Caching bitmaps on disk Android

Question

I've read this http://developer.android.com/training/displaying-bitmaps/cache-bitmap.html but now I'm looking for an easy way of implementing the disk cache into my app. I've found that lib http://square.github.io/picasso/ but it isn't working. I always get a "NoClassDefFoundError". Do you know a library that could easily allow me to cache downloaded bitmaps? Thank you

you can find the example http://stackoverflow.com/questions/16789676/caching-images-and-displaying/16978285#16978285 — Raghunandan, Jul 04 '13 at 05:25
Could I simply implement this https://github.com/thest1/LazyList ? — Romain Pellerin, Jul 04 '13 at 05:36

score 1 · Accepted Answer · answered Jul 04 '13 at 05:49

1

Regarding the "NoClassDefFoundError", this may be fixed by:

right click your project
properties
Java build path
In the "Libraries" tab - add your lib
In the "Order and Export" tab - make sure the lib you added is checked

answered Jul 04 '13 at 05:49

dors

5,802
8
45
71

Gloooops, you fixed it! Thank you so much! What does the checkbox change? – Romain Pellerin Jul 04 '13 at 05:58
1

I'm glad that helped :) This is one of eclipses more annoying bugs that I encountered :/ Sometimes adding a lib to the libs folder does not automatically adds it fully to the project's build process. That checkbox does that manually. – dors Jul 04 '13 at 06:00

score 0 · Answer 2 · answered Jul 04 '13 at 05:29

You can try this code to cache image from url :

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import android.graphics.Bitmap;

public class MemoryCache {

String TAG = "MemoryCache";
private Map<String, Bitmap> cache=Collections.synchronizedMap(
        new LinkedHashMap<String, Bitmap>(10,1.5f,true));//Last argument true for LRU ordering
private long size=0;//current allocated size
private long limit=1000000;//max memory in bytes

public MemoryCache(){
    //use 25% of available heap size
    setLimit(Runtime.getRuntime().maxMemory()/4);
}

public void setLimit(long new_limit){
    limit=new_limit;
}

public Bitmap get(String id){
    try{
        if(!cache.containsKey(id))
            return null;
        //NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78 
        return cache.get(id);
    }catch(NullPointerException ex){
        return null;
    }
}

public void put(String id, Bitmap bitmap){
    try{
        if(cache.containsKey(id))
            size-=getSizeInBytes(cache.get(id));
        cache.put(id, bitmap);
        size+=getSizeInBytes(bitmap);
        checkSize();
    }catch(Throwable th){
        th.printStackTrace();
    }
}

private void checkSize() {
    if(size>limit){
        Iterator<Entry<String, Bitmap>> iter=cache.entrySet().iterator();//least recently accessed item will be the first one iterated  
        while(iter.hasNext()){
            Entry<String, Bitmap> entry=iter.next();
            size-=getSizeInBytes(entry.getValue());
            iter.remove();
            if(size<=limit)
                break;
        }
    }
}

public void clear() {
    cache.clear();
}

long getSizeInBytes(Bitmap bitmap) {
    if(bitmap==null)
        return 0;
    return bitmap.getRowBytes() * bitmap.getHeight();
}
}

usage is :

memoryCache.put(photoToLoad.url, bmp);

and to get:

memoryCache.get(url);

if you have some question feel free to ask in the comment!

Thank you, but this is using memory cache right? I want to use disk cache. — Romain Pellerin, Jul 04 '13 at 05:39

score 0 · Answer 3 · answered Aug 13 '15 at 17:01

0

"Solution for android Stdio."

To use picasso lib you have to make an entry in build.gradle
dependencies section add

compile 'com.squareup.picasso:picasso:2.5.2'

"NoClassDefFoundError" will not come and now you can use picasso to cache images

answered Aug 13 '15 at 17:01

Sunil Agarwal

91
7

score 0 · Answer 4 · answered Oct 19 '17 at 11:03

I just created a new cache library VIF to answer this need:

Here is how to use it

    @Override
    public void run() {
        appCache = new DiskCache(this, "app_cache", 1024 * 1024 * 20);// 20 MB cache
        downloadImage(url);
        loadImage(imageView, url);
    }

    private void downloadImage(String imageUrl) {
        URL url = new URL(imageUrl);
        URLConnection connection = url.openConnection();
        connection.connect();

        appCache.put(imageUrl, connection.getInputStream());
    }

    private void loadImage(final ImageView imageView, String imageUrl) {
        appCache.getAsObject(MY_IMAGE, new DiskCache.ParserCallback<Bitmap>() {
            @Override
            public Bitmap parse(@NonNull File file) throws Exception {
                return BitmapFactory.decodeFile(file.getAbsolutePath());
            }

            @Override
            public void onError(@NonNull Throwable e) {

            }

            @Override
            public void onResult(@Nullable Bitmap result) {
                imageView.setImageBitmap(result);
            }
        });
    }

Caching bitmaps on disk Android

4 Answers4