Tuesday, July 10, 2012

Android Drawable Constant States

I was playing around this evening with the MonoDroid.ActionBar to add some functionality to be able to change themes at run time. For this I had to be able to add new Drawable to be reused for each Action Bar Item. Apparently when you set multiple views BackgroundDrawable with the same Drawable instance, it shares it state between these views. So in my case my Drawable was defined in XML and was a item selector for a button so that a different Drawable can be shown for each of the states: pressed, focused and so on. Then when pressing the items in the Action Bar, triggered the states for some of the other Action Bar Items, so when pressing one button the the state of another button was triggered.

I browsed around the world wide web and found some solutions using the method Mutate() which essentially should remove the shared Constant State in the Drawable, but as it still was the same exact reference I passed along nothing changed. Hence I was forced to duplicate the Drawable:

view.SetBackgroundDrawable(
    ItemBackgroundDrawable.GetConstantState().NewDrawable()
);

Above code creates a new Drawble each time I add an Item to the Action Bar and eliminates the problems with the visual state of the Item.

Wednesday, July 4, 2012

Mono for Android Color Picker sample

I have seen some people asking how to implement a color picker in their Mono for Android application, and it seemed that there were no sample applications showing how to do this. So I decided to create one with different types of Color Pickers.

The Project, which you can find on Github, at the moment contains two different Color Picker dialogs. A simple one, which can also be found in the Android SDK samples and a more advanced one, where hue and alpha can be picked, which was ported from Sergey Margaritov's android-ColorPickerPreference appication.

Simple round color picker from Android SDK samples.

Sergey's Color Picker without the alpha control.

Sergey's Color Picker with the alpha control

The images seem a bit banded, but on the actual device it shows up nice and smooth. This is because the screenshots were taken from the emulator.

Feel free to fork and watch my github repo with the project. Also leave a comment if you want to see other types of color pickers implemented or have questions.

Tuesday, July 3, 2012

New blog

Dear readers,

I have come to the conclusion that hosting a blog myself is too much hassle. Keeping CMS up to date etc., hence I have started a new blog at blogger.com instead. This way I can concentrate on posting content instead of managing the CMS.

Hope to see you here soon, where I will post some goodies for you to read.

//Tomasz
while(true)
    Console.WriteLine("Live long and prosper");