Wednesday, September 16, 2015

Using Xamarin Android Player with Android Studio

Android Studio and it's accompanying emulator have actually improved considerably. I'd even say the emulator

Android Studio and its accompanying emulator have actually improved considerably. I'd even say the emulator that ships now is perfectly sufficient to use, although there's obviously the better alternative(s) like GenyMotion.

Having said that, the Xamarin Android Player is probably the best out there for a free fast booting emulator.

First install the XAP, no need to install Xamarin Studio.

Launch Android Studio, have your project ready to launch on an emulator.

Here's thing, the running XAP (after you create a device and press play) will not show up in Android Studios list of devices in the AVD. Don't fret, as it won't matter.

When you finally push the run button you will get a screen like this with an option to now launch on the XAP:

image

Now you can use the XAP for your project :)

image

Friday, September 11, 2015

Simple Xamarin iOS Keychain code

I had searched and found a few decent examples of KeyChain (iOS) usage in Xamarin

I had searched and found a few decent examples of KeyChain (iOS) usage in Xamarin but not exactly the code I was happy with.

So this is more of a mashup of pieces of the good code I found formed into one utility class.

The key essentials are find an existing key, create a new key, delete a previous key. The examples I saw tried to do all of this in one method, it's better to break things up, have one method per responsilibity.

using Security;
using Foundation;

public class KeyChain
{

    public string ValueForKey(string key)
    {
        var record = ExistingRecordForKey (key);
        SecStatusCode resultCode;
        var match = SecKeyChain.QueryAsRecord(record, out resultCode);

        if (resultCode == SecStatusCode.Success)
            return NSString.FromData (match.ValueData, NSStringEncoding.UTF8);
        else
            return String.Empty;
    }

    public void SetValueForKey(string value, string key) 
    {
        var record = ExistingRecordForKey (key);            
        if (value.IsNullOrEmpty())
        {
            if (!ValueForKey(key).IsNullOrEmpty())
                RemoveRecord(record);

            return;
        }

        // if the key already exists, remove it
        if (!ValueForKey(key).IsNullOrEmpty())
            RemoveRecord(record);

        var result = SecKeyChain.Add(CreateRecordForNewKeyValue(key, value));
        if (result != SecStatusCode.Success)
        {
            throw new Exception(String.Format("Error adding record: {0}", result));
        }
    }

    private SecRecord CreateRecordForNewKeyValue(string key, string value)
    {
        return new SecRecord(SecKind.GenericPassword)
        {
            Account = key,
            Service = ServiceName,
            Label = key,
            ValueData = NSData.FromString(value, NSStringEncoding.UTF8),
        };
    }

    private SecRecord ExistingRecordForKey(string key)
    {
        return new SecRecord(SecKind.GenericPassword)
        {
            Account = key,
            Service = ServiceName,
            Label = key,
        };
    }

    private bool RemoveRecord(SecRecord record)
    {
        var result = SecKeyChain.Remove(record);
        if (result != SecStatusCode.Success)
        {
            throw new Exception(String.Format("Error removing record: {0}", result));
        }

        return true;
    }        
}