Appliweb

Following the first post about « using Netbeans for an IDEA user », I would like to add some more informations about maven support.

Skipping unit tests:

Each time I compile my maven project in Netbeans, it runs the unit tests, even for small changes. Fortunately, you can easily tell Netbeans to avoid unit test during compilation. Simply right-click on the project, then select Properties. You can check the « Skip tests » control like in the dialog above:

Importing a maven Web project:

I have successfully opened a Maven project that generates a .war file into Netbeans. It is recognized as a web project, you simply by sets the target application server, and then you can run and debug your web application.

It generates the .war file using Maven, and deploys it automatically to the application server.

The neat feature with Web projects:

It’s easy to use, and great for day-to-day web development: It’s tedious to wait for Maven to generate the war and deploys it each time you modify a .jsp or a .xhtml page. So Netbeans automatically deploy the webapp resources files when you save them. Great ! And IDEA does it too.

In this third installment of the Android Game Development series, I’ll try to explain how to construct the project. I know the LunaLander sample directly uses thread and SurfaceHolder.Callback, but my first goal is simply to display an image, I will complexify later.

Games don’t use Views

In Android, most of the games don’t really use the View hierarchy of objects, because it’s too slow and cumbersome. They instead write directly to a Canvas.

In order to get the Canvas displayed to the screen, you create a SurfaceView object.

Thus, the page is a  FrameLayout, and inside we put our SurfaceView class, as shown in the main resource file:

How to insert an Image into Android project ?

Using Gimp, I have drawn a small red ball:  Nice isn’t it ?

How can I use it in my project. Well it’s quite simple, you copy the file in your project res/drawable subdirectory, you update your Eclipse Project (F5 key). Automagically, you see your new image in the project, and the Eclipse Plugin regenerates the R class so that you can easily access the resource in your code or Layout file. Just take a look at this sample (called by the constructor of our SurfaceView):

We can now easily override the onDraw method on our SurfaceView derived class, and display the image:

Notice we set the position and dimension to display in the image itself, and tells it to display into the canvas. I would have expected the other way round (calling a Canvas method to draw the image).

I run the  project and here is the result :

Well something got wrong, but what ? Maybe I should check in Android documentation how to see some sort of logs or whatever, but for now, each time I get this, I’m clueless about what went wrong.
This time it was easy, I put the wrong class name in the layout.xml file, and it couldn’t find my SurfaceView class. Too bad Eclipse didn’t warn me about this. I fixed the error, started again, and then:

A Black screen. No Error but no red ball neither….

Running it under debugger shows me that the onDraw method on my SurfaceView class is not called !

After some more experiments, (checked the LunarLander sample, tried to draw a big green square on Canvas, etc….) I finally managed to make it work.
To have the SurfaceView displayed, you have to set a background color. With my init method like that:

I get the « good » result as follow: Yeepeee !!!

GC.