How do I read in FILE contents in QML?

Question

I just need something similar to Fstream to read file IO in QML. Why is there no file IO?

funkybro · Answer 1 · 2017-08-17T10:04:48.737

14

If your file is plain text you can use XMLHttpRequest. For example:

var xhr = new XMLHttpRequest;
xhr.open("GET", "mydir/myfile.txt");
xhr.onreadystatechange = function() {
    if (xhr.readyState == XMLHttpRequest.DONE) {
        var response = xhr.responseText;
        // use file contents as required
    }
};
xhr.send();

edited Aug 17 '17 at 10:04

answered Oct 16 '11 at 13:30

funkybro

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score 5 · Answer 2 · edited May 23 '17 at 12:08

5

I know this is old question but you might be still interested in answer. Here it is: Reading a line from a .txt or .csv file in qml (Qt Quick)

In short, you have here explained how to read files in QML: http://www.developer.nokia.com/Community/Wiki/Reading_and_writing_files_in_QML

All you need is to extend QML with C++.

edited May 23 '17 at 12:08

Community

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answered Dec 16 '12 at 13:06

DRAX

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The linked solution involves reading it in C++ and making that available to QML - it isn't a solution using only QML and the Qt Javascript engine. – DavidJ Feb 21 '19 at 23:05

score 4 · Answer 3 · answered Oct 14 '11 at 22:24

QML has no built-in file I/O. But - judging from the tone of your post - you already knew that.

How do I read in FILE contents in QML?

You can extend QML's functionalities using C++.

The Getting Started Programming with QML tutorial from the Qt Reference Documentation shows you how to build a text editor. This includes file I/O using C++.

Why is there no file I/O?

Because QML is based on JavaScript, and JavaScript has no built-in file I/O either.

QML is designed as an (easy) way to build a user interface. You need an actual program to do the rest.

score 2 · Answer 4 · edited Dec 07 '20 at 09:56

2

There is built-in file I/O available for QML with the Felgo SDK (formerly V-Play) FileUtils. It works cross-platform on desktop, iOS and Android. More info and examples are also in the latest blog post.

It looks like this:

var documentsData = fileUtils.readFile("subfolder/file.json")

edited Dec 07 '20 at 09:56

NG_

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answered Jun 13 '18 at 13:39

Alex Huber

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score 0 · Answer 5 · edited Dec 07 '20 at 09:59

function readConfigFile() {
    var xhr = new XMLHttpRequest;
    var configaddress = "File:///" + root + "/webconfig.txt" //root = "c:/folder/file.ini";
    console.log(configaddress);
    xhr.open("GET", configaddress);
    xhr.onreadystatechange = function() {
        if (xhr.readyState == XMLHttpRequest.DONE) {
            var response = xhr.responseText;
            var js = JSON.parse(response)
            if (js.address != "") {
                service_address = js.address
            }
            // use file contents as required
        }
    };
    xhr.send();
}

score -2 · Answer 6 · answered Oct 23 '11 at 19:27

What do you want to read the file for?... if its simple data.. then you are probably better off using QML Offline storage API. Look for that section here.

If you want to deploy a db with your application read this conversation.

If you really want to read the file still, learn C++ and expose your code to QML. That, then, is beyond the scope of my answer.

How do I read in FILE contents in QML?

6 Answers6