Android imagebutton how to change icon size

Question

I have been working on interfaces lately and I have many problems with imagebutton sizes. I'm very bad at designing stuff and I'm having major problems with the Android Icons. Thus, I have some questions regarding those.

First of all this is my current layout:

As you can see, I have two icons that have different sizes and that's not good. I can't seem to force them to take the same size.

My questions are:

1 - How do I force them to take the same size?

2 - What are the recommended size differences for hdpi, ldpi,mdpi and xhdpi?

3 - Why, if I set the imageButton background color to the same color as the layout background, the Icon is moved as if there was no button in the background?

Example:

Thanks in advance!!

Answer 1

For these ImageButtons set the images using (instead of src):

android:background="@drawable/image_name"

Next thing is set:

android:layout_height="10dp" //or any size required
android:layout_width="10dp" //or any size required ... let these 2 sizes be same for both the ImageButtons

"dp" or "dip" is device independent pixels. The android system will take care of the resizing for different screen resolutions

Also, a better thing to do would be to set-up hover images for your button separately.

Answer 2

Instead of replacing android:src with android:background you can use android:scaleType attribute and set it to "fitXY".

see: Android - Image Button Scale