Q: Why isn't my app working?

Question

Q: Why isn't my app working?

Arthur Van Loo 41

I am trying to make a YouTube-downloader, but when I insert a link and click download nothing happens. (I've already enabled the permissions for storage, but somehow they also don't show up when I test).
Here's my code:

using System.Threading.Tasks;
using Xamarin.Forms;
using YoutubeExplode;
using YoutubeExplode.Videos.Streams;

namespace YouTubeDL
{
    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();
        }
        async Task btnDownload_ClickedAsync(System.Object sender, System.EventArgs e)
        {
            var youtube = new YoutubeClient();
            var streamManifest = await youtube.Videos.Streams.GetManifestAsync(iptLink.Text);
            if (btnVideo.IsChecked)
            {
                var streamInfo = streamManifest.GetMuxed().WithHighestVideoQuality();
                if (streamInfo != null)
                {
                    var stream = await youtube.Videos.Streams.GetAsync(streamInfo);
                    await youtube.Videos.Streams.DownloadAsync(streamInfo, $"video.{streamInfo.Container}");
                }
            }
            else if (btnAudio.IsChecked)
            {
                var streamInfo = streamManifest.GetAudioOnly().WithHighestBitrate();
                if (streamInfo != null)
                {
                    var stream = await youtube.Videos.Streams.GetAsync(streamInfo);
                    await youtube.Videos.Streams.DownloadAsync(streamInfo, $"video.{streamInfo.Container}");
                }
            }

        }
    }
}

MainPage.xml

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:YouTubeDL;assembly=YouTubeDL"
             x:Class="YouTubeDL.MainPage"
             BackgroundColor="White">
    <StackLayout Padding="24" Spacing="30">
        <Frame BackgroundColor="#E62117" Padding="24" CornerRadius="0">
            <Label Text="Youtube downloader" HorizontalTextAlignment="Center" TextColor="White" FontSize="36"/>
        </Frame>
        <Entry Text="Yt-link"
               x:Name="iptLink"
               TextColor="Black"/>
        <local:PatchedRadioButton Text="Video"
                     x:Name="btnVideo"
                     GroupName="Options"
                     IsChecked="True"
                     TextColor="Black"/>
        <local:PatchedRadioButton Text="Only audio"
                     x:Name="btnAudio"
                     GroupName="Options"
                     TextColor="Black"/>
        <Button Text="Download"
                x:Name="btnDownload"
                TextColor="White"
                FontSize="Large"
                BackgroundColor="#E62117"
                CornerRadius="15"
                />
    </StackLayout>
</ContentPage>

Anonymous

2020-12-17T14:35:20.323+00:00

Agree with alessandrocaliaro, you should add btnDownload.Clicked += BtnDownload_Clicked;, but I use your code, I gave all of stroage permission, I still get the System.UnauthorizedAccessException: 'Access to the path "/video.mp4" is denied.' If you just want to download file in xamarin forms, you can refer to this thread https://www.c-sharpcorner.com/article/how-to-download-files-in-xamarin-forms/
Arthur Van Loo 41 Reputation points

2020-12-17T15:08:30.883+00:00
That was very helpful, but I still can't figure out how to use the

await youtube.Videos.Streams.DownloadAsync(streamInfo, $"video.{streamInfo.Container}");

With the download interface.
What do I use as url?

(https://github.com/Tyrrrz/YoutubeExplode)

Accepted answer

1 additional answer

Your answer

Anonymous

2020-12-17T14:35:20.323+00:00

Agree with alessandrocaliaro, you should add btnDownload.Clicked += BtnDownload_Clicked;, but I use your code, I gave all of stroage permission, I still get the System.UnauthorizedAccessException: 'Access to the path "/video.mp4" is denied.' If you just want to download file in xamarin forms, you can refer to this thread https://www.c-sharpcorner.com/article/how-to-download-files-in-xamarin-forms/
Arthur Van Loo 41 Reputation points

2020-12-17T15:08:30.883+00:00

That was very helpful, but I still can't figure out how to use the

await youtube.Videos.Streams.DownloadAsync(streamInfo, $"video.{streamInfo.Container}");

With the download interface.
What do I use as url?

(https://github.com/Tyrrrz/YoutubeExplode)

Answer 1

Hello,

Welcome to our Microsoft Q&A platform!

but I still can't figure out how to use the

await youtube.Videos.Streams.DownloadAsync(streamInfo, $"video.{streamInfo.Container}");

I open the DownloadAsync method, I found we can add path to it like following code.

   string folder = FileSystem.AppDataDirectory;  
                       string path =Path.Combine(folder, "MAudio.mp4");  
                       await youtube.Videos.Streams.DownloadAsync(streamInfo, path, null);

I change background code.

   public AboutPage()  
           {  

               InitializeComponent();  

                btnDownload.Clicked += BtnDownload_Clicked;  

            }  



           private async void BtnDownload_Clicked(object sender, EventArgs e)  
           {  
               var youtube = new YoutubeClient();  
               var streamManifest = await youtube.Videos.Streams.GetManifestAsync(iptLink.Text);  
               if (btnVideo.IsChecked)  
               {  
                   var streamInfo = streamManifest.GetMuxed().WithHighestVideoQuality();  
                   if (streamInfo != null)  
                   {  
                       var stream = await youtube.Videos.Streams.GetAsync(streamInfo);  

                       string folder = FileSystem.AppDataDirectory;  
                       string path =Path.Combine(folder, "MAudio.mp4");  
                       await youtube.Videos.Streams.DownloadAsync(streamInfo, path, null);  
                   }  
               }  
               else if (btnAudio.IsChecked)  
               {  
                   var streamInfo = streamManifest.GetAudioOnly().WithHighestBitrate();  
                   if (streamInfo != null)  
                   {  
                       var stream = await youtube.Videos.Streams.GetAsync(streamInfo);  
                       string folder = FileSystem.AppDataDirectory;  
                       string path = Path.Combine(folder, "MAudio.mp3");  

                       await youtube.Videos.Streams.DownloadAsync(streamInfo, path, null);  
                   }  
               }  

           }

I set it path with Xamarin.Essentials: File System Helpers https://learn.microsoft.com/en-us/xamarin/essentials/file-system-helpers?context=xamarin%2Fandroid&tabs=android

It store files in the internal storage. In the Android, it store /data/data/com.companyname.shellnavi/files/

================
Update====================

If you want to see the download file in your emulator and target framework is blew Android 10(Android 11 or later, Google do not allow store file in the external folder), you can store it in the external folder, add following permission and add android:requestLegacyExternalStorage="true" to the application tag.

   <application android:label="ShellNavi.Android" android:theme="@style/MainTheme" android:requestLegacyExternalStorage="true"></application>  
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />  
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Then Add following code to request run-time permission. For testing, I add following code to OnCreate method of MainActivity normally

   if (ContextCompat.CheckSelfPermission(this, Manifest.Permission.WriteExternalStorage) != (int)Permission.Granted)  
               {  
                   RequestPermissions(new string[] { Manifest.Permission.ReadExternalStorage, Manifest.Permission.WriteExternalStorage }, 0);  
               }

If you want to store the file in download folder. You need to use dependenceService to the path of download folder.

Create an interface.

   public interface IgetFile1  
       {  

          string getExternalFile();  
       }

Achieve it in android project .

   [assembly: Dependency(typeof(getFileService))]  
   namespace ShellNavi.Droid  
   {  
       class getFileService : IgetFile1  
       {  

           public string getExternalFile()  
           {  
               string path= Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads).AbsolutePath;  
               return path;  
           }  
       }  
   }

Use it when you want to download .

   private async void BtnDownload_Clicked(object sender, EventArgs e)  
           {  
               var youtube = new YoutubeClient();  
               var streamManifest = await youtube.Videos.Streams.GetManifestAsync(iptLink.Text);  
               if (btnVideo.IsChecked)  
               {  
                   var streamInfo = streamManifest.GetMuxed().WithHighestVideoQuality();  
                   if (streamInfo != null)  
                   {  
                       var stream = await youtube.Videos.Streams.GetAsync(streamInfo);  
                       string folder=  DependencyService.Get<IgetFile1>().getExternalFile();  
                      // string folder = FileSystem.AppDataDirectory;  
                       string path =Path.Combine(folder, "MAudio.mp4");  
                       await youtube.Videos.Streams.DownloadAsync(streamInfo, path, null);  
                   }  
               }  
               else if (btnAudio.IsChecked)  
               {  
                   var streamInfo = streamManifest.GetAudioOnly().WithHighestBitrate();  
                   if (streamInfo != null)  
                   {  
                       var stream = await youtube.Videos.Streams.GetAsync(streamInfo);  
                       string folder = DependencyService.Get<IgetFile1>().getExternalFile();  
                      // string folder = FileSystem.AppDataDirectory;  
                       string path = Path.Combine(folder, "MAudio.mp3");  

                       await youtube.Videos.Streams.DownloadAsync(streamInfo, path, null);  
                   }  
               }  

           }

Best Regards,

Leon Lu

If the response is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Arthur Van Loo 41 Reputation points

2020-12-19T17:38:12.547+00:00

I'm still getting an error, but that might be because I don't understand the File System Helpers. Would you mind explaining it further?

Thank you for the help you've already given me!
Anonymous

2020-12-22T07:15:07.057+00:00

still getting an error

Could you share this error? Is this error about storage? If you use this File System Helpers, you can download this YouTobe file then store it to your internal storage(In your application folder)
Anonymous

2020-12-22T07:25:42.917+00:00

@Arthur Van Loo And my test url: https://youtube.com/watch?v=u_yIGGhubZs

<Entry Text="https://youtube.com/watch?v=u_yIGGhubZs" x:Name="iptLink" TextColor="Black"/>
Arthur Van Loo 41 Reputation points

2020-12-23T08:41:54.237+00:00

Sharing violation on path /data/user/0/com.arthurvanloo.youtubedl/files/MAudio.mp4

I think it has something to do with my permissions, they don't show up when I run my app.
Anonymous

2020-12-23T11:03:24.047+00:00

@Arthur Van Loo I updated my answer. you can refer to it.

Answer 2

Alessandro Caliaro 4,196

I think you have to write something like

btnDownload.Clicked += btnDownload_ClickedAsync; (I think the syntax is not correct...)

under the InitializeComponent()

Arthur Van Loo 41 Reputation points

2020-12-17T15:00:07.257+00:00

Still doesn't work

Share via

Q: Why isn't my app working?

1 additional answer

Your answer