Re: ReadFile and data manipulati
Hello arqlz,
The issue described in that article was due to an unimplemented blobToString method at the time. This has since been seemingly fixed. I just tested the following sample with success on my PlayBook.
Note that before this sample could run, I had to manually create the expected readme.txt file on the PlayBook's filesystem under:
\media\downloads\
To complete the above, I went into my PlayBook's Storage and Sharing settings and enabled File Sharing, as well as Wi-Fi Sharing (so I could create the file over-the-air from my PC.) I then created the file manually and populated it with the text:
Hello World!
My config.xml looks as follows.
<?xml version="1.0" encoding="utf-8"?> <widget xmlns="http://www.w3.org/ns/widgets" xmlns:rim="http://www.blackberry.com/ns/widgets" version="1.0.0"> <name>Sandbox</name> <author>Oros</author> <content src="index.html"/> <access uri="*" subdomains="true"/> <feature id="blackberry.io.file" /> <feature id="blackberry.utils" /> <rim:permissions> <rim:permit>access_shared</rim:permit> </rim:permissions> </widget>
The majority of this is just a standard configuration.
- The <access> whitelisting isn't required but I included it out of habit.
- The blackberry.io.file <feature> gives me access to readFile and saveFile.
- The blackberry.utils <feature> gives me access to the blobToString and stringToBlob methods.
- The access_shared permission ensures we can access the shared folder on the PlayBook.
My index.html file looks like so.
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
</head>
<body>
<div id="log"></div>
<script type="text/javascript">
/*global document, blackberry */
function log(text) {
"use strict";
var div = document.createElement("div");
div.innerHTML = text;
document.querySelector("#log").appendChild(div);
}
function handleOpenedFile(fullPath, blobData) {
"use strict";
try {
log("File opened.");
var filepath = 'file:///accounts/1000/shared/downloads/test.txt',
stringData = blackberry.utils.blobToString(blobData);
log("Write path: " + filepath);
log("Read data: " + stringData);
stringData = "Modified: " + stringData;
log("Write data: " + stringData);
blobData = blackberry.utils.stringToBlob(stringData);
log("Write blob created.");
blackberry.io.file.saveFile(filepath, blobData);
log("File saved.");
} catch (err) {
log("handleOpenedFile: " + err);
}
}
function ready() {
"use strict";
try {
log("Ready.");
var path = 'file:///accounts/1000/shared/downloads/readme.txt
From top to bottom, a brief description of the major pieces:
- The #log <div> will hold our logging messages so we can keep track of what is happening.
- The /*global */ definitions are there just to satisfy JSLint. Basically it announces that those variables are defined elsewhere.
- The log function takes text and adds it within its own <div> to #log. You'lll notice a lot of calls to this function dispersed through the code; basically I just like to keep track of what's happening. These calls are not necessary though.
- The handleOpenedFile function gets invoked if we successfully execute blackberry.io.file.readFile. This is where we do our manipulation of the read data. The manipulation converts the blob to a String, prepends the text "Modified: " to the String, then converts that String back to a blob which is then saved to our output file: test.txt.
- The ready function gets invoked when the DOMContentLoaded event is triggered. We supply our default readme.txt filepath then attempt to read the data.
- Finally, outside of the functions, we register the DOMContentLoaded event to trigger our ready function. We place it outside of all functions to ensure the event is registered when the <script> is loaded.
The final output on my screen was as follows:
And I can see on my PlayBook's filesystem that test.txt was created and contains:
Modified: Hello World!
If you have any questions about the above, please let me know.
Erik Oros
BlackBerry Development Advisor
