book

Professional Android™ 2 Application Development

Name: Professional Android™ 2 Application Development
Author: Reto Meier
ISBN: 9780470565520

by Reto Meier

March 2010

Intermediate to advanced

575 pages

14h 25m

English

Wrox

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Copyright
ABOUT THE AUTHOR
ABOUT THE TECHNICAL EDITOR
CREDITS
ACKNOWLEDGMENTS
INTRODUCTION
WHOM THIS BOOK IS FORWHAT THIS BOOK COVERSHOW THIS BOOK IS STRUCTUREDWHAT YOU NEED TO USE THIS BOOKCONVENTIONSSOURCE CODEERRATAP2P.WROX.COM
1. Hello, Android
1.1. A LITTLE BACKGROUND1.1.1. The Not-So-Distant Past1.1.2. The Future1.2. WHAT IT ISN'T1.3. ANDROID: AN OPEN PLATFORM FOR MOBILE DEVELOPMENT1.4. NATIVE ANDROID APPLICATIONS1.5. ANDROID SDK FEATURES1.5.1. Access to Hardware, Including Camera, GPS, and Accelerometer1.5.2. Native Google Maps, Geocoding, and Location-Based Services1.5.3. Background Services1.5.4. SQLite Database for Data Storage and Retrieval1.5.5. Shared Data and Interapplication Communication1.5.6. Using Widgets, Live Folders, and Live Wallpaper to Enhance the Home Screen1.5.7. Extensive Media Support and 2D/3D Graphics1.5.8. Optimized Memory and Process Management1.6. INTRODUCING THE OPEN HANDSET ALLIANCE1.7. WHAT DOES ANDROID RUN ON?1.8. WHY DEVELOP FOR MOBILE?1.9. WHY DEVELOP FOR ANDROID?1.9.1. What Has and Will Continue to Drive Android Adoption?1.9.2. What Does It Have That Others Don't?1.9.3. Changing the Mobile Development Landscape1.10. INTRODUCING THE DEVELOPMENT FRAMEWORK1.10.1. What Comes in the Box1.10.2. Understanding the Android Software Stack1.10.3. The Dalvik Virtual Machine1.10.4. Android Application Architecture1.10.5. Android Libraries1.11. SUMMARY
2. Getting Started
2.1. DEVELOPING FOR ANDROID2.1.1. What You Need to Begin2.1.1.1. Downloading and Installing the SDK2.1.1.2. Developing with Eclipse2.1.1.3. Using the Eclipse Plug-In2.1.1.3.1. Installing the ADT Plug-In2.1.1.3.2. Updating the Plug-In2.1.2. Creating Your First Android Application2.1.2.1. Starting a New Android Project2.1.2.2. Creating a Launch Configuration2.1.2.3. Running and Debugging Your Android Applications2.1.2.4. Understanding Hello World2.1.3. Types of Android Applications2.1.3.1. Foreground Applications2.1.3.2. Background Services and Intent Receivers2.1.3.3. Intermittent Applications2.1.3.4. Widgets2.2. DEVELOPING FOR MOBILE DEVICES2.2.1. Hardware-Imposed Design Considerations2.2.1.1. Be Efficient2.2.1.2. Expect Limited Capacity2.2.1.3. Design for Small Screens2.2.1.4. Expect Low Speeds, High Latency2.2.1.5. At What Cost?2.2.2. Considering the Users' Environment2.2.3. Developing for Android2.2.3.1. Being Fast and Efficient2.2.3.2. Being Responsive2.2.3.3. Developing Secure Applications2.2.3.4. Ensuring a Seamless User Experience2.3. TO-DO LIST EXAMPLE2.4. ANDROID DEVELOPMENT TOOLS2.4.1. The Android Virtual Device and SDK Manager2.4.1.1. Android Virtual Devices2.4.1.2. SDK Manager2.4.2. The Android Emulator2.4.3. Dalvik Debug Monitor Service (DDMS)2.4.4. The Android Debug Bridge (ADB)2.5. SUMMARY
3. Creating Applications and Activities
3.1. WHAT MAKES AN ANDROID APPLICATION?3.2. INTRODUCING THE APPLICATION MANIFEST3.3. USING THE MANIFEST EDITOR3.4. THE ANDROID APPLICATION LIFE CYCLE3.5. UNDERSTANDING APPLICATION PRIORITY AND PROCESS STATES3.6. EXTERNALIZING RESOURCES3.6.1. Creating Resources3.6.1.1. Creating Simple Values3.6.1.1.1. Strings3.6.1.1.2. Colors3.6.1.1.3. Dimensions3.6.1.2. Styles and Themes3.6.1.3. Drawables3.6.1.4. Layouts3.6.1.5. Animations3.6.1.5.1. Tweened Animations3.6.1.5.2. Frame-by-Frame Animations3.6.1.6. Menus3.6.2. Using Resources3.6.2.1. Using Resources in Code3.6.2.2. Referencing Resources within Resources3.6.2.3. Using System Resources3.6.2.4. Referring to Styles in the Current Theme3.6.3. To-Do List Resources Example3.6.4. Creating Resources for Different Languages and Hardware3.6.5. Runtime Configuration Changes3.7. INTRODUCING THE ANDROID APPLICATION CLASS3.7.1. Extending and Using the Application Class3.7.2. Overriding the Application Life Cycle Events3.8. A CLOSER LOOK AT ANDROID ACTIVITIES3.8.1. Creating an Activity3.8.2. The Activity Life Cycle3.8.2.1. Activity Stacks3.8.2.2. Activity States3.8.2.3. Monitoring State Changes3.8.2.4. Understanding Activity Lifetimes3.8.2.4.1. The Full Lifetime3.8.2.4.2. The Visible Lifetime3.8.2.4.3. The Active Lifetime3.8.3. Android Activity Classes3.9. SUMMARY
4. Creating User Interfaces
4.1. FUNDAMENTAL ANDROID UI DESIGN4.2. INTRODUCING VIEWS4.2.1. Creating Activity User Interfaces with Views4.2.2. The Android Widget Toolbox4.3. INTRODUCING LAYOUTS4.3.1. Using Layouts4.3.2. Optimizing Layouts4.4. CREATING NEW VIEWS4.4.1. Modifying Existing Views4.4.1.1. Customizing Your To-Do List4.4.2. Creating Compound Controls4.4.3. Creating Custom Views4.4.3.1. Creating a New Visual Interface4.4.3.1.1. Drawing Your Control4.4.3.1.2. Sizing Your Control4.4.3.2. Handling User Interaction Events4.4.3.3. Creating a Compass View Example4.4.4. Using Custom Controls4.5. DRAWABLE RESOURCES4.5.1. Shapes, Colors, and Gradients4.5.1.1. Color Drawable4.5.1.2. Shape Drawable4.5.1.3. Gradient Drawable4.5.2. Composite Drawables4.5.2.1. Transformative Drawables4.5.2.2. Layer Drawable4.5.2.3. State List Drawables4.5.2.4. Level List Drawables4.5.3. NinePatch Drawable4.6. RESOLUTION AND DENSITY INDEPENDENCE4.6.1. The Resource Framework and Resolution Independence4.6.1.1. Resource Qualifiers for Screen Size and Pixel Density4.6.1.2. Specifying Supported Screen Sizes4.6.2. Best Practices for Resolution Independence4.6.2.1. Relative Layouts and Density-Independent Pixels4.6.2.2. Using Scalable Graphics Assets4.6.2.3. Provide Optimized Resources for Different Screens4.6.3. Testing, Testing, Testing4.6.3.1. Emulator Skins4.6.3.2. Testing for Custom Resolutions and Screen Sizes4.7. CREATING AND USING MENUS4.7.1. Introducing the Android Menu System4.7.2. Defining an Activity Menu4.7.3. Menu Item Options4.7.4. Dynamically Updating Menu Items4.7.5. Handling Menu Selections4.7.6. Submenus and Context Menus4.7.6.1. Creating Submenus4.7.6.2. Using Context Menus4.7.6.2.1. Creating Context Menus4.7.6.2.2. Handling Context Menu Selections4.7.7. Defining Menus in XML4.7.8. To-Do List Example Continued4.8. SUMMARY

5. Intents, Broadcast Receivers, Adapters, and the Internet
5.1. INTRODUCING INTENTS5.1.1. Using Intents to Launch Activities5.1.1.1. Explicitly Starting New Activities5.1.1.2. Implicit Intents and Late Runtime Binding5.1.1.3. Returning Results from Activities5.1.1.3.1. Launching Sub-Activities5.1.1.3.2. Returning Results5.1.1.3.3. Handling Sub-Activity Results5.1.1.4. Native Android Actions5.1.2. Using Intent Filters to Service Implicit Intents5.1.2.1. How Android Resolves Intent Filters5.1.2.2. Finding and Using the Launch Intent Within an Activity5.1.2.3. Passing on Responsibility5.1.2.4. Select a Contact Example5.1.3. Using Intent Filters for Plug-Ins and Extensibility5.1.3.1. Supplying Anonymous Actions to Applications5.1.3.2. Incorporating Anonymous Actions in Your Activity's Menu5.1.4. Introducing Linkify5.1.4.1. The Native Linkify Link Types5.1.4.2. Creating Custom Link Strings5.1.4.3. Using the Match Filter5.1.4.4. Using the Transform Filter5.1.5. Using Intents to Broadcast Events5.1.5.1. Broadcasting Events with Intents5.1.5.2. Listening for Broadcasts with Broadcast Receivers5.1.5.2.1. Registering Broadcast Receivers in Your Application Manifest5.1.5.2.2. Registering Broadcast Receivers in Code5.1.5.3. Broadcasting Sticky and Ordered Intents5.1.5.4. Native Android Broadcast Actions5.2. INTRODUCING PENDING INTENTS5.3. INTRODUCING ADAPTERS5.3.1. Introducing Some Native Adapters5.3.2. Customizing the Array Adapter5.3.3. Using Adapters for Data Binding5.3.3.1. Customizing the To-Do List Array Adapter5.3.3.2. Using the Simple Cursor Adapter5.4. USING INTERNET RESOURCES5.4.1. Connecting to an Internet Resource5.4.2. Using Internet Resources5.5. INTRODUCING DIALOGS5.5.1. Introducing the Dialog Classes5.5.1.1. The Alert Dialog Class5.5.1.2. Specialist Input Dialogs5.5.2. Using Activities as Dialogs5.5.3. Managing and Displaying Dialogs5.6. CREATING AN EARTHQUAKE VIEWER5.7. SUMMARY
6. Files, Saving State, and Preferences
6.1. SAVING SIMPLE APPLICATION DATA6.2. CREATING AND SAVING PREFERENCES6.3. RETRIEVING SHARED PREFERENCES6.4. CREATING A SETTINGS ACTIVITY FOR THE EARTHQUAKE VIEWER6.5. INTRODUCING THE PREFERENCE ACTIVITY AND PREFERENCES FRAMEWORK6.5.1. Defining a Preference Screen Layout in XML6.5.1.1. Native Preference Controls6.5.1.2. Using Intents to Import System Preference Screens6.5.2. Introducing the Preference Activity6.5.3. Finding and Using Preference Screen Shared Preferences6.5.4. Introducing Shared Preference Change Listeners6.6. CREATING A STANDARD PREFERENCE ACTIVITY FOR THE EARTHQUAKE VIEWER6.7. SAVING ACTIVITY STATE6.7.1. Saving and Restoring Instance State6.7.2. Saving the To-Do List Activity State6.8. SAVING AND LOADING FILES6.9. INCLUDING STATIC FILES AS RESOURCES6.10. FILE MANAGEMENT TOOLS6.11. SUMMARY
7. Databases and Content Providers
7.1. INTRODUCING ANDROID DATABASES7.1.1. Introducing SQLite Databases7.1.2. Introducing Content Providers7.2. INTRODUCING SQLite7.3. CURSORS AND CONTENT VALUES7.4. WORKING WITH SQLite DATABASES7.4.1. Introducing the SQLiteOpenHelper7.4.2. Opening and Creating Databases without SQLiteHelper7.4.3. Android Database Design Considerations7.4.4. Querying a Database7.4.5. Extracting Results from a Cursor7.4.6. Adding, Updating, and Removing Rows7.4.6.1. Inserting New Rows7.4.6.2. Updating a Row7.4.6.3. Deleting Rows7.4.7. Saving Your To-Do List7.5. CREATING A NEW CONTENT PROVIDER7.5.1. Exposing Access to the Data Source7.5.2. Registering Your Provider7.6. USING CONTENT PROVIDERS7.6.1. Introducing Content Resolvers7.6.2. Querying for Content7.6.3. Adding, Updating, and Deleting Content7.6.3.1. Inserts7.6.3.2. Deletes7.6.3.3. Updates7.6.4. Accessing Files in Content Providers7.7. CREATING AND USING AN EARTHQUAKE CONTENT PROVIDER7.7.1. Creating the Content Provider7.7.2. Using the Provider7.8. NATIVE ANDROID CONTENT PROVIDERS7.8.1. Using the Media Store Provider7.8.2. Using the Contacts Provider7.8.2.1. Introducing the Contacts Contract Content Provider7.8.2.2. Reading Contact Details7.8.2.3. Modifying and Augmenting Contact Details7.9. SUMMARY
8. Maps, Geocoding, and Location-Based Services
8.1. USING LOCATION-BASED SERVICES8.2. CONFIGURING THE EMULATOR TO TEST LOCATION-BASED SERVICES8.3. UPDATING LOCATIONS IN EMULATOR LOCATION PROVIDERS8.4. SELECTING A LOCATION PROVIDER8.4.1. Finding the Available Providers8.4.2. Finding Location Providers Using Criteria8.5. FINDING YOUR LOCATION8.5.1. 'Where Am I?' Example8.5.2. Tracking Movement8.5.3. Updating Your Location in 'Where Am I?'8.6. USING PROXIMITY ALERTS8.7. USING THE GEOCODER8.7.1. Reverse Geocoding8.7.2. Forward Geocoding8.7.3. Geocoding 'Where Am I?'8.8. CREATING MAP-BASED ACTIVITIES8.8.1. Introducing Map View and Map Activity8.8.2. Getting Your Maps API Key8.8.2.1. Getting Your Development/Debugging MD5 Fingerprint8.8.2.2. Getting your Production/Release MD5 Fingerprint8.8.3. Creating a Map-Based Activity8.8.4. Configuring and Using Map Views8.8.5. Using the Map Controller8.8.6. Mapping 'Where Am I?'8.8.7. Creating and Using Overlays8.8.7.1. Creating New Overlays8.8.7.2. Introducing Projections8.8.7.3. Drawing on the Overlay Canvas8.8.7.4. Handling Map Tap Events8.8.7.5. Adding and Removing Overlays8.8.7.6. Annotating 'Where Am I?'8.8.8. Introducing My Location Overlay8.8.9. Introducing Itemized Overlays and Overlay Items8.8.10. Pinning Views to the Map and Map Positions8.9. MAPPING EARTHQUAKES EXAMPLE8.10. SUMMARY
9. Working in the Background
9.1. INTRODUCING SERVICES9.1.1. Creating and Controlling Services9.1.1.1. Creating a Service9.1.1.2. Registering a Service in the Manifest9.1.1.3. Self-Terminating a Service9.1.1.4. Starting, Controlling, and Interacting with a Service9.1.1.5. An Earthquake Monitoring Service Example9.1.2. Binding Activities to Services9.1.3. Prioritizing Background Services9.2. USING BACKGROUND THREADS9.2.1. Using AsyncTask to Run Asynchronous Tasks9.2.1.1. Creating a new Asynchronous Task9.2.1.2. Running an Asynchronous Task9.2.2. Moving the Earthquake Service to a Background Thread Using AsyncTask9.2.3. Manual Thread Creation and GUI Thread Synchronization9.2.3.1. Creating a New Thread9.2.3.2. Using the Handler for Performing GUI Operations9.3. LET'S MAKE A TOAST9.3.1. Customizing Toasts9.3.2. Using Toasts in Worker Threads9.4. INTRODUCING NOTIFICATIONS9.4.1. Introducing the Notification Manager9.4.2. Creating Notifications9.4.2.1. Creating a Notification and Configuring the Status Bar Icon9.4.2.2. Configuring the Extended Status Notification Display9.4.3. Triggering Notifications9.4.4. Adding Notifications and Toasts to the Earthquake Monitor9.4.5. Advanced Notification Techniques9.4.5.1. Using the Defaults9.4.5.2. Making Sounds9.4.5.3. Vibrating the Phone9.4.5.4. Flashing the Lights9.4.6. Ongoing and Insistent Notifications9.5. USING ALARMS9.5.1. Setting Repeating Alarms9.5.2. Using Repeating Alarms to Update Earthquakes9.6. SUMMARY
10. Invading the Phone-Top
10.1. INTRODUCING HOME-SCREEN WIDGETS10.2. CREATING APP WIDGETS10.2.1. Creating the Widget Layout10.2.1.1. Widget Design Guidelines10.2.1.1.1. Widget Layout Sizes10.2.1.1.2. Widget Visual Styling10.2.1.2. Supported Widget Views and Layouts10.2.2. Defining Your Widget Settings10.2.3. Creating Your Widget Intent Receiver and Adding It to the Application Manifest10.2.4. Introducing Remote Views and the App Widget Manager10.2.4.1. Creating Remote Views and Using the App Widget Manager to Apply Them10.2.4.2. Using a Remote View within the App Widget Provider's onUpdate Handler10.2.4.3. Using Remote Views to Modify UI10.2.4.4. Making Your Widgets Interactive10.2.4.4.1. Using a Click Listener10.2.4.4.2. Changing Image Views Based on Selection Focus10.2.5. Refreshing Your Widgets10.2.5.1. Using the Minimum Update Rate10.2.5.2. Listening for Intents10.2.5.3. Using Alarms10.2.6. Creating and Using a Widget Configuration Activity10.3. CREATING AN EARTHQUAKE WIDGET10.4. INTRODUCING LIVE FOLDERS10.4.1. Creating Live Folders10.4.1.1. Live Folder Content Providers10.4.1.2. Live Folder Activity10.4.2. Creating an Earthquake Live Folder10.5. ADDING SEARCH TO YOUR APPLICATIONS AND THE QUICK SEARCH BOX10.5.1. Adding Search to Your Application10.5.1.1. Creating a Search Activity10.5.1.2. Responding to Search Queries from a Content Provider10.5.2. Surfacing Search Results to the Quick Search Box10.5.3. Adding Search to the Earthquake Example10.6. CREATING LIVE WALLPAPER10.6.1. Creating a Live Wallpaper Definition Resource10.6.2. Creating a Wallpaper Service10.6.3. Creating a Wallpaper Service Engine10.7. SUMMARY
11. Audio, Video, and Using the Camera
11.1. PLAYING AUDIO AND VIDEO11.1.1. Introducing the Media Player11.1.2. Preparing Audio for Playback11.1.2.1. Packaging Audio as an Application Resource11.1.2.2. Initializing Audio Content for Playback11.1.3. Preparing for Video Playback11.1.3.1. Playing Video Using the Video View11.1.3.2. Setting up a Surface for Video Playback11.1.3.3. Initializing Video Content for Playback11.1.4. Controlling Playback11.1.5. Managing Media Playback Output11.2. RECORDING AUDIO AND VIDEO11.2.1. Using Intents to Record Video11.2.2. Using the Media Recorder11.2.2.1. Configuring and Controlling Video Recording11.2.2.2. Previewing Video Recording11.3. USING THE CAMERA AND TAKING PICTURES11.3.1. Using Intents to Take Pictures11.3.2. Controlling the Camera and Taking Pictures11.3.2.1. Controlling and Monitoring Camera Settings and Image Options11.3.2.2. Monitoring Auto Focus11.3.2.3. Using the Camera Preview11.3.2.4. Taking a Picture11.3.3. Reading and Writing JPEG EXIF Image Details11.4. ADDING NEW MEDIA TO THE MEDIA STORE11.4.1.11.4.1.1. Using the Media Scanner11.4.1.2. Inserting Media into the Media Store11.5. RAW AUDIO MANIPULATION11.5.1. Recording Sound with Audio Record11.5.2. Playing Sound with Audio Track11.6. SPEECH RECOGNITION11.7. SUMMARY
12. Telephony and SMS
12.1. TELEPHONY12.1.1. Launching the Dialer to Initiate Phone Calls12.1.2. Replacing the Native Dialer12.1.3. Accessing Phone and Network Properties and Status12.1.3.1. Reading Phone Device Details12.1.3.2. Reading Data Connection and Transfer State12.1.3.3. Reading Network Details12.1.3.4. Reading SIM Details12.1.4. Monitoring Changes in Phone State, Phone Activity, and Data Connections12.1.4.1. Monitoring Incoming Phone Calls12.1.4.2. Tracking Cell Location Changes12.1.4.3. Tracking Service Changes12.1.4.4. Monitoring Data Connectivity and Activity12.2. INTRODUCING SMS AND MMS12.2.1. Using SMS and MMS in Your Application12.2.2. Sending SMS and MMS from Your Application Using Intents and the Native Client12.2.3. Sending SMS Messages Manually12.2.3.1. Sending Text Messages12.2.3.2. Tracking and Confirming SMS Message Delivery12.2.3.3. Conforming to the Maximum SMS Message Size12.2.3.4. Sending Data Messages12.2.4. Listening for Incoming SMS Messages12.2.4.1. Simulating Incoming SMS Messages in the Emulator12.2.4.2. Handling Data SMS Messages12.2.5. Emergency Responder SMS Example12.2.6. Automating the Emergency Responder12.3. SUMMARY
13. Bluetooth, Networks, and Wi-Fi
13.1. USING BLUETOOTH13.1.1. Accessing the Local Bluetooth Device Adapter13.1.2. Managing Bluetooth Properties and State13.1.3. Being Discoverable and Remote Device Discovery13.1.3.1. Managing Device Discoverability13.1.3.2. Discovering Remote Devices13.1.4. Bluetooth Communications13.1.4.1. Opening a Bluetooth Server Socket Listener13.1.4.2. Selecting Remote Bluetooth Devices for Communications13.1.4.2.1. Bluetooth Device Connection Requirements13.1.4.2.2. Finding a Bluetooth Device to Connect To13.1.4.3. Opening a Client Bluetooth Socket Connection13.1.4.4. Transmitting Data Using Bluetooth Sockets13.1.5. Bluetooth Data Transfer Example13.2. MANAGING NETWORK CONNECTIVITY13.2.1. Introducing the Connectivity Manager13.2.2. Reading User Preferences for Background Data Transfer13.2.3. Monitoring Network Details13.2.4. Finding and Configuring Network Preferences and Controlling Hardware Radios13.2.5. Monitoring Network Connectivity13.3. MANAGING YOUR WI-FI13.3.1. Monitoring Wi-Fi Connectivity13.3.2. Monitoring Active Connection Details13.3.3. Scanning for Hotspots13.3.4. Managing Wi-Fi Configurations13.3.5. Creating Wi-Fi Network Configurations13.4. SUMMARY
14. Sensors
14.1. USING SENSORS AND THE SENSOR MANAGER14.1.1. Introducing Sensors14.1.1.1. Supported Android Sensors14.1.1.2. Finding Sensors14.1.1.3. Using Sensors14.2. INTERPRETING SENSOR VALUES14.3. USING THE COMPASS, ACCELEROMETER, AND ORIENTATION SENSORS14.3.1. Introducing Accelerometers14.3.2. Detecting Acceleration Changes14.3.3. Creating a G-Forceometer14.3.4. Determining Your Orientation14.3.4.1. Determining Orientation Using the Orientation Sensor14.3.4.2. Calculating Orientation Using the Accelerometer and Magnetic Field Sensors14.3.4.3. Remapping the Orientation Reference Frame14.3.5. Creating a Compass and Artificial Horizon14.4. CONTROLLING DEVICE VIBRATION14.5. SUMMARY
15. Advanced Android Development
15.1. PARANOID ANDROID15.1.1. Linux Kernel Security15.1.2. Introducing Permissions15.1.3. Declaring and Enforcing Permissions15.1.4. Enforcing Permissions for Broadcast Intents15.2. USING WAKE LOCKS15.3. INTRODUCING ANDROID TEXT TO SPEECH15.4. USING AIDL TO SUPPORT IPC FOR SERVICES15.4.1. Implementing an AIDL Interface15.4.2. Passing Class Objects as Parcelables15.4.2.1. Creating the AIDL Service Definition15.4.3. Implementing and Exposing the IPC Interface15.5. USING INTERNET SERVICES15.6. BUILDING RICH USER INTERFACES15.6.1. Working with Animations15.6.1.1. Introducing Tweened Animations15.6.1.2. Creating Tweened Animations15.6.1.3. Applying Tweened Animations15.6.1.4. Using Animation Listeners15.6.1.5. Animated Sliding User Interface Example15.6.1.6. Animating Layouts and View Groups15.6.1.6.1. Creating Layout Animations15.6.1.6.2. Using Layout Animations15.6.1.7. Creating and Using Frame-by-Frame Animations15.6.2. Advanced Canvas Drawing15.6.2.1. What Can You Draw?15.6.2.2. Getting the Most from Your Paint15.6.2.2.1. Using Translucency15.6.2.2.2. Introducing Shaders15.6.2.2.3. Defining Gradient Shaders15.6.2.2.4. Using Shader Tile Modes15.6.2.2.5. Using Mask Filters15.6.2.2.6. Using Color Filters15.6.2.2.7. Using Path Effects15.6.2.2.8. Changing the Xfermode15.6.2.3. Improving Paint Quality with Anti-Aliasing15.6.2.4. Canvas Drawing Best Practice15.6.2.5. Advanced Compass Face Example15.6.2.6. Bringing Map Overlays to Life15.6.3. Introducing the Surface View15.6.3.1. When Should You Use a Surface View?15.6.3.2. Creating a New Surface View15.6.3.3. Creating 3D Controls with a Surface View15.6.4. Creating Interactive Controls15.6.4.1. Using the Touch Screen15.6.4.1.1. Processing Single and Multiple Touch Events15.6.4.1.2. Tracking Movement15.6.4.1.3. Using an On Touch Listener15.6.4.2. Using the Device Keys, Buttons, and D-Pad15.6.4.3. Using the On Key Listener15.6.4.4. Using the Trackball15.7. SUMMARY

Content preview from Professional Android™ 2 Application Development

Chapter 6. Files, Saving State, and Preferences

WHAT'S IN THIS CHAPTER?

Persisting simple application data
Saving Activity instance data between sessions
Creating Preference Screens and managing application preferences
Saving and loading files and managing the local file system
Including static files as external resources

In this chapter you'll be introduced to two of the simplest but most versatile data persistence techniques in Android — Shared Preferences and local files.

Saving and loading data are essential for most applications. At a minimum, an Activity should save its user interface (UI) state each time it moves into the background. This ensures that the same UI state is presented when the Activity returns to the foreground, even if the process has been killed and restarted before that happens.

It's also likely that you'll need to save user application preferences and UI selections or data entry. Android's nondeterministic Activity and application lifetimes make persisting UI state and application data between sessions particularly important. Android offers several alternatives for saving application data, each optimized to fulfill a particular need.

Shared Preferences are a simple, lightweight key/value pair mechanism for saving primitive application data, most commonly a user's application preferences. Android also provides access to the local file system, through both specialized methods and the normal Java.IO classes.

SAVING SIMPLE APPLICATION DATA

The data-persistence techniques ...

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Professional Android™ 2 Application Development

by Reto Meier

Chapter 6. Files, Saving State, and Preferences

SAVING SIMPLE APPLICATION DATA

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