Groovy on Android -- Groovy Grails eXchange 2014

For 10 years, Groovy has dramatically improved the productivity of Java developers on the desktop. With unique like closures, builders, AST transformations, traits, optional static compilation and many more, Groovy turned out to be a very competitive language on the JVM. Compared to other JVM languages, Groovy has the major advantage of being totally Java-friendly, both in terms of syntax and interpretability. But during those years, what happened on the mobile world? In particular, Android developers are used to develop applications in Java, so why Groovy, a JVM language, wouldn't be usable for Android development too? Can we ease the pain of Android developers too?

Transcript

1. Groovy on Android Guillaume Laforge Groovy project lead @glaforge
3. Total Android Newbie!
5. Android is in the Java stone age state
6. Is there something we can do about it?
7. Yes, Groovy!
8. New York Times — Getting Groovy with Android 4
9. New York Times — Getting Groovy with Android 4 http://bit.ly/nyt-groovy
10. New York Times — Getting Groovy with Android 5
11. New York Times — Getting Groovy with Android 5 New York Times recruits a Groovy / Android expert http://bit.ly/nyt-job
12. What does NYT likes about Groovy on Android? • No Java 8, no lambda on Android… 6 Func0 func = new Func0<string>() { @Override public String call() { return "my content"; } }; Async.start(func);
13. What does NYT likes about Groovy on Android? • No Java 8, no lambda on Android… 7 Async.start { "my content" }
14. What does NYT likes about Groovy on Android? • No Java 8, no lambda on Android… 7 Async.start { "my content" } Good bye annonymous inner classes!
15. What does NYT likes about Groovy on Android? • Groovy code more concise and more readable • but just as type-safe as needed!
 (with @TypeChecked) • but just as fast as needed!
 (with @CompileStatic) 8
16. @glaforge — Groovy on Android Brief overview of Groovy
17. @glaforge — Groovy on Android Brief overview of Groovy You probably know it through Gradle already!
18. Groovy — a multi-faceted language Open-source project (Apache 2 licensed) • http://groovy.codehaus.org/ • http://beta.groovy-lang.org/ 10
19. Groovy — a multi-faceted language Open-source project (Apache 2 licensed) • http://groovy.codehaus.org/ • http://beta.groovy-lang.org/ 10 New « shiny » website coming soon!
20. Groovy — a multi-faceted language Alternative language 
 for the JVM 11
21. Groovy — a multi-faceted language Alternative language 
 for the JVM 11 An alternative language for the JVM
22. Groovy — a multi-faceted language Alternative language 
 for the JVM 11 With 3 million downloads a year
23. Groovy — a multi-faceted language Closely 
 resembles 
 Java 12
24. Groovy — a multi-faceted language Closely 
 resembles 
 Java 12 Java code is also valid Groovy code!
25. Groovy — a multi-faceted language Closely 
 resembles 
 Java 12 But Groovy goes beyond!
26. Groovy — a multi-faceted language Multiple 
 programming 
 flavors 13
27. Groovy — a multi-faceted language Multiple 
 programming 
 flavors 13 Object-oriented
28. Groovy — a multi-faceted language Multiple 
 programming 
 flavors 13 Dynamic
29. Groovy — a multi-faceted language Multiple 
 programming 
 flavors 13 Functional
30. Groovy — a multi-faceted language Multiple 
 programming 
 flavors 13 Statically type checked and / or compiled
31. Groovy — a multi-faceted language Seamless Java integration
 & interoperability 14
32. Groovy — a multi-faceted language Seamless Java integration
 & interoperability 14 No bridge to cross between languages
33. @glaforge — Groovy on Android Let’s get started?
34. With a Hello World? 16
35. Android Studio 17
36. Android Studio 17 Click on « New Project »
37. Android Studio 18
38. Android Studio 18 Fill in the project details
39. Android Studio 19
40. Android Studio 19 Choose your target platform
41. Android Studio 20
42. Android Studio 20 Create a 
 blank activity
43. Android Studio 21
44. Android Studio 21 Details for your new activity
45. Android Studio 22
46. Android Studio 22 Now let’s have fun!
47. Modify your app’s Gradle build 23 apply plugin: 'com.android.application' android { compileSdkVersion 20 buildToolsVersion "20.0.0" defaultConfig { applicationId "com.appspot.glaforge.hellogroovyworld" minSdkVersion 15 targetSdkVersion 20 versionCode 1 versionName "1.0" } buildTypes { release { runProguard false proguardFiles getDefaultProguardFile('proguard-android.txt'), 
 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) }
48. Modify your app’s Gradle build 23 apply plugin: 'com.android.application' android { compileSdkVersion 20 buildToolsVersion "20.0.0" defaultConfig { applicationId "com.appspot.glaforge.hellogroovyworld" minSdkVersion 15 targetSdkVersion 20 versionCode 1 versionName "1.0" } buildTypes { release { runProguard false proguardFiles getDefaultProguardFile('proguard-android.txt'), 
 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) } buildscript { repositories { jcenter() } dependencies { classpath 'com.android.tools.build:gradle:0.12.2' classpath 'me.champeau.gradle:gradle-groovy-android-plugin:0.3.0' } }
49. Modify your app’s Gradle build 23 apply plugin: 'com.android.application' android { compileSdkVersion 20 buildToolsVersion "20.0.0" defaultConfig { applicationId "com.appspot.glaforge.hellogroovyworld" minSdkVersion 15 targetSdkVersion 20 versionCode 1 versionName "1.0" } buildTypes { release { runProguard false proguardFiles getDefaultProguardFile('proguard-android.txt'), 
 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) } apply plugin: 'me.champeau.gradle.groovy-android' buildscript { repositories { jcenter() } dependencies { classpath 'com.android.tools.build:gradle:0.12.2' classpath 'me.champeau.gradle:gradle-groovy-android-plugin:0.3.0' } }
50. Modify your app’s Gradle build 23 apply plugin: 'com.android.application' android { compileSdkVersion 20 buildToolsVersion "20.0.0" defaultConfig { applicationId "com.appspot.glaforge.hellogroovyworld" minSdkVersion 15 targetSdkVersion 20 versionCode 1 versionName "1.0" } buildTypes { release { runProguard false proguardFiles getDefaultProguardFile('proguard-android.txt'), 
 'proguard-rules.pro' } } } dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) } compile 'org.codehaus.groovy:groovy:2.4.0-beta-3:grooid' apply plugin: 'me.champeau.gradle.groovy-android' buildscript { repositories { jcenter() } dependencies { classpath 'com.android.tools.build:gradle:0.12.2' classpath 'me.champeau.gradle:gradle-groovy-android-plugin:0.3.0' } }
51. Java to Groovy… • Rename your activity from .java to .groovy • Remove… • public and return keywords • some parentheses • use the property notation • getMenuInflater() becomes menuInflater • use interpolated strings • and more. 24
52. Java to Groovy… 25 import android.app.Activity import android.os.Bundle import android.view.* class HelloGroovyWorld extends Activity { protected void onCreate(Bundle savedInstanceState) { super.onCreate savedInstanceState setContentView R.layout.activity_hello_groovy_world } boolean onCreateOptionsMenu(Menu menu) { menuInflater.inflate R.menu.hello_groovy_world, menu true } boolean onOptionsItemSelected(MenuItem item) { int id = item.itemId if (id == R.id.action_settings) { return true } super.onOptionsItemSelected item }
53. Run your Groovy-powered app in the emulator 26
54. What about weight? On a demo application (conference agenda) 27 Artifact Size Groovy JAR 4.5 MB Generated APK 2 MB After ProGuard 1 MB (8K methods)
55. ProGuard rules 28 -dontobfuscate -keep class org.codehaus.groovy.vmplugin.** -keep class org.codehaus.groovy.runtime.dgm* -keepclassmembers class org.codehaus.groovy.runtime.dgm* { *; } -keepclassmembers class ** implements org.codehaus.groovy.runtime.GeneratedClosure { *; } -dontwarn org.codehaus.groovy.** -dontwarn groovy**
56. @glaforge — Groovy on Android How does the Groovy support work?
57. Standard process 30 Compile-time Runtime
58. Standard process 30 Compile-time Runtime .class
59. Standard process 30 Compile-time Runtime .class .dex
60. Standard process 30 Compile-time Runtime .class .dex .apk
61. Standard process 30 Compile-time Runtime .class .dex .apk
62. First attempt — DiscoBot 31 Compile-time Runtime
63. First attempt — DiscoBot 31 Compile-time Runtime .apk
64. First attempt — DiscoBot 31 Compile-time Runtime .class .apk
65. First attempt — DiscoBot 31 Compile-time Runtime .class .jar .apk
66. First attempt — DiscoBot 31 Compile-time Runtime .class .jar .dex .apk
67. First attempt — DiscoBot 31 Compile-time Runtime .class .jar .dex .apk
68. First attempt — DiscoBot 31 Compile-time Runtime .class .jar .dex .apk « Ruboto » approach, slow & inneficient
69. New process — just like Java! 32 Compile-time Runtime
70. New process — just like Java! 32 Compile-time Runtime .class
71. New process — just like Java! 32 Compile-time Runtime .class .dex
72. New process — just like Java! 32 Compile-time Runtime .class .dex .apk
73. New process — just like Java! 32 Compile-time Runtime .class .dex .apk
74. Evaluating Groovy code at runtime 33 Compile-time Runtime .class .dex .apk
75. Evaluating Groovy code at runtime 33 Compile-time Runtime .class .dex .apk .class
76. Evaluating Groovy code at runtime 33 Compile-time Runtime .class .dex .apk .class .jar
77. Evaluating Groovy code at runtime 33 Compile-time Runtime .class .dex .apk .class .jar .dex
78. Evaluating Groovy code at runtime 33 Compile-time Runtime .class .dex .apk .class .jar .dex
79. @glaforge — Groovy on Android What does Groovy bring?
80. What does Groovy bring? 35 Optional
81. What does Groovy bring? 35 Optional Semi-colons
82. What does Groovy bring? 35 Optional Parentheses
83. What does Groovy bring? 35 Optional Typing
84. What does Groovy bring? 35 Optional return keyworkd
85. What does Groovy bring? 35 Optional public keyworkd
86. From Java to Groovy… 36 public class Greeter { private String owner; public String getOwner() { return owner; } public void setOwner(String owner) { this.owner = owner; } public String greet(String name) { return "Hello " + name + ", I am " + owner; } } Greeter greeter = new Greeter(); greeter.setOwner("Guillaume"); System.out.println(greeter.greet("Marion"));
87. From Java to Groovy… 36 public class Greeter { private String owner; public String getOwner() { return owner; } public void setOwner(String owner) { this.owner = owner; } public String greet(String name) { return "Hello " + name + ", I am " + owner; } } Greeter greeter = new Greeter(); greeter.setOwner("Guillaume"); System.out.println(greeter.greet("Marion")); class Greeter { String owner String greet(String name) { "Hello ${name}, I am ${owner}" } } def greeter = new Greeter(owner: "Guillaume") println greeter.greet("Marion")
88. Special Groovy syntax sugar — special operators 37
89. Special Groovy syntax sugar — special operators 37 // Groovy truth // if (s != null && s.length() > 0) {...} if (s) { ... } // Elvis def name = person.name ?: "unknown" // save navigation order?.lineItem?.item?.name
90. Special Groovy syntax sugar — special operators 37 // Groovy truth // if (s != null && s.length() > 0) {...} if (s) { ... } // Elvis def name = person.name ?: "unknown" // save navigation order?.lineItem?.item?.name if (person.name != null && person.name.length() > 0)
91. Special Groovy syntax sugar — special operators 37 // Groovy truth // if (s != null && s.length() > 0) {...} if (s) { ... } // Elvis def name = person.name ?: "unknown" // save navigation order?.lineItem?.item?.name Copied by Swift, C# 
 and CoffeeScript!
92. Special Groovy syntax sugar — special operators 37 // Groovy truth // if (s != null && s.length() > 0) {...} if (s) { ... } // Elvis def name = person.name ?: "unknown" // save navigation order?.lineItem?.item?.name Anything null in the chain? Null
93. Special Groovy syntax sugar — special operators 37 // Groovy truth // if (s != null && s.length() > 0) {...} if (s) { ... } // Elvis def name = person.name ?: "unknown" // save navigation order?.lineItem?.item?.name Better NPEs: Cannot get property name on null object
94. Special Groovy syntax sugar — collections, regex, closures 38 // lists def list = [1, 2, 3, 4, 5] // maps def map = [a: 1, b: 2, c: 3] // regular expressions def regex = ~/.*foo.*/ // ranges def range 128..255 // closures def adder = { a, b -> a + b }
95. Builders
96. Builders With closures come Groovy « builders »!
97. Groovy builders — XML, JSON… Android views & layouts! 40 import groovy.json.* def json = new JsonBuilder() json.person { name 'Guillaume' age 37 daughters 'Marion', 'Erine' address { street '1 Main St' zip 75001 city 'Paris' } }
98. Groovy builders — XML, JSON… Android views & layouts! 40 import groovy.json.* def json = new JsonBuilder() json.person { name 'Guillaume' age 37 daughters 'Marion', 'Erine' address { street '1 Main St' zip 75001 city 'Paris' } } { "person": { "name": "Guillaume", "age": 37, "daughters": [ "Marion", "Erine" ], "address": { "street": "1 Main St", "zip": 75001, "city": "Paris" } } }
99. HTTP GET and JSON parsing in 4 lines 41 import groovy.json.* def url = "https://api.github.com/repos" +
 "groovy/groovy-core/commits" def commits = new JsonSlurper().parseText(url.toURL().text) assert commits[0].commit.author.name == 'Cedric Champeau'
100. HTTP GET and JSON parsing in 4 lines 41 import groovy.json.* def url = "https://api.github.com/repos" +
 "groovy/groovy-core/commits" def commits = new JsonSlurper().parseText(url.toURL().text) assert commits[0].commit.author.name == 'Cedric Champeau' An HTTP GET in a one-liner!
101. HTTP GET and JSON parsing in 4 lines 41 import groovy.json.* def url = "https://api.github.com/repos" +
 "groovy/groovy-core/commits" def commits = new JsonSlurper().parseText(url.toURL().text) assert commits[0].commit.author.name == 'Cedric Champeau' No complex object graph marshalling!
102. Annotations
103. Annotations Actually, code transformations triggered by annotations
104. Annotations Actually, code transformations triggered by annotations No APT, sorry!
105. AST transformations — only a short list! Code generation • @ToString • @EqualsAndHashCode • @Canonical • @TupleConstructor • @InheritConstructors • @Category • @Lazy • @Sortable • @Builder Class design • @Delegate • @Immutable • @Memoized • @Singleton Compiler directives • @AnnotationCollector • @DelegatesTo • @TypeChecked • @CompileStatic • @TailRecursive 43
106. AST transformations — @Immutable Implement immutability by the book • final class • tuple-style constructor • private final backing fields • defensive copying of collections • equals() and hashCode() methods • toString() method • ... 44
107. AST transformations — @Immutable • A person class • a String name • an int age 45 public final class Person { private final String name; private final int age; public Person(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public int getAge() { return age; } public int hashCode() { return age + 31 * name.hashCode(); } public boolean equals(Object other) { if (other == null) { return false; } if (this == other) { return true; } if (Person.class != other.getClass()) { return false; } Person otherPerson = (Person)other; if (!name.equals(otherPerson.getName()) { return false; } if (age != otherPerson.getAge()) { return false; } return true; } public String toString() { return "Person(" + name + ", " + age + ")"; } }
108. AST transformations — @Immutable • A person class • a String name • an int age 46 import groovy.transform.* @Immutable class Person { String name int age }
109. AST transformations 47
110. AST transformations 47 Groovy allows you to be lazy
111. AST transformations 47 The compiler will do the job for you
112. AST transformations 47 More concise, more readable code
113. AST transformations 47 Less stuff to maintain and worry about
114. Traits • Like interfaces, but with method bodies – similar to Java 8 interface default methods • Elegant way to compose behavior – multiple inheritance without the « diamond » problem • Traits can also be stateful – traits can have properties like normal classes • Compatible with static typing and static compilation – class methods from traits also visible from Java classes • Also possible to implement traits at runtime 48
115. Traits — example: melix / speakertime 49 @CompileStatic class PresentationActivity extends Activity implements GoogleApiProvider { // ... protected void onCreate(Bundle savedState) { super.onCreate(savedState) // ... createGoogleApi() } protected void onStart() { super.onStart() connectGoogleApi() } protected void onStop() { super.onStop() disconnectGoogleApi() } // ... @CompileStatic trait GoogleApiProvider { GoogleApiClient googleApiClient void createGoogleApi() { /* ... */ } void connectGoogleApi() { /* ... */ } void disconnectGoogleApi() { /* ... */ } }
116. Compare Java and Groovy 50
117. Compare Java and Groovy 50
118. Event listeners 51 button.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { Log.i(tag, "clicked!") } })
119. Event listeners 51 button.onClickListener = { Log.i(tag, "clicked!") } button.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { Log.i(tag, "clicked!") } })
120. Properties and equality 52 if (intent.getAction().equals(Intent.ACTION_VIEW)) { Log.i(tag, "view"); }
121. Properties and equality 52 if (intent.getAction().equals(Intent.ACTION_VIEW)) { Log.i(tag, "view"); } if (intent.action == Intent.ACTION_VIEW) { Log.i(tag, "view") }
122. Groovy Development Kit methods 53 new Thread() { public void run() { // … } }.start();
123. Groovy Development Kit methods 53 new Thread() { public void run() { // … } }.start(); Thread.start { // … }
124. Groovy’s with {} method 54 view = new TextView(context); view.setText(name); view.setTextSize(16f); view.setTextColor(Color.WHITE);
125. Groovy’s with {} method 54 view = new TextView(context); view.setText(name); view.setTextSize(16f); view.setTextColor(Color.WHITE); view = new TextView(context) view.with { text = name textSize = 16f textColor = Color.WHITE }
126. Groovy Truth and GStrings 55 EditText phone = (EditText)findViewById(R.id.phone); if ((phone.getText() != null) && !phone.getText().equals("")) { String phoneString = parsePhone(phone.getText().toString()); Intent intent = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + phoneString)); startActivity(intent); }
127. Groovy Truth and GStrings 55 EditText phone = (EditText)findViewById(R.id.phone); if ((phone.getText() != null) && !phone.getText().equals("")) { String phoneString = parsePhone(phone.getText().toString()); Intent intent = new Intent(Intent.ACTION_CALL, Uri.parse("tel:" + phoneString)); startActivity(intent); } EditText phone = findViewById(R.id.phone) if (phone.text) { def phoneString = parsePhone(phone.text) def intent = new Intent(Intent.ACTION_CALL, Uri.parse("tel:${phoneString}")) startActivity intent }
128. Resource handling with closures and file methods 56 File f = new File("/sdcard/dir/f.txt"); if (f.exists() && f.canRead()) { FileInputStream fis = null; try { fis = new FileInputStream(rFile); byte[] bytes = new byte[fis.available()]; while (fis.read(bytes) != -1) {} textView.setText(new String(bytes)); } catch (IOException e) { // log and or handle } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { // swallow } } } }
129. Resource handling with closures and file methods 56 File f = new File("/sdcard/dir/f.txt"); if (f.exists() && f.canRead()) { FileInputStream fis = null; try { fis = new FileInputStream(rFile); byte[] bytes = new byte[fis.available()]; while (fis.read(bytes) != -1) {} textView.setText(new String(bytes)); } catch (IOException e) { // log and or handle } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { // swallow } } } } def f = new File("/sdcard/dir/f.txt") if (f.exists() && f.canRead()) { f.withInputStream { fis -> def bytes = new byte[fis.available()] while (fis.read(bytes) != -1) {} textView.text = new String(bytes) } }
130. Resource handling with closures and file methods 56 File f = new File("/sdcard/dir/f.txt"); if (f.exists() && f.canRead()) { FileInputStream fis = null; try { fis = new FileInputStream(rFile); byte[] bytes = new byte[fis.available()]; while (fis.read(bytes) != -1) {} textView.setText(new String(bytes)); } catch (IOException e) { // log and or handle } finally { if (fis != null) { try { fis.close(); } catch (IOException e) { // swallow } } } } def f = new File("/sdcard/dir/f.txt") if (f.exists() && f.canRead()) { f.withInputStream { fis -> def bytes = new byte[fis.available()] while (fis.read(bytes) != -1) {} textView.text = new String(bytes) } } def f = new File("/sdcard/dir/f.txt") if (f.exists() && f.canRead()) { textView.text = f.text }
131. @glaforge — Groovy on Android What else?
132. What else? • Projects with dedicated Groovy support • Swiss Knife • similar to Butter Knife & 
 Android Annotations • Grooid Playground • a builder for creating views
 in a hierarchical & visual manner 58
133. Swiss Knife — Arasthel / SwissKnife 59
134. Swiss Knife — Arasthel / SwissKnife 59 Like Butter Knife & Android Annotations, but for Groovy
135. Swiss Knife 60 class MyActivity extends Activity { @OnClick(R.id.button) void onButtonClicked(Button button) { Toast.makeText(this, "Clicked", Toast.LENGTH_SHOT).show() } @OnBackground void doSomeProcessing(URL url) { // Contents will be executed on background } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate savedInstanceState setContentView R.layout.activity_main SwissKnife.inject this } }
136. Swiss Knife 60 class MyActivity extends Activity { @OnClick(R.id.button) void onButtonClicked(Button button) { Toast.makeText(this, "Clicked", Toast.LENGTH_SHOT).show() } @OnBackground void doSomeProcessing(URL url) { // Contents will be executed on background } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate savedInstanceState setContentView R.layout.activity_main SwissKnife.inject this } } View injection
137. Swiss Knife 60 class MyActivity extends Activity { @OnClick(R.id.button) void onButtonClicked(Button button) { Toast.makeText(this, "Clicked", Toast.LENGTH_SHOT).show() } @OnBackground void doSomeProcessing(URL url) { // Contents will be executed on background } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate savedInstanceState setContentView R.layout.activity_main SwissKnife.inject this } } Execute code outside the UI thread
138. Swiss Knife 60 class MyActivity extends Activity { @OnClick(R.id.button) void onButtonClicked(Button button) { Toast.makeText(this, "Clicked", Toast.LENGTH_SHOT).show() } @OnBackground void doSomeProcessing(URL url) { // Contents will be executed on background } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate savedInstanceState setContentView R.layout.activity_main SwissKnife.inject this } } Injection point of views and callbacks
139. Swiss Knife — available annotations • @OnUIThread • @OnBackground • @OnClick • @OnLongClick • @OnItemClick • @OnItemLongClick • @OnItemSelected • @OnChecked • @OnFocusChanged • @OnTouch • @OnPageChanged • @OnTextChanged • @OnEditorAction 61
140. Swiss Knife — available annotations • @OnUIThread • @OnBackground • @OnClick • @OnLongClick • @OnItemClick • @OnItemLongClick • @OnItemSelected • @OnChecked • @OnFocusChanged • @OnTouch • @OnPageChanged • @OnTextChanged • @OnEditorAction 61 AST transformations
141. Swiss Knife — setup 62 dependencies { … compile 'com.arasthel:swissknife:1.0.4' … }
142. Grooid Playground — karfunkel / grooid-playground • When you need to build dynamic views (ie. not XML-driven) 63 def layout = new RelativeLayout(this) layout.width = MATCH_PARENT layout.height = MATCH_PARENT layout.setPaddingRelative(64, 16, 64, 16) def textView = new TextView(this) textView.width = MATCH_PARENT textView.height = 20 textView.setText R.string.hello_world layout.addView textView setContentView(layout)
143. Grooid Playground — karfunkel / grooid-playground • When you need to build dynamic views (ie. not XML-driven) 63 def layout = new RelativeLayout(this) layout.width = MATCH_PARENT layout.height = MATCH_PARENT layout.setPaddingRelative(64, 16, 64, 16) def textView = new TextView(this) textView.width = MATCH_PARENT textView.height = 20 textView.setText R.string.hello_world layout.addView textView setContentView(layout) Imperative
144. Grooid Playground — karfunkel / grooid-playground • When you need to build dynamic views (ie. not XML-driven) 63 setContentView new AndroidBuilder().build(this) { relativeLayout(width: MATCH_PARENT, height: MATCH_PARENT, padding: [64.dip, 16.dip]) { textView(width: MATCH_PARENT, height: 20.dip, text: R.string.hello_world) } } Declarative, hierarchical, visual
145. @glaforge — Groovy on Android Want more?
146. Programming your Android applications in Groovy • You can use Groovy to code Android apps! • use Groovy 2.4.0-beta-1+ (latest: beta-4) • prefer @CompileStatic • Two great posts to get started: • http://bit.ly/grooid-1 • http://bit.ly/grooid-2 • Gradle plugin support: • http://bit.ly/grooid-gradle 65
147. Demo conference application 66
148. Demo conference application 66 Source code available: http://bit.ly/grooid-app
149. Demo Google Wear + Phone application 67
150. Demo Google Wear + Phone application 67 Source code available: http://bit.ly/grooid-wear
151. @glaforge — Groovy on Android Summary
152. Summary • Groovy can make your Android code… • more concise & readable • more maintainable • Without compromising • type safety • speed 69
153. Feedback welcome 70
154. Feedback welcome 70 We need you to help figure out how Groovy can help you!
155. @glaforge — Groovy on Android Q & A
157. Image credits • Stone age • http://3.bp.blogspot.com/-lMDyyBdibG4/UxDYLq5ItiI/AAAAAAAALf8/HPpKRixHOIE/s1600/Neanderthal+Man+1.jpg • Many thanks • http://www.trys.ie/wp-content/uploads/2013/06/many-thanks.jpg • Disclaimer • http://3.bp.blogspot.com/-RGnBpjXTCQA/Tj2h_JsLigI/AAAAAAAABbg/AB5ZZYzuE5w/s1600/disclaimer.jpg • Builders • http://detroittraining.com/wp-content/uploads/Construction-Women2.jpg • Newbie • http://contently.com/strategist/wp-content/uploads/2014/05/bigstock-Shocked-Computer-Nerd-1520709.jpg • Alternative rock band • http://upload.wikimedia.org/wikipedia/commons/b/b2/Arcade_Fire_live_20050315.ext.jpg • Twins • http://images.doctissimo.fr/1/jumeaux-jumelles/photo/hd/4424027442/137540656da/jumeaux-jumelles-jumeaux-jumelles-2-big.jpg • Annotations • http://3.bp.blogspot.com/-f94n9BHko_s/T35ELs7nYvI/AAAAAAAAAKg/qe06LRPH9U4/s1600/IMG_1721.JPG • Apple & Orange • http://cdni.wired.co.uk/1920x1280/a_c/comparison.jpg • We need you • http://media.moddb.com/images/mods/1/14/13849/WickedSunshine_UncleSam_Blank_800x1000.png 73
158. Image credits • Macarons • http://www.thatfoodcray.com/wp-content/uploads/2013/12/that-food-cray-pierre-herme-paris-hong-kong-christmas-flavors-foie-gras- truffle-9.jpg?4dd047 • Bridge • http://tenspeedhero.com/wp-content/uploads/Bridge_3.jpg • Swiss knife • http://www.formengifts.com/wp-content/uploads/2011/04/swiss-army-champ-multitool-knife2.jpg • Hello World • http://www.warrenpriestley.com/wp-content/uploads/2012/01/helloworld.gif • George Clooney • http://www.brewville.ca/wp-content/uploads/2014/05/nespresso-george-clooney.jpg • Weight scale • http://images.wisegeek.com/person-stands-on-scale.jpg • Nexus 5 • http://fs01.androidpit.info/userfiles/2692059/image/Blog/nexus-5-weiss_628.jpg • File icon • https://dl.vecnet.org/assets/default.png • Gear • http://www.pvzgears.com/wp-content/uploads/2013/03/gears2a.png • Sugar • http://images.wisegeek.com/cane-sugar.jpg • London • http://www.100percentoptical.com/images/2014/10/london.jpg 74