Databases
StackOverflow2013
Postsdbo
POWhen should I recycle a bitmap using LRUCache?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POWhen should I recycle a bitmap using LRUCache?
    primarykey
    data
    text
    <p>I'm using an <code>LRUCache</code> to cache bitmaps which are stored on the file system. I built the cache based on the examples here: <a href="http://developer.android.com/training/displaying-bitmaps/cache-bitmap.html" rel="noreferrer">http://developer.android.com/training/displaying-bitmaps/cache-bitmap.html</a></p> <p>The problem is that I'm seeing OutOfMemory crashes frequently while using the app. I believe that when the LRUCache evicts an image to make room for another one, the memory is not being freed.</p> <p>I added a call to Bitmap.recycle() when an image is evicted:</p> <pre><code> // use 1/8 of the available memory for this memory cache final int cacheSize = 1024 * 1024 * memClass / 8; mImageCache = new LruCache&lt;String, Bitmap&gt;(cacheSize) { @Override protected int sizeOf(String key, Bitmap bitmap) { return bitmap.getByteCount(); } @Override protected void entryRemoved(boolean evicted, String key, Bitmap oldBitmap, Bitmap newBitmap) { oldBitmap.recycle(); oldBitmap = null; } }; </code></pre> <p>This fixes the crashes, however it also results in images <em>sometimes</em> not appearing in the app (just a black space where the image should be). Any time that occurs I see this message in my Logcat: <code>Cannot generate texture from bitmap</code>.</p> <p>A quick google search reveals that this is happening because the image which is displaying has been recycled.</p> <p>So what is happening here? Why are recycled images still in the LRUCache if I'm only recycling them after they've been removed? What is the alternative for implementing a cache? The Android docs clearly state that LRUCache is the way to go, but they do not mention the need to recycle bitmaps or how to do so.</p> <p><strong>RESOLVED:</strong> In case its useful to anyone else, the solution to this problem as suggested by the accepted answer is to <em>NOT</em> do what I did in the code example above (don't recycle the bitmaps in the <code>entryRemoved()</code> call).</p> <p>Instead, when you're finished with an ImageView (such as <code>onPause()</code> in an activity, or when a view is recycled in an adapter) check if the bitmap is still in the cache (I added a <code>isImageInCache()</code> method to my cache class) and, if it's not, then recycle the bitmap. Otherwise, leave it alone. This fixed my <code>OutOfMemory</code> exceptions and prevented recycling bitmaps which were still being used.</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. UShowettl
    1. UShowettl
    plurals
    1. This table or related slice is empty.
    1. PL
      singulars
      1. LTLinked
    2. PL
      singulars
      1. LTLinked
    3. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POWhen should I recycle a bitmap using LRUCache?
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POWhen should I recycle a bitmap using LRUCache?
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. POWhen should I recycle a bitmap using LRUCache?
      1. This table or related slice is empty.
      1. VTUpMod
    1. COHow are you checking if the bitmap is still in the cache?
      singulars
      1. POWhen should I recycle a bitmap using LRUCache?
      1. USLuxuryMode
    2. COYou can check if image is cached by using ImageLoader like imageLoader.isCached(url, maxWidth, maxHeight); maxWidth and maxHeight can be 0...
      singulars
      1. POWhen should I recycle a bitmap using LRUCache?
      1. US66CLSjY
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload