Phonegap - Creating a .txt file on first load

问题:

I am creating a phonegap app and need to create a new .txt file on first load. After this I need to check whether the file exists and then ignore the creation if that is the case, below is the general flow that I am after:

1 - onDeviceReady - loading phoengap app 2 - Check is readme.txt exist (if yes load home page) 3 - Create a file readme.txt and add to www folder 4 - Continue loading homepage

EDIT - Rather than the valid answer mentioned below I decided to use HTML5s local storage as this was simply 1 line of code.

localStorage.setItem("name", "Email Supplied!");

and can be checked using this simple if statement

 if (localStorage.getItem("name") == "Email Supplied!")
        {
            // What you want to happen here
        }

回答1:

You can take a look at the full example here:

http://docs.phonegap.com/en/1.4.1/phonegap_file_file.md.html#FileWriter

This line create the file if it doesn't exist :

fileSystem.root.getFile("readme.txt", {create: true, exclusive: false}, gotFileEntry, fail);

Supported Platforms

Android BlackBerry WebWorks (OS 5.0 and higher) iOS Windows Phone 7 ( Mango )

I don't know about there others but in iOS, the document is created in /var/mobile/Application/YOU_APP/Documents

[CODE]

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

            // Wait for PhoneGap to load
            //
            document.addEventListener("deviceready", onDeviceReady, false);

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

            function gotFS(fileSystem) {
                fileSystem.root.getFile("readme.txt", {create: true}, gotFileEntry, fail);
            }

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

            function gotFileWriter(writer) {
                writer.onwrite = function(evt) {
                    console.log("write success");
                };

                writer.write("some sample text");
                writer.abort();
                // contents of file now 'some different text'
            }

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

        </script>

Hope it helps

回答2:

Depending on the devices you are developing for you can look at using their native file creation APIs. For example, iOS uses plists. Android does use .txt files, look at this link for more information.