Web and WebWorks Development

[Gerii]

I'm trying to use the FileAPI in my app, but I can't get the FileWriter working on BlackBerry. I'm able to create a new file, but the FileWriter keeps hanging at ReadyState 0.

I've tried different ways (that I've already used successfully on MeeGo, Android and Symbian) to get it working, but without any success.

function initFile() {
	//get current time and date for filename
	timeDate = getTimeAndDate();

	if(device.platform == "PlayBook" || device.platform == null || device.platform == "BB10") {
		try {
			//TODO no permission error
			blackberry.io.sandbox = false;
			console.log("requesting FS");
			window.requestFileSystem(LocalFileSystem.PERSISTENT, 1024*1024, fileSystemInitialised, reqFileFail);
		}
		catch (er) {
			console.log(er.toString());
		}
	}

}

function reqFileFail(error)
{
	//TODO change
	console.log(error.code);
}

function fileSystemInitialised(p_fileSystem) {
	console.log("FS initialisiert");
	if(device.platform == "PlayBook" || device.platform == "BB10") {
		console.log("PB/BB10");
		try {
			p_fileSystem.root.getFile(blackberry.io.sharedFolder + '/documents/' + datumZeit + ".kml", { create: true, exclusive: false }, initWriter, fileError);
		}
		catch(er) {
			alert(er.toString());
		}
	}
}

function initWriter(p_fileEntry) {
	console.log(p_fileEntry.name);
	p_fileEntry.createWriter(writerCreated, fileError);
	//p_fileWriter = new FileWriter(p_fileEntry);
	//writerCreated(p_fileWriter);
}

function writerCreated(p_fileWriter) {
	p_fileWriter.onwriteend = function(e) {
		console.log('Write completed.');
    };

	p_fileWriter.onerror = function(e) {
		console.log('Write failed: ' + e.toString());
	};
	
	console.log(p_fileWriter.fileName);
	console.log("ReadyState: " + p_fileWriter.readyState);
	
	if(p_fileWriter.readyState == 0) {
		setTimeout(writerCreated(p_fileWriter), 1000);
	}
	else {
		p_fileWriter.write('<?xml version="1.0" encoding="UTF-8"?>\n' + '<kml xmlns="http://www.opengis.net/kml/2.2">\n' + '<Document>\n' + '<Placemark>\n' + '<name>Alpintouren-Tour</name>\n' + '<description>Tour erstellt mit der Alpintouren-App</description>' + '<visibility>0</visibility>' + '<Style>\n' + '<LineStyle><color>ff00ffff</color><width>4</width></LineStyle>\n' + '<PolyStyle><color>7f00ff00</color></PolyStyle>\n' + '</Style>\n', false);
	}
}

function fileError(p_fileError) {
	console.log("Fehler: " + p_fileError.code);
}

[haahmad]

Hi Gerri,

It looks like the problem is that every time you hit the writerCreated function, you call writerCreated again, with no change in state.

This is because the readyState is still 0 (which is INIT), and you haven't given the writer a chance to start writing before you read the readyState again.

The writerCreated function can never enter the else block because on the first entry into this function the readyState is 0, so you hit setTimeout and exit the function. After the timeout has expired writerCreated is fired again but the writer's readyState has not changed.

Try writing the file without the setTimeout logic and see if that helps you.

[Gerii]

 That was definitely an issue, thanks for pointing that out. Unfortunately it still doesn't work.

My code now look like this: 

function initWriter(p_fileEntry) {
	console.log(p_fileEntry.name);
	//DOESN'T WORK (p_fileWriter.fileName returns undefined):
             //p_fileEntry.createWriter(writerGlobalSpeichern, fileError);
	p_fileWriter = new FileWriter(p_fileEntry);
	writerGlobalSpeichern(p_fileWriter);
}

function writerCreated(p_fileWriter) {
	p_fileWriter.onwriteend = function(e) {
		console.log('Write completed.');
         };
	p_fileWriter.onerror = function(e) {
		console.log('Write failed: ' + e.toString());
	};
	
	console.log(p_fileWriter.fileName);
	console.log("ReadyState: " + p_fileWriter.readyState);
	
	p_fileWriter.write('test', false);
	
	console.log("ReadyState: " + p_fileWriter.readyState);
}

 In the console of the WebInspector, I get the following:

XHR finished loading: "http://localhost:8472/blackberry.io/sharedFolder". [native code]:1
2012-11-18_14-24-44.kml
/accounts/1000/appdata/alpintouren.gYABgOVu8z7kR_6k1IwmhCOjnsc/shared/documents/2012-11-18_14-24-44.kml
ReadyState: 0
Error: Status=2 Message=Class File cannot be found cordova-2.2.0.js:959
Write failed: [object Object]
Write completed.
ReadyState: 2

[chadtatro]

Hi there,

Took a look and everything appeared to look proper on my end.  FileAPI can be a little tricky sometimes.  We have a great sample that's being worked on by one of my teammates to greatly simplify the HTML5 File API.  I'll report back ASAP as to when that'll be ready..

[Gerii]

Thanks, looking forward to it.

[Gerii]

Any news on the sample?

I have now tried to remove PhoneGap from my app and use only WebWorks with the code from https://developer.blackberry.com/html5/apis/blackberry.io.html

This works fine for reading a file. But when I tried to change the FileReader 

var reader = new FileReader();

 reader.onloadend = function (e) {
	var txtArea = document.createElement('textarea');
	txtArea.value = this.result;
	document.body.appendChild(txtArea);
};

reader.readAsText(file);

 to the FileWriter

writer = new FileWriter(file);

p_fileWriter.onwriteend = function(e) {
	console.log('Write completed.');
};

p_fileWriter.onerror = function(e) {
	console.log('Write failed: ' + e.toString());
	console.log(e);
};
p_fileWriter.write('test', false);

 I get ReferenceError: Can't find variable: FileWriter

So I wonder whether the FileWriter is even supported in the current OS build or not.

[chadtatro]

Right,

In the current version of PhoneGap the FileAPI isn't supported.  I suspect there will be a new build out any time though, as they release pretty much on a monthly basis.

One of my teammates is actually working very close to the PhoneGap project, and is adding more and more API support with each build.

In regards to the FileAPI wrapper sample, I'll follow up on that today again.

[Gerii]

Thanks for checking.
Even if I create a new project without PhoneGap, it fails to find the FileWriter. FileReader works fine though.