I want to use ConcurrentLinkedQueue in an android application, have written the code, but now I'm getting an error when the project builds:
Conversion to Dalvik format failed with error 2
I'm using Eclipse with the lastest version of the ADT plugin.
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I'm trying to launch a lot of remote connection retrieve picture on a server. To do this, I use AsyncTask.
This pics are displayed in a listview using adapter.
If I implement this in my adapter, images are retrieved but the display is bad (problem with index or something like that).
If I try to retrieve image when I build my object list (contained in my listview), I get the exception 04-07 13:35:57.744: ERROR/AndroidRuntime(4132):
CODE:.................
What is this exception ? Why I can launch multiple asynctask in my listview (giving to me a bad result) and not in a simple object without having this issue ?
I want to know about the util Class used in Java. I am currently working on one Application in Android where I need to used a class from one file to another different file. I was told to import it like "import com.android.utli.(ClassName)" here the "com.android.util" is a package name.
Can I use thast class in my another file simply by importing the package along with the Class Name?
Can I rely on Timer and TimerTask to work properly on Android?
I have a background Service with a single Timer, and I schedule (possibly multiple) TimerTask's via Timer.schedule()
At the beginning of each implemented TimerTask.run() method, I check the TimerTask.scheduledExecutionTime() and compare it with the current time. Sometimes things are fine, and the difference is a small number of ms. But sometimes things are nowhere near fine, and the invocation of my TimerTask is *way* late -- like multiple hours late.
Can an Android phone go into some deep sleep mode when it doesn't think anything is going on that would cause a TimerTask to be so late? Can I not reliably use TimerTask for scheduling events, and should I be using some Android-specific means (e.g. the AlarmManager, or a Handler) instead?
I have not found anything that says that java.util.TimerTask shouldn't be sufficient, the Android docs include no kinds of qualifiers, and this post (from Mark Murphy, who's written several good Android books) specifically mentions it as being available:
http://groups.google.com/group/android-developers/browse_thread/threa...
I want to create a java.util.map in android from a resource. I want to do this because I have a lot of entries to populate into the java.util.map and I want to store the values in the res folder of the project in xml format.
Is there an effecient way to do this in android? My map will have around 2500 entries so I want to do this as effeciently as possible and I don't want to hard code them...
That is the only thing I can think of. When I generate a random number (for the radius of a ball), after a while, the radius goes to one number and sticks that way. I've even tried setting the random number value to 0 before getting the random number, and java.util.Random must be at fault, it still gives the same random number. Here is an apk if you would like to try it yourself: http://74.118.194.50:84/Balls.apk
Here is a snippet of the code (I would rather not release the full source): <code> Random randomizer = new Random(System.currentTimeMillis()); int hw; hw = randomizer.nextInt(95-15+1)+15; </code>
In a Android application I want to use Scanner class to read a list of floats from a text file (it's a list of vertex coordinates for OpenGL). Exact code is:
CODE:.................
It seems however that this is incredibly slow (it took 30 minutes to read 10,000 floats!) - as tested on the 2.1 emulator. What's going on?
I don't remember Scanner to be that slow when I used it on the PC (truth be told I never read more than 100 values before). Or is it something else, like reading from an asset input stream?
I want to make calendar view in order to support touch interaction. So I'd like to build new custom calendar view. I tried to make mapping function between view offset and real date value.
Here is my idea:
If I can compute the number of weeks since base date(in my case, 1989-12-31), it is easy to know offset. HEIGHT_FOR_WEEK * NUM_OF_WEEK is very simple computation to know exact offset.
My problem is this:
First I got milliseconds value from base date. And I set the milliseconds to another calendar object. I expected same date from that object. But actually it was different date.
CODE:...............
Here is my CODE:.........................
My app needs to save its state before being killed, and since that state is really small (one Long), I've decided to use java.util.Preferences. I use it like the way I would be using in any Java application (and never had problems), though I am not sure this is the correct way here on Android platform: private static final Preferences prefs = Preferences.userNodeForPackage (WordChoice.class);
I update preferences in onPause() method, to ensure that data is always persisted no matter how my app ends: Here is that fragment of code: protected void onPause() { super.onPause(); prefs.putLong("currIndex", somePositiveValue); }
Which one should I use java.util.Date or android.text.format.Time? It seems you can accomplish what one needs to do with either. What I need to do is at times get the current date and time and sometimes set a date and time specified by the user.
View 5 Replies View RelatedI'm creating a android.text.format.Time Object from a java.util.Calendar Instance, and I read it out field by field.
View 1 Replies View RelatedI've done changes in an Android native library and installed a new system.img file but am now getting an unrelated Error on startup. I can get past it by swallowing the error but I wanted to know if anyone can explain what the issue is.
The Android implementation of Logger.java claims that it is Forcing the LogManager to be initialized since its class init code performs necessary one-time setup. But this forced initialization results in a NoClassDefFoundError. I'm thinking that it has something to do with the class not having been preloaded by Zygote yet but am not that familiar with the whole class loaders and VM business.
code:....................
I am using the Eclipse plugin and I have the above error. I know why it is occurring, it is because I want to override a class file in one of my imported jar files. I am including a new Util class before the jar file in question. I have tried it both as a simple .class file in my package hierarchy and I have tried putting it into another jar file and including it before the one to be overridden.
I would like it to behave like the Java classpath and use the first one it comes to when running through all the classes. I don't mind if dex wants to give me a warning that it is not using the second Util.class file but it should let me build my application. To build my app, I have to create a special jar file without the old Util.class in it. This is annoying as I would like to use the bog standard version so that others can use it with ease too.
In an Android app I have a utility class that I use to parse strings for 2 regEx's. I compile the 2 patterns in a static initializer so they only get compiled once, then activities can use the parsing methods statically.
This works fine except that the first time the class is accessed and loaded, and the static initializer compiles the pattern, the UI hangs for close to a MINUTE while it compiles the pattern! After the first time, it flies on all subsequent calls to parseString().
My regEx that I am using is rather large - 847 characters, but in a normal java webapp this is lightning fast. I am testing this so far only in the emulator with a 1.5 AVD.
Could this just be an emulator issue or is there some other reason that this pattern is taking so long to compile?
CODE:.......................
For the buzzer round, I was thinking of writing 2 app for android (we have a few handsets), one for the quiz master and the other for the contestants.The contestants will be connected to the quiz master through bluetooth.After reading the question, the quiz-master clicks a button in his/her app, the button in the contestant apps will be enabled for X seconds. As soon as a contestant clicks his/her button, the quiz master's app will flash the name of that contestant.Is it even possible to have multiple connections and accept concurrent (or multiplexed) messages from them in bluetooth (something similar to select() in unix/c)?If possible, where should I look for any examples? What kind of problems will I face trying to develop this (I know reliability is an issue here) and how to avoid them?
View 2 Replies View RelatedI have an application with several tables, each being updated by AsyncTask fired by different Activities and used by UI with SimpleCursorAdapter. Though i am not developping a game, I would like to avoid to interrupt the user as mush as possible. Has SQLite is not multiaccess proof, what is the best way of handling such situation?
- I consider adding lock from each DB open and to each close sequence but this seems quite subject to bugs - The solution i am using now is that each DB access (read/write) is done in UI thread (when AsyncTask completes, DB write is done typically in onPostExecute), but that means user is blocked for several seconds during the DB write.
Is there any better solution for that? Should i use a ContentProvider? when i read "Content providers store and retrieve data and make it accessible to all applications", this does not seems to be what i need. Any idea?
I'm doing some stress testing of my SQLite database using the testing monkey and I got the following exception, which appears to be from inside SQLite. My app has many threads accessing the database but all of them do so in locking mode so I don't think this exception is my fault. Any opinions on whether I should worry about this exception or if it's just an artifact of the extremely fast monkey keyboard access? Code...
View 9 Replies View RelatedI have an app on Android Market right now with a minSdkVersion corresponding to Android 1.6. I'd like to make an update that is only visible to users of Android 2.2 and higher (there is a good reason for this, which I will explain below). So I have two questions:
- First, if I publish an update with a higher minSdkVersion than the one it replaces, will existing users still be able to see and download the old version if their device is not >= that minSdkVersion? - Secondly, if so, would it be possible to publish updates to that older version branch? Or would it become a fossil relic, but at least always there for downlevel users? Now for the background. My apps use a large amount of resource files-- about 15MB for the Lite version, and about 55 for the Full version. Prior to Android 2.2, it was not possible to install an app on the SD card, so my solution to this was to have the app contain the bare essentials, and simply download the other resources from my web servers at first-run. However, this means that I must maintain external infrastructure, and it's also a bad experience for users who must download the app, then start another download sequence (I already have had several complaints about this in my user comments). What I would like to do is to keep the app as it is for users with Android OS < 2.2. I'd like to publish an update that is only visible to users with Android OS >= 2.2 which packages everything into the app and allows it to be stored on the SD card. And I'd like to be able to perform maintenance on both versions as needed. Why can't I just do the update as described above to a single branch of the app? Because it would mean that users with Android OS < 2.2 would have to download a massive application to their internal memory, which could be a deal-breaker for devices with only 128MB or 256MB, which is shared with the OS. Since I already have paying customers, I don't think I can ethically create an update that would potentially consume most of a user's internal memory, when the version they purchased was only a couple MB.
I am testing my multiplayer game by running several instances of the emulator (which is, sadly, extremely slow and dis-satisfying). I depend on a little trick using currentTimeMillis() to keep a synchronized clock between the players (but NOT the absolute value of currentTimeMillis() since no two phones are probably set exactly the same)Anyway, I *do* naively assume that two emulators, running on the same PC would return near identical values for calls to currentTimeMillis(), and what I find is that they start off the same, but pull rapidly apart.Which makes me think the underlying implementation of currentTimeMillis() in the emulator is not at all based on the host PC's calendar, and rquires the emulator to get enough Windows compute cycles to be anything close to accurate. (and one emulator is always running at a lower priority to the other, depending on which one is on top)
If this is just an artifact of the emulator, then I can deal with it, but if it implies I have a fundamental misunderstanding of currentTimeMillis(), then that would be something i need to deal with. Part two of the question is: any way I can speed up the emulator? When I run two, are they sharing one of my cores? Can I split them onto separate cores?
This post is in addition to: http://groups.google.com/group/android-developers/browse_thread/threa. I have exactly the same problem and Doug pinpointed what's probably the issue in my case exactly: So here's the deal: I have a Vector containing traffic messages (received from a server via UDP in an own thread). Each time a message is received, I create a new overlay object and populate it with the traffic messages: Code...
View 4 Replies View RelatedI have used content resolver in my project and override the applyBatch() for writting data into the database :
@Override
public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations)
throws OperationApplicationException {
final Context context = getContext();
final SQLiteDatabase db = getDatabase(context);
db.beginTransaction();
[Code]...
If there is any writing operation to the database, applyBatch() method get called and in same time if I will make query from database(using CursorLoader), ANR comes and the following exception will also comes :
W/SQLiteConnectionPool(18025): The connection pool for database '+data+data+com.abc.xyz+databases+XYZ' has been unable to grant a connection to thread 8073 (pool-17-thread-3) with flags 0x2 for 64.105 seconds.
W/SQLiteConnectionPool(18025): Connections: 0 active, 1 idle, 0 available.
The above issue will not come if I remove the methode db.beginTrasaction() and db.endTrasaction() from applyBatch(). But in that case reading/writing time becomes large. I have used methods db.beginTrasaction() and db.endTrasaction() which reduces database access time to ten times.
Is there any approach, so that SQLite DataBse response quickly and there is no ANR ?
My company is importing some Android-based TV boxes from China, and we're experiencing a strange bug with some apps we are developing to run on them. I'm trying to find a specific solution that I can tell them to implement in a firmware upgrade, but I am not sure where to look.
In some apps (especially Adobe AIR-based ones), there seems to be a limit to concurrent HTTP requests to a web server. On an earlier ICS 4.0.4 firmware for these devices, this did not cause any problems. But they recently released a JB 4.1.1 firmware, and this problem occurs.
Let's say an app requests 20 items by HTTP from a web server (XML files, PNG or JPG images). What will happen is about 2/3 of these will be sent back, and the rest just remains blank, as if in a perpetual waiting status.
Looking at the web server's logs, there is no requests at all for these missing items.
And, it's totally random. If you re-launch the app, the missing items will be different ones.
So, I am guessing the app can only request so many things at the same time. Any system property that could be adjusted to solve this?
BTW I am unable to replicate this bug on any other device. The TV boxes in question are based on Rockchip 3066 SoC's
I'm developing an application and I want to use android.text.util.Regex.WEB_URL_PATTERN as the pattern for the Linkify. But, as I have notice, I cannot import android.text.util.Regex for some reason.
Why so? Is there a way to workaround this?
I need a map from int to certain objects. I wanted to use the HashMap, but in the documentation of SparseArray it says that SparseArray is intented to be *more efficient*: http://developer.android.com/reference/android/util/SparseArray.html
However i think the documentation is not entirely correct and needs more info: When reviewing the sourcecode of SparseArray and comparing it with the HashMap i come to the following conclusion
Source code of Sparse Array: [url]
For SpareArray: Time complexity for reads and writes on a map of size N is log2(N) + 1,
However the time complexity for a HashMap of size N is C*N (where C is a constant) (according to the javadoc [url]
So maybe SparseArray is more efficient with respect to space complexity it is not for time complexity. So for programs that need high performance a HashMap may be better.
At least thats what i think. Am i right? Am i wrong? I need a very fast implementation for my game.
Considering writing a wifi cracking (wep, wpa) auditing tool for the android platform, but I am wondering if it is possible to do without a rooted phone.
I had thought it would be impossible to run on an unrooted phone due to the phones wifi chip ignoring packets not addressed to the phone. That is, without the ability to set the wifi chip to monitor mode many of these attacks wont work. I was surprised to learn that android supports multicast packets. That is, android phones can be set to receive packets not addressed to them.
My questions are: Does having a multicast lock mean I can receive all packets broadcast, or does it only apply to packets with a multicast flag (if such a thing exists)?
Is there a difference between monitor mode and multicast? Does the android api have a system for switching channels?
More generally I'm curious: Is anyone familar with other wifi cracking projects running on android (google searches turned up very little)?
What difficulties am I likely to run into?
This question is related to SO question Is there anyway to put Android WIFI (droid handset) into permiscuous monitoring mode?
i have two files
App.java
Gallery.java
App. java contains frontend buttons and functionalities Gallery.java lists the imagesin the sd card. i want to call Gallery.java in click event in app.java
App.java
package gallery.display;
import android.app.Activity;
import android.os.Bundle;
import android.view.View.OnClickListener;
import android.view.View;...........
I'm trying to call a java method from javascript using addJavascriptInterface(); but seems does not work, it always display "failure"; java code...
View 2 Replies View RelatedJava packages like Java.io, Java.Lang etc used in android, are they different from Java packages in windows ? means specially made for android ?
View 2 Replies View RelatedI'm having some problems porting a Java application to work in Android platform. I detected an incompatibility problem between java sun and Adroid sdk in java.lang.Class. I oberved that: public Field[] getFields() Returns an array containing Field objects describing all fields which are defined. That's array is sorted as attributes are declared in the main Class in sun jdk. For example, next Class is defined as: public class Example { public boolean stop; public int atr1; public String name; ....
}
I do an import of the full package name / java file, and if I do a <classname>.<method>, SOMETIMES I can get it to access - other times I get a lot of can't use a static in a non static bunch of talk. I'll admit I'm new to Java, so what do I need to do? Call a class instance first, then call my methods? I'm rather confused by this, as I want to put all of my 'functions' into a FunctionsList.java file, and all of my main Activity (UI) into a MyActivity.java file.
For example:
<MyActivity.java>
import com.example.FunctionsList;
private class MyActivity extends Activity {
FunctionsList.function();
}
9/10 times I get that static/non-static error. If I put all of my functions into MyActivity.java, I have zero problems!