Geekcamp Android
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The document is a guide for Android development presented during GeekCamp Singapore in 2009, focusing on tools, architecture, and component types involved in Android application development. It outlines the setup process for the Android SDK with Eclipse, various application components like activities and services, and provides code examples for creating a simple photo viewer application. Additionally, it covers the creation of user interfaces, handling intents, and responding to menu selections in Android applications.
Geekcamp Android
- 1. Android Development GeekCamp Singapore 22 nd August 2009 Leong Hean Hong (CC) BY-SA Some rights preserved.
- 2. About Usernames: hongster, ahhong
- 3. DOB: 490204800 (GMT +8)
- 4. Work: LAMP | Android | iPhone
- 5. Interest: Python, Rubik Cube, Number Theory, Web Technologies
- 6. Groups: SG PHP User Group, KL Google Technology User Group
- 9. Setup
- 11. Views
- 12. Intents
- 13. Demo
- 14. Intro Android != OS “ Android™ delivers a complete set of software for mobile devices: an operating system, middleware and key mobile applications. ”
- 15. Android Architecture ( http://bit.ly/s73P2 )
- 16. Dalvik_VM != JVM Designed and written by Dan Bornstein with contributions from other Google engineers
- 17. Bytecode on which it operates is not Java bytecode.
- 18. Development Tools Android 1.5 SDK
- 19. Optional, recommended Eclipse (Java or RCP version recommended)
- 20. Android Development Tools ( ADT ) eclipse plugin (http s ://dl-ssl.google.com/android/eclipse/)
- 21. Setup Download and unzip Android SDK.
- 22. Install Eclipse.
- 23. Install ADT.
- 24. Set SDK path in Eclipse preference section.
- 25. Create Android Virtual Device ( AVD ).
- 26. RTFM and start coding.
- 28. Linux Tips Don’t use package manger, download Eclipse and unzip it.
- 29. Use Sun Java ( “requires plug-in org.eclipse.wst.sse.ui” error )
- 30. If installed Eclipse using root , update using root .
- 31. Run <android-sdk>/tools/ddms once, before installing ADT. (solved in ADT 0.9.1 http://bit.ly/15FdZt )
- 32. Application Components Activity Presents a visual UI for user to interact with.
- 33. Similar to UIViewController. Service No visual UI, run in background for an indefinite period of time.
- 34. Similar to daemon. Broadcast Receiver Does nothing but receive and react to broadcast announcements (E.g. Timezone changed, battery low, ...). Content Provider Makes a specific set of the application's data available to other applications. (E.g. Wrapper for data in file system or DB)
- 36. Android Project Folders src/ Source code. Android 1.5/ Library you will use. gen/ AIDL (Android Interface Definition Language), auto generated. asset/ Save data as asset when you need to read raw bytes.
- 37. Android Project Files res/ (application resources access through R class) drawable/ (bitmap files)
- 38. layout/ (design Views , similar to HTML)
- 39. values/ (predefined values, can be referenced in application) AndroidManifest.xml Similar to iPhone’s Info.plist.
- 40. Contains application settings (E.g. Intent filters, permission, activities, …) default.properties Contains project settings such as build target.
- 41. /res/layout/main.xml Layout for main activity.
- 42. Contains: LinearLayout for arranging subviews
- 43. TextView for displaying text
- 44. Button An ID (helloButton) is assigned to the button. Can be referenced through R.id.helloButton .
- 45. Button text is defined in /res/values/string.xml .
- 46. Add Button (main.xml) <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:gravity="center" android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:layout_width=" wrap_content " android:layout_height="wrap_content" android:text="@string/hello" /> <Button android:id="@+id/helloButton" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/hello_button" /> </LinearLayout>
- 47. Launch Image Gallery private static final int REQUEST_PICK_IMAGE = 1; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button button = (Button)findViewById(R.id.helloButton); button.setOnClickListener(new OnClickListener() { @Override public void onClick(View arg0) { Intent pickImage = new Intent(Intent.ACTION_PICK); pickImage.setType("image/*"); startActivityForResult(pickImage, REQUEST_PICK_IMAGE); } }); }
- 48. Intent Abstract description of an action to be preformed.
- 49. Intent messaging is a facility for late run-time binding between components in the same or different applications.
- 50. Activity , Service , BroadcastReceiver are activated through Intent .
- 52. New Activity Create a new Activity called PhotoViewer
- 53. Create a Layout to display the photo (photo_viewer.xml)
- 54. Use a ImageView to display photo
- 55. GoodByeWorld launch PhotoViewer by sending it an Intent
- 56. The Intent contains the URI of the selected image
- 57. ImageView load image from the URI
- 58. /res/layout/photo_viewer.xml Layout for the PhotoViewer Activity
- 59. Contains an ImageView for displaying image
- 60. The ImageView is given an ID ( photoView )
- 61. photo_viewer.xml <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> < ImageView android:id="@+id/photoView" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout>
- 62. PhotoViewer.java protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView( R.layout.photo_viewer ); ImageView photoView = (ImageView)findViewById( R.id.photoView ); photoView.setImageURI( getIntent().getData() ); }
- 63. AndroidManifest.xml <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".GoodByeWorld" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".PhotoViewer"></activity> </application>
- 64. Create Menu private static final int MENU_RED = Menu.FIRST; private static final int MENU_GREEN = Menu.FIRST + 1; private static final int MENU_BLUE = Menu.FIRST + 2; private static final int MENU_RAND = Menu.FIRST + 3; public boolean onCreateOptionsMenu (Menu menu) { super.onCreateOptionsMenu(menu); menu.add(Menu.NONE, MENU_RED, Menu.NONE, "Filter Red"); menu.add(Menu.NONE, MENU_GREEN, Menu.NONE, "Filter Green"); menu.add(Menu.NONE, MENU_BLUE, Menu.NONE, "Filter Blue"); menu.add(Menu.NONE, MENU_RAND, Menu.NONE, "Random Filter"); return true; }
- 65. Response to Menu Selection public boolean onMenuItemSelected (int featureId, MenuItem item) { super.onMenuItemSelected(featureId, item); switch(item.getItemId()) { case MENU_RED: photoView. setColorFilter (redFilter()); break; case MENU_GREEN: photoView. setColorFilter (greenFilter()); break; case MENU_BLUE: photoView. setColorFilter (blueFilter()); break; case MENU_RAND: photoView. setColorFilter (randFilter()); break; } return true; }
- 67. ColorMatrixColorFilter private ColorMatrixColorFilter redFilter() { return new ColorMatrixColorFilter(new float[] { 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0 }); }
- 68. Q & A Any question?