Why does Kit Kat require the use of the isValidFragment?

Question

Ever since KitKat was released, I\'ve noticed a whole bunch of my apps updating with \"Fixing a crash in Kit Kat\". Recently when I released my own app, I figured out the likely

Answer 1

You got this documented:

Subclasses should override this method and verify that the given fragment is a valid type to be attached to this activity. The default implementation returns true for apps built for android:targetSdkVersion older than KITKAT. For later versions, it will throw an exception.

so as long as your targetSdk is below 19, you do not need to care. If it is 19 then your app will crash due to the exception, unless you implement isValidFragment()..