The document provides a comprehensive guide on speeding up Android application development using data binding with examples for both Java and Kotlin. It includes setup instructions, binding model implementations, and typical use cases like user login, profile management, and displaying lists with RecyclerView and ViewPager components. Additionally, it outlines various binding expressions, methods, and observable data models with relevant code snippets to facilitate better understanding of data binding in Android development.

1. Speed Up Application Development
with Data Binding
Anokhin Mikle / Android Developer / MWDN Ltd.

2. First Part: Introduction

3. How to start (Java)
android {
buildToolsVersion "24.0.1"
dataBinding {
enabled = true
}
}
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:2.1.2'
}
}
3

4. How to start (Kotlin)
apply plugin: 'kotlin-android'
android {
buildToolsVersion "24.0.1"
dataBinding {
enabled = true
}
}
dependencies {
kapt 'com.android.databinding:compiler:2.1.2'
}
kapt {
generateStubs = true
}
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:2.1.2'
classpath 'org.jetbrains.kotlin:kotlin-gradle-plugin:1.0.3'
}
}
4

5. Binding (Model)
<layout
xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable
name="user"
type="com.anokmik.databinding.model.User" />
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{user.firstName}"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@{user.lastName}"/>
</LinearLayout>
</layout>
public class BindingModelFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(
R.layout.fragment_binding_model, container, false);
FragmentBindingModelBinding binding
= FragmentBindingModelBinding.bind(view);
binding.setUser(User.getDefault());
return view;
}
}
5

6. Data Binding doesn’t handle view state
so you should specify id for such views as usual

7. Binding (Ids)
public class BindingIdsFragment extends Fragment {
private TextView firstName;
private TextView lastName;
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(
R.layout.fragment_binding_ids, container, false);
FragmentBindingIdsBinding binding
= FragmentBindingIdsBinding.bind(view);
firstName = binding.firstName;
lastName = binding.lastName;
return view;
}
@Override
public void onViewCreated(View view,
Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
User user = User.getDefault();
firstName.setText(user.firstName);
lastName.setText(user.lastName);
}
}
<layout
xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/first_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<TextView
android:id="@+id/last_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
</layout>
7

8. Generated Binding
8
public class FragmentBindingModelBinding
extends android.databinding.ViewDataBinding {
@Override
protected void executeBindings() {
long dirtyFlags = 0;
synchronized(this) {
dirtyFlags = mDirtyFlags;
mDirtyFlags = 0;
}
java.lang.String firstNameUser = null;
java.lang.String lastNameUser = null;
com.anokmik.databinding.model.User user = mUser;
if ((dirtyFlags & 0x3L) != 0) {
user = user;
if (user != null) {
firstNameUser = user.firstName;
lastNameUser = user.lastName;
}
}
if ((dirtyFlags & 0x3L) != 0) {
this.mboundView1.setText(firstNameUser);
this.mboundView2.setText(lastNameUser);
}
}
}

9. Bindings are generated at compile-time

10. Variables and Imports
<data>
<import type="android.graphics.drawable.Drawable" />
<import type="com.anokmik.databinding.model.User" />
<import type="android.util.SparseArray"/>
<import type="java.util.Map"/>
<import type="java.util.List"/>
<variable name="user" type="User" />
<variable name="image" type="Drawable" />
<variable name="text" type="String" />
<variable name="array" type="String[]" />
<variable name="list" type="List&lt;String>"/>
<variable name="sparse" type="SparseArray&lt;String>"/>
<variable name="map" type="Map&lt;String, String>"/>
<variable name="index" type="int"/>
<variable name="key" type="String"/>
</data>
<data>
<import type="android.app.Fragment"/>
<import type="android.support.v4.app.Fragment" alias="SupportFragment"/>
</data>
10

11. Simple Data Model
public class User {
private final String firstName;
private final String lastName;
public User(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
public String getFirstName() {
return firstName;
}
public String getLastName() {
return lastName;
}
}
public class User {
public final String firstName;
public final String lastName;
public User(String firstName, String lastName) {
this.firstName = firstName;
this.lastName = lastName;
}
}
11

12. Observable Data Model
public class NotifyGreeting extends BaseObservable {
private String name;
@Bindable
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
notifyPropertyChanged(BR.name);
}
}
public class ObservableGreeting {
public ObservableString name
= new ObservableString();
}
12

13. Include and Merge
<layout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:bind="http://schemas.android.com/apk/res-auto">
<data>
<variable name="user" type="com.example.User" />
</data>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<include
layout="@layout/name"
bind:user="@{user}" />
</LinearLayout>
</layout>
<layout
xmlns:bind="http://schemas.android.com/apk/res-auto">
<data>
<variable name="user" type="com.example.User"/>
</data>
<merge>
<include layout="@layout/name"
bind:user="@{user}"/>
</merge>
</layout>
13

14. Expressions
● mathematical +, -, /, *, %
● string concatenation +
● logical &&, ||
● binary &, |, ^
● unary +, -, !, ~
● shift >>, >>>, <<
● comparison ==, >, <, >=, <=
● instanceof
● grouping ()
● literals - character, String, numeric, null
● cast
● method calls
● field access
● array access []
● ternary operator ?:
android:enabled="@{communicator.isLoginValid &amp; communicator.isPasswordValid}"
14

15. Binding Providers
15
@BindingMethods({
@BindingMethod(type = TextView.class, attribute = "android:autoLink", method = "setAutoLinkMask"),
@BindingMethod(type = TextView.class, attribute = "android:inputType", method = "setRawInputType"),
@BindingMethod(type = TextView.class, attribute = "android:textAllCaps", method = "setAllCaps")
})
public class TextViewBindingAdapter {
@BindingAdapter("android:text")
public static void setText(TextView view, CharSequence text) {
...
}
}
public class Converters {
@BindingConversion
public static String convertObservableToString(ObservableString observableString) {
return observableString.get();
}
}

16. Data Binding Component
16
public class MainDataBindingComponent {
@BindingAdapter(value = {"defaultColor", "pressedColor"})
public void setButtonStateListBackground(Button button, int defaultColor, int pressedColor) {
button.setBackground(getButtonStateListDrawable(defaultColor, pressedColor));
}
}
public class DataBindingComponentProvider implements DataBindingComponent {
@Override
public MainDataBindingComponent getMainDataBindingComponent() {
return new MainDataBindingComponent();
}
}
DataBindingUtil.setDefaultComponent(new DataBindingComponentProvider());
DataBindingUtil.setContentView(this, R.layout.activity_main, new DataBindingComponentProvider());
DataBindingUtil.inflate(inflater, R.layout.fragment_main, container, false, new DataBindingComponentProvider());

17. Two-way Binding
17
android:text="@={communicator.editTextValue}"
AdapterView android:selectedItemPosition
CalendarView android:date
CompoundButton android:checked
DatePicker android:year / android:month / android:day
NumberPicker android:value
RadioGroup android:checkedButton
RatingBar android:rating
SeekBar android:progress
TabHost android:currentTab
TextView android:text
TimePicker android:hour / android:minute
app:color="@={communicator.color}"

18. Two-way binding requires getters and setters for fields

19. Second Part: Typical Use Cases

20. User Flow
20
Login Profile

21. User Layout Custom Items
21
Toolbar
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
android:theme="@style/ToolbarTheme"
app:onNavigationClick="@{navigationClickListener}"
app:popupTheme="@style/PopupTheme" />

22. Support Toolbar Component
22
@BindingMethods({
@BindingMethod(type = Toolbar.class, attribute = "onMenuItemClick", method = "setOnMenuItemClickListener"),
@BindingMethod(type = Toolbar.class, attribute = "onNavigationClick", method = "setNavigationOnClickListener")
})
public final class SupportToolbarComponent {
}
@BindingMethods(
BindingMethod(type = Toolbar::class, attribute = "onMenuItemClick", method = "setOnMenuItemClickListener"),
BindingMethod(type = Toolbar::class, attribute = "onNavigationClick", method = "setNavigationOnClickListener")
)
class SupportToolbarComponent

23. User Layout Custom Items
23
Text Input Layout Button
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="@{() -> presenter.login()}"
android:text="@string/login" />
<android.support.design.widget.TextInputLayout
style="@style/TextInputLayoutStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:editable="@{presenter.isEditing}"
app:error="@{@string/error_name_not_valid}"
app:showError="@{!presenter.firstNameValid}">
<android.support.design.widget.TextInputEditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/hint_first_name"
android:text="@={presenter.observableUser.firstName}" />
</android.support.design.widget.TextInputLayout>

24. Text Input Layout Component
24
public final class TextInputLayoutComponent {
@BindingAdapter({"error", "showError"})
public void setError(
TextInputLayout view, String error, boolean showError
) {
view.setError(showError ? error : null);
}
@BindingAdapter("editable")
public void setEditable(
TextInputLayout view, boolean isEditable
) {
view.setFocusable(isEditable);
EditText editText = view.getEditText();
if (editText != null) {
editText.setCursorVisible(isEditable);
editText.setFocusable(isEditable);
editText.setFocusableInTouchMode(isEditable);
Drawable background = editText.getBackground();
if (background != null) {
background.setAlpha(isEditable ? 255 : 0);
}
if (isEditable) {
Editable editableText = editText.getText();
int selectionStart = editText.getSelectionStart();
int selectionEnd = editText.getSelectionEnd();
if (!TextUtils.isEmpty(editableText)
&& (selectionStart == 0)
&& (selectionEnd == 0)) {
editText.setSelection(editableText.length());
}
}
}
}
}
class TextInputLayoutComponent {
@BindingAdapter("error", "showError")
fun setError(
view: TextInputLayout, error: String, showError: Boolean
) {
view.error = if (showError) error else null
}
@BindingAdapter("editable")
fun setEditable(
view: TextInputLayout, isEditable: Boolean
) {
view.isFocusable = isEditable
view.editText?.apply {
isCursorVisible = isEditable
isFocusable = isEditable
isFocusableInTouchMode = isEditable
background?.apply {
alpha = if (isEditable) 255 else 0
}
if (isEditable) {
val editableText = text
if (!TextUtils.isEmpty(editableText)
&& (selectionStart == 0)
&& (selectionEnd == 0)) {
setSelection(editableText.length)
}
}
}
}
}

25. Trips Flow
25
Trips List
Trip Event
Trip Details

26. Trips Layout Custom Items
26
Recycler View
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:padding="@dimen/fragment_padding"
app:decoration="@{decoration}"
app:items="@{presenter.trips}"
app:layoutManager="@{layoutManager}"
app:viewHolderPresenter="@{presenter.viewHolderPresenter}" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@{trip.title}"
android:textColor="@color/material_dark_primary_text_color"
android:textSize="@dimen/title_text_size"
android:textStyle="bold" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@{DateUtils.format(trip.startDate, trip.finishDate)}"
android:textColor="@color/material_dark_secondary_text_color"
android:textSize="@dimen/caption_text_size"
android:textStyle="bold" />
TextView (Title) TextView (Dates)

27. Recycler View Component
27
public final class RecyclerViewComponent {
@BindingAdapter({"items", "viewHolderPresenter"})
public void setContent(
final RecyclerView view,
List<?> list,
ViewHolderPresenter<?> viewHolderPresenter
) {
BinderRecyclerViewAdapter adapter = new BinderRecyclerViewAdapter(
LayoutInflater.from(view.getContext()),
list,
viewHolderPresenter
);
view.setAdapter(adapter);
if (list instanceof ObservableList) {
view.addOnAttachStateChangeListener(
new ObservableListAttachStateChangeListener(
(ObservableList) list,
new RecyclerViewListChangedCallback(adapter)
)
);
}
}
@BindingAdapter("decoration")
public void setDecoration(RecyclerView view,
RecyclerView.ItemDecoration decoration) {
view.addItemDecoration(decoration);
}
@BindingAdapter("decoration")
public void setDecoration(RecyclerView view,
RecyclerView.ItemDecoration[] decorations) {
for (RecyclerView.ItemDecoration decoration : decorations) {
view.addItemDecoration(decoration);
}
}
}
class RecyclerViewComponent {
@BindingAdapter("items", "viewHolderPresenter")
fun <T> setContent(
view: RecyclerView,
list: List<T>,
viewHolderPresenter: ViewHolderPresenter<T>
) {
val adapter = BinderRecyclerViewAdapter<T, ViewDataBinding>(
LayoutInflater.from(view.context),
list,
viewHolderPresenter
)
view.adapter = adapter
if (list is ObservableList<T>) {
view.addOnAttachStateChangeListener(
ObservableListAttachStateChangeListener(
list,
RecyclerViewListChangedCallback(adapter)
)
)
}
}
@BindingAdapter("decoration")
fun setDecoration(view: RecyclerView,
decoration: RecyclerView.ItemDecoration) {
view.addItemDecoration(decoration)
}
@BindingAdapter("decoration")
fun setDecoration(view: RecyclerView,
decorations: Array<RecyclerView.ItemDecoration>) {
for (decoration in decorations) {
view.addItemDecoration(decoration)
}
}
}

28. Trips Layout Custom Items
28
View Pager
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
app:items="@{presenter.photoAttachments}"
app:viewHolderPresenter="@{presenter.viewHolderPresenter}" />

29. View Pager Component
29
class ViewPagerComponent {
@BindingAdapter("items", "viewHolderPresenter")
fun <T> setContent(view: ViewPager, list: List<T>, viewHolderPresenter: ViewHolderPresenter<T>) {
val adapter = BinderViewPagerAdapter(
LayoutInflater.from(view.context), list, viewHolderPresenter
)
view.adapter = adapter
if (list is ObservableList<T>) {
view.addOnAttachStateChangeListener(
ObservableListAttachStateChangeListener(
list, ViewPagerListChangedCallback(adapter)
)
)
}
}
}
public final class ViewPagerComponent {
@BindingAdapter({"items", "viewHolderPresenter"})
public void setContent(ViewPager view, List<?> list, ViewHolderPresenter<?> viewHolderPresenter) {
BinderViewPagerAdapter adapter = new BinderViewPagerAdapter(
LayoutInflater.from(view.getContext()), list, viewHolderPresenter
);
view.setAdapter(adapter);
if (list instanceof ObservableList) {
view.addOnAttachStateChangeListener(new ObservableListAttachStateChangeListener(
(ObservableList) list, new ViewPagerListChangedCallback(adapter))
);
}
}
}

30. Image View Component
30
class ImageViewComponent {
@BindingAdapter("android:src")
fun loadImage(view: ImageView, imageUrl: String) {
Picasso.with(view.context).load(imageUrl).into(view)
}
}
public final class ImageViewComponent {
@BindingAdapter("android:src")
public void loadImage(ImageView view, String imageUrl) {
Picasso.with(view.getContext()).load(imageUrl).into(view);
}
}

31. Thanks for your attention!
sources:
first part: https://github.com/anokmik/data-binding
second part: https://github.com/anokmik/trip-assistant
mail: anokmik@gmail.com
skype: anokmik

32. References
● Data Binding Guide from Google (https://goo.gl/1yFPtt)
● No More findViewById (https://goo.gl/ugV86t)
● Android Data Binding: Adding Some Variability (https://goo.gl/aDTMmp)
● Android Data Binding: Express Yourself (https://goo.gl/NZ15Tz)
● Android Data Binding: Custom Setters (http://goo.gl/DnKgON)
● Android Data Binding: The Big Event (https://goo.gl/qcpdpU)
● Android Data Binding: That <include> Thing (https://goo.gl/QiqpQT)
● Android Data Binding: Let’s Flip This Thing (https://goo.gl/Gok1gv)
● Descent into Data Binding (https://goo.gl/1PTE7F)
● Two-way Data Binding (https://goo.gl/DQtRrh | https://goo.gl/KjY2Ze)
● Porting to Data Binding (https://goo.gl/7CA7vX)
● Advanced Data Binding (https://www.youtube.com/watch?v=DAmMN7m3wLU)
● Data Binding Techniques (https://www.youtube.com/watch?v=WdUbXWztKNY)
32

33. Q&A