Xamarin in Action: Creating native cross-platform mobile apps

2018·14.38 MB·English

by  Jim Bennett

Creating native cross-platform mobile apps
Jim Bennett
F James Montemagno
OREWORDBY
M A N N I N G
A sneak peak...
By building Xamarin apps using the MVVM design pattern, you too can reuse
80% of your code across iOS and Android.
iOS Android
C# C#
App
layer
C#
UI layer C# C# View
Binding
UI logic View
C#
layer model
Business
C# Model
logic layer
Picking the right thread...
We all hate mobile apps that are unresponsive. Here’s how to decide what to run
on a background thread.
Does this use Does this take UI thread or
Does this No No No
external resources more than 100 ms background
involve the UI?
(DB, web)? on a slow device? thread
Yes Yes Yes
Background Background
UI thread
thread thread
Xamarin in Action
CREATING NATIVE CROSS-PLATFORM
MOBILE APPS
JIM BENNETT
MANNING
SHELTERISLAND
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brief contents
PART 1 GETTING STARTED WITH XAMARIN....................................1
1 ■ Introducingnativecross-platformapplicationswithXamarin 3
2 ■ HelloMVVM—creatingasimplecross-platform
appusingMVVM 25
3 ■ MVVM—themodel-view–viewmodeldesignpattern 50
4 ■ Helloagain,MVVM—understandingandenhancingoursimple
MVVMapp 81
5 ■ Whatarewe(a)waitingfor?Anintroductiontomultithreading
forXamarinapps 113
PART 2 BUILDING APPS.............................................................153
6 ■ DesigningMVVMcross-platformapps 155
7 ■ Buildingcross-platformmodels 195
8 ■ Buildingcross-platformviewmodels 241
9 ■ BuildingsimpleAndroidviews 288
10 ■ BuildingmoreadvancedAndroidviews 319
11 ■ BuildingsimpleiOSviews 345
12 ■ BuildingmoreadvancediOSviews 385
v
vi BRIEFCONTENTS
PART 3 FROM WORKING CODE TO THE STORE............................409
13 ■ Runningmobileappsonphysicaldevices 411
14 ■ TestingmobileappsusingXamarinUITest 436
15 ■ UsingAppCentertobuild,test,andmonitorapps 467
16 ■ Deployingappstobetatestersandthestores 505
contents
foreword xv
preface xvii
acknowledgments xix
aboutthisbook xxi
aboutthecoverillustration xxvi
PART 1 GETTING STARTED WITH XAMARIN.................... 1
1 Introducing native cross-platform applications with Xamarin 3
1.1 IntroducingXamarinmobileapps 4
Vendor-specificnativeapps 5 ■ Cordova 6 ■ Xamarinnative
apps 7 ■ Xamarin.Forms 10 ■ Xamarindevelopertools 12
Mobile-optimizeddevelopmentlifecycle 13
1.2 Creatingproduction-qualitymobileapps 14
Design 15 ■ Develop 17 ■ Test 18 ■ Build 21
Distribute 22 ■ Monitor 22
1.3 Rinseandrepeat… 23
2 Hello MVVM—creating a simple cross-platform
app using MVVM 25
2.1 WhatareUIdesignpatterns? 26
2.2 MVVM—thedesignpatternforXamarinapps 27
2.3 Whatiscross-platformcode? 31
.NETStandardclasslibraries 32
vii
viii CONTENTS
2.4 Gettingstarted—creatingyourfirstsolution 34
Requirements—whathardwareorsoftwaredoyouneedforeach
mobileplatform? 35 ■ Creatingthesolution 36 ■ Whathavewe
justcreated? 42 ■ Buildingandrunningtheapps 43
2.5 Isthisreallyacross-platformapp? 47
3 MVVM—the model-view–view model design pattern 50
3.1 Themodellayer 52
3.2 Theview-modellayer 53
Stateandbehavior 54 ■ Valueconversion 65 ■ Testability 67
3.3 Theviewlayer 68
3.4 Binding 69
Sourceandtarget 69 ■ Bindingmode 70 ■ Bindingisnot
cross-platform 70 ■ Valueconverters 72
3.5 Theapplicationlayer 74
3.6 Navigation 75
View-first 76 ■ View-model–first 76 ■ Whichonetouse? 78
3.7 Revisitingthesquare-rootcalculatorapp 78
4 Hello again, MVVM—understanding and
enhancing our simple MVVM app 81
4.1 AdeeperdiveintoourHelloCross-PlatformWorld
app 82
Themodel 82 ■ Theviewmodel 82 ■ Theapplication
layer 83 ■ Theview 84
4.2 ExpandingonourHelloWorldapp 92
Using.NETStandardpluginstoaccessdevice-specificcode 93
InstallingtheXamarintext-to-speechplugin 95 ■ Addingthe
cross-platformcode 97 ■ Inversionofcontrol 98 ■ Wiringupthe
AndroidUI 105 ■ WiringuptheiOSUI 106
5 What are we (a)waiting for? An introduction to multithreading
for Xamarin apps 113
5.1 Whydoweneedmultithreadedcode? 114
5.2 Whatarethreads? 117
Buyingcoffee 117 ■ Sowhatisathread? 120 ■ Aquick
roundup 121