I am learning the application programming on Android OS. I found that is easier to catch up because I am a WPF Programmer. Both of them are using xml to draw UI. That is not a strange thing for myself.
I like to use regular expression validation. That is simple.
You only need to use:
For the numeric value validation:
I faced a number of error for parsing a string into int. In most of cases, there is a validation missing.
You can use regex inside IsNumber or use foreach loop to check whether each character is numberic.
BUT NEVER NEVER DO LIKE THIS:
Try-catch is an expensive operation!!!!!!!!
Secondly, I like to use TryParse even in the case, the progam can tolrate invalid value. TryParse can allow the logic to continue execution. I hate some things like stack track on the screen.