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How do you load an audio asset from "the standard locations" in Xamarin.Forms?

I am trying to play an audio asset in my Xamarin.Forms app, and following this guide I always get a System.NullReferenceException. I have placed my two audio files, "device_off.mp3" and "device_on.mp3", in the Android "Assets" folder with the build action AndroidAsset and in the Apple Resources folder with the build action BundleResource. According to the tutorial, I should be able to simply reference the file names to load the files since they are in what Microsoft there terms "the standard locations". My code to play the audio files is as follows:
using(var player = Plugin.SimpleAudioPlayer.CrossSimpleAudioPlayer.Current)
{
if(color == Color.Green)
{
string filepath = "device_on.mp3";
player.Load(filepath);
player.Play();
}else
{
string filepath = "device_off.mp3";
player.Load(filepath);
player.Play();
}
}
What should I be doing differently so I no longer get a System.NullReferenceException when the program reaches the line "player.Load(filepath);"?

Locating file path of image in android devices

sorry im very new to unity and c#.
Im trying to read an image and apply it as a texture.
The code works when i try it with an image on my computer, however, when i try it with my android devices (phone and AR glasses), i've not been able to specify the file path correctly. How do i specify the file path properly of android devices or is there a way i can get these file path?
Thank you so much for any help in advance! :)
void Start()
{
thisTexture = new Texture2D(100, 100);
//string path = "C:/Users/kenny/Desktop/5th March/im.png"; //this works
string path = "file:///storage/emulated/0/im2.png"; // this doesnt work
bytes = File.ReadAllBytes(path);
thisTexture.LoadImage(bytes);
GetComponent<Renderer>().material.mainTexture = thisTexture;
}

For mobile devices it is not as straightforward to get a file from a plain path.
One way of doing so is by using the Resources folder. In your root folder (Assets), create a new folder named Resources. Put your image there.
Then you can do something like this:
// path without file extension!
var texture = Resources.Load<Texture2D>("path/to/texture");
You can get more references for this functionality here: https://forum.unity.com/threads/how-to-load-a-image-from-the-resources-folder-to-a-texture2d.101542/
Alternatively, you could use the StreamingAssets folder, but that's another story.

Can't play this video Xamarin.Android

I need to play video from sdcard on VideoView and always getting "Can't play this video message". I am testing on physical device. File is on external storage, and can be played by build in phone apps with no problem.
I have read some topics before and tried changing file format and resolution with no effect.
Second guess was path to the file so tried to change it multiple times in many variants using Android.OS.Environment.ExternalStorageDirectory.AbsolutePath, creating File variable and getting path from File.Path.
Got the TextView where I put path every time and it is always correct.
I have no idea why it does not work.
Code:
Java.IO.File file = new Java.IO.File (Android.OS.Environment.ExternalStorageDirectory.AbsolutePath + "/myimage/", "video.mp4");
tView.Text = file.Path;
MediaController mediaController = new MediaController(context: this);
vView.SetMediaController(mediaController);
mediaController.SetAnchorView(vView);
vView.SetVideoPath(file.Path);
vView.Start();
File.Path value:
"/storage/emulated/0/myimage/video.mp4"
EDIT: I have created "raw" folder in resource putted file there and then used following path:
vView.SetVideoPath("android.resource://" + PackageName + "/" + Resource.Raw.video);
It works, but if anyone know how to get the proper path to folder on sdCard?

Finally I figured it out. The problem was that my phone mounted card at path /storage/xxxx-xxxx/ my research revealed that the dir's name come from volume serial number(where android automatically mount card) and ExternalStorageDirectory refers to other locations in each android device. Sometimes it's internal sometimes usb mass storage.
Anyway didn't manage to find any method that returns the path so created following method:
string GetCardMountPoint()
{
string[] listOfDirs = Directory.GetDirectories("/storage/");
string path = null;
foreach ( string dir in listOfDirs)
{
if(dir.Contains('-'))
{
path = dir;
}
}
return path;
It's not much of sophisticated solution but it works for now.

Xamarin media plugin get android image path

I am using the media plugin for xamarin forms (by james montemagno) and the actual taking of the picture and storing it works fine, I have debugged the creation of the image on the emulator and it is stored in
/storage/emulated/0/Android/data/{APPNAME}.Android/files/Pictures/{DIRECTORYNAME}/{IMAGENAME}
however in my app it will get a list of file names from an API I want to check if the image exists in that folder.
The following works fine on IOS
var documentsDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Personal);
string jpgFilename = System.IO.Path.Combine(documentsDirectory, App.IMAGE_FOLDER_NAME);
jpgFilename = System.IO.Path.Combine(jpgFilename, name);
I have tried the 2 following methods for getting it on android but both are incorrect
var documentsDirectory = System.Environment.GetFolderPath(System.Environment.SpecialFolder.Personal);
string jpgFilename = System.IO.Path.Combine(documentsDirectory, App.IMAGE_FOLDER_NAME);
jpgFilename = System.IO.Path.Combine(jpgFilename, name);
Java.IO.File dir = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DataDirectory + "/" + App.IMAGE_FOLDER_NAME + "/" + name);
dir ends up as
/storage/emulated/0/data/{DIRECTORY}/{IMAGENAME}
jpgFileName ends up as /data/data/{APPNAME}.Android/files/{DIRECTORYNAME}/{IMAGENAME}
I dont want to hardcode anything in the paths but neither of these are right. I could not find anything in the GIT documentation for getting the file path except by looking at the path of the file created when taking a picture

The problem
I had the same kind of issue with Xamarin Media Plugin. For me, the problem is:
we don't really know where the plugin save the picture on android.
After reading all documentation I found, I just noted this:
... When your user takes a photo it will still store temporary data, but also if needed make a copy to the public gallery (based on platform). In the MediaFile you will now see a AlbumPath that you can query as well.
(from: Github plugin page)
so you can save your photo to your phone gallery (it will be public) but the path is known.
and we don't know what means "store the temporary data".
Solution
After investigating on how/where an app can store data, I found where the plugin stores photos on Android >> so I can generate back the full file names
In your Android app, the base path you are looking for is:
var basePath = Android.App.Application.Context.GetExternalFilesDir(null).AbsolutePath
It references your app's external private folder. It looks like that:
/storage/emulated/0/Android/data/com.mycompany.myapp/files
So finally to get your full file's path:
var fullPath = basePath + {DIRECTORYNAME} + {FILENAME};
I suggest you to make a dependency service, for instance 'ILocalFileService', that will expose this 'base path' property.
Please let me know if it works for you !

I resolved a similar problem. I wanted to collect all files for my app in a folder visible to all users.
var documentsDirectory = Android.OS.Environment.GetExternalStoragePublicDirectory(
Android.OS.Environment.DirectoryDocuments);
If you want to create Directory, add to your class using System.IO; and you have the same functions in a normal .NET application.
if (!Directory.Exists(path))
Directory.CreateDirectory(path);
If you want to create files or directory, you can use PCLStorage.
public async Task<bool> CreateFileAsync(string name, string context)
{
// get hold of the file system
IFolder folder = FileSystem.Current.LocalStorage;
// create a file, overwriting any existing file
IFile file = await folder.CreateFileAsync(name,
CreationCollisionOption.ReplaceExisting);
// populate the file with some text
await file.WriteAllTextAsync(context);
return true;
}

to get the private path
var privatePath = file.Path;
to get the public Album path
var publicAlbumPath = file.AlbumPath;
se the documentation here https://github.com/jamesmontemagno/MediaPlugin

Playlist Create and PLay in C#

So I am trying to add a music player to my web browser so users can play music in it from a specific folder in it's app data folder ("\AppData\Roaming\MantouWeb360\MWP360")
I was looking around a came accross a solution here
The user can select files (multiple ones too) which is then added to a playlist and then played.
However I am not so experienced at C# and VS doesn't recognise the wmp.playlistCollection.newPlaylist("myplaylist"); part of the code (and the following code using the wmp. part). This must mean there was code outside the example defining wmp. but I do not know what it is. Any way to get this code to work so that users can play music from their selected files on my web browser or is there possibly a better way which copies the music to the folder I said above and plays them in order (loop at the end of the last file) so that the user does not need to keep selecting files?
WMPLib.IWMPPlaylist playlist = wmp.playlistCollection.newPlaylist("myplaylist");
WMPLib.IWMPMedia media;
if (ofdSong.ShowDialog() == DialogResult.OK)
{
foreach (string file in ofdSong.FileNames)
{
media = wmp.newMedia(file);
playlist.appendItem(media);
}
}
wmp.currentPlaylist = playlist;
wmp.Ctlcontrols.play();