Android Architecture Components meets Data Binding : Lifecycle awareness!

Finally Android Data Binding library got updated to play nice with Android Architecture Components library and became life-cycle aware! This means that any changes to the LiveData objects will be reflected in the layouts... automagically! :)
* Tested on Android Studio 3.1 - canary 6

Whats new?


To make the binding life-cycle aware you need to pass the life-cycle owner to the ViewDataBinding by calling the setLifecycleOwner method.

The ViewModel:

Our view model consists of the LiveData object that is simply and observable data container, where the observer gets notified of data changes.

The model:

Our model has one field that is used to store user's name. A POJO.

The layout:

-Out layout consists of a text field that is bound to the user's name. And will be updated when our LiveData container posts a change.
-We also have an EditText that is two-way bound to the user's name, meaning when text gets entered, the name is updated and vise-versa, when the user LiveDate is updated the EditText is updated.
-And finally a button onClick of which we post a change to our LiveData and all the observers get notified.

The result:



Resources:

  • Full source for the project: here




Comments

Post a Comment

Popular posts from this blog

Android Data Binding : Dynamic RecyclerView Adapter

Image
One of the most common list design patterns that I encounter as Android developer is a list with a variation of the following:

Multiple row types. Expandable/Collapsible rows or sections. Load more/Scroll to load more. Delete rows/Sections. 
And all of these can be implemented in a generic manner with Android Data Binding library. You can write one adapter for all the RecycleViews in your app and use it to render all the common design patterns. Check out the source for the example in this tutorial here.

Final result:

Lets begin by defining our adapter:

public class RecyclerViewBindingAdapter extends RecyclerView.Adapter<RecyclerViewBindingAdapter.BindingViewHolder> { private ObservableList<AdapterDataItem> data; public RecyclerViewBindingAdapter(ObservableList<AdapterDataItem> data) { this.data = data; data.addOnListChangedCallback(new ObservableListCallback()); } @Override public BindingViewHolder onCreateViewHolder(ViewGroup par…
Read more

Android Architecture Components : LiveData

Image
Live Data : Life-cycle aware Observables
As an Android developer you often have to work with data that is dynamic and changing with user input, device configuration changes, or even time changes. On top of this as a developer you have to respect the life-cycle of an Activity of Fragment that contains this dynamically changing data: stop updates onStop() or onPause() and restart the updates onStart() and onResume(). Examples of this is location data, countdown timers, user's list selections and any other type of dynamically changing data. Lets see how we can make these tasks easier using LiveData. We will demonstrate LiveData by creating a self contained timer.

Subclass LiveData LiveData object is set active when the observer's lifecycle is stated or resumed. And the LiveData object is set inactive when the observer's lifecycle is stopped or pause. In our TimerLiveData we start timer when onActive() is called and stop the timer when onInactive() is called. This way the obs…
Read more

Android Data Binding : Tricks and Magic

Image
You can do a lot of awesome things while using the Android Data Binding library. Some will save you a lots of time and some will seem like magic. You can see the full source code for this tutorial here.
Custom XML attributes You can create custom xml attributes and add them to existing UI elements. For example if you ever had to use a custom font files in your application you would always have to set the type face programmatically as the TextView or its sub classes did not have an xml attribute to set the custom type face file from xml. With data binding you can implement your own attributes quick and easy. First lets define our binding adapter. 
public class AttributeBindings { @BindingAdapter({"bind:typeface"}) public static void setTypeFace(TextView view, TypeFaceType tft) { Log.i("AttributeBindings", "setting typeface:"+tft); Typeface typeface = null; switch (tft) { case NORMAL: typeface = …
Read more