Android Databinding Library in Kan-moba #5

1. Android'Data'Binding'Library
Takuji'Nishibayashi

2. About&me
• Takuji(Nishibayashi
• @takuji31
• Fenrir(Inc.
• Nintendo(Network(ID(available!!!
• Udemae:(BD(/(Rank:(20

3. About&me
• Android(engineer((2010/02~)
• Loves(Kotlin
• Interest(RoboVM

4. Data$Binding

5. android'binding

6. Not$ac've$!

7. RoboBinding

8. Not$work$with$AppCompat$!

9. RxBinding

10. Not$tested...

11. One$way(only

12. Code%only

13. Xamarin'+'MvvmCross'/'Forms'etc.

14. Cool

15. Cross%pla)orm%!!!

16. but$..

17. Too#expensive#for#private#
development

18. DIY!

19. Next%day

20. Google&I/O&2015

21. Android'Data'Binding'Library

22. !

23. Usage

24. build.gradle
buildscript {
repositories {
jcenter()
}
dependencies {
classpath "com.android.tools.build:gradle:1.3.0-beta1"
classpath "com.android.databinding:dataBinder:1.0-rc1"
}
}

25. build.gradle
apply plugin: 'com.android.application'
apply plugin: 'com.android.databinding'

26. View%model
public class ViewModel extends BaseObservable {
@Bindable
public String getFirstName() {}
@Bindable
public String getLastName() {}
@Bindable
public OffsetDateTime getLastUpdated() {}
public void setFirstName(String firstName) {
this.firstName = firstName;
notifyPropertyChanged(BR.firstName);
}
public void setLastName(String lastName) {
this.lastName = lastName;
notifyPropertyChanged(BR.lastName);
}
public void setLastUpdated(OffsetDateTime lastUpdated) {
this.lastUpdated = lastUpdated;
notifyPropertyChanged(BR.lastUpdated);
}
}

27. Converter
public class Converters {
@BindingConversion
public static String convertOffsetDateTime(OffsetDateTime dateTime) {
return dateTime != null ? dateTime.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME) : "";
}
private Converters() {}
}

28. Layout'XML
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".MainActivity">
<data>
<variable name="viewModel" type="jp.takuji31.databindingexample.ViewModel" />
</data>
<!-- ... -->
<TextView
android:text="@{viewModel.firstName + ' ' + viewModel.lastName}" />
<TextView
android:text="@{viewModel.lastUpdated}" />
<!-- ... -->
</layout>

29. Ac#vity
//onCreate
ActivityMainBinding binding = DataBindingUtil.setContentView(this, R.layout.activity_main);
binding.setViewModel(viewModel);
binding.firstNameEditText.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start, int before, int count) {
viewModel.setFirstName(s.toString());
}
});
binding.lastNameEditText.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start, int before, int count) {
viewModel.setLastName(s.toString());
}
});
binding.submitButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
viewModel.setLastUpdated(OffsetDateTime.now());
}
});

30. Run

31. Good
• Auto&data&binding&more&less&codes
• Support&most&Android&version&(2.1~)
• Binding&adapter
• Converter

32. Good
• Expression+support
• No+more+findViewById!
• No+more+ViewHolder!

33. Bad
• One%way%binding%only!
• Supported%future?
• Unstable%support%(Android%Studio)
• development%in%progress
• Cannot%use%Kotlin%(Kotlin%M11%used%internally)

34. Example

35. github.com/takuji31/databinding3
example

36. Thank&you!