Boil Boilerplate Code with Data Binding

Data Binding is a great utility in Android. It helps us extract all the UI related code and keep our classes clean. All the code pertaining to UI resides inside the “declarative” layouts and hence the glue code logic is minimized.

Here is a common use case where we want to create a login form in which the Login Button gets enabled only when the email and password fields are set. Following is a visual representation for the same:

Login with Email and Password

The usual and more insipid solution will be to use TextWatcher to watch the text as and when it changes and design some logic accordingly. With 2-way Data Binding, it’s only a play of a few lines. ThenotifyPropertyChanged helps us get the callbacks from different elements. Show me the code! Ok 👇🏻

1. Enable Data Binding

In your app-level build.gradle, enable Data Binding

android {
    ....
    dataBinding {
        enabled = true
    }
}

2. Create a View Model

3. Create a Handler

Create a Handler interface for the onClick callback which we can implement in our Activity/Fragment.

4. Bind in XML Layout

5. Instantiate in View

Lets connect all the dots. In your View (Activity/Fragment), instantiate binding and set theViewModel and Handler.

Unlike RxBindings, this approach is pretty straight forward and simple. You can also use ObservableField<T> alternatively if you don’t want to extend BaseObservable. If this post made you happy , you can sing the Pharrell Williams song and clap along 👏🏻😊

Github Sample

chetdeva/login-bindings

Also Try

Scroll ⇈ Pull ⇊ Bind Paginate RecyclerView

Swipe ⇆ Drag ⇅ Bind RecyclerView

Reference

• Data Binding Library