Question

I implemented a file cache to load small images for a long grid view. After scrolling a while, I get a lot of libcore.io.ErrnoException: open failed: EMFILE (Too many open files)

How do I avoid this? This is the code to read one bitmap:

File fullCacheDir = new File(Environment.getExternalStorageDirectory().toString(), cacheDir);
File file = new File(fullCacheDir.toString(), fileName);

if (!file.exists()) {
    return null;
}

Bitmap bm = BitmapFactory.decodeFile(file.toString());

This is to save one bitmap:

FileOutputStream outputStream = new FileOutputStream(fileUri);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
outputStream.flush();
outputStream.close();

Answer 1

Any chance your close() call isn’t being reached due to an exception? I generally code like this:

try {
  new FileOutputStream(fileUri);
  bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
  outputStream.flush();
} finally {
  try {
    outputStream.close();
  } catch (Exception ignored) {
    // ignore exceptions generated by close()
  }
}

I couldn’t see anything obviously wrong with the first code fragment.