The android docs say that it adds the runnable to the queue and it runs in the UI thread. What does this mean? So, for example, the same thread I use to create my layout is used to run the Runnable? What if I want it as an independent thread that executes while I am creating my layout and defining my activity?
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I have this element in my layout XML:
<FrameLayout android:id="@+id/FrameLayout01"
android:layout_width="320sp" android:layout_height="380sp"
android:layout_gravity="center" android:background="#99CC33">
</FrameLayout>
And I want to get its position on the screen with getTop(), getBottom() but I want to do it only once.
I was trying to do it on the onCreate(), but those methods return all 0 as response.
I would like to create a widget that can reads its attributes from an XML file onCreate. I've created a Custom Button that extends Button widget. I would like to define its layout and styling in an XML, such that the widget can be reused across different views, with the same styling attributes. The notepad sample code does carry some pointers to this problem, however, it defines a XML layout with the component as View, inside LinearLayout, which is not really what I'm trying to achieve here.
View 4 Replies View RelatedCan anybody tell me what method of an activity executes when an application closes?. Like I have a main activity and if I press back button on my phone. The Application closes so I want to know what method executes at that time.
View 1 Replies View RelatedI am working on a screen that needs to look fine at HVGA-L resolution as well as 640x480 resolution. Lets say I have a button that is 200 pixels wide and 50 pixels high on HVGA-L skin. When the same layout xml is shown at 640x480 skin, I want my button size increase proportionately. The hardware the app runs on supports both the resolutions.
None of the units that the android framework provides seems to have this facility. If I use px, then the button size will stay same. dip doesn't matter because it is the same hardware. sp is meant for fonts, not for button width/heights.
Is there a way to define xml layout resources in a modular way? I am building individual 'panels' through code only, it would probably make sense if each were defined in their own xml file, which I can pull at runtime, something like the following pseudopod: Code...
View 2 Replies View RelatedI would like to define the z order of the views of a Relative Layout in Android.I know one of doing this is calling breakfront.Is there are better way of doing this? It would be great if I could define the z order in the layout xml.
View 1 Replies View RelatedI am creating an app which allows for many different Activities to be started from a TabActivity(up to ~25). Most of the activities require data from the sqlite database, so when onCreate is run, an AsyncTask creates an SQLiteOpenHelper object(which will open a readable/writable database), runs a query, data is retrieved, and everything is then closed.
I was just testing messing around to see if i could break something, so i added every Activityto the TabActivity's TabHost. I then started mashing each tab as quickly as possible.
I noticed that very quickly i began to see in the LogCat: Caused by: android.database.sqlite.SQLiteException: database is locked: BEGIN EXCLUSIVE; and the app proceeded to die.
Typically there will only be about 4-6 tabs(i can just limit the user anyway) for the TabHost. I haven't been able to break anything with a small amount of tabs to mash, but i am still worried that maybe i am accessing the database in a poor way.
How can i prevent my SQLiteDatabase objects to cause a lock?
If i create a ContentProvider will that eliminate the possibility of database locking?
Do you have any suggestions for changes I could make for accessing data from an SQLiteDatabase?
I ended up taking the approach of using the Application class and storing 1 SQLiteOpenHelper and trying my best to keep it synchronized. This seems to be working great - i put all my 25 activities in the TabHost and mashed away on them with no errors.
I am calling ((SQLiteDbApplication)getApplication()).setDbHelper(new DBHelper(this, Constants.DB_NAME, null, Constants.DB_VERSION_CODE)); method(shown below) in every onCreate() in my activities
Any further suggestions to this approach or to the changes i made using this Application class?
CODE:...................
I'm trying to create a "scrollable" layout in Android. Even using developers.android.com, though, I feel a little bit lost at the moment. I'm somewhat new to Java, but not so much that I feel I should be having these issues--being new to Android is the bigger problem right now.The layout I'm trying to create should scroll in a sort of a "grid". I THINK what I'm looking for is the Gallery view, but I'm really lost as to how to implement it at the moment. I want it to "snap" to center the frame, like in the actual Gallery application.Essentially, if I had a photo gallery of 9 pictures, the idea is to scroll between them up/down AND side to side, in a 3x3 manner. Doesn't need to dynamically adjust, or anything like that, I just want a grid I can scroll through.I'm also not asking for anyone to give me explicit code for it--I'm trying to learn, more than anything. But pointing me in the right direction for helpful layout programming resources would be greatly appreciated, and confirming if it's a Gallery view I'm looking for would also be really helpful.EDIT: To clarify, the goal is to have ONE item on screen at a time. If you scroll between one item and the next, the previous one leaves the screen, and the new one snaps into place. So if it were a photo gallery, each spot on the grid would take up the entire screen size, approximately, and would be flung out of the viewable area when you slide across to the next photo, in either direction. (Photos are just an example for illustration purposes)
View 2 Replies View RelatedI have an Activity which uses a layout with a LinearLayout in it. Now I want to create in runtime a subactivity which loads some other layout and add this layout as item of my LinearLatout.
View 1 Replies View RelatedI was wondering if it were possible to dynamically create an XML layout file to be displayed to the user. The idea would be to be able to retrieve a layout file from a central server, which could display this dynamic, server driven GUI.
View 2 Replies View Relatednot sure how to inflate this from my layout file: MyView v = LayoutInflater.from(this).inflate(R.layout.myview, null); the inflater of course does not know what 'MyView' type is, and returns only View. What's a good way to reconcile this?
View 1 Replies View RelatedIs it possible to create a layout based on (background) images? For example, there is well know app called Appie that uses this picture as a homescreen:
I might be able to recreate the layout with a TableLayout, but this will be difficult to get it perfectly aligned with the buttons in the image. The default layout options make it very difficult, or maybe impossible, to allow for selection of the buttons on the image (especially when the buttons are in an arc-path). Can anyone tell me how this is done?
I'm starting a calendar app and I'm trying to figure out what the best way to create the layout is. I don't want to use the built in CalendarView as it's only in API >11 which limits the potential users too much.
I've toyed around with a GridView with and Adapter behind it. Truth be told I'm still figuring out how that one works, but it seems the most promising.I tried a nested LinearLayout of TextViews but that requires accessing each TextView be it's ID.
I'm creating a menu in XML using the eclipse software.Unfortunately, I'm no expert in XML but I have attempted to create a basic menu.
The issue I'm having is the alignment of the menu buttons. The buttons on the left column are smaller in width compared to the buttons in the right column. I know this may not seem much of an issue now, but the problem is made worse if I edit the text value of the buttons.
I want to achieve even distribution for both columns of buttons but I have been scratching my head trying to figure this one out!
find below an image describing my program and the code:
Code:
<TableLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<TableRow android:background="#FFFFFF">
[code]....
I am using:
Android 4.0.3
OpenCV 2.4.2
Samsung Galaxy S2
The face-detection example (from the opencv 2.4.2) is working perfectly. But now, I would like to create a custom layout and actually work with just the data extracted from face detection and build a game on it. Not necessarily having the FdView surface taking the entire screen.
I have done these modifications below, but just a black screen is displayed. Nothing appears on the screen.
Changed the BaseLoaderCallback in FdActivity.java
Code:
//EXPERIMENT
setContentView(R.layout.fd);
FdView surface = (FdView) (findViewById(R.id.FdView));[code]....
In a broadcast receiver I want to do the following:
1. See if MyActivity is alive somewhere. 2. If it is, bring it to the foreground. 3. Otherwise, start a new MyActivity.
My code is calling setContentView(R.layout.someLayoutID); from an activities' onCreate method. The activity is launched with the following: Code...
View 4 Replies View RelatedI have an compiled executable that is supposed to copy itself from the res folder, and into the /data/data/package-name/ folder, and change the permissions, and then execute. Every step completes all the way to the end. The output stream seems to be writing, etc. Except when I go check the file system, nothing has been done. I first tried with 'sh' then with 'su' (I have a rooted Cyanogen rom).
Here is the code:
CODE:.........................
I want to create a stub of one of my Activities, but I want to keep it in the test project so not to have it in the actual apk. I don't seem to be able to find a way to do it though. I get this:
java.lang.RuntimeException: Unable to resolve activity for: Intent { act=android.intent.action.MAIN flg=0x10000000 cmp=com.example.test.StubActivity }
I did find if I put it in the main project and put it in the manifest accordingly (IntentFilter:(Action:Main, Category:Default)) it will work, well it actually crashed, but I am not bothered by that. Something to fix later on.I did think about putting everything in the same main project and just have a test package, but that would then involve messing the manifest, I think. It seems better to keep them separate. It's just cleaner.
I have noticed that when display goes to sleep, my TimerTask is also freezed, until display is waked up. I need my TimerTask to execute (a BlueTooth operation every few minutes) even while the display is sleeping.
How do i achieve this (eventually using something else instead of a TimerTask)?
In 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?
My problem is: Activity A called Activity B, and in Activity B, it start a background thread to do some client-server work. But it maybe takes too much time. So i add a cancel button to call the stop() method to stop the thread, and call finish() to finish the Activity B and go back to Activity A. Although it is back to Activity A, the thread isn't stop immediately. Can i just call the finish() to go back to Activity A, and leave the thread to exit by itself? If it is not the right way, which is?
View 10 Replies View RelatedI had a bunch of code in an activity that displays a running graph of some external data. As the activity code was getting kind of cluttered, I decided to extract this code and create a GraphView class:
public class GraphView extends LinearLayout {
public GraphView(Context context, AttributeSet attrs) {
super(context, attrs);
LayoutInflater inflater = (LayoutInflater)
context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
inflater.inflate(R.layout.graph_view, this, true);
}
public void start() {
// Perform initialization (bindings, timers, etc) here
}
public void stop() {
// Unbind, destroy timers, } }
Moving stuff into this new LinearLayout-derived class was simple. But there was some lifecycle management code associated with creating and destroying timers and event listeners used by this graph (I didn't want this thing polling in the background if the activity was paused, for example). Coming from a MS Windows background, I kind of expected to find overridable onCreate() and onDestroy() methods or something similar, but I haven't found anything of the sort in LinearLayout (or any of its inherited members). Having to leave all of this initialization code in the Activity, and then having to pass it into the view seemed like it defeated the original purpose of encapsulating all of this code into a reusable view. I ended up adding two additional public methods to my view: start() and stop(). I make these calls from the activity's onResume() and onPause() methods respectively. This seems to work, but it feels like I'm using duct tape here. Does anyone know how this is typically done?
If I want to send an event, e.g. OnClick, to an activity from a thread? The expected work flow is below:public class HelloAndroid extends Activity {public void onCreate(Bundle savedInstanceState)Code...
View 4 Replies View RelatedI am want to pass data back from a Thread to Activity (which created the thread). So I am doing like described on Android documentation.Only one thing I am missing here - where and how should be defined mResults so I could access it from both Activity and Thread, and also would be able to modify as needed? If I define it as final in MyActivity, I can't change it anymore in Thread - as it is shown in example.
View 1 Replies View RelatedI have some questions about android ui api.
Give a example, that I want to implement.
Main_UI_Thread.java. code...
I know the message passing can be do that;
But I want the ui program is be implemented in DisplayClass.java. Is it possible?
How can I kill Android activity from asynchronous thread? In my android application, I start another activity using startActivity. Is there anyway for me to kill that activity I started after several minutes?Or is there any way beside using thread?
View 2 Replies View RelatedSuppose my activity ui-thread spawns a separate thread at some point. Is it safe for that new thread to fire off an Intent for launching a new activity?
View 1 Replies View Relatedcan someone please help me? I would like to write a program which uses a service to periodically update a text view on an activity. I do this by having ActivityA with a 2 buttons to start/stop my service. In the service I run a timer which triggers every second. From here I need to have this launch and update a text view on ActivityB which at present is just a counter value.I'm sure there are likely better ways to do this, such as using only one activity, maybe using a thread but the main design consideration is to have the service running even if my activity is destoyed (the counter value would instead go trigger some alarm or file write instead of a text view update). Sorry for rambling. I find the android developer resources offer too many solutions!
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