#sachtech

Radio buttons allow the user to select one option from a set. You should use radio buttons for optional sets that are mutually exclusive if you think that the user needs to see all available options side-by-side. If it's not necessary to show all options side-by-side, use a spinner instead.

A RatingBar is an extension of SeekBar and ProgressBar that shows a rating in stars. The user can touch/drag or use arrow keys to set the rating when using the default size RatingBar. The smaller RatingBar style ( ratingBarStyleSmall) and the larger indicator-only style (ratingBarStyleIndicator) do not support user interaction and should only be used as indicators. When using a RatingBar that supports user interaction, placing widgets to the left or right of the RatingBar is discouraged. The number of stars set (via setNumStars(int) or in an XML layout) will be shown when the layout width is set to wrap content (if another layout width is set, the results may be unpredictable).

Every Button is styled using the system's default button background, which is often different from one device to another and from one version of the platform to another. If you're not satisfied with the default button style and want to customize it to match the design of your application, then you can replace the button's background image with a state list drawable. A state list drawable is a drawable resource defined in XML that changes its image based on the current state of the button. Once you've defined a state list drawable in XML, you can apply it to your Button with the android:background attribute.