How do I create a Java GUI (Graphics User Interface)?
Instead of using the console to output Java code, you might prefer visualizing your creation by using a JFrame. A JFrame opens a new window on your computer in which you can customize it by changing the title, layout, and adding components such as buttons, text boxes, and labels.
How can I run a DC motor through an Arduino?
After following the wiring diagram of connecting a DC motor to an H-bridge, which enable voltage to be applied across a load, you will need to define the enable pin, and 2 control pins in your Arduino sketch. To move the motor forwards you need to set the enable pin to high, the 1st input pin to high, and the 2nd input pin to low. For reverse, the enable pin is high, the 1st input pin is low, and the 2nd is high.
What layout do you recommend I should use for my Android application?
The layout you use for your Android app would depend on what you want your app to do. One example of a layout is the TableLayout which groups the view into columns and rows. A RelativeLayout groups the objects based on the positioning of other objects. If you need an app that stores a database of information I would recommend the TableLayout, but if you want the app to be more dynamic I would go with the RelativeLayout.