Develop Reference

How to play a simple audio file with Xamarin iOS/Android

I'm trying to learn and play a bit with Xamarin :)
I wanted to play a simple sound at the end of a certain time and in part I succeeded, this works on the android and ios emulators but when I try to build the app on my iPhone this crush at the moment of sound reproduction!
the code I wrote I copied from here!
so my code is this:
iAudio.cs :
using System;
namespace StopWatch
{
public interface IAudio
{
void PlayAudioFile(string fileName);
}
}
AudioService.cs in Android :
using System;
using Xamarin.Forms;
using StopWatch.Droid;
using Android.Media;
using Android.Content.Res;
[assembly: Dependency(typeof(AudioService))]
namespace StopWatch.Droid
{
public class AudioService : IAudio
{
public AudioService()
{ }
public void PlayAudioFile(string fileName)
{
var player = new MediaPlayer();
var fd = global::Android.App.Application.Context.Assets.OpenFd(fileName);
player.Prepared += (s, e) =>
{
player.Start();
};
player.SetDataSource(fd.FileDescriptor, fd.StartOffset, fd.Length);
player.Prepare();
}
}
}
AudioService.cs in iOS:
using System; using Xamarin.Forms; using StopWatch; using StopWatch.iOS; using System.IO; using Foundation; using AVFoundation; [assembly: Dependency(typeof(AudioService))] namespace StopWatch.iOS {
public class AudioService : IAudio
{
public AudioService()
{ }
public void PlayAudioFile(string fileName)
{
string sFilePath = NSBundle.MainBundle.PathForResource(Path.GetFileNameWithoutExtension(fileName), Path.GetExtension(fileName));
NSUrl url = NSUrl.FromString(sFilePath);
var _player = AVAudioPlayer.FromUrl(url);
_player.FinishedPlaying += (object sender, AVStatusEventArgs e) =>
{
_player = null;
};
_player.Play();
}
}
}
and this is mi MainPage.xaml.cs :
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
namespace StopWatch
{
// Learn more about making custom code visible in the Xamarin.Forms previewer
// by visiting https://aka.ms/xamarinforms-previewer
[DesignTimeVisible(false)]
public partial class MainPage : ContentPage
{
Stopwatch stopwatch;
public MainPage()
{
InitializeComponent();
stopwatch = new Stopwatch();
lblStopWatch.Text = "00:00:00";
lblStopWatchAllert.Text = "";
}
private void btnStartClicked(object sender, EventArgs e)
{
stopwatch.Start();
Device.StartTimer(TimeSpan.FromMilliseconds(10), () =>
{
lblStopWatch.Text = stopwatch.Elapsed.ToString().Substring(0, 8);
controll(lblStopWatch.Text);
return true;
});
}
private void btnStopClicked(object sender, EventArgs e)
{
stopwatch.Stop();
}
private void btnResetClicked(object sender, EventArgs e)
{
stopwatch.Reset();
}
private void controll(String time)
{
if (string.Compare(time, "00:00:03:0000") > 0)
{
stopwatch.Reset();
lblStopWatchAllert.Text = "time is over!";
DependencyService.Get<IAudio>().PlayAudioFile("Alert.mp3");
}
}
}
}
the code crashes me at this point of the iOS AudioService.cs file:
I think the problem lies in the info.plist (although I am most likely wrong) but I don't know how to solve it :(
can someone help me? thank you

I have checked this code , it works in my site . Invoking the play method as follow :
DependencyService.Get<IAudio>().PlayAudioFile("Alan_Walker.mp3");
The other codes are the same with yours in iOS and Android , they all play the sound successfully.
Here you need to notice that ,the local sound file should be added to each platform .And each platform has its specical folder to put the auido file .
In Android , you need to put it in Assets folder as follow :
And in iOS , you need to put it in Resources folder as follow :
==========================Update===================================
You should first add file to this folder as follow :
Then add Existing file to this folder :
Then when installing app , this filw will be added to mobile . No matter what is a simulator or a physical device.
Note :
Not copying file from other path to Xamarin.iOS project , this can't make sure the file be added to the project .

Writing form state to xml C#

My aim is to save the all form data via button click (as opposed to upon closing). To that end, I've used the example given in the following thread. Saving the form state then opening it back up in the same state
I've tried to adapt my code to the best of my ability, but nothing happens, and there are no errors shown. What am I doing wrong?
Here's the relevant parts of my code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Xml.Serialization;
namespace WindowsFormsApplication1
{
public partial class frmPayroll : Form
{
SaveData sd = new SaveData();
public frmPayroll()
{
InitializeComponent();
}
private void saveToolStripMenuItem_Click(object sender, EventArgs e)
{
writeConfig();
}
private void writeConfig()
{
using (StreamWriter sw = new StreamWriter("config.xml"))
{
sd.Married = rdoMarr.Checked;
sd.PayPd = cbPayPd.Text;
sd.Allow = cbAllow.Text;
sd.Gross = txtGross.Text;
sd.Fit = txtFit.Text;
sd.Soc = txtSoc.Text;
sd.Med = txtMed.Text;
sd.NetPay = txtNet.Text;
sd.PayPd = cbPayPd.Text;
XmlSerializer ser = new XmlSerializer(typeof(SaveData));
ser.Serialize(sw, sd);
}
}
private void frmPayroll_Load(object sender, EventArgs e)
{
if (File.Exists("config.xml"))
{
loadConfig();
}
sd.Married = rdoMarr.Checked;
sd.PayPd = cbPayPd.Text;
sd.Allow = cbAllow.Text;
sd.Gross = txtGross.Text;
sd.Fit = txtFit.Text;
sd.Soc = txtSoc.Text;
sd.Med = txtMed.Text;
sd.NetPay = txtNet.Text;
}
private void loadConfig()
{
XmlSerializer ser = new XmlSerializer(typeof(SaveData));
using (FileStream fs = File.OpenRead("config.xml"))
{
sd = (SaveData)ser.Deserialize(fs);
}
}
}
public struct SaveData
{
public bool Married;
public string PayPd;
public string Allow;
public string Gross;
public string Fit;
public string Soc;
public string Med;
public string NetPay;
}
}

You are loading your object by deserializing.
But Where are you assigning the states back to your controls?
look at frmPayroll_Load function.
You are trying to assign the data back to the object again.
You have to assign data back to form controls.
Should be something like this (you may need to apply data conversions if required):
rdoMarr.Checked = sd.Married;
.
.
.
.
txtFit.Text = sd.Fit;
.
.
.
.

Writing in the console while program is writing in this console

Is it possible to write something in the console while the program is writing something in this console ? It can be useful when you rename, or remove some files, when you do a repetitive action, and the program is writing a lot in the console. Then you will be able to write a command to stop the execution of the repetitive action while the program is continuing to write in the console. I think it's not very clear, well I illustrated you this fact with the code which I think the most apt (but I precise that it doesn't work ;) ). We have 3 classes.
The main class :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication1
{
class Program
{
private static bool m_Write;
public static bool write
{
get { return m_Write; }
set { m_Write = value; }
}
static void Main(string[] args)
{
int index = 0;
Console.ReadLine();
m_Write = true;
Reader reader = new Reader();
while (m_Write)
{
index++;
Writer writer = new Writer(index.ToString());
}
}
}
}
The reading class :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
namespace ConsoleApplication1
{
class Reader
{
private Thread m_Reading_Thread;
private string m_text_To_Read;
public Reader()
{
m_Reading_Thread = new Thread(new ThreadStart(Read));
m_Reading_Thread.Start();
}
public void Read()
{
m_text_To_Read = Console.ReadLine();
if (m_text_To_Read == "Stop")
{
Program.write = false;
}
}
}
}
And the writing class :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Threading;
namespace ConsoleApplication1
{
class Writer
{
private Thread m_Writing_Thread;
private string m_Text_To_Write;
public Writer(string text_To_Write)
{
m_Text_To_Write = text_To_Write;
m_Writing_Thread = new Thread(new ThreadStart(Write));
m_Writing_Thread.Start();
}
public void Write()
{
Console.WriteLine(m_Text_To_Write);
}
}
}

This isn't nearly as complicated as you're trying to make it. In general there are two ways you can do this. You can start a background thread to do the writing, and have the main thread block on the console waiting for the read, or you can have the main thread writing and have the background thread do the read. I like the first solution best:
public class Program
{
private static readonly ManualResetEvent StopWriting = new ManualResetEvent(false);
private static void Main(string[] args)
{
Thread t = new Thread(WriterFunc);
t.Start();
string input;
do
{
input = Console.ReadLine();
} while (input != "stop");
// Tell the thread to stop writing
StopWriting.Set();
// And wait for the thread to exit
t.Join();
}
private static void WriterFunc()
{
int index = 0;
while (!StopWriting.WaitOne(Timeout.Infinite))
{
++index;
Console.WriteLine(index.ToString());
}
}
}
Note that I used a ManualResetEvent here rather than a Boolean flag. An even better solution would be to use a CancellationToken. Using a flag can cause all kinds of interesting problems because the compiler might determine that the variable can't change (it assumes single-threaded access). Your thread might continue running even after the variable is changed.
If you want the main thread to do the writing, and the background thread to do the reading:
public class Program
{
private static readonly ManualResetEvent StopWriting = new ManualResetEvent(false);
private static void Main(string[] args)
{
Thread t = new Thread(ReaderFunc);
t.Start();
int index = 0;
while (!StopWriting.WaitOne(Timeout.Infinite))
{
++index;
Console.WriteLine(index.ToString());
}
// Wait for the background thread to exit
t.Join();
}
private static void ReaderFunc()
{
string input;
do
{
input = Console.ReadLine();
} while (input != "stop");
// Tell the main thread to stop writing
StopWriting.Set();
}
}

Something like this would work:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
var w = new Writer();
var r = new Reader();
while (!r.finish)
{
w.enabled = true;
string k = Console.ReadKey(false).KeyChar.ToString();
w.enabled = false;
string line = k + Console.ReadLine();
r.Read(line);
}
}
}
class Writer
{
public bool enabled = true;
public Writer()
{
var timer = new System.Timers.Timer(1000);
timer.Elapsed += (a, b) =>
{
if(enabled)
Console.WriteLine("Test");
};
timer.Start();
}
}
class Reader
{
public bool finish = false;
public void Read(string line)
{
if (line == "stop")
{
finish = true;
}
}
}
}
Don't worry if the Writer writes above what you are typing, the Console.ReadLine() only considers what you have typed.

In the case of a console application, no two threads can write data to the screen at the exact same time.
AFAIK, in the above answer, the Writes()'s constructor is continuously executed until it finishes running. Then the control will be passed to the Reader(). So I don't think that works for what you need. Correct me if I am wrong.

Windows form loads then quits

I'm creating a checkout system for a supermarket. It consists of a checkout, server and MIS program an operates WCF services between them. The problem I have is that the checkout program, which is a windows form, does a few neccessaries in it's application_load method and then just quits.
Here's the code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using CheckoutLibrary;
using Checkout.ServerLibraryService;
using Checkout.MarketService;
namespace Checkout
{
public partial class theForm : Form
{
private static int checkoutID = 3;
private Product[] allProducts;
public theForm()
{
InitializeComponent();
}
private void theForm_Load(object sender, EventArgs e)
{
// First cache all products
SupermarketServiceSoapClient marketService = new SupermarketServiceSoapClient();
allProducts = marketService.GetAllProducts();
// Load the service provided by the server
ServiceClient serverService = new ServiceClient();
// Load the event handlers for the bar code scanner
BarcodeScanner scanner = new BarcodeScanner();
scanner.ItemScanned += new BarcodeScanner.ItemScannedHandler(scanner_ItemScanned);
scanner.AllItemsScanned += new BarcodeScanner.AllItemsScannedHandler(scanner_AllItemsScanned);
scanner.Start(checkoutID);
}
void scanner_AllItemsScanned(EventArgs args)
{
throw new NotImplementedException();
}
void scanner_ItemScanned(ScanEventArgs args)
{
itemTextBox.Text = "Scanned " + GetItemName(args.Barcode);
}
private void scanItemButton_Click(object sender, EventArgs e)
{
scanner_ItemScanned(new ScanEventArgs(GetRandBarcode()));
}
// A barcode -> product name look up method
public string GetItemName(int barcode)
{
return allProducts[barcode].Description + " # " + allProducts[barcode].Price;
}
// Method to grab a random barcode for simulation
private int GetRandBarcode()
{
Random rand = new Random();
return rand.Next(0,500);
}
}
}
And program.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace Checkout
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new theForm());
}
}
}
Thanks for any insight.

In WinForms, if your form_load throws an exception, it quits without displaying anything. Annoying, but I'm guessing that's the problem.
You can try a try/catch, or you can hit CTRL+ALT+E and check the Thrown Column for Common Language Runtime Exceptions to see the error.
UPDATE:
Based on comments, here's a sample way to execute something on another thread.
ThreadStart ts = new ThreadStart(() => {
try {
scanner.Start(checkoutID);
} catch {
// Log error
}
});
Thread t = new Thread(ts);
t.Start();

Does WqlEventQuery contain a constructor with 1 argument?

I am trying to create a simple service in C# using VS2008 that creates a text file when the computer goes into sleep mode. My current code throws out the following error:
'SleepNotifierService.WqlEventQuery' does not contain a constructor that takes '1' arguments
Now I looked in the Object browser, and it looks like it does take in one argument. This is what the browser had to say:
public WqlEventQuery(string queryOrEventClassName)
Here is my code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.ServiceProcess;
using System.Text;
using System.Management;
using System.IO;
namespace SleepNotifierService
{
public class WqlEventQuery : EventQuery { }
public partial class Service1 : ServiceBase
{
ManagementEventWatcher _watcher;
public Service1()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
WqlEventQuery query = new WqlEventQuery("Win32_PowerManagementEvent");
_watcher = new ManagementEventWatcher(query);
_watcher.EventArrived += new EventArrivedEventHandler(watcher_EventArrived);
_watcher.Start();
}
protected override void OnStop()
{
_watcher.Stop();
}
void watcher_EventArrived(object sender, EventArrivedEventArgs e)
{
try
{
int eventType = Convert.ToInt32(e.NewEvent.Properties["EventType"].Value);
switch (eventType)
{
case 4:
Sleep();
break;
case 7:
Resume();
break;
}
}
catch (Exception ex)
{
//Log(ex.Message);
}
}
public void Sleep()
{
StreamWriter SW;
SW = File.CreateText("c:\\MyTextFile.txt");
SW.WriteLine("Sleep mode initiated");
SW.Close();
}
public void Resume()
{
}
}
}
Am I interpreting that object browser wrong? I'm new to creating services and C#/.NET in general so it might be something trivial.
Appreciate any help,
Tomek

You're using wrong WqlEventQuery. There's one defined in System.Management and it indeed has a one-argument constructor, but there's also your custom WqlEventQuery class.
If you want to use .NET BCL's class, you'll have to fully qualify it:
var query = new System.Management.WqlEventQuery("Win32_PowerManagementEvent");
or even prefix it with global keyword:
var query = new global::System.Management.WqlEventQuery("Win32_PowerManagementEvent");