Expert Android

Chapter    6

Advanced Form Processing

Form processing is a common need in writing computer applications, including mobile apps. In Android, you can address this need by designing activities, dialogs, or fragments that behave like forms that have a number of data entry fields.

Out of the box, the Android SDK has the basic mechanisms to control the behavior of each field based on its type. Android SDK also allows you to set error icons and messages on each field programmatically when you detect if that field is in error. These basic mechanisms serve well when you have one or two fields on the form. Based on our experience, though, this field-by-field validation gets to be repetitive and unwieldy for even as fews as three or four fields.

So we ...