This document discusses data binding in Android, which provides a simple and robust way to bind data to UI views without needing to write Java code to insert or read data from views. It facilitates unit testing of UI. The key steps outlined are: 1. Enabling data binding in build.gradle 2. Updating layout files to use data binding 3. Binding data objects to views using DataBindingUtil 4. Mapping objects and properties between Java and XML using @Bindable This allows updating UI automatically when data changes, without findViewById calls. Two-way binding is supported by implementing BaseObservable in view models.

1. Começando no Data Bind
Rogério C. Santos

2. Sobre
Tech Lead - Sambatech - Kast (iOS, Android, back-end, front-end)
Bacharel S.I Puc - MG
Especialização Testes - UFPE Cin/Motorola
Mestrado Puc - MG
PalmOS, JavaME, C/C++, JavaEE, Linux/Unix ..
Puc, Una, Cefet MG, Uni, Izabela Hendrix …
GetSet, Netbee, .MOBI, Avenue Code, Lalubema, Stefanini …
Hobby desenvolvimento de jogos

3. Data Bind
O databind é uma maneira simples e robusta de ligar seus dados a UI sem precisar
utilizar aquela salada de código java para inserir ou ler dados das views.
Facilita testes de unitários em UI

4. public class Login {
private String email;
private String password;
}
...
EditText edtEmail = (EditText) findViewById(R.id.email);
EditText edtPassword = (EditText) findViewById(R.id.password);
...
login.setEmail(edtEmail.getText());
login.setPassword(edtPassword.getText());

5. Binding
ActivityLoginBinding binding = DataBindingUtil.setContentView(this,R.layout.activity_login);
Login login = new Login("rogerio.celestino@gmail.com","1234");
binding.setLoginview(login);

6. Setup
//<app-module>/build.gradle
apply plugin: "com.android.application"
android {
dataBinding {
enabled = true
}
}
}

7. Mudanças no layout
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<LinearLayout ...>
<AutoCompleteTextView
android:id="@+id/email" ../>
<EditText
android:id="@+id/password" .../>
</LinearLayout>
</layout>
res/layout/activity_login.xml
ActivityLoginBinding
activity_login.xml

8. ActivityLoginBinding binding = DataBindingUtil.setContentView(this,R.layout.activity_login);
binding.email.setText("rogerio.celestino@gmail.com");
Id da view
Good by FindViewByID :D
CamelCase/Nome
do layout

9. res/layout/activity_login.xml
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data class="LoginBinding">
...
</data>
LoginActivity.java
public class LoginActivity extends AppCompatActivity {
protected void onCreate(Bundle savedInstanceState) {
...
LoginBinding binding = DataBindingUtil.setContentView(this,R.layout.activity_login);
…
}
…
}

10. Binding utils
DataBindingUtil.setContentView(activity, layoutId);
DataBindingUtil.inflate(inflater, layoutId, parent, attachToParrent);
ListItemBinding binding = ListItemBinding.bind(viewRoot);
Qualquer view
Activities
View já
prontas/inflated

11. Mapeando Objetos
public class Login {
private String email;
private String password;
}
...
EditText edtEmail = (EditText) findViewById(R.id.email);
EditText edtPassword = (EditText) findViewById(R.id.password);
...
login.setEmail(edtEmail.getText());
login.setPassword(edtPassword.getText());

12. Mapeando Objetos
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data class="LoginBinding">
<variable name="loginview"
type="com.rogerio.databindsample.model.Login"/>
</data>
<LinearLayout
<AutoCompleteTextView android:text="@{loginview.email}"../.>
<EditText android:text="@{loginview.password}" .../>
</LinearLayout>
</layout>

13. Mapeando Objetos
ActivityLoginBinding binding = DataBindingUtil.setContentView(this,R.layout.activity_login);
Login login = new Login("rogerio.celestino@mgail.com","1234");
binding.setLoginview(login);

14. Mão Dupla
public class ViewLogin extends BaseObservable {
Login login;
public ViewLogin(Login login) {
this.login = login;
}
@Bindable
public String getEmail() {
return login.getEmail();
}
public void setEmail(String email) {
login.setEmail(email);
notifyPropertyChanged(BR.email);
}
public void setPassword(String password) {
login.setPassword(password);
notifyPropertyChanged(BR.password);
}
@Bindable
public String getPassword(){
return login.getPassword();
}
}

15. Mapeando Objetos
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data class="LoginBinding">
<variable name="loginview"
type="com.rogerio.databindsample.model.view.ViewLogin"/>
</data>
<LinearLayout
<AutoCompleteTextView android:text="@={loginview.email}"../.>
<EditText android:text="@{loginview.password}" .../>
</LinearLayout>
</layout>

16. Referências
Dominando o Data Binding no Android
http://www.slideshare.net/nglauber/dominando-o-data-binding-no-android
Deep dive into Android Data Binding
http://www.slideshare.net/radekpiekarz/deep-dive-into-android-data-binding

17. Obrigado!
www.rogeriocs.com.br