Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
188 views
in Technique[技术] by (71.8m points)

android - Load files bigger than 1M from assets folder

I'm going crazy, I created a file object, so it can be read with ObjectInputStream, and I placed the assets folder. The method works with a file smaller than 1M, and give error with larger files. I read that is a limit of Android platform, but I also know that can be "easily" avoided. Those who have downloaded the game Reging Thunder, for example, can easily see that in their assets folder is a file 18.9M large. This is my code for read 1 object from a ObjecInputStream

File f = File.createTempFile("mytempfile", "dat");
FileOutputStream fos = new FileOutputStream(f);

InputStream is = mc.getAssets().open(path,3);

ObjectInputStream ois=new ObjectInputStream(is);
byte[] data = (byte[]) ois.readObject();
fos.write(data);

fos.flush();
fos.close();
ois.close();
is.close();

now I have an uncompressed file and I can use it without worrying about the error "This file can not be opened as a file descriptor; it is probably compressed"

This function works well with files smaller than 1M, with bigger files return an java.io.IOException on line "ObjectInputStream ois=new ObjectInputStream(is);"

why??

question from:https://stackoverflow.com/questions/2860157/load-files-bigger-than-1m-from-assets-folder

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

Faced the same issue. I've cut up my 4MB file into 1 MB chunks, and on the first run I join the chunks into a data folder on the phone. As an added bonus, the APK is properly compressed. The chunk files are called 1.db, 2.db, etc. The code goes like this:

File Path = Ctxt.getDir("Data", 0);
File DBFile = new File(Path, "database.db");

if(!DBFile.exists() || DatabaseNeedsUpgrade)  //Need to copy...
    CopyDatabase(Ctxt, DBFile);


static private void CopyDatabase(Context Ctxt, File DBFile) throws IOException
{
    AssetManager assets = Ctxt.getAssets();
    OutputStream outstream = new FileOutputStream(DBFile);
    DBFile.createNewFile();
    byte []b = new byte[1024];
    int i, r;
    String []assetfiles = assets.list("");
    Arrays.sort(assetfiles);
    for(i=1;i<10;i++) //I have definitely less than 10 files; you might have more
    {
        String partname = String.format("%d.db", i);
        if(Arrays.binarySearch(assetfiles, partname) < 0) //No such file in assets - time to quit the loop
            break;
        InputStream instream = assets.open(partname);
        while((r = instream.read(b)) != -1)
            outstream.write(b, 0, r);
        instream.close();
    }
    outstream.close();
}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...