Speaking about common features of Android Data Binding support library (http://developer.android.com/tools/data-binding/guide.html).

1. Android Data Binding

2. public class AndroidVersion {
private final String mName;
private final String mNumber;
public AndroidVersion(String name, String number) {
mName = name;
mNumber = number;
}
public String getNumber() { return mNumber; }
public String getName() { return mName; }
}

3. <LinearLayout
style="@style/AndroidVersion.Root"
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<TextView
android:id="@+id/name"
style="@style/AndroidVersion.Name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
<TextView
android:id="@+id/number"
style="@style/AndroidVersion.Number"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>

4. public class VersionViewHolder extends RecyclerView.ViewHolder {
public final TextView name;
public final TextView number;
public VersionViewHolder(View itemView) {
super(itemView);
name = (TextView) itemView.findViewById(R.id.name);
number = (TextView) itemView.findViewById(R.id.number);
}
public void setVersion(AndroidVersion version) {
name.setText(version.getName());
number.setText(version.getNumber());
}
}

5. <layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="version" type=“com.exposit.databindingsample.AndroidVersion" />
</data>
<LinearLayout
style="@style/AndroidVersion.Root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<TextView
android:id="@+id/name"
style="@style/AndroidVersion.Name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{version.name}"
/>
<TextView
android:id="@+id/number"
style="@style/AndroidVersion.Number"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{version.number}"
/>
</LinearLayout>
</layout>

6. <layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="version" type=“com.exposit.databindingsample.AndroidVersion" />
</data>
<LinearLayout
style="@style/AndroidVersion.Root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<TextView
android:id="@+id/name"
style="@style/AndroidVersion.Name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{version.name}"
/>
<TextView
android:id="@+id/number"
style="@style/AndroidVersion.Number"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{version.number}"
/>
</LinearLayout>
</layout>

7. <layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="version" type=“com.exposit.databindingsample.AndroidVersion" />
</data>
<LinearLayout
style="@style/AndroidVersion.Root"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>
<TextView
android:id="@+id/name"
style="@style/AndroidVersion.Name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{version.name}"
/>
<TextView
android:id="@+id/number"
style="@style/AndroidVersion.Number"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{version.number}"
/>
</LinearLayout>
</layout>

8. public class VersionBindingViewHolder extends RecyclerView.ViewHolder {
private final ItemVersionBinding mBinding;
public VersionBindingViewHolder(View itemView) {
super(itemView);
mBinding = ItemVersionBinding.bind(itemView);
}
public void setVersion(AndroidVersion version) {
mBinding.setVersion(version);
}
}

9. <data>

10. <layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<import type="com.exposit.databindingsample.MyStringUtils" />
<variable name="version"
type="com.exposit.databindingsample.AndroidVersion" />
</data>
<TextView
android:id="@+id/name"
…
android:text="@{MyStringUtils.toLowerCase(version.name)}"
/>
</layout>
Type import

11.
<data>
<import type="android.graphics.drawable.Drawable" />
<variable name="user" type="com.example.User" />
<variable name="image" type="Drawable" />
<variable name="note" type="String" />
</data>
Variables

12. <data>
<import type="com.exposit.databindingsample.View"
alias="CustomView" />
</data>
Type alias

13. Expression language

14. • Математические операторы
• Конкатенация строк
• Логические операторы
• Бинарные операторы
• Унарные операторы
• Битовые сдвиги
• Операторы сравнения
• instanceof
• Литералы: строковые, числовые, символьные, null
• Приведения типа
• Вызов методов и доступ к полям
• Доступ к элементам массива, List, Sparse List и Map через оператор []
• Тернарный оператор ?:
Поддерживаемые операторы

15. Неподдерживаемые
операторы
• this
• super
• new
• Явное выполнение типизированных методов
( Sample.<String>method() )

16. Null Coalescing Operator
android:text="@{user.displayName ?? user.lastName}"android:text="@{user.displayName ?? user.lastName}"

17. Null Coalescing Operator
android:text="@{user.displayName ?? user.lastName}"
android:text="@{user.displayName != null ? user.displayName : user.lastName}"

18. Null safety
Код, сгенерированный библиотекой Data Binding,
автоматом проверяет на null все объекты и
предотвращает NullPoinerException.
Например, если в выражение @{version.name} version
является null, значение version.name будет являться его
значение по умолчанию - null. Если поле или метод будут
возвращать примитивный тип данных, то будет
использовано значение этого типа по умолчанию.

19. Ресурсы

20. android:padding="@{@dimen/largePadding}"
Dimension resources

21. android:text="@{@string/nameFormat(firstName, lastName)}"
String format resources

22. android:text="@{@plurals/banana(bananaCount)}"
Plurals resources

23. Type Normal Reference Expression Reference
String[] @array @stringArray
int[] @array @intArray
TypedArray @array @typedArray
Animator @animator @animator
StateListAnimator @animator @stateListAnimator
color (int) @color @color
ColorStateList @color @colorStateList

24. Обработка событий

25. public class VersionEventsHandler {
private final VersionBindingViewHolder mViewHolder;
public VersionEventsHandler(
VersionBindingViewHolder viewHolder) {
mViewHolder = viewHolder;
}
public void onVersionClicked(View view) {…}
}

26. public class VersionBindingViewHolder extends RecyclerView.ViewHolder {
private final ItemVersionBinding mBinding;
public VersionBindingViewHolder(View itemView) {
super(itemView);
mBinding = ItemVersionBinding.bind(itemView);
mBinding.setHandler(new VersionEventsHandler() {
public void onVersionClicked(View view) {…}
});
}
public void setVersion(@NonNull AndroidVersion version) {
mBinding.setVersion(version);
}
}

27. <layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="version"
type=“com.exposit.databindingsample.AndroidVersion" />
<variable name=“handler"
type=“com.exposit.databindingsample.VersionEventsHandler" />
</data>
<View
…
android:onClick="@{handler.onVersionClicked}"
/>
</layout>

28. Data objects

29. Observable Object
public class AndroidVersion extends BaseObservable {
private String mName;
private String mNumber;
public AndroidVersion(String name, String number) {
mName = name;
mNumber = number;
}
@Bindable public String getNumber() { return mNumber; }
@Bindable public String getName() { return mName; }
public void setName(String name) {
mName = name;
notifyPropertyChanged(BR.name);
}
public void setNumber(String number) {
mNumber = number;
notifyPropertyChanged(BR.number);
}
}

30. Observable Fields
public class AndroidVersion {
public final ObservableField<String> name;
public final ObservableField<String> number;
public AndroidVersion(String name, String number) {
this.name = new ObservableField<>(name);
this.number = new ObservableField<>(number);
}
}

31. Observable Collections
• ObservableArrayList<T>
• ObservableMap<K, V>
• ObservableArrayMap<K, V>

32. Attribute setters

33. Automatic Setters
<layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:bind="http://schemas.android.com/apk/res-auto"
>
<android.support.v4.widget.DrawerLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
bind:scrimColor="@{@color/scrim}"
bind:drawerListener=“@{activity.drawerListener}”/>
<layout/>

34. Renamed Setters
@BindingMethods({
@BindingMethod(
type = "android.widget.ImageView",
attribute = "android:tint",
method = "setImageTintList"),
})

35. Custom attributes

36. public class TypefaceTextView extends TextView {
public TypefaceTextView(Context context) { super(context);}
public TypefaceTextView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context, attrs, 0);
}
public TypefaceTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context, attrs, defStyleAttr);
}
private void init(Context context, AttributeSet attrs, int defStyleAttr) {
TypedArray attrsArray =
context.obtainStyledAttributes(attrs, R.styleable.TypefaceTextView, defStyleAttr, 0);
String font = attrsArray.getString(R.styleable.TypefaceTextView_font);
attrsArray.recycle();
if (font != null) {
AssetManager assets = context.getAssets();
setTypeface(Typeface.createFromAsset(assets, "fonts/" + font + ".ttf"));
}
}
}

37. <LinearLayout
style="@style/AndroidVersion.Root"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
…
>
<com.exposit.databindingsample.TypefaceTextView
…
app:font="Roboto-Medium"
/>
<com.exposit.databindingsample.TypefaceTextView
…
app:font="Roboto-Italic"
/>
</LinearLayout>

38. @BindingAdapter("bind:font")
public static void setFont(TextView textView, String font) {
AssetManager assets = textView.getContext().getAssets();
String fontPath = "fonts/" + font + ".ttf"
Typeface typeface = Typeface.createFromAsset(assets, fontPath);
textView.setTypeface(typeface);
}

39. <layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:bind="http://schemas.android.com/apk/res-auto"
>
<LinearLayout>
<TextView
…
bind:font="@{"Roboto-Medium"}"
/>
<TextView
…
bind:font="@{`Roboto-Italic`}"
/>
</LinearLayout>
</layout>

40. @BindingAdapter({"bind:imageUrl", "bind:errorDrawable"})
public static void loadImage(
ImageView imageView, String imageUrl, Drawable error) {
Picasso.with(imageView.getContext())
.load(imageUrl)
.error(error)
.into(imageView);
}

41. <layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:bind="http://schemas.android.com/apk/res-auto"
>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
bind:imageUrl=“@{`http://exposit-ds.com/logo.png`}”
bind:errorDrawable="@{@drawable/error}"
/>
</layout>

42. <layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:bind="http://schemas.android.com/apk/res-auto"
>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
bind:errorDrawable="@{@color/error}"
bind:imageUrl=“@{`sample_image_url`}”
/>
</layout>

43. @BindingConversion
public static ColorDrawable colorToDrawable(int color) {
return new ColorDrawable(color);
}
Binding conversion