Comments on: Playing with graphics in Android – Part IV

By: Pj

Pj — Mon, 09 Jan 2012 10:59:46 +0000

Hi, Thanks for this tutorial. It has been quite helpful. I am developing an application which requires me to apply pinch-zoom and zoom-pan features to my custom view having several bitmap images. In your code you are adding more images when a user ouches the screen. But in my application, I am using another class which extends Activity and in this class, I decide how many more images should be added to the view and at what co-ordinates. But I don’t know how to pass this information from my main activity to the Custom view class. Can you help?

One more question, if I want to take some action when a user clicks or touches an image(something like OnClickListener), how can I do that?

By: Martin

Martin — Thu, 05 Jan 2012 10:16:17 +0000

Yes, the thread runs even when nothing new happens. Not the best solution, but at the point of writing this tutorial, I wasn’t aware of a solution for a “draw on demand”.

By: Dan D

Dan D — Thu, 05 Jan 2012 08:00:45 +0000

Quick question… After you have added a new graphic object to the list, what causes the thread to run thru the list and add the newly created graphic? Is the thread just continually running and redrawing over the old graphics even if I havent added a new one by clicking on the screen?

By: Yerac

Yerac — Mon, 26 Sep 2011 14:23:23 +0000

Thanks for fast replay. I have manage to draw on my ImageView making a bitmap from that image, than Canvas and draw on that canvas but problem is that i then get just my image and a drawing on screen. I want my currently layout to be permanent and to draw on images. My layout consist of 2 ImageView, some bar and few other stuffs.

By: Martin

Martin — Mon, 26 Sep 2011 08:38:09 +0000

You can only draw on the ImageView in two ways:

1. Draw on the bitmap you load in the ImageView
2. Modify the draw() method of the ImageView. That also means that you need to extend the ImageView class.

Afaik these questions are already answered on stackoverflow.com. You should search there for some solutions.

By: Yerac

Yerac — Sun, 25 Sep 2011 23:56:54 +0000

Hi! nice tut. But i have a Q, how can i draw over an ImageView? I have an image and when i click on it i get xy coordinates and i want to draw something at that coordinates, say circle or rectangle. I tried a code from stackoverflow but nothing helps. Thanks!

By: augusta kapp

augusta kapp — Sun, 07 Aug 2011 15:52:40 +0000

hi! this is so nice.. I have a question regarding the //thread.getSurfaceHolder()// -thing
is it possible to replace this with just getHolder()? I mean the surfaceHolder seams to be more connected to the Panel class then the thread class? why is it necessary to first send the surfaceholder to the thread class and then get it back again???
Will there later on be more surfaceHolder connected to different threads??
Thank you again…for this clear tutorial Now I have to move on to Part 5

By: augusta kapp

augusta kapp — Sun, 07 Aug 2011 15:51:49 +0000

By: Lars

Lars — Wed, 13 Jul 2011 15:25:05 +0000

Very nice tutorial.

Answer for Lee Ponzo:
Navigate to your SDK platform-tools/ directory and execute:
adb logcat
to look at logcat.

By: Martin

Martin — Mon, 04 Jul 2011 13:25:09 +0000

This should be pretty easy. One solution ist to load the panel as a custom view inside an xml layout with the right size or you change the border proving and the touch event handling.