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Interface Design For Developers – Glossy Buttons

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In this series each topic will be split into two parts – First, creating the graphics using Photoshop and normally with a screencast. The second part will be a blog post on how to use the newly created graphics in a project — normally websites.

This screencast shows how to create a glossy, reusable button with Photoshop and then make changes to the colors, text and icons it displays. We also discuss adding a reflection to buttons by using a Smart Object. Additionally, we look at how to add text and change the color of the button.

Creating Glossy Buttons

[Watch the screencast]

Resources

Below are resources for the content created in this screencast. You can use the .PSD file to get the finished Photoshop file. You can use the .PNG file to create buttons with a different art program.

[Tutorial PSD file]
[Buttons.png]
[Buttons-No-Shadow.png]

Check back for the next blog post where we discuss how to use the buttons in a website.

Is there a topic you’d like to see covered in this series? Make sure to leave a comment with your ideas!

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Written by hugoware

September 6, 2010 at 12:52 am

Interface Design For Developers – Introduction

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Simple is better when it comes to design. Adding a bunch special effects doesn’t automatically make an interface element better. Good design is normally very subtle and involves very few special effects (if any at all)

See what I mean?

However, a hint of gloss or a slight reflection for an interface element can make a plain website much more attractive (no, not System.Reflection, stay with me here…).

Design Tutorials For Developers

If you’ve ever seen my personal websites then you can tell I’m interested both code and graphics. I’m more or less one of those jack of a couple trades, master of none sort of guys.

So, this series of posts we’re going to discuss both how to create attractive interface elements and how to use them in our code – a little bit of both worlds in the same post!

I’ll be using Photoshop for these tutorials but I’ll try and use concepts that apply to other art programs as well. If you don’t have Photoshop then you can download a trial version.

The Tutorials

Below are previews for the tutorials I’ll be releasing the next couple weeks. I’ll also come back and add to this list as more come out.

Shiny 'Web 2.0' style buttons with HTML and CSS

Create a simple 'Post-It' note and then write dynamic text to the image

Extend the 'Post-it' note by creating a photo frame and change the subject dynamically

These should be a good start to but if you have ideas that you’d like to see then leave a comment or send an e-mail my direction.

Written by hugoware

September 3, 2010 at 11:57 pm

Anonymous Types As Object Templates

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I’ve got a bit of an addiction to intellisense. Dynamic types are interesting but I still prefer being able to see a nice neat list of properties on each of my objects.

Since anonymous types are ‘real’ classes then you can actually create them at runtime. This means you can use them as templates for other objects if you can provide all of the required parameters.

Below is a simple class that allows you to perform queries against a database and use an anonymous type to provide a template for the records to return.

/// <summary>
/// Helps working with database connections
/// </summary>
public class DataConnection {

    #region Constructors

    /// <summary>
    /// Creates a new DataConnection for the connection string
    /// </summary>
    public DataConnection(string connection) {
        this.ConnectionString = connection;
    }

    #endregion

    #region Properties

    /// <summary>
    /// The connection string to use with this DataConnection
    /// </summary>
    public string ConnectionString { get; private set; }

    #endregion

    #region Performing Queries

    /// <summary>
    /// Performs a query for the connection without any parameters
    /// </summary>
    public IEnumerable<T> Query<T>(string query, T template)
        where T : class {
        return this.Query(query, (object)null, template);
    }

    /// <summary>
    /// Performs a query for the connection with the provided paramters
    /// </summary>
    public IEnumerable<T> Query<U, T>(string query, U parameters, T template)
        where T : class 
        where U : class {

        //prepare the connection and command
        Type type = template.GetType();

        //create the connection - (thanks @johnsheehan about the 'using' tip)
        using (SqlConnection connection = new SqlConnection(this.ConnectionString)) {
            using (SqlCommand command = new SqlCommand(query, connection)) {

                //assign each of the properties
                if (parameters != null) {
                    this._UsingProperties(
                        parameters,
                        (name, value) => command.Parameters.AddWithValue(name, value));
                }

                //execute the query
                connection.Open();
                SqlDataReader reader = command.ExecuteReader();

                //start reading each of the records
                List<T> results = new List<T>();
                Dictionary<string, int> fields = null;
                while (reader.Read()) {

                    //prepare the fields for the first time if needed
                    fields = fields == null ? this._ExtractFields(reader) : fields;

                    //generate the record
                    T record = this._CreateAnonymousResult(reader, fields, type, template);
                    results.Add(record);
                }

                //return the results for the query
                return results.AsEnumerable();
            }

        }

    }

    #endregion

    #region Helpers

    //creates a new anonymous type from 
    private T _CreateAnonymousResult<T>(SqlDataReader reader, Dictionary<string, int> fields, Type templateType, T template)
        where T : class {

        //create a container to queue up each record
        List<object> values = new List<object>();

        //use the template to find values
        this._UsingProperties(template, (name, @default) => {

            //try and find the field name
            if (fields.ContainsKey(name)) {

                //check if this is a value
                int index = fields[name];
                object value = reader[index];
                Type convert = @default.GetType();

                //try and copy the va;ue
                if (value != null) {
                    values.Add(Convert.ChangeType(value, convert));
                }
                //not the same type, use the default
                else {
                    value.Equals(@default);
                }

            }
            //no field was found, just use the default
            else {
                values.Add(@default);
            }

        });

        //with each of the values, invoke the anonymous constructor
        //which accepts each of the values on the template
        try {
            return Activator.CreateInstance(templateType, values.ToArray()) as T;
        }
        catch (Exception e) {
            Console.WriteLine(e.Message);
            return template;
        }

    }

    //reads a set of records to determine the field names and positions
    private Dictionary<string, int> _ExtractFields(SqlDataReader reader) {
        Dictionary<string, int> fields = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
        for (int i = 0; i < reader.FieldCount; i++) {
            fields.Add(reader.GetName(i), i);
        }
        return fields;
    }

    //performs an action with each of the properties on an object
    private void _UsingProperties(object obj, Action<string, object> with) {
        
        //if there isn't anything to work with, just cancel
        if (obj == null) { return; }

        //get the type and peform an action for each property
        Type type = obj.GetType();
        foreach (PropertyInfo prop in type.GetProperties()) {
            with(prop.Name, prop.GetValue(obj, null));
        }

    }

    #endregion

}

This class allows us to perform basic queries against a database and then provide a template of the records to return. This means that if the information is found then the database value is used but if it is missing then the template value is used instead.

In order to create an anonymous type we need to know the type and each of the properties in the order they appear. After collecting this information we simply need to use the Activator.CreateInstance method to instantiate the class and we’re set! (method _CreateAnonymousResult)

This means we can write a ‘dynamic’ query with results that have intellisense!

//set up the connection
DataConnection data = new DataConnection(CONNECTION_DATA);

//perform the query
var results = data.Query(
    "select * from orders where orderId > @orderId",
    new { orderId = 11000 },
    new {
        orderId = -1,
        shipName = "missing",
        shipRegion = "none"
    });

//access properties
var record = results.First();
int id = record.orderId; //intellisense!

I’ve actually used this same approach before in CSMongo as a way to provide intellisense without knowing anything about the database in advance.

Of course, this is just some code I hacked out this evening. You aren’t going to be able to do a lot with it but it is a good example of how you can reuse anonymous types in your code.

Written by hugoware

August 30, 2010 at 12:19 am

Using jLinq With JSON APIs

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I’ve had a few e-mails asking how to perform a query on JSON data from an external source, for example Flickr Services. This post we will go over accessing Flickr data but also performing a secondary query on the information returned.

You can download a .zip file at the end of the post with the files used in the examples.

Let’s take a look at what we’re going to create…

You can see we’ve included a search box along with a few additional check boxes with options we can use for the secondary query. These options aren’t available for the API call, but we can intercept the records and apply additional filters before we use them on the page.

To start, we need to create an extension method for downloading the data from the Flickr APIs. jLinq allows you to create extension methods and plug them directly into the framework.

//extend jLinq to search Flickr
jlinq.flickr = function(search, action) {
    search = escape(search);
    $.getJSON(
        "http"+"://api.flickr.com/services/feeds/photos_public.gne?"+
        "tagmode=any&format=json&jsoncallback=?&tags="+search, 
        function(data) {
            var query = jlinq.from(data.items);
            action(query);
        });
};

This example creates a method named flickr that resides with the rest of the jLinq library. The method accepts a keyword to search with and an anonymous function that will be used to work with the data. This is because we have to wait for the server to return a response.

This means you would use the function with a search phrase and a jLinq query to perform.

//start a new jLinq query
jlinq.flickr("cake", function(query) {

    //perform a normal query and use the data
    query.contains("title", "red")
        .sort("title");
});

At this point we need to wire up all of the UI elements on the page. I won’t go into detail on this part but you can always refer to the example for help if you get stuck.

So lets take a step back and take a look at how the filtering is done for the records. You’ll notice that we can selectively perform certain parts of the query depending on which check boxes are selected.

//sample.js - line 31     - - - - - -
//if excluding titles with digits
if (flickr.ui.filterNumbers.is(":checked")) {
    query.notMatch("title", /\d/g);
}

//if requiring a photo to have a title
if (flickr.ui.requireTitle.is(":checked")) { 
    query.notEmpty("title"); 
}

//if requiring sorting of titles
if (flickr.ui.sortTitle.is(":checked")) { 
    query.sort("title"); 
}

//snip...

You’ll notice that you don’t have to chain the entire query together. You can do sections at a time. This means you can decide when certain parts of the script run and when they are skipped.

Now, we can write queries against Flickr and also perform our own secondary queries using jLinq. In this case we are sorting data and filtering out records that wasn’t part of the query to the server.

Of course, this is a simple example but is does show some of the neat ways you can you can use jLinq to help you work with JSON data.

[Sample Files]
http://hugoware.com/examples/jlinq-flickr.zip

Written by hugoware

August 26, 2010 at 1:12 am

Null Instance Extension Methods

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Checking for null can be time consuming and add a lot of extra noise to the code you write. In some ways it can reduce the readability of your code and obscure the purpose of your functions.

For example, check out all of the null checks required for this bit of code.

public static int GetVersion() {
	
	//check if this exists
	if (!File.Exists(PATH_APP_DETAILS)) { return DEFAULT_VERSION; }

	//try and load the document
	XDocument document = null;
	try {
		document = XDocument.Load(PATH_APP_DETAILS);
	}
	catch {
		return DEFAULT_VERSION;
	}
	if (document == null) { return DEFAULT_VERSION; }
	
	//find the element
	XElement release = document.XPathSelectElement("app/release");
	if (release == null) { return DEFAULT_VERSION; }
	
	//get the value
	XAttribute version = release.Attribute("version");
	if (version == null) { return DEFAULT_VERSION; }
	
	//convert the version
	int current = int.TryParse(version.Value, out current) ? current : DEFAULT_VERSION;
	return current;
	
}

Yikes… that is a lot of code for such a small task but what else can you do? You can’t just call methods on something that is null or your app is going to blow up… or can you?

Null Instance Extension Methods

Extension methods feel magical the first time you see them in action but ultimately they are just static methods that can be invoked from anywhere in your project.

But here is the neat thing — Since an extension method isn’t tied to the instance of a class then they can be invoked without an instance of the class.

Sound confusing? Here is an example of what I mean…

//create an extension method
public static class StringExtensions {
	public static void Test(this string value) {
		Console.WriteLine("Hello from a null test!");
	}
}

//and then call it
string nothing = null;
nothing.Test(); //ok!
nothing.ToUpper(); //crash

You’ll notice that the call to Test worked fine – If you put a break point in the method and check the value argument then you’ll notice it is actually null! We were able to call the method Test even though there wasn’t an instance of a string.

So how can this help us? Well let’s take the same XML problem from earlier in the post and create some extension methods that don’t care if the instance being invoked is null or not.

//helper extension methods for XML documents
public static class XmlExtensions {
	
	//loads an xml document to use
	public static XDocument LoadDocument(this XDocument document, string path) {
		if (!File.Exists(path)) { return null; }
		try { return XDocument.Load(path); }
		catch { return null; }
	}
	
	//uses an XPath to find an element
	public static XElement GetElement(this XDocument document, string path) {
		return document is XDocument ? document.XPathSelectElement(path) : null;
	}
	
	//returns the value of an attribute
	public static string GetAttribute(this XElement element, string name) {
		XAttribute attribute = element is XElement ? element.Attribute(name) : null;
		return attribute is XAttribute ? attribute.Value : string.Empty;
	}
}

Now let’s take a look at how we can solve the same problem as before but with these new extension methods…

public static int GetVersion() {
	
	//open the document (Mono)
	XDocument document = document.LoadDocument(PATH_APP_DETAILS);

	//It appears you have to do it like this in Visual Studio
	//XDocument document = ((XDocument)null).LoadDocument(PATH_APP_DETAILS);
	
	//find the element
	XElement release = document.GetElement("app/release");
	
	//get the version
	string version = release.GetAttribute("version");
	
	//convert and return the value
	int current = int.TryParse(version, out current) ? current : DEFAULT_VERSION;
	return current;
}

As far as I can tell, no matter what you throw at this code, you will either get the default version or the value in the XML document. This definitely reduces the lines of code count… but the clarity gains might be debatable.

  1. A developer modifying this code might not realize the value could be null or could be a real object. If they call an instance method and the value ends up being null then the application is going to crash.
  2. Some developers are going to scratch their heads when they read the line XDocument document = document.LoadDocument(...). Invoking a method on a value you’re declaring and should be null and returning the result it to itself? Huh?
  3. The more forgiving your code is then the more prone to external errors it will be, which in turn will introduce subtle runtime errors in your applications. Sometimes it’s a better idea just to throw an exception and keep the program from running.

So, while this approach has benefits it also has pitfalls. Make sure to evaluate the risks before using something like this in your code. If implemented carefully this could reduce complexity in your application…

…or at least make for a neat parlor trick the next time you’re with your dev team.

Written by hugoware

August 22, 2010 at 9:14 pm

Installing CobaltMVC

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Got an interesting piece of anonymous feedback today reminding me of something rather obvious…

How exactly do you install CobaltMVC?

Oh yeah… That would be handy information… and it probably should have already been released. That said, lets get right to it.

Download CobaltMVC

The new CobaltMVC site is still in beta (like the rest of the framework) but you can still download the libraries you need to get started.

Add CobaltMVC To Your Project

Unpack the files to an easy to reach location and then add them as references to your project. You don’t need to add both, the Cobalt.dll is good enough.

‘Initialize’ CobaltMVC

Next, open up the Global.asax file and include the Cobalt.CobaltConfiguration.Initialize(); call to the Application_Start method. This makes sure that CobaltMVC is set up fully before it begins processing requests.

Update Web.config (sorta optional)

This step can be skipped but it will make coding your pages less convenient since you’ll have to add the namespaces all over the rest of your project. Add the Cobalt and the Cobalt.Web namespaces to your system.web/pages/namespaces section. This opens up the extension methods used to start Cobalt commands from your views.

You’re Done!

At this point we can test CobaltMVC to see if it is working. For example, here is a command you can run on the default MVC Index view.

And you’ll get the following results…

Not bad, huh?

It is worth mentioning that CobaltMVC might have unexpected results if you use .browser files with your project. Why?

Well, part of the Initialize() call actually creates a .browser file that is used to capture rendering for content on the page.

So, if you see this file floating around in your project, don’t delete it.

Who knows what happens when too many .browser files are fighting for the same thing but I doubt it will be a good thing.

Good luck!

Written by hugoware

August 20, 2010 at 12:09 am