CODEWITHSUNDEEP
apifilecordovaxmlhttprequest
user2471501
user2471501

Reputation: 153

Phonegap File API

After weeks of research I decided to use Phonegap's File API to update my app. On the Phonegap Google Group I discovered that I have to go through following steps:

  1. load this file using XHR
  2. write the file to the file system
  3. check for internet connection
  4. if yes, download latest file using FileTransfer object.
  5. if no, use your cached file

I already did step 1, my file is now being loaded in XHR. Now I'm stuck at step 2. I tried the filewriter, but without success and the information on Phonegap's File API isn't really clear. Can anyone help me with this?

Here's my XHR script: 

<script language="javascript" type="text/javascript">
function loadHome() {
    var request = new XMLHttpRequest();
    request.open("GET", "file:///sdcard/Download/home.json", true);
    request.onreadystatechange = function() {//Call a function when the state changes.
    if (request.readyState == 4) {
        if (request.status == 200 || request.status == 0) {

            var home = JSON.parse(request.responseText);
            var data = "<table cellspacing='0'>";
            for (i = 0; i < home.length; i++) {
                data += "<td>";
                data += "<a href='" + home[i].link + "'/>";
                data += "<img src='" + home[i].img + "'/>";
                data += "<div class='dsc'>" + home[i].expo + "<br><em>";
                data += home   [i].datum + "</em></div></a></td>";
            }
            data += "</table>";
            var twitter = document.getElementById("home2");
            twitter.innerHTML = data;
        }
    }
}
console.log("asking for home");
request.send();

</script>

And here's my first try at the filewriter:

<script type="text/javascript" charset="utf-8">

document.addEventListener("deviceready", onDeviceReady, false);

function onDeviceReady() {
    window.requestFileSystem(LocalFileSystem.PERSISTENT, 0, gotFS, fail);
}

function gotFS(fileSystem) {
    fileSystem.root.getFile("file:///sdcard/Download/home.json", {create: true, exclusive: false}, gotFileEntry, fail);
}

function gotFileEntry(fileEntry) {
    fileEntry.createWriter(gotFileWriter, fail);
}

function gotFileWriter(writer) {
    writer.onwriteend = function(evt) {
        console.log("contents of file now 'some sample text'");
        writer.truncate(11);  
        writer.onwriteend = function(evt) {
            console.log("contents of file now 'some sample'");
            writer.seek(4);
            writer.write(" different text");
            writer.onwriteend = function(evt){
                console.log("contents of file now 'some different text'");
            }
        };
    };
    writer.write("some sample text");
}

function fail(error) {
    console.log(error.code);
}

</script>

Upvotes: 0

Views: 901

Answers (1)

YishaiG
YishaiG

Reputation: 99

I have had lots of problems and frustration with the Phonegap File Api, and so decided to make a simple API to deal with it. My API is posted here:

https://github.com/poja/PhoneGap-FileAPI-Improved

Hope it helps.

Upvotes: 2

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