How To Read From A Zipfile In A Folder Which Was Selected By The Action_open_document_tree Intent?

how to read from a zipfile in a folder which was selected by the ACTION_OPEN_DOCUMENT_TREE Intent ? My app let the user choose a folder through the ACTION_OPEN_DOCUMENT_TREE Intent

Solution 1:

How do I instantiate a ZipFile with this specific Zipfilename from the provided URI (Folderinfo) in onActivityResult ?

You can't, as there is no file, and ZipFile needs a file. You can only get an InputStream, using openInputStream() on a ContentResolver, and that only if you get a Uri to that specific file that you are looking for.

Your options appear to be:

• Use ZipInputStream, which can wrap an InputStream

• Find some third-party library that accepts an InputStream as input and gives you a better API

• Copy the ZIP flie to your app's portion of internal storage and read its contents using ZipFile

Solution 2:

I was working on this problem and ended up going with a strategy @CommonsWare mentioned as the third option, which is copying a file to non-sdcard place and load as a ZipFile. It works well so I share my snippet for everybody.

publicstatic ZipFile loadCachedZipFromUri(Context context, Uri uri, String filename){
    Filefile=newFile(context.getCacheDir(), filename);
    StringfileName= context.getCacheDir().getAbsolutePath() + '/' + filename;
    ZipFilezip=null;

    if (file.exists()){
        Log.d(TAG, "file exists");
        try {
            if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) { // N for Nougat
                zip = newZipFile(fileName, Charset.forName("ISO-8859-1"));

            }else{
                zip = newZipFile(fileName);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
        return zip;
    }

    DocumentFiledest= DocumentFile.fromFile(file);

    InputStreamin=null;
    OutputStreamout=null;

    Log.d(TAG, "Copy started");
    try {
        in = context.getContentResolver().openInputStream(uri);
        out = context.getContentResolver().openOutputStream(dest.getUri());
        byte[] buf = newbyte[2048];
        intlen=0;
        while((len = in.read(buf)) >= 0){
            out.write(buf, 0, len);
        }

    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }finally {
        try {
            in.close();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    Log.d(TAG, "Load copied file");
    try {
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) { // N for Nougat
            zip = newZipFile(fileName, Charset.forName("ISO-8859-1"));

        }else{
            zip = newZipFile(fileName);
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    return zip;
}