Curious about Android, but never found the time to look into it? Come to this session for an accelerated introduction. We will look at the basic structure of an Android app, then deep dive into two aspects that differentiate Android from iOS: layout and intents. How does the layout system deal with the myriad of Android devices? How do intents facilitate deep integration among Android apps?

1. Intro to Android
for iOS developers
Chiu-Ki Chan
@chiuki

2. @chiuki@chiuki

3. @chiuki@chiuki
Hello World
Layouts
Intents & Components

4. Hello World

5. @chiuki

6. @chiuki
ViewController

7. @chiuki

8. @chiuki

9. @chiuki
xib

10. @chiuki

11. @chiuki

12. @chiuki

13. @chiuki

14. @chiuki
IBOutlet

15. @chiuki

16. @chiuki@chiuki
Center
<TextView
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" />

17. @chiuki

18. @chiuki@chiuki
Button
<Button
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="@string/add" />

19. @chiuki
LinearLayout

20. @chiuki

21. @chiuki@chiuki
LinearLayout
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical" >
<TextView
android:id="@+id/count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="128sp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/add"
android:onClick="add" />
</LinearLayout>

22. @chiuki@chiuki
IBAction
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical" >
<TextView
android:id="@+id/count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="128sp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/add"
android:onClick="add" />
</LinearLayout>

23. @chiuki@chiuki
IBAction
public class MainActivity extends Activity {
private TextView countView;
private int count = 0;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
countView = (TextView) findViewById(R.id.count);
updateCount();
}
public void add(View v) {
count += 1;
updateCount();
}
private void updateCount() {
countView.setText(String.valueOf(count));
}
}
android:onClick="add"

24. @chiuki@chiuki
Update view
public class MainActivity extends Activity {
private TextView countView;
private int count = 0;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
countView = (TextView) findViewById(R.id.count);
updateCount();
}
public void add(View v) {
count += 1;
updateCount();
}
private void updateCount() {
countView.setText(String.valueOf(count));
}
}

25. @chiuki

26. @chiuki

27. @chiuki
RelativeLayout

28. @chiuki

29. @chiuki

30. @chiuki

31. @chiuki

32. @chiuki
<RelativeLayout>
<TextView
android:id="@+id/count"
android:layout_centerInParent="true" />
<Button
android:id="@+id/reset"
android:layout_below="@id/count"
android:layout_centerHorizontal="true"
android:text="@string/reset" />
<Button
android:layout_below="@id/count"
android:layout_toLeftOf="@id/reset"
android:text="@string/subtract" />
<Button
android:layout_below="@id/count"
android:layout_toRightOf="@id/reset"
android:text="@string/add" />
</RelativeLayout>

33. @chiuki
<RelativeLayout>
<TextView
android:id="@+id/count"
android:layout_centerInParent="true" />
<Button
android:id="@+id/reset"
android:layout_below="@id/count"
android:layout_centerHorizontal="true"
android:text="@string/reset" />
<Button
android:layout_below="@id/count"
android:layout_toLeftOf="@id/reset"
android:text="@string/subtract" />
<Button
android:layout_below="@id/count"
android:layout_toRightOf="@id/reset"
android:text="@string/add" />
</RelativeLayout>

34. @chiuki
<RelativeLayout>
<TextView
android:id="@+id/count"
android:layout_centerInParent="true" />
<Button
android:id="@+id/reset"
android:layout_below="@id/count"
android:layout_centerHorizontal="true"
android:text="@string/reset" />
<Button
android:layout_below="@id/count"
android:layout_toLeftOf="@id/reset"
android:text="@string/subtract" />
<Button
android:layout_below="@id/count"
android:layout_toRightOf="@id/reset"
android:text="@string/add" />
</RelativeLayout>

35. @chiuki
<RelativeLayout>
<TextView
android:id="@+id/count"
android:layout_centerInParent="true" />
<Button
android:id="@+id/reset"
android:layout_below="@id/count"
android:layout_centerHorizontal="true"
android:text="@string/reset" />
<Button
android:layout_toLeftOf="@id/reset"
android:text="@string/subtract" />
<Button
android:layout_below="@id/count"
android:layout_toRightOf="@id/reset"
android:text="@string/add" />
</RelativeLayout>

36. @chiuki
<RelativeLayout>
<TextView
android:id="@+id/count"
android:layout_centerInParent="true" />
<Button
android:id="@+id/reset"
android:layout_below="@id/count"
android:layout_centerHorizontal="true"
android:text="@string/reset" />
<Button
android:layout_below="@id/count"
android:layout_toLeftOf="@id/reset"
android:text="@string/subtract" />
<Button
android:layout_below="@id/count"
android:layout_toRightOf="@id/reset"
android:text="@string/add" />
</RelativeLayout>

37. @chiuki@chiuki
Device Preview

38. @chiuki@chiuki
Bigger text on tablets

39. Resource Folders

40. @chiuki@chiuki
textSize
<TextView
android:id="@+id/count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="128sp" />
res/layout/activity_main.xml

41. @chiuki@chiuki
res/values/dimens.xml
<TextView
android:id="@+id/count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="@dimen/counter_size" />
res/layout/activity_main.xml
<dimen name="counter_size" value="128sp" />
res/values/dimens.xml

42. @chiuki@chiuki
res/values-sw600dp/dimens.xml
<TextView
android:id="@+id/count"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="@dimen/counter_size" />
res/layout/activity_main.xml
<dimen name="counter_size" value="128sp" />
<dimen name="counter_size" value="256sp" />
res/values/dimens.xml
res/values-sw600dp/dimens.xml

43. @chiuki@chiuki
Resource Folders
Type Variation
layout
values
drawable
menu
Language & Region: en, fr, fr-rCA, ja
Screen size: small, large, sw600dp, h400dp
Screen orientation: port, land
Screen density: ldpi, mdpi, hdpi, xhdpi, nodpi, tvdpi
Platform version: v4, v11, v14
UI mode: car, desk, television, appliance
http://developer.android.com/guide/topics/resources/providing-resources.html

44. @chiuki@chiuki
Resource Folders
Type Variation
layout
values
drawable
menu
Language & Region: en, fr, fr-rCA, ja
Screen size: small, large, sw600dp, h400dp
Screen orientation: port, land
Screen density: ldpi, mdpi, hdpi, xhdpi, nodpi, tvdpi
Platform version: v4, v11, v14
UI mode: car, desk, television, appliance
http://developer.android.com/guide/topics/resources/providing-resources.html
res/values-sw600dp/dimens.xml

45. @chiuki@chiuki
Resource Folders
Type Variation
layout
values
drawable
menu
Language & Region: en, fr, fr-rCA, ja
Screen size: small, large, sw600dp, h400dp
Screen orientation: port, land
Screen density: ldpi, mdpi, hdpi, xhdpi, nodpi, tvdpi
Platform version: v4, v11, v14
UI mode: car, desk, television, appliance
http://developer.android.com/guide/topics/resources/providing-resources.html
res/drawable-hdpi/ic_launcher.png

46. @chiuki@chiuki
Resource Folders
Type Variation
layout
values
drawable
menu
Language & Region: en, fr, fr-rCA, ja
Screen size: small, large, sw600dp, h400dp
Screen orientation: port, land
Screen density: ldpi, mdpi, hdpi, xhdpi, nodpi, tvdpi
Platform version: v4, v11, v14
UI mode: car, desk, television, appliance
http://developer.android.com/guide/topics/resources/providing-resources.html
res/drawable-hdpi/ic_launcher.png
@2x

47. @chiuki@chiuki
Resource Folders
Type Variation
layout
values
drawable
menu
Language & Region: en, fr, fr-rCA, ja
Screen size: small, large, sw600dp, h400dp
Screen orientation: port, land
Screen density: ldpi, mdpi, hdpi, xhdpi, nodpi, tvdpi
Platform version: v4, v11, v14
UI mode: car, desk, television, appliance
http://developer.android.com/guide/topics/resources/providing-resources.html
res/layout-ja/name.xml

48. Activity Lifecycle

49. @chiuki@chiuki
onCreate()
Activity Lifecycle

50. @chiuki@chiuki
onCreate()
Activity Lifecycle

51. @chiuki@chiuki
onCreate() viewDidLoad:
Activity Lifecycle

52. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
Activity Lifecycle

53. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
Activity Lifecycle

54. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
viewWillAppear:
viewDidAppear:
Activity Lifecycle

55. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
viewWillAppear:
viewDidAppear:
onPause()
Activity Lifecycle

56. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
viewWillAppear:
viewDidAppear:
onPause()
onStop()
Activity Lifecycle

57. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
viewWillAppear:
viewDidAppear:
onPause()
onStop()
viewWillDisappear:
viewDidDisappear:
Activity Lifecycle

58. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
viewWillAppear:
viewDidAppear:
onPause()
onStop()
viewWillDisappear:
viewDidDisappear:
onDestroy()
Activity Lifecycle

59. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
viewWillAppear:
viewDidAppear:
onPause()
onStop()
viewWillDisappear:
viewDidDisappear:
onDestroy() viewDidUnload:
Activity Lifecycle

60. @chiuki@chiuki
onCreate() viewDidLoad:
onStart()
onResume()
viewWillAppear:
viewDidAppear:
onPause()
onStop()
viewWillDisappear:
viewDidDisappear:
onDestroy() viewDidUnload:
Activity Lifecycle

61. @chiuki@chiuki
Visibility

62. More Activities

63. @chiuki@chiuki
startActivity (explicit)
Intent intent = new Intent(this, NumberActivity.class);
intent.putExtra("count", count);
startActivity(intent);

64. @chiuki@chiuki
startActivity (explicit)
Intent intent = new Intent(this, NumberActivity.class);
intent.putExtra("count", count);
startActivity(intent);

65. @chiuki@chiuki
startActivity (explicit)
Intent intent = new Intent(this, NumberActivity.class);
intent.putExtra("count", count);
startActivity(intent);

66. @chiuki@chiuki
startActivity (implicit)
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

67. @chiuki@chiuki
startActivity (implicit)
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

68. @chiuki@chiuki
startActivity (implicit)
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

69. @chiuki@chiuki
startActivity (implicit)
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

70. @chiuki@chiuki
Register your Activity
<activity android:name=".YourActivity">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="http" android:host="twitter.com" />
</intent-filter>
</activity>
AndroidManifest.xml
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);
Info.plist

71. @chiuki@chiuki
IntentFilter: Action
<activity android:name=".YourActivity">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="http" android:host="twitter.com" />
</intent-filter>
</activity>
AndroidManifest.xml
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

72. @chiuki@chiuki
IntentFilter: Data
<activity android:name=".YourActivity">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="http" android:host="twitter.com" />
</intent-filter>
</activity>
AndroidManifest.xml
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

73. @chiuki@chiuki
IntentFilter: Category
<activity android:name=".YourActivity">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="http" android:host="twitter.com" />
</intent-filter>
</activity>
AndroidManifest.xml
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

74. @chiuki@chiuki
IntentFilter: Category
<activity android:name=".YourActivity">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="http" android:host="twitter.com" />
</intent-filter>
</activity>
AndroidManifest.xml
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("http://twitter.com/chiuki"));
startActivity(intent);

75. @chiuki@chiuki
Intent Data
<activity android:name=".YourActivity">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="http" android:host="twitter.com" />
</intent-filter>
</activity>
Uri uri = getIntent().getData();
AndroidManifest.xml
YourActivity.java

76. @chiuki@chiuki
startActivityForResult
private static final int REQUEST_CODE_CAMERA = 1;
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, REQUEST_CODE_CAMREA);
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE_CAMERA &&
resultCode == RESULT_OK) {
Bitmap bitmap = (Bitmap) data.getExtras().get("data");
}
}

77. @chiuki@chiuki
startActivityForResult
private static final int REQUEST_CODE_CAMERA = 1;
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, REQUEST_CODE_CAMERA);
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE_CAMERA &&
resultCode == RESULT_OK) {
Bitmap bitmap = (Bitmap) data.getExtras().get("data");
}
}

78. @chiuki@chiuki
Providing Result
Intent data = new Intent();
data.putExtra("data", bitmap);
setResult(RESULT_OK, data);
finish();
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE_CAMERA &&
resultCode == RESULT_OK) {
Bitmap bitmap = (Bitmap) data.getExtras().get("data");
}
}

79. @chiuki@chiuki
Intent Data
Intent data = new Intent();
data.putExtra("data", bitmap);
setResult(RESULT_OK, data);
finish();
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE_CAMERA &&
resultCode == RESULT_OK) {
Bitmap bitmap = (Bitmap) data.getExtras().get("data");
}
}

80. @chiuki@chiuki
Result Code
Intent data = new Intent();
data.putExtra("data", bitmap);
setResult(RESULT_OK, data);
finish();
protected void onActivityResult(
int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_CODE_CAMERA &&
resultCode == RESULT_OK) {
Bitmap bitmap = (Bitmap) data.getExtras().get("data");
}
}

81. @chiuki@chiuki
Share intent
Intent intent = new Intent(Intent.ACTION_SEND);
intent.putExtra(Intent.EXTRA_SUBJECT, subject);
intent.putExtra(Intent.EXTRA_TEXT, message);
intent.setType("image/*");
Uri uri = Uri.fromFile(new File(path));
intent.putExtra(Intent.EXTRA_STREAM, uri);

82. @chiuki@chiuki
IntentFilter: Type
<activity android:name=".YourActivity">
<intent-filter>
<action android:name="android.intent.action.ACTION_SEND" />
<category android:name="android.intent.category.DEFAULT" />
<data android:mimeType="image/*" />
</intent-filter>
</activity>
AndroidManifest.xml
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setType("image/*");

83. @chiuki@chiuki
Intent Data
String subject = intent.getStringExtra(Intent.EXTRA_SUBJECT);
String message = intent.getStringExtra(Intent.EXTRA_TEXT);
Uri imageUri = (Uri) intent.getParcelableExtra(Intent.EXTRA_STREAM);
YourActivity.java
Intent intent = new Intent(Intent.ACTION_SEND);
intent.putExtra(Intent.EXTRA_SUBJECT, subject);
intent.putExtra(Intent.EXTRA_TEXT, message);
intent.setType("image/*");
Uri uri = Uri.fromFile(new File(path));
intent.putExtra(Intent.EXTRA_STREAM, uri);

84. Beyond Activities

85. @chiuki@chiuki
Service BroadcastReceiver
ContentProvider Notification

86. @chiuki@chiuki
Service
Look ma, no UI!

87. @chiuki@chiuki
Service
Long-running

88. @chiuki@chiuki
BroadcastReceiver
Respond

89. @chiuki@chiuki
BroadcastReceiver
Respond
Battery low
Wifi connected
Incoming SMS
App installed
Screen off

90. @chiuki@chiuki
ContentProvider
Provide data to other apps

91. @chiuki@chiuki
ContentProvider
Provide data to other apps
Contacts
Images Music
Calendar

92. @chiuki@chiuki
ContentProvider
Internal data
(unless you need SQLite interface)

93. @chiuki@chiuki
Notification
Notify

94. @chiuki@chiuki
Notify

95. @chiuki@chiuki
Notification
Communicate with background Service

96. @chiuki@chiuki
Background Service

97. Case study

98. @chiuki
Email Outbox

99. @chiuki

100. @chiuki@chiuki
Notification

101. @chiuki@chiuki
AlarmService

102. @chiuki@chiuki
Connectivity change

103. Summary

104. @chiuki@chiuki
Summary
Hello World
Layouts
Resource Folders
Activity Lifecycle
Intents & Components
Case Study

105. @chiuki@chiuki
Thank you!
http://eepurl.com/lR5uD
http://blog.sqisland.com
http://twitter.com/chiuki