How to get the android Path string to a file on Assets folder?

AFAIK the files in the assets directory don't get unpacked. Instead, they are read directly from the APK (ZIP) file.

So, you really can't make stuff that expects a file accept an asset 'file'.

Instead, you'll have to extract the asset and write it to a seperate file, like Dumitru suggests:

  File f = new File(getCacheDir()+"/m1.map");
  if (!f.exists()) try {

    InputStream is = getAssets().open("m1.map");
    int size = is.available();
    byte[] buffer = new byte[size];
    is.read(buffer);
    is.close();


    FileOutputStream fos = new FileOutputStream(f);
    fos.write(buffer);
    fos.close();
  } catch (Exception e) { throw new RuntimeException(e); }

  mapView.setMapFile(f.getPath());

You can use this method.

    public static File getRobotCacheFile(Context context) throws IOException {
        File cacheFile = new File(context.getCacheDir(), "robot.png");
        try {
            InputStream inputStream = context.getAssets().open("robot.png");
            try {
                FileOutputStream outputStream = new FileOutputStream(cacheFile);
                try {
                    byte[] buf = new byte[1024];
                    int len;
                    while ((len = inputStream.read(buf)) > 0) {
                        outputStream.write(buf, 0, len);
                    }
                } finally {
                    outputStream.close();
                }
            } finally {
                inputStream.close();
            }
        } catch (IOException e) {
            throw new IOException("Could not open robot png", e);
        }
        return cacheFile;
    }

You should never use InputStream.available() in such cases. It returns only bytes that are buffered. Method with .available() will never work with bigger files and will not work on some devices at all.

In Kotlin (;D):

@Throws(IOException::class)
fun getRobotCacheFile(context: Context): File = File(context.cacheDir, "robot.png")
    .also {
        it.outputStream().use { cache -> context.assets.open("robot.png").use { it.copyTo(cache) } }
    }

Have a look at the ReadAsset.java from API samples that come with the SDK.

       try {
        InputStream is = getAssets().open("read_asset.txt");

        // We guarantee that the available method returns the total
        // size of the asset...  of course, this does mean that a single
        // asset can't be more than 2 gigs.
        int size = is.available();

        // Read the entire asset into a local byte buffer.
        byte[] buffer = new byte[size];
        is.read(buffer);
        is.close();

        // Convert the buffer into a string.
        String text = new String(buffer);

        // Finally stick the string into the text view.
        TextView tv = (TextView)findViewById(R.id.text);
        tv.setText(text);
    } catch (IOException e) {
        // Should never happen!
        throw new RuntimeException(e);
    }