Apps sometimes can misbehave. Before you go reaching for that task killer (and we can't stress this enough — don't do it!) here's something else to try.
Every Android smartphone has an application manager that you can get to through the settings menu. It's usually in the top level somewhere, though it can vary a little by phone. (Samsung, for instance, has started splitting its app settings into different sections, showing feature settings for its own apps at the top level and requiring you to tap through to get to the actual application manager.) But once you get to it, you're at the heart of the matter. This is where you can see every application that's installed on your phone. And it's a handy place to clean things up a bit should they go wonky. Here's what's up:
Clearing the app cache
As you use applications, they start storing files for reference later. These files are stored in an app "cache." For instance: When you're using the Android Central app, it'll save images and other pieces of the stories you've read so that they don't have to be downloaded each and every single time the app needs them. This saves you time and data.
But maybe you want to clear an app's cached data, either to regain some used space, or to try to fix a misbehaving app. This is where you can do it. Just tap into the app, and then tap the "Clear cache" button.
Clear app data — or resetting an app
Clearing app data is a little more drastic. You're wiping the cache, but also clearing any and all settings that go along with that app. You're basically starting that app over, from scratch, and it'll behave as it did the first time you installed it. This is generally a last resort type of thing. If you clear app data on, say, the Facebook app, you'll need to log back in. If you clear data on a game you've been playing, you'll be back at the beginning, as if you'd never played it. (And let's hope that game is properly saving your place to the cloud.)
When to clear cache or data ...
So when should you clear an app's cache manually? Chances are you'll never need to. But should an app start to "feel" sluggish or otherwise start misbehaving, this is where I'd start. Clear the cache.
And should an app really go haywire — or if you just want to start it from scratch — you can go all out and clear its data and start over from the beginning. Just tap the "clear data" button. You'll get a warning asking if that's really what you want to do. Confirm that, and you've reset the app to scratch.