Develop Reference

What is LeastRecentlyUsedCacheEvictor in ExoPlayer?

I am very confused with exoplayer and their documentation, They have explained everything in very short.
Can anyone please tell me what exactly leastRecentlyUsedCacheEvictor is and how it work? use case and methods?

ExoPlayer video cache uses a CacheEvictor instance to tell the library when to delete cached files. LeastRecentlyUsedCacheEvictor as the name represents declares that policy in a least recently used order.
Assuming you have watched video A, B, C, A (again) and D (order matters) and you hit the maximum cache capacity passed in LeastRecentlyUsedCacheEvictor constructor. The evictor instance lists the cache usages and finds video B as the least recently used one and deletes it to free space.
Here is a simple usage example:
public class VideoCacheSingleton {
private static final int MAX_VIDEO_CACHE_SIZE_IN_BYTES = 200 * 1024 * 1024; // 200MB
private static Cache sInstance;
public static Cache getInstance(Context context) {
if (sInstance != null) return sInstance;
else return sInstance = new SimpleCache(new File(context.getCacheDir(), "video"), new LeastRecentlyUsedCacheEvictor(MAX_VIDEO_CACHE_SIZE_IN_BYTES), new ExoDatabaseProvider(context)));
}
}

Limiting Square Picasso's cache size to 60MB max

I am currently using Picasso to download and cache images in my app inside multiple recycler views. So far Picasso has used around 49MB cache size and i am worried that as more images come into play, this will become much higher.
I am using the default Picasso.with(context) object. Please answer the following:
1) Is there a way to restrict the Size of Picasso's cache. MemoryPolicy and NetworkPolicy set to NO_CACHE isn't an option. I need caching but upto a certain level (60MB max)
2) Is there a way in picasso to store Resized/cropped images like in Glide DiskCacheStrategy.RESULT
3) If the option is to use OKHTTP, please guide me to a good tutorial for using it to limit Picasso's cache size. (Picasso 2.5.2)
4) Since i am using a Gradle dependency of Picasso, how can i add a clear Cache function as shown here:
Clear Cache memory of Picasso

Please try this one, it does seem to work great for me:
I use it as a Singleton.
Just put 60 where DISK/CACHE size parameters are.
//Singleton Class for Picasso Downloading, Caching and Displaying Images Library
public class PicassoSingleton {
private static Picasso mInstance;
private static long mDiskCacheSize = CommonConsts.DISK_CACHE_SIZE * 1024 * 1024; //Disk Cache
private static int mMemoryCacheSize = CommonConsts.MEMORY_CACHE_SIZE * 1024 * 1024; //Memory Cache
private static OkHttpClient mOkHttpClient; //OK Http Client for downloading
private static Cache diskCache;
private static LruCache lruCache;
public static Picasso getSharedInstance(Context context) {
if (mInstance == null && context != null) {
//Create disk cache folder if does not exist
File cache = new File(context.getApplicationContext().getCacheDir(), "picasso_cache");
if (!cache.exists())
cache.mkdirs();
diskCache = new Cache(cache, mDiskCacheSize);
lruCache = new LruCache(mMemoryCacheSize);
//Create OK Http Client with retry enabled, timeout and disk cache
mOkHttpClient = new OkHttpClient();
mOkHttpClient.setConnectTimeout(CommonConsts.SECONDS_TO_OK_HTTP_TIME_OUT, TimeUnit.SECONDS);
mOkHttpClient.setRetryOnConnectionFailure(true);
mOkHttpClient.setCache(diskCache);
//For better performence in Memory use set memoryCache(Cache.NONE) in this builder (If needed)
mInstance = new Picasso.Builder(context).memoryCache(lruCache).
downloader(new OkHttpDownloader(mOkHttpClient)).
indicatorsEnabled(CommonConsts.SHOW_PICASSO_INDICATORS).build();
}
}
return mInstance;
}
public static void updatePicassoInstance() {
mInstance = null;
}
public static void clearCache() {
if(lruCache != null) {
lruCache.clear();
}
try {
if(diskCache != null) {
diskCache.evictAll();
}
} catch (IOException e) {
e.printStackTrace();
}
lruCache = null;
diskCache = null;
}
}

1) Yeah, easy: new com.squareup.picasso.LruCache(60 * 1024 * 1024). (just use your Cache instance in your Picasso instance like new Picasso.Builder(application).memoryCache(cache).build())
2) Picasso automatically uses the resize() and other methods' parameters as part of the keys for the memory cache. As for the disk cache, nope, Picasso does not touch your disk cache. The disk cache is the responsibility of the HTTP client (like OkHttp).
3) If you are talking about disk cache size: new OkHttpClient.Builder().cache(new Cache(directory, maxSize)).build(). (now you have something like new Picasso.Builder(application).memoryCache(cache).downloader(new OkHttp3Downloader(client)).build())
4) Picasso's Cache interface has a clear() method (and LruCache implements it, of course).

Ok, I did a lot of digging inside Picasso, and OKHTTP's internal working to find out how caching happens, whats the policy etc.
For people trying to use latest picasso 2.5+ and Okhttp 3+, the accepted answer WILL NOT WORK!! (My bad for not checking with the latest :( )
1) The getSharedInstance was not Thread safe, made it synchronized.
2) If you don't to do this calling everytime, do a Picasso.setSingletonInstance(thecustompicassocreatedbygetsharedinstance)
P.S. do this inside a try block so as to avoid illegalstateexception on activity reopening very quickly after a destroy that the static singleton is not destroyed. Also make sure this method gets called before any Picasso.with(context) calls
3) Looking at the code, I would advise people not to meddle with LruCache unless absolutely sure, It can very easily lead to either waste of unused RAM or if set low-> Outofmemoryexceptions.
4)It is fine if you don't even do any of this. Picasso by default tries to make a disk cache from it's inbuilt okhttpdownloader. But this might or might not work based on what picasso version you use. If it doesn't work, it uses default java URL downloader which also does some caching of its own.
5) Only main reason i see to do all this is to get the Clear Cache functionality. As we all know Picasso does not give this easily as it is protected inside the package. And most mere mortals like me use gradle to include the package leaving us out in the dust to not have cache clearing access.
Here is the code along with all the options for what i wanted. This will use Picasso 2.5.2 , Okhttp 3.4.0 and OkHttp3Downloader by jakewharton.
package com.example.project.recommendedapp;
import android.content.Context;
import android.util.Log;
import com.jakewharton.picasso.OkHttp3Downloader;
import com.squareup.picasso.LruCache;
import com.squareup.picasso.Picasso;
import java.io.File;
import java.io.IOException;
import java.util.concurrent.TimeUnit;
import okhttp3.Cache;
import okhttp3.OkHttpClient;
//Singleton Class for Picasso Downloading, Caching and Displaying Images Library
public class PicassoSingleton {
private static Picasso mInstance;
private static long mDiskCacheSize = 50*1024*1024; //Disk Cache limit 50mb
//private static int mMemoryCacheSize = 50*1024*1024; //Memory Cache 50mb, not currently using this. Using default implementation
private static OkHttpClient mOkHttp3Client; //OK Http Client for downloading
private static OkHttp3Downloader okHttp3Downloader;
private static Cache diskCache;
private static LruCache lruCache;//not using it currently
public static synchronized Picasso getSharedInstance(Context context)
{
if(mInstance == null) {
if (context != null) {
//Create disk cache folder if does not exist
File cache = new File(context.getApplicationContext().getCacheDir(), "picasso_cache");
if (!cache.exists()) {
cache.mkdirs();
}
diskCache = new Cache(cache, mDiskCacheSize);
//lruCache = new LruCache(mMemoryCacheSize);//not going to be using it, using default memory cache currently
lruCache = new LruCache(context); // This is the default lrucache for picasso-> calculates and sets memory cache by itself
//Create OK Http Client with retry enabled, timeout and disk cache
mOkHttp3Client = new OkHttpClient.Builder().cache(diskCache).connectTimeout(6000, TimeUnit.SECONDS).build(); //100 min cache timeout
//For better performence in Memory use set memoryCache(Cache.NONE) in this builder (If needed)
mInstance = new Picasso.Builder(context).memoryCache(lruCache).downloader(new OkHttp3Downloader(mOkHttp3Client)).indicatorsEnabled(true).build();
}
}
return mInstance;
}
public static void deletePicassoInstance()
{
mInstance = null;
}
public static void clearLRUCache()
{
if(lruCache!=null) {
lruCache.clear();
Log.d("FragmentCreate","clearing LRU cache");
}
lruCache = null;
}
public static void clearDiskCache(){
try {
if(diskCache!=null) {
diskCache.evictAll();
}
} catch (IOException e) {
e.printStackTrace();
}
diskCache = null;
}
}

Xamarin: No ClearCache method in Picasso

I have installed a xamarin Picasso in my application, but wanted to clear the cached when the user logout my application. I can't find a ClearCache method which original Picasso library has one.

Not sure if you mean the memory or disk cache, so:
Disk cache:
Picasso defines its disk cache name as (PICASSO_CACHE = "picasso-cache"), so if you are not using a custom disk cache, you can delete the application's Picasso defined disk cache directly:
_picasso.Dispose(); // Done using Picasso
var cache = new File(BaseContext.ApplicationContext.CacheDir, "picasso-cache");
if (cache.Exists())
{
cache.Delete();
}
// Recreate if needed, but Picasso Build() will recreate it if it does not exist
if (!cache.Exists())
{
cache.Mkdirs();
}
If you are using your own LruCache or custom disk Cache implementation:
var cache = new File(BaseContext.ApplicationContext.CacheDir, "picasso-cache");
if (!cache.Exists())
cache.Mkdirs();
_lruCache = new LruCache((int)Runtime.GetRuntime().MaxMemory() / 1024 * 8);
_diskLruCache = new DiskLruCache(cache, 10 * 1024 * 1024);
_picasso = new Picasso.Builder(BaseContext).MemoryCache(_lruCache).Downloader(new OkHttpDownloader(_OkHttp3Client)).IndicatorsEnabled(true).Build();
Clear memory:
_lruCache.Clear();
Clear disk cache via your custom disk cache implementation:
_diskLruCache.Delete(); // Assumes Android style DiskLruCache

as3 worker thread communication issue on android

i am having issues with speed of communication between workers in AS3 coding for AIR for android. my test device is a Galaxy S2 (android 4.0.4) and i am developing in flashdevelop using AIR18.0.
first things first.
i tried the good old AMF serialisation copying via shared object. i was getting smack average 49 calculations/second on the physics engine (the secondary thread) with a stable 60FPS on main thread. had to crank it up over to over 300 dynamic objects to get any noticeable slowdown.
all went well, so i started the on-device testing and that is when shit started to go sideways. i was getting less than 1.5 steps/s.
started to dig a bit deeper, write a shitton of code to check what the hell is so slow and i found that looking at shared objects was kinda like watching other people watching paint dry.
at this point i started to get deeper into researching. i found that there are a number of people already complaining about the speed of message channels (found not much on shared objects, "developers" status quo i guess). so i decided to go the lowest i could using shared bytearrays and mutexes. (i skipped over condition since i don't particularly want any of my threads to pause).
cranked up the desktop debugger i was getting 115-ish calculations/s and over 350 calculations/s with direct callback (the debugger did throw the exception, wasn't designed for that kind of continuous processing i guess.. anywho..). shared bytearray and mutexes was as advertised, faster than the orgasm of my ex girlfriend.
i do the debugging on the S2 and behold, i get 3.4 calculations/s with 200 dynamic objects.
so.. concurrency on mobile was pretty much done for me. then i thought i do a little test with no communication whatsoever. same scene, physics doing a more than acceptable 40 calculations/s and graphics running at the expected 60FPS...
so, my bluntly evident question:
WHAT the FAPPING FIREFLY is going on?
here is my Com code:
package CCom
{
import Box2D.Dynamics.b2Body;
import Box2D.Dynamics.b2World;
import flash.concurrent.Condition;
import flash.concurrent.Mutex;
import flash.utils.ByteArray;
import Grx.DickbutImage;
import Phx.PhxMain;
/**
* shared and executed across all threads.
* provides access to mutex and binary data.
*
* #author szeredai akos
*/
public class CComCore
{
//===============================================================================================//
public static var positionData:ByteArray = new ByteArray();
public static var positionMutex:Mutex = new Mutex();
public static var creationData:ByteArray = new ByteArray();
public static var creationMutex:Mutex = new Mutex();
public static var debugData:ByteArray = new ByteArray();
public static var debugMutex:Mutex = new Mutex();
//===============================================================================================//
public function CComCore()
{
positionData.shareable = true;
creationData.shareable = true;
debugData.shareable = true;
}
//===============================================================================================//
public static function encodePositions(w:b2World):void
{
var ud:Object;
positionMutex.lock();
positionData.position = 0;
for (var b:b2Body = w.GetBodyList(); b; b = b.GetNext())
{
ud = b.GetUserData();
if (ud && ud.serial)
{
positionMutex.lock();
positionData.writeInt(ud.serial); // serial
positionData.writeBoolean(b.IsAwake); // active state
positionData.writeInt(b.GetType()) // 0-static 1-kinematic 2-dynamic
positionData.writeDouble(b.GetPosition().x / PhxMain.SCALE); // x
positionData.writeDouble(b.GetPosition().y / PhxMain.SCALE); // y
positionData.writeDouble(b.GetAngle()); // r in radians
}
}
positionData.length = positionData.position;
positionMutex.unlock();
}
//===============================================================================================//
public static function decodeToAry(ar:Vector.<DickbutImage>):void
{
var index:int;
var rot:Number = 0;
positionData.position = 0;
while (positionData.bytesAvailable > 0)
{
//positionMutex.lock();
index = positionData.readInt();
positionData.readBoolean();
positionData.readInt();
ar[index].x -= (ar[index].x - positionData.readDouble()) / 10;
ar[index].y -= (ar[index].y - positionData.readDouble()) / 10;
ar[index].rotation = positionData.readDouble();
//positionMutex.unlock();
}
}
//===============================================================================================//
}
}
(disregard the lowpass filter on the position y-=(y-x)/c)
so.
please note that having the mutex only on the parsing of the physics does increase performance by about 20% while having minimal impact on the framerate of the main thread. this leads me to believe that the problem does not lie in the writing and reading of the data per say but in the speed at which that data is made available for a second thread. i mean,.. those are bytearray ops, it's only natural that it is fast. i did check the speed by simply dumping the remote thread into the main, and the speed is still sound. hell,.. it gets acceptable even on the S2 without dumping the extra calculations.
ps: i did try release version too.
if no one has a viable solution (besides a .2-.4s buffer, and the obvious single thread) i do want to hear about wanky workarounds or at least the specific source of the problem.
thx in advance

Think I found the issue.
As always things are more complex than one initially thinks.
Timer events, as well as set interval and timeout are all limited to 60fps. The timer does execute on time as long as the app is idle at that particular point or IMMEDIATELY after it is free to execute and the delay has passed. But the delay, obviously, can't be shorter than 15-ish (and its less on desktop, I guess). Shouldn't be a problem, right?
However.
If that piece of code manipulates shared objects the timer suddenly decides to shit himself and look at it for those 15ms regardless if it had its idle time or not.
Anyhow, the thing is that there is an buggy interaction between shared objects, workers, timer events and the adobe imposed 60FPS limitation.
The workaround is quite simple. Have the timer on some massive delay of like 5000ms and do like 5000 loops within the callback of the timer event. Obviously, the next timer event won't fire until the 5000loop is completed but most importantly it also won't add that monumental delay.
Another weird thing that came up is the greedy ownership of mutexes during the 5000loop so the usage of flash.concurrent.Condition is a must.
The good thing is that the performance boost is there and its impressive.
The downside is that the entire physics thing is now intimately locked to the framerate of the main thread (or whatever contraption the main game loop consists of), but hey. 60Fps is good enough, I guess.
Zi MuleTrex-Condition thing for those interested:
package CCom
{
import Box2D.Dynamics.b2Body;
import Box2D.Dynamics.b2World;
import flash.concurrent.Condition;
import flash.concurrent.Mutex;
import flash.utils.ByteArray;
import Grx.DickbutImage;
import Phx.PhxMain;
/**
* shared and executed across all threads.
* provides access to mutex and binary data.
*
* #author szeredai akos
*/
public class CComCore
{
//===============================================================================================//
public static var positionData:ByteArray = new ByteArray();
public static var positionMutex:Mutex = new Mutex();
public static var positionCondition:Condition = new Condition(positionMutex);
public static var creationData:ByteArray = new ByteArray();
public static var creationMutex:Mutex = new Mutex();
public static var debugData:ByteArray = new ByteArray();
public static var debugMutex:Mutex = new Mutex();
//===============================================================================================//
public function CComCore()
{
positionData.shareable = true;
creationData.shareable = true;
debugData.shareable = true;
}
//===============================================================================================//
public static function encodePositions(w:b2World):void
{
var ud:Object;
positionData.position = 0;
positionMutex.lock();
for (var b:b2Body = w.GetBodyList(); b; b = b.GetNext())
{
ud = b.GetUserData();
if (ud && ud.serial)
{
positionData.writeBoolean(b.IsAwake); // active state
positionData.writeInt(ud.serial); // serial
positionData.writeInt(b.GetType()) // 0-static 1-kinematic 2-dynamic
positionData.writeDouble(b.GetPosition().x / PhxMain.SCALE); // x
positionData.writeDouble(b.GetPosition().y / PhxMain.SCALE); // y
positionData.writeDouble(b.GetAngle()); // r in radians
}
}
positionData.writeBoolean(false);
positionCondition.wait();
}
//===============================================================================================//
public static function decodeToAry(ar:Vector.<DickbutImage>):void
{
var index:int;
var rot:Number = 0;
positionMutex.lock();
positionData.position = 0;
while (positionData.bytesAvailable > 0 && positionData.readBoolean())
{
//positionMutex.lock();
index = positionData.readInt();
positionData.readInt();
ar[index].x = positionData.readDouble();
ar[index].y = positionData.readDouble();
ar[index].rotation = positionData.readDouble();
//positionMutex.unlock();
}
positionCondition.notify();
positionMutex.unlock();
}
//===============================================================================================//
}
}
Sync will become a lot more complex as more channels and byteArrays start to pop up.

Can't set GlideBuilder

I use Glide library for Android. I want to set the cache in my custom folder, so the standard cache folder can be clean (with Master Clean for example).
For this reason I use this code from manual, but this don't work for me.
My code:
DiskCache.Factory diskCacheFactory = new DiskCache.Factory() {
#Override
public DiskCache build() {
DiskCache diskCache = DiskLruCacheWrapper.get(getFilesDir(), 1024*1024*100);
return diskCache;
}
};
new GlideBuilder(this).setDiskCache(diskCacheFactory);
Glide.with(this)
.load("http://www.website.com/1.jpg")
.into(imageView);
After I run this app Glide saves the image in the default folder.

In Glide 3.5, Glide.isSetup() and Glide.setup() are deprecated. The best way to do this is to use GlideModules to do this kind of configuration lazily. Check out the wiki page on configuration.

Try use:
if (!Glide.isSetup()) {
GlideBuilder gb = new GlideBuilder(this);
DiskCache dlw = DiskLruCacheWrapper.get(new File(Environment.getExternalStorageDirectory().getAbsolutePath() + "/myCatch/"), 250 * 1024 * 1024);
gb.setDiskCache(dlw);
Glide.setup(gb);
}