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JoseAlcerrecaJoseAlcerreca
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Jetifies and updates samples (with LiveData migration) (#23)
* Jetifies and updates two-way sample * Use resources from activity + minor fixes * Updates circle to api 28 stable * Jetifies basic sample * Migrates basic sample to LiveData * Fixes typo and improves README
1 parent 273c77f commit 0832387

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‎.circleci/config.yml‎

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@@ -2,7 +2,7 @@ version: 2
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config_android: &config_android
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docker:
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- image: circleci/android:api-28-alpha
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- image: circleci/android:api-28
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working_directory: ~/project
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environment:
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JAVA_TOOL_OPTIONS: "-Xmx1024m"

‎BasicSample/README.md‎

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@@ -5,7 +5,7 @@ This sample showcases the following features of the
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[Data Binding library](https://developer.android.com/topic/libraries/data-binding/index.html):
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* Layout variables and expressions
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* Observability through Observable Fields and Observable classes
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* Observability through Observable Fields, LiveData and Observable classes
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* Binding Adapters, Binding Methods and Binding Converters
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* Seamless integration with ViewModels
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### Observability
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In order to update the UI automatically when the data changes, Data Binding lets you bind attributes with
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observable objects. You can choose between two mechanisms to achieve this: Observable fields and
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Observable classes.
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In order to update the UI automatically when the data changes, Data Binding lets you bind attributes
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with observable objects. You can choose between three mechanisms to achieve this: Observable fields,
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LiveData and Observable classes.
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#### Observable fields
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@@ -55,7 +55,7 @@ fields will update the layout automatically.
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```kotlin
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class ProfileObservableFieldsViewModel : ViewModel() {
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val likes = ObservableInt(0)
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val likes = ObservableInt(0)
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fun onLike() {
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likes.increment() // Equivalent to set(likes.get() + 1)
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In this example, when `onLike` is called, the number of likes is incremented
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and the UI is updated. There is no need to notify that the property changed.
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#### LiveData
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LiveData is an observable from
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[Android Architecture Components](https://developer.android.com/topic/libraries/architecture)
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that is lifecycle-aware.
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The advantages over Observable Fields are that LiveData supports
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[Transformations](https://developer.android.com/reference/android/arch/lifecycle/Transformations)
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and it's compatible with other components and libraries, like Room and WorkManager.
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```kotlin
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class ProfileLiveDataViewModel : ViewModel() {
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private val _likes = MutableLiveData(0)
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val likes: LiveData<Int> = _likes // Expose an immutable LiveData
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fun onLike() {
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_likes.value = (_likes.value ?: 0) + 1
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}
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}
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```
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It requires an extra step done on the binding:
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```kotlin
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binding.lifecycleOwner = this // use viewLifecycleOwner when assigning a fragment
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```
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#### Observable classes
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For maximum flexibility and control, you can implement a fully observable class and decide when

‎BasicSample/app/build.gradle‎

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@@ -23,14 +23,14 @@ apply plugin: 'kotlin-android-extensions'
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apply plugin: 'kotlin-kapt'
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android {
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compileSdkVersion 27
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compileSdkVersion rootProject.compileSdkVersion
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defaultConfig {
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applicationId "com.example.android.databinding.basicsample"
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minSdkVersion 17
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targetSdkVersion 27
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applicationId "com.example.android.databinding.twowaysample"
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minSdkVersion rootProject.minSdkVersion
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targetSdkVersion rootProject.targetSdkVersion
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versionCode 1
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versionName "1.0"
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testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
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testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
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vectorDrawables.useSupportLibrary = true
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}
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buildTypes {
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dependencies {
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implementation fileTree(dir: 'libs', include: ['*.jar'])
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implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
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implementation 'com.android.support:appcompat-v7:27.1.1'
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implementation 'com.android.support:support-v4:27.1.1'
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implementation 'com.android.support.constraint:constraint-layout:1.1.3'
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implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlinVersion"
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implementation "androidx.appcompat:appcompat:$appCompatVersion"
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implementation "androidx.constraintlayout:constraintlayout:$constraintLayoutVersion"
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// For ViewModelActivity
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implementation "android.arch.lifecycle:extensions:1.1.1"
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implementation "androidx.lifecycle:lifecycle-extensions:$archLifecycleVersion"
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testImplementation 'junit:junit:4.12'
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testImplementation "junit:junit:$junitVersion"
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testImplementation "org.hamcrest:hamcrest-all:$hamcrestVersion"
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androidTestImplementation 'com.android.support.test:runner:1.0.2'
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androidTestImplementation 'com.android.support.test:rules:1.0.2'
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androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
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androidTestImplementation "androidx.test:runner:$androidXTestVersion"
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androidTestImplementation "androidx.test.ext:junit:$runnerExtVersion"
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androidTestImplementation "androidx.test:rules:$androidXTestVersion"
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androidTestImplementation "androidx.test.espresso:espresso-core:$espressoVersion"
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}

‎BasicSample/app/src/androidTest/java/com/example/android/databinding/basicsample/BasicUsageTest.kt‎

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package com.example.android.databinding.basicsample
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import android.support.test.espresso.Espresso.onView
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import android.support.test.espresso.action.ViewActions.click
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import android.support.test.espresso.assertion.ViewAssertions.matches
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import android.support.test.espresso.matcher.ViewMatchers.isDisplayed
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import android.support.test.espresso.matcher.ViewMatchers.withId
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import android.support.test.espresso.matcher.ViewMatchers.withText
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import android.support.test.rule.ActivityTestRule
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import android.support.test.runner.AndroidJUnit4
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import androidx.test.espresso.Espresso.onView
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import androidx.test.espresso.action.ViewActions.click
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import androidx.test.espresso.assertion.ViewAssertions.matches
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import androidx.test.espresso.matcher.ViewMatchers.isDisplayed
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import androidx.test.espresso.matcher.ViewMatchers.withId
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import androidx.test.espresso.matcher.ViewMatchers.withText
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import androidx.test.ext.junit.runners.AndroidJUnit4
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import androidx.test.rule.ActivityTestRule
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import com.example.android.databinding.basicsample.ui.MainActivity
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import org.junit.Rule
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import org.junit.Test
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class BasicUsageTest {
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@get:Rule
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var mActivityRule = ActivityTestRule(MainActivity::class.java)
42+
var activityRule = ActivityTestRule(MainActivity::class.java)
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@Test
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fun observableFieldsActivity_likes() {
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// Click on button to open activity
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onView(withId(R.id.observable_fields_activity_button)).perform(click())
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// Click Like 5 times
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(0 until 5).forEach {
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repeat(5) {
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onView(withId(R.id.like_button)).perform(click())
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}
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onView(withId(R.id.viewmodel_activity_button)).perform(click())
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// Click Like 5 times
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(0 until 5).forEach {
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repeat(5) {
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onView(withId(R.id.like_button)).perform(click())
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}
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‎BasicSample/app/src/main/java/com/example/android/databinding/basicsample/data/ObservableFieldProfile.kt‎

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package com.example.android.databinding.basicsample.data
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import android.databinding.ObservableInt
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import androidx.databinding.ObservableInt
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/**
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* Used as a layout variable to provide static properties (name and lastName) and an observable
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val name: String,
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val lastName: String,
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val likes: ObservableInt
29-
)
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)

‎BasicSample/app/src/main/java/com/example/android/databinding/basicsample/data/ProfileObservableViewModel.kt‎

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package com.example.android.databinding.basicsample.data
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import android.arch.lifecycle.ViewModel
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import android.databinding.Bindable
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import android.databinding.ObservableField
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import android.databinding.ObservableInt
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import androidx.databinding.Bindable
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import androidx.databinding.ObservableField
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import androidx.databinding.ObservableInt
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import androidx.lifecycle.LiveData
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import androidx.lifecycle.MutableLiveData
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import androidx.lifecycle.Transformations
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import androidx.lifecycle.ViewModel
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import com.example.android.databinding.basicsample.BR
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import com.example.android.databinding.basicsample.util.ObservableViewModel
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/**
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* This class is used as a variable in the XML layout and it's fully observable, meaning that
28-
* changes to any of the public fields automatically refresh the UI.
32+
* changes to any of the exposed observables automatically refresh the UI. *
33+
*/
34+
class ProfileLiveDataViewModel : ViewModel() {
35+
private val _name = MutableLiveData("Ada")
36+
private val _lastName = MutableLiveData("Lovelace")
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private val _likes = MutableLiveData(0)
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val name: LiveData<String> = _name
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val lastName: LiveData<String> = _lastName
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val likes: LiveData<Int> = _likes
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// popularity is exposed as LiveData using a Transformation instead of a @Bindable property.
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val popularity: LiveData<Popularity> = Transformations.map(_likes) {
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when {
46+
it > 9 -> Popularity.STAR
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it > 4 -> Popularity.POPULAR
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else -> Popularity.NORMAL
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}
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}
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fun onLike() {
53+
_likes.value = (_likes.value ?: 0) + 1
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}
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}
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/**
58+
* As an alternative to LiveData, you can use Observable Fields and binding properties.
2959
*
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* `Popularity` is exposed here as a `@Bindable` attribute, see the
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* [ProfileObservableFieldsViewModel] for an alternative using Observable fields.
60+
* `Popularity` is exposed here as a `@Bindable` property so it's necessary to call
61+
* `notifyPropertyChanged` when any of the dependent properties change (`likes` in this case).
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*/
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class ProfileObservableViewModel : ObservableViewModel() {
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val name = ObservableField("Ada")
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}
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}
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/**
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* As an alternative, the @Bindable attribute can be replaced with an
58-
* `ObservableField`. In this case 'popularity' is an `ObservableField` which has to be computed when
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* `likes` change.
60-
*/
61-
class ProfileObservableFieldsViewModel : ViewModel() {
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val name = ObservableField("Ada")
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val lastName = ObservableField("Lovelace")
64-
val likes = ObservableInt(0)
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// popularity is exposed as an ObservableField instead of a @Bindable property.
67-
val popularity = ObservableField<Popularity>(Popularity.NORMAL)
68-
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fun onLike() {
70-
likes.set(likes.get() + 1)
71-
72-
popularity.set(likes.get().let {
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if (it > 9) Popularity.STAR
74-
if (it > 4) Popularity.POPULAR
75-
Popularity.NORMAL
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})
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}
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}
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8086
enum class Popularity {
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NORMAL,
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POPULAR,

‎BasicSample/app/src/main/java/com/example/android/databinding/basicsample/ui/MainActivity.kt‎

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package com.example.android.databinding.basicsample.ui
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import android.content.Intent
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import android.databinding.DataBindingUtil
20+
import androidx.databinding.DataBindingUtil
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import android.os.Bundle
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import android.support.v7.app.AppCompatActivity
22+
import androidx.appcompat.app.AppCompatActivity
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import com.example.android.databinding.basicsample.R
2424
import com.example.android.databinding.basicsample.databinding.ActivityMainBinding
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‎BasicSample/app/src/main/java/com/example/android/databinding/basicsample/ui/ObservableFieldActivity.kt‎

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package com.example.android.databinding.basicsample.ui
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import android.databinding.DataBindingUtil
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import android.databinding.ObservableInt
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import android.os.Bundle
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import android.support.v7.app.AppCompatActivity
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import android.view.View
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import androidx.appcompat.app.AppCompatActivity
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import androidx.databinding.DataBindingUtil
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import androidx.databinding.ObservableInt
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import com.example.android.databinding.basicsample.R
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import com.example.android.databinding.basicsample.data.ObservableFieldProfile
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import com.example.android.databinding.basicsample.databinding.ObservableFieldProfileBinding

‎BasicSample/app/src/main/java/com/example/android/databinding/basicsample/ui/ViewModelActivity.kt‎

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package com.example.android.databinding.basicsample.ui
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import android.arch.lifecycle.ViewModelProviders
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import android.databinding.DataBindingUtil
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import android.os.Bundle
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import android.support.v7.app.AppCompatActivity
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import androidx.appcompat.app.AppCompatActivity
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import androidx.databinding.DataBindingUtil
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import androidx.lifecycle.ViewModelProviders
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import com.example.android.databinding.basicsample.R
24-
import com.example.android.databinding.basicsample.data.ProfileObservableViewModel
24+
import com.example.android.databinding.basicsample.data.ProfileLiveDataViewModel
2525
import com.example.android.databinding.basicsample.databinding.ViewmodelProfileBinding
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/**
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3636
super.onCreate(savedInstanceState)
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// Obtain ViewModel from ViewModelProviders
39-
val viewModel = ViewModelProviders.of(this).get(ProfileObservableViewModel::class.java)
39+
val viewModel = ViewModelProviders.of(this).get(ProfileLiveDataViewModel::class.java)
40+
41+
// An alternative ViewModel using Observable fields and @Bindable properties can be used:
42+
// val viewModel = ViewModelProviders.of(this).get(ProfileObservableViewModel::class.java)
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4144
// Obtain binding
4245
val binding: ViewmodelProfileBinding =
4346
DataBindingUtil.setContentView(this, R.layout.viewmodel_profile)
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4548
// Bind layout with ViewModel
4649
binding.viewmodel = viewModel
50+
51+
// LiveData needs the lifecycle owner
52+
binding.lifecycleOwner = this
4753
}
4854
}

‎BasicSample/app/src/main/java/com/example/android/databinding/basicsample/util/BindingAdapters.kt‎

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import android.content.Context
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import android.content.res.ColorStateList
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import android.databinding.BindingAdapter
21+
import androidx.databinding.BindingAdapter
2222
import android.graphics.drawable.Drawable
2323
import android.os.Build
24-
import android.support.v4.content.ContextCompat
25-
import android.support.v4.widget.ImageViewCompat
24+
import androidx.core.content.ContextCompat
25+
import androidx.core.widget.ImageViewCompat
2626
import android.view.View
2727
import android.widget.ImageView
2828
import android.widget.ProgressBar
@@ -101,4 +101,4 @@ object BindingAdapters {
101101
}
102102
}
103103
}
104-
}
104+
}

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