Viewing Excel Files in My Android App

Viewing excel files in my android app

Android 7.0 Update:

Android 7.0 will throw FileUriExposedException if you try to open your app document with an external app. You need to implement FileProvider refer This Answer.

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here is a manual route.

Using JExcelApi in an Android App

How to read excel file using JXL 2.6.12 jar

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but here is a little more easier one.

open application

but i guess you have to find out the MIME TYPE.

EDIT

got the mime type as well

Setting mime type for excel document

UPDATE

so something like this might work.

Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setDataAndType(path, "application/vnd.ms-excel");
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);

try {
    startActivity(intent);
} 
catch (ActivityNotFoundException e) {
    Toast.makeText(OpenDoc.this, "No Application Available to View Excel", Toast.LENGTH_SHORT).show();
}

How to read large excel file in android app?

Check this library for parsing large xlsx files. Full doc is here

just add

repositories {
        maven {
            url "https://jitpack.io"
        }
    }

And

implementation 'com.github.kiranbjm:xlsxparser:1.01'

to your app level gradle file

and you can use it with

InputStream is = new FileInputStream(new File("/path/to/workbook.xlsx"));
Workbook workbook = StreamingReader.builder()
        .rowCacheSize(100)    // number of rows to keep in memory (defaults to 10)
        .bufferSize(4096)     // buffer size to use when reading InputStream to file (defaults to 1024)
        .open(is);            // InputStream or File for XLSX file (required)

Read Excel file in android

Try using Apache POI

Also, see this related question

Read Excel in Android

For those application who need to work with full functional excel files (i.e. drawing, VBA etc... ), you should go with Apache POI, it's plain but still the best solution for that now.

However, if you just need to read the Excel, it maybe good to go with JavaScript solution. With js-xlsx library, you can transfer Excel files into JSON. And the library size is small, just 395KB (only include xlsx.core.min.js)

I believe this not the best solution:

- WebView need to work with UI Thread, it may block the UI when reading large Excel file.

- Performance issue

But you could change this to other JavaScript engine like Rhino or V8 to fix these issues.

Here is the code

Interface for callback:

public interface ExcelReaderListener {
    void onReadExcelCompleted(List<String> stringList);
}

MainActivity:

private ProgressDialog progressDialog;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    new AlertDialog.Builder(MainActivity.this)
            .setMessage("message")
            .setTitle("title")
            .setPositiveButton(R.string.ok, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    dialog.dismiss();

                    new FileChooser(MainActivity.this, new String[]{"xls", "xlsx"})
                            .setFileListener(new FileChooser.FileSelectedListener() {
                                @Override
                                public void fileSelected(File file) {
                                    progressDialog = new ProgressDialog(MainActivity.this);
                                    progressDialog.setTitle("title");
                                    progressDialog.setMessage("message");
                                    progressDialog.setIndeterminate(true);
                                    progressDialog.setCanceledOnTouchOutside(false);

                                    Toast.makeText(MainActivity.this, file.getName(), Toast.LENGTH_SHORT).show();
                                    String filePath = file.getAbsolutePath();
                                    ExcelReaderListener excelReaderListener = MainActivity.this;

                                    progressDialog.show();
                                    try {
                                        final WebView webView = new WebView(MainActivity.this);
                                        new JSExcelReader(filePath, webView, excelReaderListener);
                                    } catch (Exception ex) {
                                        Log.e("Import excel error", ex.getMessage());
                                    }
                                }
                            })
                            .showDialog();
                }
            })
            .show();
}

@Override
public void onReadExcelCompleted(List<String> stringList) {
    Toast.makeText(MainActivity.this, "Parse Completed", Toast.LENGTH_SHORT).show();

    if (progressDialog != null && progressDialog.isShowing()) {
        progressDialog.dismiss();
    }

    // Write into DB
    ...
}

Interface for user to select excel file:

https://rogerkeays.com/simple-android-file-chooser

JSExcelReader: (Core part to read excel and transform it to ArrayList)

public class JSExcelReader {

    private ExcelReaderListener callback;

    public JSExcelReader(String filePath, final WebView webView, ExcelReaderListener callback) {
        this.callback = callback;

        File file = new File(filePath);

        try (InputStream is = new FileInputStream(file)) {
            // convert file to Base64
            if (file.length() > Integer.MAX_VALUE)
                Log.e("File too big", "file too big");
            byte[] bytes = new byte[(int) file.length()];

            int offset = 0;
            int numRead;
            while (offset < bytes.length &&
            (numRead = is.read(bytes, offset, bytes.length - offset)) >= 0) {
                offset += numRead;
            }

            if (offset < bytes.length)
                throw new Exception("Could not completely read file");

            final String b64 = Base64.encodeToString(bytes, Base64.NO_WRAP);

            // feed the string into webview and get the result
            WebSettings webSettings = webView.getSettings();
            webSettings.setJavaScriptEnabled(true);
            webView.loadUrl("file:///android_asset/AndroidParseExcel.html");
            webView.setWebViewClient(new WebViewClient() {
                public void onPageFinished(WebView view, String url) {
                    webView.evaluateJavascript("convertFile('" + b64 + "');", new ValueCallback<String>() {
                        @Override
                        public void onReceiveValue(String value) {
                            parseJSON(value);
                        }
                    });
                }
            });
        } catch (Exception ex) {
            Log.e("Convert Excel failure", ex.getMessage());
        }
    }

    private void parseJSON(String jsonString) {
        try {
            // return value is something like "{\n\"Sheet1\":\n[\"title\"...
            // you need to remove those escape character first
            JSONObject jsonRoot = new JSONObject(jsonString.substring(1, jsonString.length() - 1)
                                                            .replaceAll("\\\\n", "")
                                                            .replaceAll("\\\\\"", "\"")
                                                            .replaceAll("\\\\\\\\\"", "'"));
            JSONArray sheet1 = jsonRoot.optJSONArray("Sheet1");
            List<String> stringList = new ArrayList<>();

            JSONObject jsonObject;
            for (int i = 0; i < sheet1.length(); i++) {
                jsonObject = sheet1.getJSONObject(i);

                stringList.add(jsonObject.optString("title"));
            }

            callback.onReadExcelCompleted(stringList);
        } catch (Exception ex) {
            Log.e("Error in parse JSON", ex.getMessage());
        }
    }
}

AndroidParseExcel.html: (You should put this and the JavaScript library into asset folder)

<html>
<script src="file:///android_asset/xlsx.core.min.js"></script>
<head></head>
<body>
</body>
<script type ="text/javascript">

    "use strict";

    var X = XLSX;

    function convertFile(b64data) {
        var wb = X.read(b64data, {type: 'base64',WTF: false});

        var result = {};
        wb.SheetNames.forEach(function(sheetName) {
            var roa = X.utils.sheet_to_row_object_array(wb.Sheets[sheetName]);
            if(roa.length > 0){
                result[sheetName] = roa;
            }
        });

        return JSON.stringify(result, 2, 2);
    }
</script>
</html>

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