Question

I am dynamically generating midi files (in cache dir) with an android app.

After generation, I play the file with MediaPlayer within the same app.

When running the app for the first time, it already needs the file to be there in the cache directory (the app crashes). It works on the emulator if I use the filemanager to put a dummy file there first. How can I circumvent this?

I need the app to run on a tablet for the first time, without requiring the file.

I am using these commands now:

try {

            filePath = getCacheDir() + "/optimuse" + song + ".mid";
            file = new File(filePath);

            inputStream = new FileInputStream(file);
            if (inputStream.getFD().valid()) {
                System.out.println("Valid!");
            }
        } catch (Exception e1) {
            e1.printStackTrace();
            System.exit(-1);
        }

        try {
            mediaPlayer = new MediaPlayer();
            mediaPlayer.setDataSource(inputStream.getFD());
            inputStream.close();
        } catch (Exception e1) {
            e1.printStackTrace();
            System.exit(-1);
        }

        try {
            mediaPlayer.prepare();
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

Is there any way around this?

Thanks!

Answer 1

Maybe check whether the file exists before using it? You can achieve this using the File#exists() method.

First, you use the Context#getFileStreamPath(String) method – where the String is the filename of the file you are trying to access. Then you can call File#exists() on the returned object.