Understanding Android Application Development

Rakeeb helped participants get basic understanding of Android Studio, Gradle build system, Android's fundamental application components, basic Android development patterns, common operations performed by an Android application, various tools, platforms and libraries assisting towards a smooth development process and various sources of inspiration and knowledge for Android. Ncell App Camp 2015.

Transcript

1. Understanding Android Application Development Rakeeb Rajbhandari
2. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ Understanding the Android gradle plugin ➔ Recommendations
3. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ Understanding the Android gradle plugin ➔ Recommendations
4. Planning the development process 1. Identify your problem statement a. What problem is your application trying to address 2. Understand your target users a. Who are your users, their goals and requirements 3. Understand a minimally viable solution set a. Plan to release a basic functional application ASAP b. Plan for incremental updates taking advantage of efficient upgrade paths offered via regular updates 4. Build prototypes and mock-ups for your application a. Gives you a sense of direction and feel for the application before development
5. Planning the development process (Contd.) 5. Establish a user testing focus group a. Get insights on what the users are looking for b. Use closed beta testing using Google Groups or Google+ communities c. Great platform to get user feedback and feature requests and catch bugs d. Make changes to application accordingly 6. Plan for multiple releases a. New features re-engage users b. 2-3 months interval for major releases is recommended
6. Planning the development process (Contd.) 7. Know what’s out there a. Skim through competitors as well as various alternatives b. Take inspiration from them 8. Decide on technology you can live (and grow) with a. Includes libraries, analytics tools and cloud platforms powering your application 9. Plan to analyze a. Define milestones and ways to measure success b. Review your process
7. Planning the development process (Contd.) ➔ Further readings: ◆ 10 Things to Plan for When Developing a Mobile App ◆ Alpha/Beta testing for users ◆ Google Analytics ◆ Google Cloud Platform ◆ Fabric ◆ Firebase ◆ Martin's series on creating your own Android app blog
8. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ 3rd party libraries ➔ Understanding the Android gradle plugin
9. Getting to know your APIs ➔ Best source of knowledge: ◆ Android developers section ➔ Recommended navigation path: ◆ API Guides ◆ Training ◆ API References
10. Getting to know your APIs (Contd.) ➔ Browse through samples, open source projects and other applications
11. Getting to know your APIs (Contd.) ➔ Browse through samples, open source projects and other applications
12. Getting to know your APIs (Contd.) ➔ Recommended app: Libraries for developers
13. Getting to know your tools ➔ Best source of knowledge: ◆ Android tools section ◆ Android tools project site ◆ Android Support Library ◆ Data Binding Library
14. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ Understanding the Android gradle plugin ➔ Recommendations
15. Implementing Material Design ➔ Step 1: Include the support appcompat and design library in your project dependencies compile "com.android.support: appcompat-v7:23.1.0" compile "com.android.support: design:23.1.0" ➔ Step 2: Define the theme for your application <style name="AppTheme" parent=" Theme.AppCompat.Light" /> To use toolbars be sure to disable the action bar and window title <item name="windowActionBar">false</item> <item name=" windowNoTitle">true</item>
16. Implementing Material Design (Contd.) ➔ Step 3: Extend the AppCompatActivity ➔ Step 4: Survey through various UI elements to be initialized
17. Material Design Elements 1. Toolbar
18. Material Design Elements (Contd.) 2. Floating Action Button
19. Material Design Elements (Contd.) 3. Navigation View
20. Material Design Elements (Contd.) 4. Coordinator Layout, Appbar Layout and Collapsing Toolbar
21. Material Design Elements (Contd.) 5. Tab Layouts
22. Material Design Elements (Contd.) 6. Snackbars
23. Material Design Elements (Contd.) 7. TextInputLayout
24. Material Design Elements (Contd.) 8. Material Icons a. Import the design icons from Android Studio as Vector Assets
25. Material Design Elements (Contd.) 8. Material Icons b. Material icons are available for download c. Use the Android Iconics library for access to tons of design icons
26. Implementing Material Design (Contd.) ➔ Be sure to check out the Material Design Guidelines ➔ Make sure your application adheres to Metrics and Keyline through Keyline Pushing
27. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ Understanding the Android gradle plugin ➔ Recommendations
28. Supporting multiple devices 1. Screen size a. Actual physical size, measured as the screen's diagonal 2. Screen density a. The quantity of pixels within a physical area of the screen; usually referred to as dpi (dots per inch)
29. Supporting multiple devices (Contd.) ➔ Four generalized sizes ◆ small, normal, large, and xlarge ➔ Set of six generalized densities ◆ ldpi (low) ~120dpi ◆ mdpi (medium) ~160dpi ◆ hdpi (high) ~240dpi ◆ xhdpi (extra-high) ~320dpi ◆ xxhdpi (extra-extra-high) ~480dpi ◆ xxxhdpi (extra-extra-extra-high) ~640dpi ➔ Formula: px = dp * (dpi / 160)
30. Supporting multiple devices (Contd.) 3. Configuring resource qualifiers a. <resources_name>-<config_qualifier> i. <resources_name> is the directory name of the corresponding default resources. ii. <qualifier> is a name that specifies an individual configuration for which these resources are to be used. iii. You can append more than one <qualifier>. Separate each one with a dash.
31. Supporting multiple devices (Contd.) ➔ Further readings: ◆ Official documentation ◆ Android UI tutorial ◆ Understanding pixel density ◆ New tools for managing screen sizes ◆ Supporting different screen sizes ◆ Providing Resources
32. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ Understanding the Android gradle plugin ➔ Recommendations
33. Network operations
34. Network operations ➔ Common operations: ◆ Defining a HTTP client ◆ Checking if network is available ◆ Performing network operations on a separate thread ◆ Connection and data download ◆ Converting InputStream to String ➔ PRO-TIP Always fetch JSON data wherever possible, it’s relatively easier working with them, as opposed to working with XML responses.
35. Network operations (Contd.) ➔ PRO-TIP Serialize JSON to Java Objects. ◆ Using ‘gson’ • Provides simple toJson() and fromJson() methods to convert Java objects to JSON and vice-versa ◆ Generate POJO’s via jsonschem2pojo ➔ PRO-TIP Use ‘OkHttp’ as your default HTTP client and use ‘Retrofit’ to make api requests
36. Listing items
37. Listing items ➔ Use ListView, GridView or RecyclerView according to your need
38. ListView RecyclerView
39. ListView RecyclerView ➔ Rigid API ➔ Provides a lot of functionality out of the box ◆ setEmptyView() ◆ addHeaderView() ◆ addFooterView() ➔ Flexible API ➔ Separation of concerns ➔ Plug and play ◆ Add ItemDecoration ◆ Add LayoutManager ◆ Add ItemAnimator
40. Listing items (Contd.) ➔ PRO-TIP Data bind all things! ◆ Removes boilerplate code for view and view data initialization ◆ Allows custom attribute definition for views
41. Saving Data ➔ Working with data presents us with the following options: ◆ Using Preferences • SharedPreferences allows us to store primitive data in ‘key-value’ pairs ◆ Using Storage • Either use cache or directly store files ◆ Using Database ➔ PRO-TIP Use libraries like DiskLruCache, Picasso, GreenDAO, Tray, Realm, etc. to make development process easier. ➔ PRO-TIP Use ORM’s or POJO’s when working with Cursors.
42. Debugging
43. Debugging ➔ adb ◆ middleman between a device and your development system ➔ DDMS ◆ DDMS is a graphical program that communicates with your devices through adb ◆ DDMS can be used to: • Capture screenshots • Spoof incoming calls and messages • Mock locations • Memory profiling
44. Debugging (Contd.) ➔ Use ‘Log’ to send log outputs ◆ Common logging methods include: • v(String, String) (verbose) • d(String, String) (debug) • i(String, String) (information) • w(String, String) (warning) • e(String, String) (error) ➔ PRO-TIP Use Timber and Stetho to make your application development friendly.
45. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ Understanding the Android gradle plugin ➔ Recommendations
46. Build Tools “Build tools are series of executable & ordered tasks that lead to source code compilation and assemblance of a deliverable” ➔ General anatomy of a build tool comprises of: ◆ Build files ◆ Build inputs & outputs ◆ Build engines ◆ Dependency manager
47. ➔ Gradle is a build tool ➔ Gradle takes inspiration from Ant, Maven, Ivy and uses Groovy as a DSL ➔ Gradle is based on plugins ◆ Plugins define tasks
48. Android Gradle Plugin apply plugin: 'com.android.application'
50. android { compileSdkVersion 23 buildToolsVersion "23.0.1" defaultConfig { applicationId "com.appcampdemo" minSdkVersion 15 targetSdkVersion 23 versionCode 1 versionName "1.0" } ... }
51. AppExtension ➔ 'android' extension for 'com.android.application' project. ➔ Required properties: ◆ buildToolsVersion ◆ compileSdkVersion
52. android { compileSdkVersion 23 buildToolsVersion "23.0.1" defaultConfig { applicationId "com.appcampdemo" minSdkVersion 15 targetSdkVersion 23 versionCode 1 versionName "1.0" } ... }
53. AppExtension: ProductFlavor (defaultConfig) ➔ defaultConfig is a ‘ProductFlavor’ ➔ What are Product Flavors ? ◆ “A product flavor defines a customized version of the application build by the project. A single project can have different flavors which change the generated application.” ➔ Default configuration shared by all product flavors ➔ Contains basic properties such as applicationId, versionName, etc. ➔ Mainly consists of variables that were previously assigned in ‘AndroidManifest.xml’
54. AppExtension: ProductFlavor (defaultConfig) ➔ PRO-TIP BuildConfig class is generated for each product flavor, use it if(BuildConfig.DEBUG) { ... } StringBuilder requestBody = new StringBuilder(); requestBody.append(BuildConfig.baseUrl);
55. AppExtension: ProductFlavor (defaultConfig) ➔ PRO-TIP Use ‘buildConfigField’ or ‘resValue’ to define variables specific to your flavor defaultConfig { … buildConfigField('String', 'baseUrl', "...") resValue(‘string’, ‘appName’, “...”) }
56. android { compileSdkVersion 23 buildToolsVersion "23.0.1" buildTypes { ... } ... }
57. AppExtension: BuildTypes ➔ A build type allows configuration of how an application is packaged for debugging or release purpose. buildTypes { release { minifyEnabled false ... } debug { applicationIdSuffix ".debug" ... } }
58. android { compileSdkVersion 23 buildToolsVersion "23.0.1" productFlavor { free { ... } paid { ... } } ... }
59. AppExtension: ProductFlavor ➔ Provides a great way to separate builds for your app productFlavor { free { buildConfigField ‘int’, ‘SIGNING_KEY’, ‘xxx’ ... } paid { buildConfigField ‘int’, ‘SIGNING_KEY’, ‘yyy’ ... } }
60. AppExtension: BuildTypes & ProductFlavor ➔ PRO-TIP Structure your project to accommodate changes for debug and different flavor builds
61. Table of Contents ➔ Planning the development process ➔ Getting to know your APIs and tools ➔ Implementing Material Design ➔ Supporting multiple devices ➔ Common operations performed by applications ➔ Understanding the Android gradle plugin ➔ Recommendations
62. Recommendations ➔ GAS© your problems ◆ G >> Google your problems ◆ A >> Ask for help (stack overflow, groups, forums, etc.) ◆ S >> Search for alternatives
63. ➔ Communities to join: ◆ Android Development ◆ Android projects on Github ◆ Android performance patterns ◆ Android Studio
64. ➔ People to follow: ◆ Chet Haase ◆ Chris Banes ◆ Colt McAnlis ◆ Ian Lake ◆ Roman Nurik, and other people from the Android team add google developer experts and don’t forget to follow me :)
65. ➔ Podcasts ◆ Android Developers Backstage ◆ Designer Notes ◆ Fragmented Podcast ◆ The Blerg ◆ The Java Posse
66. ➔ Channels to follow ◆ Android Developers ◆ Android Dialogs ◆ Google Developers ◆ NewCircle Training ◆ Search for “droidcon” on Youtube
67. ➔ Inspiration ◆ Android Niceties ◆ Android Experiments ◆ MaterialUp ◆ Material design awards ◆ Panda
68. Watch Silicon Valley
69. Thank you Github: rakeeb11 Google+: Rakeeb Rajbhandari Stack overflow: Rakeeb Rajbhandari Twitter: @RakeebJH11