I use AnySoftKeyboard as my keyboard of choice on Android. It’s great, except when my SD Card becomes corrupted. When that happens, AnySoftKeyboard no longer works. If my device is locked at the time, there doesn’t appear to be a way to type in my password to unlock the device.
There is a solution to this problem, if you have enabled Developer options and USB debugging on the device. Boot into recovery (Volume Up, Home & Power, all at the same time). Start adb on the device. Connect it to your computer with adb and reboot. Then from a command prompt on the computer, type in the following:
$ adb shell input text password && adb shell input keyevent 66
This will basically work just like the displayed keyboard on your device. keyevent 66 is the equivalent of Enter. Then, you can reformat your SDCard in Settings. Then, reboot the device and you will be good to go.