Android Programming: The Big Nerd Ranch Guide, Third Edition

Binding to Data

With data binding, you can declare data objects within your layout file:

<layout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools">
    <data>
        <variable
            name="crime"
            type="com.bignerdranch.android.criminalintent.Crime"/>
    </data>
    ...
</layout>

And then use values from those objects directly in your layout file by using the binding mustache operator – @{}:

<CheckBox
    android:id="@+id/list_item_crime_solved_check_box"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:checked="@{crime.isSolved()}"
    android:padding="4dp"/>

In an object diagram, that would look like Figure 20.7:

Figure 20.7  The ...