ACTION_VIEW intent for a file with unknown MimeType

Solution 1:

This should detect the mimetype and open with default:

MimeTypeMap myMime = MimeTypeMap.getSingleton();
Intent newIntent = new Intent(Intent.ACTION_VIEW);
String mimeType = myMime.getMimeTypeFromExtension(fileExt(getFile()).substring(1));
newIntent.setDataAndType(Uri.fromFile(getFile()),mimeType);
newIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
try {
    context.startActivity(newIntent);
} catch (ActivityNotFoundException e) {
    Toast.makeText(context, "No handler for this type of file.", Toast.LENGTH_LONG).show();
}

Using this function:

private String fileExt(String url) {
    if (url.indexOf("?") > -1) {
        url = url.substring(0, url.indexOf("?"));
    }
    if (url.lastIndexOf(".") == -1) {
        return null;
    } else {
        String ext = url.substring(url.lastIndexOf(".") + 1);
        if (ext.indexOf("%") > -1) {
            ext = ext.substring(0, ext.indexOf("%"));
        }
        if (ext.indexOf("/") > -1) {
            ext = ext.substring(0, ext.indexOf("/"));
        }
        return ext.toLowerCase();

    }
}

Solution 2:

createChooser should do the trick:

Intent myIntent = new Intent(Intent.ACTION_VIEW);
myIntent.setData(Uri.fromFile(item));
Intent j = Intent.createChooser(myIntent, "Choose an application to open with:");
startActivity(j);

Solution 3:

try this one almost covers all file extensions

  public void openFile(File url) {

    Uri uri = Uri.fromFile(url);

    Intent intent = new Intent(Intent.ACTION_VIEW);
    if (url.toString().contains(".doc") || url.toString().contains(".docx")) {
        // Word document
        intent.setDataAndType(uri, "application/msword");
    } else if (url.toString().contains(".pdf")) {
        // PDF file
        intent.setDataAndType(uri, "application/pdf");
    } else if (url.toString().contains(".ppt") || url.toString().contains(".pptx")) {
        // Powerpoint file
        intent.setDataAndType(uri, "application/vnd.ms-powerpoint");
    } else if (url.toString().contains(".xls") || url.toString().contains(".xlsx")) {
        // Excel file
        intent.setDataAndType(uri, "application/vnd.ms-excel");
    } else if (url.toString().contains(".zip") || url.toString().contains(".rar")) {
        // WAV audio file
        intent.setDataAndType(uri, "application/x-wav");
    } else if (url.toString().contains(".rtf")) {
        // RTF file
        intent.setDataAndType(uri, "application/rtf");
    } else if (url.toString().contains(".wav") || url.toString().contains(".mp3")) {
        // WAV audio file
        intent.setDataAndType(uri, "audio/x-wav");
    } else if (url.toString().contains(".gif")) {
        // GIF file
        intent.setDataAndType(uri, "image/gif");
    } else if (url.toString().contains(".jpg") || url.toString().contains(".jpeg") || url.toString().contains(".png")) {
        // JPG file
        intent.setDataAndType(uri, "image/jpeg");
    } else if (url.toString().contains(".txt")) {
        // Text file
        intent.setDataAndType(uri, "text/plain");
    } else if (url.toString().contains(".3gp") || url.toString().contains(".mpg") || url.toString().contains(".mpeg") || url.toString().contains(".mpe") || url.toString().contains(".mp4") || url.toString().contains(".avi")) {
        // Video files
        intent.setDataAndType(uri, "video/*");
    } else {
        //if you want you can also define the intent type for any other file
        //additionally use else clause below, to manage other unknown extensions
        //in this case, Android will show all applications installed on the device
        //so you can choose which application to use
        intent.setDataAndType(uri, "*/*");
    }

    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    context.startActivity(intent);

}