android-databinding.md

title: Android Databinding basics tags: android,android-databinding

Although a large topic, databinding is simple to set up. From Android Studio 2.0, in your app's AndroidManifest.xml:

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

Then change your layout file, main_activity.xml for the most basic version, to something like:

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">
  <data>
    <variable
        name="thingvar"
        type="com.example.blar.myapplication.Thing"
        />
  </data>
  ...
</layout>

The data section defines variables, and specify a type. In our case, the Thing class is POJO:

public class Thing {
  private String thing;

  public Thing(String thing) {
    this.thing = thing;
  }

  public String getThing() {
    return thing;
  }

  public void setThing(String thing) {
    this.thing = thing;
  }
}

To bind a property, in an element, TextView for example, set the attribute android:text=@{thingvar.thing}.

Now in your Activity, instead of setContentView(), use the follow binding methods:

Thing test = new Thing("Test");
final MainActivityBinding binding = DataBindingUtil.setContentView(this, R.layout.main_activity);
binding.setThing(test);

The MainActivityBinding class is autogenerating based on your layout file name, main_activity in this case.

Not only does setting the Thing class on the binding update the TextView we mentioned, but you can also avoid findViewById() call. They're now available via binding.theIDofYourElement.