Using the Touchscreen and Sensors | Android 9 Development Cookbook

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Android 9 Development Cookbook

By : Boyer

3.4 (9)

Android 9 Development Cookbook

3.4 (9)

By: Boyer

Overview of this book

The Android OS has the largest installation base of any operating system in the world. There has never been a better time to learn Android development to write your own applications, or to make your own contributions to the open source community! With this extensively updated cookbook, you'll find solutions for working with the user interfaces, multitouch gestures, location awareness, web services, and device features such as the phone, camera, and accelerometer. You also get useful steps on packaging your app for the Android Market. Each recipe provides a clear solution and sample code you can use in your project from the outset. Whether you are writing your first app or your hundredth, this is a book that you will come back to time and time again, with its many tips and tricks on the rich features of Android Pie.

Preface

Preface

Who this book is for

What this book covers

To get the most out of this book

Sections

Get in touch

Free Chapter

Activities

Activities

Introduction

Declaring an activity

Starting a new activity with an intent object

Switching between activities

Passing data to another activity

Returning a result from an activity

Saving an activity's state

Storing persistent activity data

Understanding the activity life cycle

Layouts

Layouts

Introduction

Defining and inflating a layout

Using RelativeLayout

Using LinearLayout

Creating tables – TableLayout and GridLayout

RecyclerView replaces ListView

Changing layout properties during runtime

Views, Widgets, and Styles

Views, Widgets, and Styles

Introduction

Inserting a widget into a layout

Using graphics to show button state

Creating a widget at runtime

Creating a custom component

Applying a style to a View

Turning a style into a theme

Selecting a theme based on the Android version

Menus and Action Mode

Menus and Action Mode

Introduction

Creating an options menu

Modifying menus and menu items during runtime

Enabling Contextual Action Mode for a view

Using Contextual Batch Mode with RecyclerView

Creating a pop-up menu

Fragments

Fragments

Introduction

Creating and using a Fragment

Adding and removing Fragments during runtime

Passing data between Fragments

Handling the Fragment back stack

Home Screen Widgets, Search, and the System UI

Home Screen Widgets, Search, and the System UI

Introduction

Creating a shortcut on the Home screen

Creating a Home screen widget

Adding Search to the Action Bar

Showing your app full-screen

Data Storage

Data Storage

Introduction

Storing simple data

Read and write a text file to internal storage

Read and write a text file to external storage

Including resource files in your project

Creating and using an SQLite database

Accessing data in the background using a Loader

Accessing external storage with scoped directories in Android N

Alerts and Notifications

Alerts and Notifications

Introduction

Lights, Action, and Sound – getting the user's attention!

Creating a Toast with a custom layout

Displaying a message box with AlertDialog

Displaying a progress dialog

Lights, Action, and Sound Redux using Notifications

Creating a Media Player Notification

Making a Flashlight with a Heads-Up Notification

Notifications with Direct Reply

Using the Touchscreen and Sensors

Using the Touchscreen and Sensors

Introduction

Listening for click and long-press events

Recognizing tap and other common gestures

Pinch-to-zoom with multi-touch gestures

Swipe-to-Refresh

Listing available sensors – an introduction to the Android Sensor Framework

Reading sensor data – using Android Sensor Framework events

Reading device orientation

Graphics and Animation

Graphics and Animation

Introduction

Scaling down large images to avoid Out of Memory exceptions

A transition animation – defining scenes and applying a transition

Creating a Compass using sensor data and RotateAnimation

Creating a slideshow with ViewPager

Creating a Card Flip Animation with Fragments

Creating a Zoom Animation with a Custom Transition

Displaying animated image (GIF/WebP) with the new ImageDecoder library

Creating a circle image with the new ImageDecoder

A First Look at OpenGL ES

A First Look at OpenGL ES

Introduction

Setting up the OpenGL ES environment

Drawing shapes on GLSurfaceView

Applying the projection and camera view while drawing

Moving the triangle with rotation

Rotating the triangle with user input

Multimedia

Multimedia

Introduction

Playing sound effects with SoundPool

Playing audio with MediaPlayer

Responding to hardware media controls in your app

Taking a photo with the default camera app

Taking a picture using the Camera2 API

Telephony, Networks, and the Web

Telephony, Networks, and the Web

Introduction

How to make a phone call

Monitoring phone call events

How to send SMS (text) messages

Receiving SMS messages

Displaying a web page in your application

Checking online status and connection type

Phone number blocking API

Location and Using Geofencing

Location and Using Geofencing

Introduction

How to get the device location

Resolving problems reported with the GoogleApiClient OnConnectionFailedListener

Creating and monitoring a Geofence

Getting Your App Ready for the Play Store

Getting Your App Ready for the Play Store

Introduction

The Android 6.0 Runtime Permission Model

How to schedule an alarm

Receiving notification of device boot

Using the AsyncTask for background work

Adding speech recognition to your app

How to add Google sign-in to your app

Getting Started with Kotlin

Getting Started with Kotlin

Introduction

How to create an Android project with Kotlin

Creating a Toast in Kotlin

Runtime permission in Kotlin

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Recognizing tap and other common gestures

Unlike the Event Listeners described in the previous recipe, gestures require a two-step process:

Gather movement data
Analyze the data to determine whether it matches a known gesture

Step 1 begins when the user touches the screen, which fires the onTouchEvent() callback with the movement data sent in a MotionEvent object. Fortunately, Android makes step 2, analyzing the data, easier with the GestureDetector class, which detects the following gestures:

onTouchEvent()
onDown()
onFling()
onLongPress()
onScroll()
onShowPress()
onDoubleTap()
onDoubleTapEvent()
onSingleTapConfirmed()

This recipe will demonstrate using GestureDetector.SimpleOnGestureListener to recognize the touch and double tap gestures.

Getting ready

Create a new project in Android Studio and call it CommonGestureDetector. Use the default Phone & Tablet options and select Empty Activity when prompted for the Activity Type.

How to do it...

We will be using the activity itself to detect gestures, so...

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