Android :: Garbage Collector Conservation - Best Practice

Jul 29, 2009

I didn't use much Java before Android so my knowledge concerning the gc is marginal. Now I'm developing a highly physics-based game and therefore I need to do many calculations each time step and many (25) time steps per second. At the moment I'm almost only using local objects (float) in my methods, so I guess they are allocated every time the method is called (which might be, for example, 25*100 = 2500 times a second , for 100 objects with calculations on them). This causes massive activity of the garbage collector like freeing ~10000 objects every 1-2 seconds (taking ~200ms on a real device). Now I really want to optimize that because even there's no noticeable delay due to the GC (and the frame rate is constant), this seems just not well. But I read on many documentations concerning Java optimization, that there is not much to optimize in modern versions of (desktop) Java, because the GC is fast enough. Does this apply to Android, too? Does the compiler optimize anything like frequently, steady allocated objects (like floats)? What would be best practice: keep all local objects and allocate and free them all the time or use class-global objects, even if they are only used inside one particular method (which is bad programming style but conserves GC?

Android :: Garbage Collector conservation - best practice

Android :: Possible To Stop Droid Garbage Collector?

May 21, 2010

Is there any way to stop the garbage collector for some time?

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Android :: Subclassing SimpleCursorAdapter To Include ConvertView For Memory Conservation?

Nov 4, 2010

I've been scouring throug the examples and tutorials but I can't seem to get my head around how to handle recycling within a subclassed SimpleCursorAdapter. I know that for regular ArrayAdapters you can check convertView for null and inflate if null from the xml and if not null, recycle, but I'm having a little trouble visualizing how that works with the from and to arrays within the SimpleCursorAdapter subclass. I tried to figure this out from the The Busy Coders Guide to Android Development by Commonsware but was unsuccessful. If anyone knows of any tips, examples, or tutorials, I would be grateful to see them.

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Android :: Thread(s) Producing Garbage?

May 27, 2010

I have an app with about 15 threads. Most do mundane tasks and sleep most of their lives. Others collect information and cache it in hashmaps. The hashmaps grow to a moderate size and level out. The number of keys and size of value remains constant, but the contents of the values changes (at 33 keys per second average). When I start my app, I notice the garbage collection interval goes from minutes to once per second, and the amount of garbage is 700k+ each time. In fact as I was writing this, it caused my phone to reboot with an error "Referencetable Overflow". Here's my question: Are there any tricks to identifying which threads are producing the garbage, or even finding out more about what garbage they are producing?

05-26 22:08:57.052 W/dalvikvm( 1031): ReferenceTable overflow (max=512)
05-26 22:08:57.052 W/dalvikvm( 1031): Last 10 entries in JNI local reference table:
05-26 22:08:57.052 W/dalvikvm( 1031): 502: 0x449904a8 cls=Ljava/lang/String; (28 bytes)
05-26 22:08:57.052 W/dalvikvm( 1031): 503: 0x4494fda8 cls=Ljava/lang/String; (28 bytes)
05-26 22:08:57.052 W/dalvikvm( 1031): 504: 0x44a172c8 cls=Ljava/lang/String; (28 bytes)
05-26 22:08:57.052 W/dalvikvm( 1031): 505: 0x448c7900 cls=Ljava/lang/String; (28 bytes)........

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Android :: Need To Replace Garbage Keyboard Bundled With 1.6

Feb 11, 2010

Was looking for some guidance here. I need to replace the garbage keyboard bundled with 1.6 for something else. Which in your opinion is the best replacement and why? Maybe some comparisons would help also. Oh, by the way i'm running a mytouch 3g!

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Android : Latency Due To Garbage Collection On On PrevFrame

Jun 6, 2010

I'm writing an Augmented Reality codes that should works in realtime,

But the VM's garbage collection hinders my program's performance.

I checked my program's execution time for each in OnPrevFrame(byte[], Camera)

and it execution time increases from around 50ms to 120ms at just after each garbage collection.

I copied parts of logs below. (local time is just before and after of signal processing, and global time is time stamps for every onPreviewFrame() calling )Also I executed onPreviewFrame without any signal processing on it, but

the garbage collection is also carried showing debugging message around 60ms it spends for memory release.

Is this garbage collection come from releasing byte[] yuvs image data? ( i uses 320x240 thumb nail )

then this clearly comes from Java's limitation, so there will be no hope for improvement unless

I found a way to directly access camera device? do you think this is feasible? Hope listen to others' comments.

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Android :: Glbuffersubdata With An Offset Into Buffer Without Causing Garbage

Aug 1, 2010

I'm trying to update part of a VBO with a call to glBufferSubData(). When I update from the start (0) of my existing shadow buffer, there is no problem, as the buffer starts reading from 0. The following will read 0 to y from the buffer and place it at 0 to y in the VBO: gl.glBufferSubData(GL11.GL_ARRAY_BUFFER, 0, y, mPositionBuffer);

However, if I want to update a portion of the VBO (not from 0) I run into a problem; The following doesn't work, since it will write the values from the start of the buffer (0 to y) into position x to x+y of the VBO:........................

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Android :: Avoiding Garbage Collection For Smooth 2d Animations

Dec 28, 2009

I'm drawing a rect to a surfaceview. Nothing special, just a test like this, in the surfaceview-extended class:

private int mPosX = 0; private Paint mPaint = new Paint(); Code...

the rect just bounces around the screen. I'm watching DDMS, I still see the garbage collector being called, even with this simple draw loop. There is no other application code being executed.

I'm wondering if it's realistic to expect the gc to not be called at all if we take care to not allocate any objects during our draw loops. I'm trying to extend this example to do some smooth animations, but every once in awhile the gc is called and you can see the drawing stutter. Although none of my application code is allocating any new objects, I don't know what the underlying API is doing inside surfaceview etc, and I doubt we can control that. Just wondering if this is not possible, I'd prefer to abandon this game idea up-front if we can't guarantee smooth animation.

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Android :: Droid Camera Garbage Collection / Way To Avoid It

May 25, 2009

I am developing a camera application , where the frame rate is important. However, camera uses a preview callback function which allocates a byte[] array of 230400 bytes, which makes it necessary for the garbage collection to step in. Can someone suggest me a way to avoid garbage collection stepping in?

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Android : OpenGL Garbage Collection - With Direct ByteBuffers

May 20, 2009

Hi, I have discovered while using DDMS that the basic OpenGL system calls in my code are allocating memory and causing the garbage collector to fire! It's not the system calls themselves causing the problem but the use of direct byte buffers to pass data in.

The direct byte buffers I use in calls such as glVertexPointer & glTexCoordPointer lead to java.nio calls to read the byte buffers, leading to objects of type org.apache.harmony.luni.platform.PlatformAddress being created.

These buffers are the same as in the example OpenGL code. I am creating a ByteBuffer using allocateDirect() and then creating an IntBuffer using ByteBuffer.asIntBuffer() to pass data to the OpenGL functions. The problem occurs as the system is reading the buffers.

Is there a way around this? Maybe using something other than direct byte buffers? It seems that using this method, OpenGL code of any complexity (ie a lot of OpenGL system calls in every frame) is doomed to pause a lot. I am aware that these calls should be kept to a minimum, but I still need to use a certain amount of them.

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Android : Are Primitive Types Garbage Collected In Droid?

Mar 18, 2010

I know this may be a dumb question, but my background is more in c++ and managing my own memory.

I am currently cutting down every single allocation that I can from one of my games to try and reduce the frequency of garbage collection and perceived "lag", so for every variable that I create that is an Object (String for example) I am making sure that I create it before hand in my constructor and not create temporary variables in simple 10 line functions... (I hope that makes sense)

Anyways I was working though it some more tonight and I realized that I a may be completely wrong about my assumption on garbage collection and primitive types (int, boolean, float) are these primitive type variables that I create in a 10 line function that gets called 20 times a second adding to my problem of garbage collection?

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Android :: Avoid Garbage Collection Delays In Java Games?

Mar 20, 2010

I'm performance tuning interactive games in Java for the Android platform. Once in a while there is a hiccup in drawing and interaction for garbage collection. Usually it's less than one tenth of a second, but sometimes it can be as large as 200ms on very slow devices. I am using the ddms profiler (part of the Android SDK) to search out where my memory allocations come from and excise them from my inner drawing and logic loops. The worst offender had been short loops done like,

for(GameObject gob : interactiveObjects)

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Android :: Force Garbage Collection To Happen At Convenient Time?

Apr 15, 2009

I have screen 1 of my app which I want to transition smoothly into screen 2.

I want the transition to be smooth but I don't mind a slight pause before or after the transition. Before the transition I dump a lot of objects that are no longer needed from screen 1.

However, as luck would have it (!), the garbage collection almost always takes place during the transition causing the frame rate to drop and the transition looks terrible :(

Is there a way for me to either force the garbage collection to complete before the transition or delay until after the transition is finished? I have tried System.gc() in various places but it doesn't seem to help performance.

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Android :: Print Integer To Canvas Fast And Without Garbage Collects?

Nov 24, 2010

I have a tight game loop in a separate thread where I paint a lot of things on the canvas.

When I paint the score to the canvas I use the following function code...

When I check allocations in ddms I see that .toString not totally unsurprising allocates a char array on each conversion from an Integer to a String. This array will eventually be claimed by the garbage collect and cause uneven rendering of frames on slow android devices.

Is there a better way of painting integers on a canvas that won't cause new allocations and garbage collects?

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Android :: MotionEvent And KeyEvent Causing Excessive Garbage Collect (GC) Calls

Jan 3, 2010

I'm running into some issues with input events and garbage collection, or more precisely object allocation. I am creating a game and have pretty much got my head around the OpenGL environment. I've digested all the relevant material I could find regarding performance, memory allocation etc (and watched the excellent presentation by Chris Pruett - I've pretty much eliminated any object allocations after initial setup from my game (which is still in its infancy), but I'm still getting a bunch of GC calls, like this:...........................

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Android :: Garbage Collection Infinite Loop - Clamp GC FOR MALLOC Grow Heap

Jul 6, 2010

I have a Service which uploads a big file to a webserver. This works fine on the emulator (android 2.1). But if i run it on a Nexus One Froyo phone it starts out fine. But after a while it is in an infinite GC loop. The whole phone becomes unusable:.........................

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Android :: One Line Causing Lots Of Garbage Collection.String.format With Float?

Apr 13, 2009

In my ListView, there's one line of code in my ViewBinder that causes lots of garbage collection as I scroll through the list, about every two seconds...

D/dalvikvm(16312): GC freed 13171 objects / 659576 bytes in 162ms D/dalvikvm(16312): GC freed 13122 objects / 654128 bytes in 129ms D/dalvikvm(16312): GC freed 13134 objects / 655416 bytes in 142ms D/dalvikvm(16312): GC freed 13129 objects / 654840 bytes in 129ms D/dalvikvm(16312): GC freed 13149 objects / 655000 bytes in 110ms D/dalvikvm(16312): GC freed 13150 objects / 655720 bytes in 127ms D/dalvikvm(16312): GC freed 13075 objects / 652256 bytes in 111ms D/dalvikvm(16312): GC freed 13232 objects / 659040 bytes in 136ms D/dalvikvm(16312): GC freed 13106 objects / 653920 bytes in 110ms D/dalvikvm(16312): GC freed 13155 objects / 655152 bytes in 110ms

The offending code is here, which formats a price for each item in the list: String price = cursor.getString(columnIndex); final float pricef = Float.parseFloat(price); price = new StringBuffer("$").append(String.format("%. 2f",pricef)).toString(); ((TextView)view).setText(price);

If I comment out the line with String.format, the garbage collection goes away. So what's the "right" way to do this to avoid allocations? That database field holds an unformatted text string which I'm trying to format into proper currency format (example: format "1.5" to "$1.50")

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Motorola Droid X :: Audio Sounds Like Garbage Through Car Speakers / What To Do?

Sep 1, 2010

I started having an issue a couple days ago (after not making any changes to any settings) where anything with the slightest hint of.bass sounds awful in the car. It sounds fine on headphones, and the same car adapter I use on the DX sounds just fine with other devices through the same speakers. Doesnt matter if I use Pandora or the native music app. What gives? I checked my audio effects settings already and no changes there help. Im baffled because all the things that could be wrong work fine with other devices.

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Android :: Best Practice For Changing Min SDK Version?

Aug 2, 2010

I have a sizable install base already on some apps with Android 1.5 set as the minimum version. I want to update the apps to take advantage of some of the newer features offered in Android 2.0 and greater. What is the best way forward so I don't break things for my current 1.5 and 1.6 users?

If I simply update the application with a new min SDK version, will 1.5 and 1.6 users be prompted to uninstall? Or will they just not see the update? What about future development that I want to apply for everyone, say a bugfix. Will I have painted myself into a corner? Another solution would be to fork and create a new app for 2.0 users, but that is undesirable for several reasons.

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Android :: Uninstalling Apps Best Practice

Jun 23, 2010

I have had my Desire no for almost 2 months, and like most I have tried installing and uninstalling many apps, to see what I like.Due to doing a factory reset on my phone yesterday I have layered back all the apps I was using and have noticed that I have used considerably less memory than before, making me very suspicious of the uninstall method used within the market place.Does it leave behind pieces of the app, and if so what's the cleanest method of uninstalling apps.

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Android :: Best Practice For P2P Handset Networking

Dec 4, 2009

I've been scouring the web looking for information on setting up a peer-to-peer connection between Android handsets and so far have drawn a blank. The only thing I can definitively seem to work out is that it was made a whole lot more difficult when XMPP was removed from 1.0. Apart from that, I find a couple of threads on an OpenIntents board about porting an XMPP implementation to Android that were last posted nearly 2 years ago. Has anybody solved this problem effectively? What's the best way of doing it (from a games point of view)?

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Android :: Best Practice For Implementing Watchdog

Sep 17, 2009

I'm writing an application where real-time knowledge of the GPS state is critical to convey to the user. I request GPS updates at 1000 ms intervals -- when I haven't received another update 1500 ms past the most recent update, I want to display a yellow icon, and 5000 ms after the most recent update I want to display a red icon. Currently, I'm doing it like this: private CountDownTimer gpstimeout; public void onLocationChanged(Location location) { if (gpstimeout != null) gpstimeout.cancel(); gpstimeout = new CountDownTimer(5000, 1500) { public void onTick(long m) { setYellow(); } public void onFinish() { setRed(); } }; gpstimeout.start(); }

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Android :: Best Practice With SQLite And Phone

Mar 22, 2010

What is considered "best practice" when executing queries on a SQLite db within an Android app? Is it safe to run inserts, deletes and select queries from an AsyncTask's doInBackground ? Or should I use the UI Thread? I suppose that db queries can be "heavy" and should not use the UI thread as it can lock up the app - resulting in an ANR. If I have several AsyncTasks, should they share a connection or should they open a connection each?

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Android :: Best Practice To Pull Content From Web?

Sep 29, 2010

I'm new to developing Android applications, and have only a little experience with Java in school. I was redirected to StackOverflow from the Google groups page when I was looking for the Android Beginners group. I have a question about what is best practice to pull content from a web source and parse it. Firstly, I would eventually like to have my application threaded (by use of Handler?), however, my issue now is that the class I have created (Server) to connect and fetch content often fails to retrieve the content, which causes my JSON parser class (JSONParser) to fail, and my View to display nothing. After navigating to the previous Activity, and attempting to call the connect(), fetch(), and parse() methods on the same remote URI, it will work. Why does this (sometimes retrieve the remote data) happen sometimes, but not always? What is the best practice, including the use of ProgressDialog and the internal Handler class, to make my application seemless to the user. Is this the best place to ask this question?

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Android :: Best Practice - Passing Id To New Intent?

Sep 22, 2009

I am creating a database driven app for managing people. I am showing a list of people with each name in a TextView. When a TextView is clicked, I launch a new intent to show the detail for the person. My question: What's the best practices for passing the id of the person to the new intent? The TextView is displaying the name of the person, so how do I know the id of the person? Once I know the id, I know how to pass it to the new intent, but I don't know what the best way to associate the id of the person to the TextView. Is there a best practice for this?

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Android :: Best Practice For Specifying Pronunciation For TTS Engine?

Aug 16, 2010

In general, I'm very impressed with Android's default text to speech engine (i.e., com.svox.pico). As expected, it mispronounces some words (as do I) and it therefore occasionally needs some pronunciation guidance. So I'm wondering about best practices for phonetically spelling out those words that the pico TTS engine mispronounces. For example, the correct pronunciation of the bird Chachalaca is CHAH-chah-LAH-kah. Here is what the TTS engine produces: mTts.speak("Chachalaca", TextToSpeech.QUEUE_ADD, null); // output: chuh-KAL-uh-KUH mTts.speak("CHAH-chah-LAH-kah", TextToSpeech.QUEUE_ADD, null); // output: CHAH-chah-EL-AY-AYCH-dash-kuh mTts.speak("CHAHchahLAHkah", TextToSpeech.QUEUE_ADD, null); // output: CHA-chah-LAH-ka mTts.speak("CHAH chah LOCKah", TextToSpeech.QUEUE_ADD, null); // output: CHAH-chah-LAH-kah Here are my questions. Is there a standard phonetic spelling recognized by the Android TTS engine? If not, are there some general rules for making custom pronunciation spellings that will make the spellings more likely to be correct in future TTS engines/versions? It appears that the Android TTS engine ignores text case. What is the best way to specify emphasis?

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Android :: Best Practice For Storing Application - Configuration

Apr 8, 2010

I am still learning bu find Android the cool platform for allot of useful applications. I have written a Service for doing GPS tracking and it consists of a Service and a Control activity to manage, monitor and configure the service. I am looking for the preferred way for the Control Activity to define settings for the Service, things like IP address and Update interval. I envision something like a Registry on windows where these settings can be shares and updated.

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Android :: Best Practice For Responsive User Interfaces

Jun 16, 2009

I am quite new to Android and Java. Before I was working with C++ where the events where dispatched with messages. Now I would like to create the same user experience for Android platform and I would appreciate any of your suggestions or comments on what is the best way to bind events to user controls.

Here is an example from C++:

ON_MESSAGE(WM_RECORD_START, &CMainFrame::OnRecordStart)//Method OnRecordStarts() executes on WM_RECORD_START_MESSAGE...................

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Android :: Preferences Use Explanation - Recommended Best Practice?

Oct 6, 2010

Some of my app's preferences could use some more explanation than the scarce space available for the summary. Sadly, there doesn't seem to be support from the system, like an optional help button that shows a longer text. How do you solve this problem? The first thing that comes to mind is an additional custom "preference" like "more information to above entry" that opens an AlertDialog with the help text, but that's not really nice for both user (two entries for the same preference) and the developer (manual work to do in Preference Activity). A bit nicer for the user, but way more work for the developer would be custom dialogs for each preference with more text and/or a help button. Is there a better solution or even an officially recommended best practice?

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Android :: Building Two Versions Of Application - Best Practice?

Apr 19, 2009

What is the best way to release two versions of an application? E.g. a free version with limited features, and a paid version with the full feature set. #ifdef would be the ideal way to do this, but Java doesn't support it. Could I do something like: try {import; } catch (Exception e) { // ignore it, this must be the free version}? I could manage with this kind of construct, although #ifdef really would be ideal.

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