Windows 8

Integrating Facebook in Windows Store Apps Part 2 – Boredom Challenge Day 13

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In my previous article, we’ve seen how we can sign in to Facebook, display our user’s data and share status updates in Windows Store apps. In this article, we will take our example app further by reading and displaying the user’s timeline and allowing the user to like/unlike posts, view a post’s comments and also add comments of his/her own.

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We’ll start with the part 1’s completed app and continue from there. If you wish to go with the article step by step, you can get it here. If you’d rather not, jump to the end of the article for the completed source code. 😉

In this article, we will see how we can create Json classes for Facebook items, how we can read and display our user’s timeline, how we can like/unlike posts and how we can display and add comments. Apparently we have a lot of work to do.

➤ We’re basically making a Facebook client here…

Integrating Facebook in Windows Store Apps Part 1 – Boredom Challenge Day 12

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I believe I don’t even need to tell you why it is a good idea to use Facebook in our applications. 🙂 Apart from the fact that it is the most widely used social media service, we can use it to allow our users to share something from our app (increasing our app’s publicity and usefulness), get posts – pictures – videos about a specific topic for our users (like latest news about a music group), or we can just use it as a user account system (as I’ve mentioned in one of my previous blog posts here). 1 For this purpose, we will use Facebook’s Graph API which allows us to do basically anything we could do on Facebook from inside our apps, and combine it with the Facebook SDK for .NET. Since there is a huge number of different functionalities provided by Graph API, I will be only showing about a handful of them (most used ones), so it is a good idea to keep the documentation for Facebook Graph API and .NET Facebook SDK at your side. 2 I’ve decided to split this article into several parts. In this first part, we will create a Windows Store app that signs the user in with a Facebook account, gets and displays our user’s information and finally allows our user to publish a status update. We’ll also see how we can get a long term access token from Facebook to keep our user signed in even after our app is closed.

➤ After these articles, just please don’t send tons of application requests to others…

Using Graphs and Charts in Windows Store Apps – Boredom Challenge Day 11

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Graphs and charts are very effective tools for visualizing and summarizing data for our users. In apps they not only look cool, but also can be made interactive for further effectiveness. They are also an indispensible feature of financial apps or apps which need to show statistics.

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In Windows Store apps, there isn’t a default XAML control in Visual Studio for graphs. However, we can easily use other libraries such as WinRT XAML Toolkit or Telerik RadControls for Windows 8 (there are many more). In this article we will create a sample app which uses different types of graphs and charts to show example data (pie chart, bar chart, line chart etc.) using WinRT XAML Toolkit.

➤ Bonus points for creating a “pie chart of my favorite bars” and “bar chart of my favorite pies”…

Integrating Microsoft Account (Live ID) in Windows Store Apps with Live SDK – Boredom Challenge Day 10

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Integrating services like Microsoft Account, Google Account, Facebook, Twitter etc. in our apps undoubtedly provides several benefits, one of which is that we can use them as an account system for our app. From the developers’ point of view, it means not bothering with creating interfaces and functionalities for user profile creation – modification, not needing to mess with usernames and passwords, and also bypassing the secure storage of this information. From the users’ point of view, it means s/he won’t need to create an account for yet another app (which is a very good thing by the way, since users usually dislike creating accounts).

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To integrate Microsoft Account, we will use Live SDK, which makes it very easy to use several Microsoft services such as SkyDrive, Outlook and Skype. Live SDK is available not only for Windows 8 and Windows Phone, but also for Android and iOS.

In this article, we will create an app that allows the user to sign in with a Microsoft account, displays the user’s name, and makes the user stay signed in until s/he wants to sign out (meaning the user won’t need to sign in everytime the app is opened).

➤ You can also use Live SDK in your website, too…

Using Multiple Item Templates Together: DataTemplateSelector – Boredom Challenge Day 9

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If you spend some time developing Windows Store apps, you will notice that item templates play a major role since we have to use them to display data in many controls (most used ones are GridView and ListView). They give us total control over how we should present information to user, and if designed right, they can single-handedly make our app quite beautiful.

However, as you progress, you will also notice that sometimes just creating an item template is not enough: You may need to customize them based on the data you have. For this purpose, we can do several things that I’ve mentioned in my blog, such as using IValueConverter to bind your data to nearly every property, or creating a custom user control and using it in the item template. Still, however, if the amount of customization you need to do in the item template is way too much, you can instead decide to create several different item templates, and then use them at the same time via the DataTemplateSelector interface.

Screenshot from the example app we will create.

Screenshot from the example app we will create.

If this looks interesting to you, read on and we will create an app that uses the DataTemplateSelector interface. 🙂

➤ You can also use this for multiple GroupStyle or ItemContainerStyle items, but that is a little more advanced topic…

Tip: Passing Multiple Parameters to a New Page in Windows Store Apps – Boredom Challenge Day 8

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Today’s post will be a small tip about how we can pass multiple parameters when navigating to another page in a Windows Store app.

Frame.Navigate() method, which is used for navigating to another page, allows us to send a parameter to the new page like this:

string parameter = "The information that you wish to send to the next page.";
Frame.Navigate(typeof(AnotherPage), parameter);

Then we get the parameter in OnNavigatedTo() function of AnotherPage, like this:

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            string passedParameter = e.Parameter.ToString();
        }

So basically we can send any object we want this way. But what if we want to send more than one parameter (which is quite common)? We can not just do it like this:

string parameter = "The information that you wish to send to the next page.";
int parameter2 = 5;
Frame.Navigate(typeof(AnotherPage), argument, argument2);

In this case, we can use application level global variables (but that isn’t good practice, really), or we can use the following way of navigation instead of Frame.Navigate():

string parameter = "The information that you wish to send to the next page.";
int parameter2 = 5;
Window.Current.Content = new AnotherPage(parameter, parameter2);

        public AnotherPage(string firstArgument, int secondArgument)
        {
            this.InitializeComponent();
        }

If we use Window.Current.Content to change the page, we forgo the navigation support, and if you have more than a few pages in our app, going back and forth becomes very impractical and ineffective since you have to do everything manually.

Therefore, we can create a custom class called AnotherPagePayload instead, set our parameters in it, and send that object:

        public class AnotherPagePayload
        {
            public string parameter1 { get; set; }
            public int parameter2 { get; set; }
        }

AnotherPagePayload payload = new AnotherPagePayload();
payload.parameter1 = "Information you want to send to the next page.";
payload.parameter2 = 5;
Frame.Navigate(typeof(AnotherPage), payload);

And then retrieve it like this, in AnotherPage:

        protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            AnotherPagePayload passedParameter = e.Parameter as AnotherPagePayload;
            string parameter1 = passedParameter.parameter1;
            int parameter2 = passedParameter.parameter2;
        }

That’s it. It’s a small detail, but if you don’t know how to do it when you start developing your app, correcting it later takes some time.

Thank you for reading.

Creating and Using Custom User Controls in Windows Store Apps – Boredom Challenge Day 7

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In a software, user controls are the building blocks of the user interface. A user control is basically a piece of interface and code mixture that is designed for a specific action or purpose, and they provide the interaction between users and our app. They range from simple textblocks to more complex ones such as buttons, sliders, scrollbars, lists and grids, or to even more complex ones such as webviews, maps, pie charts or graphs. As developers, we can customize these user controls as much as they allow, like changing their texts, colors, sizes or even events (like what happens when we click a button or move a slider).

Another aspect of user controls is this: They are repeated a lot. Think what would happen if you wanted to put a button to your app but there weren’t any button controls. You would need to put a rectangle first, then a textblock in front of it, then set a click event, then arrange it’s animations for clicking and so on. Just for one button. Then if you wanted to put another button, you would need to copy all that you’ve prepared and paste it to the place you want, which would result in an absurdly big markup code composed completely of basic controls and a maintenance nightmare.

Some of the XAML user controls in Windows Store apps.

Ok then, now that we know what user controls are and why they’re nice, we’ll come to the custom user control part. Well, apart from default user controls, you can broaden the number of your user controls via adding other libraries (for Windows Store apps, like WinRT XAML Toolkit, Telerik RadControls for Windows 8 or Bing Maps control). However, you might still have a specific part of your interface (unique to your needs) that you need to repeat a lot. If this is the case, we can create a custom user control composed of other user controls that will make our work a lot easier.

Before going on to make an example app, I’d like to make it clear how custom controls are useful in Windows Store apps:
– They increase maintainability. If you want to change how it looks or works later, just make your changes to the custom user control, instead of not using a user control and changing it in every place you’ve used.
– Combined with data binding, they can be very powerful and dynamic.
– Especially useful in places where you don’t have a codebehind file, such as the item templates for gridviews or listviews. Without them, you will not be able to easily put buttons or other interactive user controls in your item template.

Alright alright, enough ranting, let’s create an example app. 🙂 We’ll now create a Windows Store app which will have a custom user control in a GridView item template. It will be a mockup app, where we will show the user his/her incoming friendship requests and the user will either accept or ignore them. 🙂

➤ For bonus points, you can create custom controls and put them on the internet for other people to use…

Downloading Files with BackgroundDownloader in Windows Store Apps – Boredom Challenge Day 6

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In one of my previous articles, I’ve mentioned the Background Transfer API for Windows 8, which allowed us to use BackgroundDownloader and BackgroundUploader classes for downloading and uploading files in our app. After mentioning it, I’ve decided to write an article about how we can use them.

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Background Transfer API has many nice features that make our work easier, such as:

– Being able to download large files,
– Tracking download progress,
– Pausing / resuming download,
– Continuing download even when our app is in the background (suspended),
– If the app is closed mid-download, allowing us to continue the next time our app starts,
– Setting cost policy (wheter downloading when connected to metered connections or not),
– Handling network situations automatically (no need to catch exceptions if the network connection is lost mid-download, it’ll continue when internet comes back),
– Multiple downloads at the same time.

As always, we will create an example application that uses these features.

➤ “Please wait 357 minutes for your next download”…

Using a Public Dropbox File as Data Source for Our Apps – Boredom Challenge Day 5

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If you are an individual developer (and especially a new-grad or a student), chances are you won’t have the resources to have a backend for your app, or maybe you need to just keep a small amount of information that you don’t want to get a server or hosting provider for. In this case, we can use an online storage service (SkyDrive, Dropbox, Google Drive, whatever you wish) to provide read only data for our apps.

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For example, you want to create a TV app that gets video streams for multiple different TV channels. If you hard-code them into your app, you’ll start getting errors when a TV channel decides to change the address of their stream, and to replace it you have to change the link in your code and publish an update for you application (which will take several days, at least). Instead, you could put the links of the streams in a public file and then read them in your app when your app starts, which will give you the opportunity to change them any time, and your changes will be effective instantly. Heck, don’t just keep the links, keep the name and picture link and any other information you want about that TV channel (you can use XML or Json formatting) and then read all of this data in your app: This way you can instantly add new channels, edit existing ones or remove them whenever you want.

Therefore, if it is not a problem for the file to be publicly visible, this is a free (emphasis on free), quick, easy to use and effective method for providing read only data to our apps. In this article, we’ll use a public Dropbox file and see how we can use this in a Windows Store app.

➤ For bonus points, you can read app settings (like background color) from this file and change it whenever you want… 😛

How to Download and Save Files in a Windows Store App Using HttpWebRequest – Boredom Challenge Day 4

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Although this may not be a frequently used feature, downloading and saving files from inside our app can be a cool addition, especially if our app is using social media or anything else where users may want to share files or pictures.

Normally, Windows 8 contains a Background Transfer API which provides us a class called BackgroundDownloader that is very useful if we need to download large files, and it comes with neat features such as tracking download progress, setting a cost policy and pausing support. However, this class is designed for more long term download operations and for small files it is more preferable to use http APIs. Using HttpWebRequest gives us a low level control over the download operation, which may be needed sometimes.

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In this article, we will make an app that will download the file from a given link, save it to a place that user chooses, and open it with the default application associated with its extension.

➤ “Please wait 60 seconds before your download is ready”…