Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Recording and Saving Audio in Cordova Applications

DZone's Guide to

Recording and Saving Audio in Cordova Applications

Create an iOS or Android application using Apache Cordova to record and save audio clips.

· Mobile Zone
Free Resource

Ah, looking at that title there you probably think, “Surely this is a simple matter in Cordova and surely this is Raymond, once again, blogging something is incredibly obvious and simple just to drive people to his Amazon Wishlist.” Yep, that’s what I thought too. This weekend I began work on a simple little Cordova app for my son. I thought it would be a great blog post too. But while working on it, I ran into an issue with audio recordings that drove me bat-shit crazy for a few hours, so I thought I’d better share so others don’t have to bang their heads against the wall too.

Because this problem turned into a royal cluster-you know what, I’ve decided to blog it about it in detail here and talk about the app itself later this week. For now, consider this use case:

“You want to allow the user to make an audio recording. Later, the user can play that recording.”

Simple, right? So I began working on a form that would let the user make the recording as well as name it. I wanted them to be able to do the recording as well as play it back to ensure they liked it.

iOS Simulator Screen Shot Jul 27, 2015, 1.38.09 PM

Clicking Record fires off a call to the Media Capture plugin:

var captureError = function(e) {
console.log('captureError' ,e);
}

var captureSuccess = function(e) {
console.log('captureSuccess');console.dir(e);
$scope.sound.file = e[0].localURL;
$scope.sound.filePath = e[0].fullPath;
}

$scope.record = function() {
navigator.device.capture.captureAudio(
captureSuccess,captureError,{duration:10});
}

This is boiler-plate Media Capture usage here. I’m storing both the URL and file path in $scope so I can save it later. The Play feature is also pretty trivial:

$scope.play = function() {
if(!$scope.sound.file) {
navigator.notification.alert("Record a sound first.", null, "Error");
return;
}
var media = new Media($scope.sound.file, function(e) {
media.release();
}, function(err) {
console.log("media err", err);
});
media.play();
}

This worked fine in Android and iOS. But I noticed something weird. When I looked at the Media Capture object in captureSuccess, I saw this in Android:

shot1

See the portion I called out there? Persistent. Cool. That gives me the warm fuzzies. However, in iOS, I saw this:

shot2

As you can see, it is being stored in a temporary location, which is not good. Unfortunately, there is nothing in the Media Capture plugin that you can change to modify this behavior. Therefore – the answer was clear.

The File System!

onesimply

So in theory, this should be easy. First, we pick a persistent location that covers both Android and iOS. The File plugin provides such an alias: cordova.file.dataDirectory

We have a folder, right? So literally all we need to do is copy a file from one location to another. Copy. A damn. File.

But we’ve got an issue. First, we have to give the file a unique name. To handle that, I just used time and the existing extension.

var extension = $scope.sound.file.split(".").pop();
var filepart = Date.now();
var filename = filepart + "." + extension;
console.log("new filename is "+filename);

I then spent about an hour trying to get the copy command to work. I began by adding numerous console.log messages with the F word in it. If you don’t know what that word is, ask your teenagers. I thought that with a file path, I could just do this:

var file = new FileEntry(some damn path);

But nah, that would be too easy. You need to use window.resolveLocalFileSYstemURL first. And since the File copy command requires a path, you have to do this twice. Here’s the code I ended up with. I removed a few console.log messages that may offend some readers. If you’re curious, I went way beyond just saying the F-word.

window.resolveLocalFileSystemURL(loc, function(d) {
window.resolveLocalFileSystemURL($scope.sound.file, function(fe) {
fe.copyTo(d, filename, function(e) {
console.log('success inc opy');
console.dir(e);
$scope.sound.file = e.nativeURL;
$scope.sound.path = e.fullPath;

Sounds.save($scope.sound).then(function() {
$ionicHistory.nextViewOptions({
    disableBack: true
});
$state.go("home");
});

}, function(e) {
console.log('error in coipy');console.dir(e);
});
}, function(e) {
console.log("error in inner bullcrap");
console.dir(e);
});

All in all, it isn’t that bad. A few nested callbacks, and nearly half my code there is related to my app, not the actual issue, it just took me a while to get there.

Luckily, everything worked perfectly.

yeah-right

So at this point, I’ve saved the location of my audio file so I can use it in the Media api, but the new location doesn’t work in the Media plugin anymore. Why? I don’t freaking know. I blogged last year about how when you use the Media plugin and a relative path, you have to do something funky on Android, basically prefix your relative URL. In my case, I’m using a file:// url and I just assumed it would work.

And here is where things got awesome – it worked perfectly in Android but not iOS. Because – reasons. I brought this up on the Cordova Slack channel and @purplecabbage mentioned that a relative path may work. In my dev tools, I tried to manually create a Media object via the console. I discovered that – given the file name – I could access the file with the Media plugin by using this as the root: "../Library/NoCloud/".

So now my play code looks like so:

var playSound = function(x) {
getSounds().then(function(sounds) {
var sound = sounds[x];

/*
Ok, so on Android, we just work.
On iOS, we need to rewrite to ../Library/NoCloud/FILE
*/
var mediaUrl = sound.file;
if(device.platform.indexOf("iOS") >= 0) {
mediaUrl = "../Library/NoCloud/" + mediaUrl.split("/").pop();
}
var media = new Media(mediaUrl, function(e) {
media.release();
}, function(err) {
console.log("media err", err);
});
media.play();
});
}

So… yeah. That’s it. My app now works. I can record and test audio, and I can persist it to a permanent file system. As I said, I’ll share the real app later this week.

Topics:
mobile ,cordova ,ios ,android ,audio

Published at DZone with permission of Raymond Camden, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

THE DZONE NEWSLETTER

Dev Resources & Solutions Straight to Your Inbox

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.

X

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}