Do apps built for old android versions run on android 3.1

For testing purposes I need to buy an android devi开发者_高级运维ce. Can I get a tablet device with android 3.1 honeycomb and use this to test apps developed on older android versions? Are new android versions backward compatible with older apps?

Not entirely. In many cases yes, but there are exceptions:

There have been some api changes, and more importantly, there are a lot of apps out there which did things that weren't entirely proper, but worked on the devices they were developed for.

Some older apps were written to use input devices not present on recent phones or tablets - hardware trackballs or dpads, buttons, etc.

Also no small number of older apps will display in a phone-sized area leaving the rest of the tablet screen blank.

Unfortunately, the flip side of the vendor customizability of android is that if you really want to do comprehensive testing you need access to a variety of devices, even for a single api version.

Can I get a tablet device with android 3.1 honeycomb and use this to test apps developed on older android versions?

Yes.

Are new android verions backward compatible with older apps?

Yes.

Back version is compatible with android 3.1 but only simple application means without any animation (Like Games) and some special features etc.