntent(R.id.Button2, button2PendingIntent);
The problem is that when I click on button2, it sends the button1 pending intent. i think that's because it's reusing the pending intent. http://groups.google.com/group/android-developers/browse_thread/threa. "If the creating application later re-retrieves the same kind of PendingIntent (same operation, same Intent action, data, categories, and components, and same flags), it will receive a PendingIntent representing the same token if that is still valid, and can thus call cancel() to remove it." So then the question is, how do I communicate which button was pressed?
View 4 Replies
View Related
Nov 20, 2010
My intention is to let two applications communicate using DBus . i know that DBus is already integrated into android,Dbus binaries DBus send,DBus-monitor,DBus-daemon are already available. i am trying to create an application which will connect to the Dbus and start sending signals and messages over DBus . for this i have used basic DBus API's to establish connection to the bus.
I have written native code to connect to the DBus.here is the code
CODE:.................................
View 2 Replies
View Related
Jun 25, 2010
I currently have a Service and an Activity in my application.I currently bind the Service to the activity without using AIDL as the Service and the Activity are in the same application.This allows me to call the methods from the Service within my Activity when I require them, however it doesn't let me call the methods of the Activity from within my Service when I want to.Can anyone comment on what would be the best way to achieve this?I could use Intents but is there an alternative option?I want to have tight communication between the Service and the Activity, I want to be able to call an Activity method from my Service when an event happens.
I now have it working the way I want, however I have come across a problem.My service gets status updates and my Activity is then supposed to react to the update sent on from the Service.The problem is that when I start my activity I get the Dialling Status and then Connected status before the onBind is called and I get the instance of iCallDialogActivity.
I need to be able to use my iCallDialogActivity when I get the Dialling and Connected Status notifications.But this gives me a NullPointer Exception due to it not being created in time when my Activity starts, binding is the first thing I do in my Activities onCreate().Is there a way to make it bind straight away?
View 1 Replies
View Related
May 16, 2010
An application I'm building uses a local Service for downloading files from the web to the phone's SD card. In this app users can browse lists of books, and read them while online. A user can also download a pdf copy of a book for offline viewing. To handle downloads I'm using a locally bound Service. I do not want this Service to run all the time, only when downloading files. So that the Service can shut itself down when its tasks are complete, I am not binding to the service, rather I'm sending an "enqueue for download" command through the Intent passed to Context.startService.
Books available for download are shown in a list. A user can choose to download a book by clicking on its row in the list. On download, I need to show download progress using a ProgressBar on the actual book list row. I need to also show, on the rows, if a book is enqueued for download, or if its download has completed or failed. The books can be shown in different activities throughout the application--in search, or in the user's list of favorite books, for example. When the books are shown in different places, these are not the same objects, but they are uniquely identified by their bookId...............
View 1 Replies
View Related
Apr 30, 2010
I have an application A and a application B that both have an activity. Now i want to send Data from activity A1 to activity B1 and back. Whats the easiest way to to dis? I tried to use Remote Service via AIDL, but this doesn't work very well in both directions because I only can pass the primitives data types and not every object i like (ok i would have to implement parceable but this is not really practicle). Then i read this post by Dianne Hackborn.
View 5 Replies
View Related
Aug 2, 2010
In the Activity I write Intent i=new Intent("IntentServiceTest"); Bundle bundle = new Bundle(); bundle.putString("abc", "def"); i.putExtra("wer", bundle); IntentTest.this.startService(i); Start Service into Service OnCreate method,but I don't know how to do get this Intent in this method.
View 11 Replies
View Related
Feb 16, 2010
I have a service that listens to a socket. When receiving certain input it is to create an activity. When receiving other input, it is to kill this activity. I have struggled for a while to make the service communicate with the activity through AIDL (http://developer.android.com/guide/developing/tools/aidl.html), but this seems to not be effective. I think AIDL is only effective when the process that is to be talked to is a service, not when it is an activity? I would love some directions or suggestions on how to solve my problem.
View 1 Replies
View Related
