Read Assets file as string

I would like to read the content of a file located in the Assets as a String. For example, a text document located in src/main/assets/

Original Question
I found that this question is mostly used as a 'FAQ' for reading an assets file, therefore I summarized the question above. Below is my original question

I'm trying to read a assets file as string. I have a file in my assets folder: data.opml, and want to read it as a string.

Some things I tried:

 AssetFileDescriptor descriptor = getAssets().openFd("data.opml");
 FileReader reader = new FileReader(descriptor.getFileDescriptor());

And also:

 InputStream input = getAssets().open("data.opml");
 Reader reader = new InputStreamReader(input, "UTF-8");

But without success, so a full example would be appreciated.

Solution 1:

getAssets().open() will return an InputStream. Read from that using standard Java I/O:

Java:

StringBuilder sb = new StringBuilder();
InputStream is = getAssets().open("book/contents.json");
BufferedReader br = new BufferedReader(new InputStreamReader(is, StandardCharsets.UTF_8 ));
String str;
while ((str = br.readLine()) != null) {
    sb.append(str);
}
br.close();

Kotlin:

val str = assets.open("book/contents.json").bufferedReader().use { it.readText() }

Solution 2:

There is a little bug CommonsWare's code - newline characters are discarded and not added to the string. Here is some fixed code ready for copy+paste:

private String loadAssetTextAsString(Context context, String name) {
        BufferedReader in = null;
        try {
            StringBuilder buf = new StringBuilder();
            InputStream is = context.getAssets().open(name);
            in = new BufferedReader(new InputStreamReader(is));

            String str;
            boolean isFirst = true;
            while ( (str = in.readLine()) != null ) {
                if (isFirst)
                    isFirst = false;
                else
                    buf.append('\n');
                buf.append(str);
            }
            return buf.toString();
        } catch (IOException e) {
            Log.e(TAG, "Error opening asset " + name);
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    Log.e(TAG, "Error closing asset " + name);
                }
            }
        }

        return null;
    }

Solution 3:

You can also do it, without using loops. It's pretty simple

AssetManager assetManager = getAssets();
InputStream input;
String text = "";

    try {
        input = assetManager.open("test.txt");

        int size = input.available();
        byte[] buffer = new byte[size];
        input.read(buffer);
        input.close();

        // byte buffer into a string
        text = new String(buffer);

    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    Log.v("TAG", "Text File: " + text);

Solution 4:

hi this is in my opinion the cleanest approach:

  public static String loadTextFromAssets(Context context, String assetsPath, Charset charset) throws IOException {
        InputStream is = context.getResources().getAssets().open(assetsPath);
        byte[] buffer = new byte[1024];
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        for (int length = is.read(buffer); length != -1; length = is.read(buffer)) {
            baos.write(buffer, 0, length);
        }
        is.close();
        baos.close();
        return charset == null ? new String(baos.toByteArray()) : new String(baos.toByteArray(), charset);
    }

because readers could get trouble with line breaks.