Thursday, March 28, 2013

User Interaction with Ubuntu Components



I am so very able to amuse myself with all these funny pictures, but there are other amusing subreddits other than funny. So today I added the ability to choose a different subreddit. This involved diving into the world of Ubuntu Components.

Ubuntu Components were surprisingly functional, but as you will see, they are still a work in progress.

So, the first thing I needed to do was to make a way for the user to say that they want to change subreddits. Ubuntu Touch provides the bottom edge for your application to add a list of commands. This is a nice way to do it because it means that the screen isn't cluttered with commands, but users know exactly where to go when they want them.

The first thing to do is to ensure that the top level of your app is a MainView, and then you are presenting the content in a Page. So, roughly your apps structure looks like ...

//imports
MainView
{
    //set MainView properties
    Page
    {
        //app UI content
    }
    //components outside pages
}

I wanted to add a "subreddit" button. To do that, I set the tools property of the page to a list of actions. So far there is only one action. Essentially, I am defining a button. I tell it the text I want, the icon to use (I downloaded an icon that I wanted) and the action to take. So this goes inside the Page tag:

        tools: ToolbarActions
        {
        Action
        {
            text: "SubReddit"
            iconSource: Qt.resolvedUrl("reddit.png")
            onTriggered: PopupUtils.open(subRedditSheet)
        }
    }
Now you can see that if swipe from the button, I get my button.
But what is that action? What I did was create a ComposerSheet that allows the user to input the reddit that they want. You do this by defining a Component that wraps a ComposerSheet. A ComponentSheet is kind of like a dialog box. It handles putting Ok and Cancel buttons on for you. Note that you have to name the ComposerSheet "sheet", or you get errors. All I added was a TextField that I called "subRedditText, but you can fill the ComposerSheet with whatever you want.

I just have to tell it what to do when the user clicks Ok. I did a little refactoring from yesterday to create a "changeSubReddit function that gets called on start up, and can get called from here. I just pass it the subreddit. (Don't forget to import Ubuntu.Components.Popups 0.1 in order to use the ComposerSheet).

Then you call PopupUtils.open to pop it open when you want it (which I specify as the action for my reddit button in the ActionList).

    Component
    {
        id: subRedditSheet

        ComposerSheet {
            id: sheet;
            title: "Choose SubReddit"
            TextField
            {
                id: subRedditText
            }

            onCancelClicked: PopupUtils.close(sheet)
            onConfirmClicked:
            {
                changeSubReddit(subRedditText.text)
                PopupUtils.close(sheet)
            }
        }
    }


As you can see, the ComposerSheet doesn't have size logic yet (or as likely I did something wrong), but none the less, it works!

I got a surprising amount of free functionality from using Page, ToolbarActions, and ComposerSheet. On top of being easy and fun, it means that my app will inherit the look and feel, interaction patterns, translations and Ubuntu Touch style guidelines!



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