All language subtitles for 3. How to Play Sound Across Platforms

So now that we've seen how a simple package such as the English words package works, and how it gets
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downloaded and incorporated into our project and automatically updated as well every time we run packages
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get, we're now ready to go ahead and incorporate a audio file playing package.
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So let's go ahead and just search for it.
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Let's search for play audio file.
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Now sometimes you might have to play around with the search terms a little bit in order to get to the
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package that you need.
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But if we scroll through this list, we can see that we probably don't want a video player.
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We probably do want something that plays audio files simultaneously.
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And there's also this one which plays audio files.
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There's something that allows us to play audio in the background while the screen is off, which sounds
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less like what we want.
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And so we're kind of choosing between audio players and audio player.
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Now notice because the authors are naming these names,
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they might often sound very similar.
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And this one's only different by an s.
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So let's take a look at the scores. Audio players has a score of 96 whereas audio player only has 93.
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So let's pick this one with the higher score.
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Now you've already seen how we can incorporate these packages into our project.
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I'm going to set this as a challenge for you.
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Go ahead and incorporate the audio players' plug in into your Xylophone project going through those three
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steps that we did in the last lesson.
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Now,
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it's important that when you're programming, don't feel like you have to memorize anything.
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It's important that you understand what's going on.
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But there's always the docs and Google whenever you get stuck, whenever you can't remember how to do
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something. Google and docs, they're your best friends as a developer.
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Don't ever let anyone make you feel bad for looking up things in Google or Stack Overflow or in the
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docs such as how to add a package.
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There are so many places that'll tell you how to do this.
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As we mentioned before, when you're using packages the first place to go when you're installing it, is
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of course the installing tab.
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And usually here it will have the instructions for you to install the package.
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So let's follow their steps.
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So first things first.
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Let's go ahead and copy this line of code and add it to our dependencies.
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So that's inside our pubspec.yaml and we're going to delete the English word package now because
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we don't need it anymore. And we're going to paste in our new package that we need.
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So I'm going to go ahead and run packages get as the second step, and that will remove our English
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words package that we had from previously.
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And it should include now our audio players package. So let's take a look inside our Dart packages once more.
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The English words is gone but the audio players is now in.
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So we're ready to go ahead and import this new package.
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We can go ahead and simply copy this line of code and replace where we imported our English words with
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this new import instruction to say that in this file, main.dart, we want to use this audioplayers
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.dart file that we incorporated just now. So now that we've got our package in our project, we're ready
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to actually use it to play some sound.
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Let's take a look at the read me to see how we can do this.
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Now it's important to read through most of the documentation before you get started because you'll discover
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that there's a section called Playing audio which seems like the right thing to use.
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But if you scroll down a little bit more,
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it tells you that for local assets, which is what we have, files that are packaged together with our project,
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you have to use the AudioCache class.
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So let's scroll down and find it.
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Here it is, AudioCache.
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And this plays local assets
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and here's the full documentation.
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So here it tells us, this is how we play an audio using AudioCache.
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First we have to switch out the import from importing audio players to importing AudioCache. So let's
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copy that and let's replace this line of code.
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And what that does is it tells our project to use this particular file that plays audio instead of this
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file that plays audio from the Internet,
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so remote files
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right?
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But what we want is to be a to play it from our assets folder.
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This is the one that we need. Now,
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the next thing it tells us to do is to create a new player using the code that we just imported. So we're
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going to do that in here.
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I'm going to delete all of this and instead of having some text, I'm going to have a flat button. And
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this flat button will have a onPressed that gets triggered when it gets pressed, and the child is just
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going to be some text that says 'Click me.' Now, what should happen when this button gets pressed?
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Well, we want to play a sound from our assets folder.
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So we have to go and build our player first.
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Now this code is a little bit outdated and there's a new way that we would write this in Dart 2.
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In all of this course, we've been working with the latest syntax or the latest way of writing Dart code,
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and that's Dart 2.0.
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So in Dart 2, the way that we would create audio player is we would write something like final. And we'll
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give it a name, we'll call it player.
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We're going to set it to equal the player that comes from audio cache, so we'll say audio cache.
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And finally we're going to finish off with a set of parentheses.
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So that line of code is all we need to do to create our new player that plays cached audio, so audio
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that's in our local assets.
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So now that when our button gets pressed we create a new player and then we just have to tell it what
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to play.
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And we specify the name of the file inside the parentheses of this play function.
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So let's go ahead and type that out.
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Let's say player.play and the file name
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Let's play note1.wav. Now, notice that previously when we were using images and we were specifying
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a file that we want to display, we would add in the name of the folder as well.
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So in this case, we would be writing something like assets/note1.wav. But
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very helpfully, the audio players package actually already assumes that your file is inside a folder
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called assets, and you don't have to write the full file path. All you need to do is to give it the name
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of the sound file that's inside the assets folder.
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So it's very important that your file structure looks like this. And this is why all of our sounds are
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inside a folder that's called assets.
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And if we changed the name of this folder, then it won't work.
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But on the plus side, we can now write much less and it looks a lot better when we're saying our audio
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player should play this particular sound.
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So that's the theory of it.
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It's time to actually put it into practice and run it and see if it works.
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Now even though we're used to hitting save or using the hot reload,
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in my experience when you're working with audio players and you've just set it up to start playing, the
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first thing to do is actually to stop your app if it's currently running and restart it from cold. And
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this allows it to update things in the background and actually make sure it gets hold of the right files
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for you. Once that's done, you should see our flat button in the center of the screen that says the words
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'click me'.
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And when you click on it, you might get a pop up that asks you for permission for Runner, which refers
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to your iOS app.
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Now if you're running your app on an Android emulator, then this shouldn't be a problem.
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Similarly if you're running it on a physical device such as your iPhone or your Android phone, then you
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won't see this pop up either.
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But make sure when it asks you for any permissions just go ahead and click ok and allow it.
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And now every time you click on the button, we hear note 1 being played.
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There's usually a lot of output in the console and it's telling you all sorts of things like what it's
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trying to do.
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Now all of this text actually comes from the audio players package that we incorporated.
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But as long as you don't see any red or any errors, then don't worry about all of these messages too
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much. Success right?
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We managed to get a sound to play with very few lines of code.
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We didn't have to do very much for this to start working. And that's all thanks to incorporating these
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open source Flutter packages and powering up our app to be able to do so much with so few lines of code.
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Now in the next lesson,
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we're going to try and see how we can play all of our sounds by hooking them up to different buttons.
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So for all of that and more, I'll see you in the next lesson.