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Introduction to React Native Workshop | PDF
September 2018
Introduction to

React Native
Nacho Martín
Nacho Martin
I write code at Limenius.
We build tailor-made projects,
and provide consultancy
and formation.
We are very happy with React and React Native.
https://github.com/Limenius/workshop-react-native.git
Before we start
🙏
Please go to where you have cloned the repo
of the project
And run git fetch
Goal of the workshop
To be able to estimate how long would
it take you to create a first React Native
project (and if you would enjoy it)
Roadmap:
What is React Native
Starting a project
Working with Styles
Layout
Lists
Navigation
Networking
Touching the native side
What is React Native?
Fundamental premise of React
Give me a state and a render() method
that depends on it and forget about
how and when to render.
render() {
return (
<div className="App">
<button onClick={this.tick}>Click me!</button>
<span>Clicks: {this.state.count}</span>
</div>
)
}
render() {
return (
<div className="App">
<button onClick={this.tick}>Click me!</button>
<span>Clicks: {this.state.count}</span>
</div>
)
}
render() {
return (
<View style={…}>
<Button onPress={this.tick}>Click me!</Button>
<Text>Clicks: {this.state.count}</Text>
</View>
)
}
render() {
return (
<div className="App">
<button onClick={this.tick}>Click me!</button>
<span>Clicks: {this.state.count}</span>
</div>
)
}
render() {
return (
<View style={…}>
<Button onPress={this.tick}>Click me!</Button>
<Text>Clicks: {this.state.count}</Text>
</View>
)
}
render() {
return (
<div className="App">
<button onClick={this.tick}>Click me!</button>
<span>Clicks: {this.state.count}</span>
</div>
)
}
render() {
return (
<View style={…}>
<Button onPress={this.tick}>Click me!</Button>
<Text>Clicks: {this.state.count}</Text>
</View>
)
}
React Native
How is this possible
Reconciliation
Determines what parts
of the tree have changed
How is this possible
Reconciliation
Determines what parts
of the tree have changed
Rendering
Actually
updates the app
How is this possible
Reconciliation
Determines what parts
of the tree have changed
Rendering
Actually
updates the app
We can have several
renderers
React targets
Main
react-dom react-native
Web iOS android
React targets
Main
react-dom react-native
Web iOS android
But also
React targets
Main
react-dom react-native
Web iOS android
But also
react-art  react-canvas react-three ReactLibertyreact-worker-dom
React targets
Main
react-dom react-native
Web iOS android
But also
react-art  react-canvas react-three ReactLibertyreact-worker-dom
react-konsul raxreact-native  react-blessedreact-tvml
React targets
Main
react-dom react-native
Web iOS android
But also
react-art  react-canvas react-three ReactLibertyreact-worker-dom
react-konsul raxreact-native  react-blessedreact-tvml
React-GLreact-vr  react-hardware react-fs-renderer react-x11
React targets
Main
react-dom react-native
Web iOS android
But also
react-art  react-canvas react-three ReactLibertyreact-worker-dom
react-konsul raxreact-native  react-blessedreact-tvml
React-GLreact-vr  react-hardware react-fs-renderer react-x11
redocx react-titanium  React-Gibbon react-pdf  react-test-renderer
React targets
Main
react-dom react-native
Web iOS android
But also
react-art  react-canvas react-three ReactLibertyreact-worker-dom
react-konsul raxreact-native  react-blessedreact-tvml
React-GLreact-vr  react-hardware react-fs-renderer react-x11
redocx react-titanium  React-Gibbon react-pdf  react-test-renderer
ink  react-sketchapp 
React targets
Main
react-dom react-native
Web iOS android
But also
react-art  react-canvas react-three ReactLibertyreact-worker-dom
react-konsul raxreact-native  react-blessedreact-tvml
React-GLreact-vr  react-hardware react-fs-renderer react-x11
redocx react-titanium  React-Gibbon react-pdf  react-test-renderer
ink  react-sketchapp 
And more
React blessed
React blessed
React Sketch.app
React VR
Demo
How Native is React Native?
JS Thread
Business logic &
Description of what
components to render
How Native is React Native?
JS Thread Main Thread
UI manipulation
with native
components
Business logic &
Description of what
components to render
How Native is React Native?
JS Thread Main Thread
UI manipulation
with native
components
Business logic &
Description of what
components to render
Bridge
How much code can we reuse?
Tip: if you develop in one platform,
test the app in the other from time to time
70%? 80%? 90%?
How to start a project
Option 1: create-react-native-app
$ npm install -g create-react-native-app
$ create-react-native-app AwesomeProject
Option 1: create-react-native-app
Only JS, no iOS or Android code
(outside node_modules)
If you want to modify native code, $ npm run eject
Uses the Expo app to test in real device
Meant to have a quick way of trying
react-native
Option 2: react-native init
$ npm install -g react-native-cli
$ react-native init AwesomeProject
Option 2: react-native init
Complete project with native code
More control
Needed to use things like CodePush
Doesn’t need external tools to publish to
the store
Getting our hands dirty
git clone https://github.com/Limenius/workshop-react-native.git
You are supposed to have done this
🙏
And then yarn install
git checkout master
react-native run-ios
And then
Or
react-native run-android
Debug tools Cmd + d
(Cmd + r)
ctrl+m / cmd+m
Play around
Open app/App.js with an editor
<Text style={styles.welcome}>Hi there!</Text>Change the text in
Try nesting
<Text>
<Text style={styles.welcome}>Hi there!</Text>
Amigo
</Text>
Try changing some styles
welcome: {
fontSize: 100,
textAlign: 'center',
margin: 10,
},
Try placing a console.log(‘hi’) before return(… and see it in
Chrome dev tools
https://www.slideshare.net/nachomartin/react-native-workshop-react-alicante
Familiarize with errors
What happens if we…
remove a closing tag (</View>)
<View style={styles.container}>
Hi there!
</View>
put text not wrapped in <Text/>
try to comment a JSX line with //
return (
<View style={styles.container}>
<Text style={styles.welcome}>Hi there!</Text>
</View>
<View/>
)
have two root elements
use wrong properties for styles ( rename flex -> flexo )
remove the words export default
Basic components
git checkout elements
git reset HEAD --hard
(To discard your changes)
Exercise:
Play with the basic components
app/App.js
Exercise: Build new components
Can you build a new component combining others?
Ideas: Image with footer (<Text/>), two buttons that display different alerts
Can you pass props to that component?
Ideas: Pass the text of the footer with props, pass also the image, pass the titles of the buttons
Can your build a component with local state?
Ideas: Modify the counter to have a “minus 1” button
Style 💅
No CSS. Everything is JS
<View style={{
borderLeftColor: Colors.accent,
borderLeftWidth: 9,
backgroundColor: Colors.backgroundSection,
padding: 18,
paddingVertical: 9,
}}>
No class
No dimensions in pixels
No things like padding: 19 9 3 1
camelCased
Use constants
StyleSheet
<View style={Styles.headline}>
const Styles = StyleSheet.create({
headline: {
borderLeftColor: Colors.accent,
borderLeftWidth: 9,
backgroundColor: Colors.backgroundSection,
paddingLeft: 18,
paddingRight: 18,
paddingTop: 9,
paddingBottom: 9,
},
})
Combination
<View style={[Styles.headline, {backgroundColor: 'red'}]}>
const Styles = StyleSheet.create({
headline: {
borderLeftColor: Colors.accent,
borderLeftWidth: 9,
paddingLeft: 18,
paddingRight: 18,
paddingTop: 9,
paddingBottom: 9,
},
})
git checkout styles
(To discard your changes)
git reset HEAD --hard
We want to build this
Our first goal is to get this
(We will practice layouts in the next section)
components/MovieHeader.js
height: 210
fontWeight:‘bold’
fontSize: FontSizes.LargeTitle
48x48, rounded
backgroundColor: Colors.highlight
color: Colors.text
color: Colors.text
fontWeight:‘bold’
border: left, size 9, Colors.accent
padding: 9, 18
backgroundColor: Colors.backgroundSection
Exercise 1
84x84
Colors.text, bold
Container has: border at bottom size 1, Colors.subtleAccent
and background is 'white'
components/ListItemActor.js
Exercise 2
FontSizes.gigantic
Colors.background
Container has: a background with color: Colors.highlight
components/MainHeader.js
Image is 40x90
FontSizes.subhead
With weight ‘200’
Colors.background
Pro exercise:Think how would you add support for themes
Dimensions
import {
Dimensions,
} from 'react-native'
const windowSize = Dimensions.get('window')
mainImage: {
height: windowSize.height /3,
width: undefined
},
components/MovieHeader.js
Dimensions
import {
Dimensions,
} from 'react-native'
const windowSize = Dimensions.get('window')
mainImage: {
height: windowSize.height /3,
width: undefined
},
Our image height depends on the
Height of the window
Use sparingly
components/MovieHeader.js
Dimensions
import {
Dimensions,
} from 'react-native'
const windowSize = Dimensions.get('window')
mainImage: {
height: windowSize.height /3,
width: undefined
},
Our image height depends on the
Height of the window
Use sparingly
Exercise: Can you make another style dependant of
Dimensions?
What will happen if the device is rotated?
Can you find anything in the documentation to fix it?
components/MovieHeader.js
Further reading
https://www.okgrow.com/posts/react-native-styling-tips
https://madebymany.com/stories/a-year-of-react-native-styling-part-1
https://medium.com/robin-powered/introducing-glamorous-for-react-native-1b8365e7f33f
https://github.com/styled-components/styled-components
Explore libraries to do CSS in JS
Layouts
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flexDirection: ‘column' flexDirection: ‘row’
(Default)
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flexDirection: ‘column' flexDirection: ‘row’
(Default)
main direction
crossdirection
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flexDirection: ‘column' flexDirection: ‘row’
(Default)
main direction
crossdirection
cross direction
maindirection
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flexDirection: ‘column’
(Default)
‘flex-start’ ‘flex-end’ ‘center' ‘space-around’ ‘space-between’
flexDirection: ‘row’
(Default)
‘flex-start’ ‘flex-end’ ‘center' ‘space-around’ ‘space-between’
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flexDirection: ‘column’
(Default)
‘flex-start’ ‘flex-end’ ‘center' ‘stretch’ ‘baseline’
flexDirection: ‘row’
(Default)
‘flex-start’ ‘flex-end’ ‘center' ‘stretch’ ‘baseline’
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flexDirection: ‘row’
‘baseline’
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flexDirection: ‘column’
alignSelf: ’end’
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flex: 1
flex: 0
flex: 0
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flex: 5
flex: 2
flex: 3
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flex: 0.5
flex: 0.2
flex: 0.3
This is flexbox realm
flexDirection
justifyContent
alignItems
alignSelf
flex
alignContent
flexBasis
flexGrow
flexShrink
flexWrap
flex: 25
flex: 10
flex: 15
git checkout layout
(To discard your changes)
git reset HEAD --hard
Our goal
app/components/MovieHeader.js
app/components/MovieHeader.js
18
Exercise 1
app/components/ListItemActor.js
Exercise 2
Hint: create subviews if you need them
Optional: can you come up with a different layout for any of our three components?
app/components/MainHeader.js
Further reading
https://facebook.github.io/yoga/docs/getting-started/
Docs:
https://github.com/jondot/ReactNativeKatas
Very good practice:
Lists
Lists are important in mobile
Naive lists, as in the web
export default class Movie extends Component {
constructor(props) {
super(props)
this.state = {
movie: movies.find((movie) => movie.name === 'Pulp Fiction')
}
}
render() {
return (
<View>
<MovieHeader movie={this.state.movie}/>
{ this.state.movie.actors.map(actor => (
<ListItem key={actor} name={actor} image={actors[actor].image}/>
))}
</View>
)
}
}
app/components/Movie.js
Naive lists, as in the web
export default class Movie extends Component {
constructor(props) {
super(props)
this.state = {
movie: movies.find((movie) => movie.name === 'Pulp Fiction')
}
}
render() {
return (
<View>
<MovieHeader movie={this.state.movie}/>
{ this.state.movie.actors.map(actor => (
<ListItem key={actor} name={actor} image={actors[actor].image}/>
))}
</View>
)
}
}
Important to help the reconciler do its work
app/components/Movie.js
Exercise
git checkout lists
Can you build a list of movies in
app/components/MovieList.js ?
(To discard your changes)
git reset HEAD --hard
FlatList
Highly optimized List component
Features:
• Scroll loading (onEndReached).
• Pull to refresh (onRefresh / refreshing).
• Configurable viewability (VPV) callbacks (onViewableItemsChanged / viewabilityConfig).
• Horizontal mode (horizontal).
• Intelligent item and section separators.
• Multi-column support (numColumns)
• scrollToEnd, scrollToIndex, and scrollToItem
• Better Flow typing.
FlatList
render() {
return (
<View>
<MovieHeader movie={this.state.movie}/>
<FlatList
data={this.state.movie.actors}
renderItem={({item}) =>
<ListItem name={item} image={this.state.actors[item].image}/>
}
/>
</View>
)
}
app/components/Movie.js
FlatList
FlatList
What about the keys?
FlatList
What about the keys?
<FlatList
data={this.state.movie.actors}
keyExtractor={item => item}
renderItem={({item}) =>
<ListItem name={item} image={this.state.actors[item].image}/>
}
/>
FlatList
What about the keys?
<FlatList
data={this.state.movie.actors}
keyExtractor={item => item}
renderItem={({item}) =>
<ListItem name={item} image={this.state.actors[item].image}/>
}
/>
FlatList
Scrolleable area
<FlatList
data={this.state.movie.actors}
keyExtractor={item => item}
renderItem={({item}) =>
<ListItem name={item} image={this.state.actors[item].image}/>
}
/>
<MovieHeader movie={this.state.movie}/>
FlatList
Desired scrolleable area
FlatList
Desired scrolleable area
<FlatList
data={this.state.movie.actors}
ListHeaderComponent={<MovieHeader movie={this.state.movie}/>}
keyExtractor={item => item}
renderItem={({item}) =>
<ListItem name={item} image={this.state.actors[item].image}/>
}
/>
FlatList
Desired scrolleable area
<FlatList
data={this.state.movie.actors}
ListHeaderComponent={<MovieHeader movie={this.state.movie}/>}
keyExtractor={item => item}
renderItem={({item}) =>
<ListItem name={item} image={this.state.actors[item].image}/>
}
/>
Exercise
Can you use FlatList in
app/components/MovieList.js ?
git checkout flatLists
item => item
reminder
In this case works as
function(item) {
return item
}
git reset HEAD —hard
(To discard your changes)
Further reading
https://facebook.github.io/react-native/blog/2017/03/13/
better-list-views.html
Read the docs of the components:
FlatList
SectionList
VirtualizedList
Navigation
Navigation
react-navigation
Several options
StackNavigator TabNavigator DrawerNavigator Or combine them
Several options
StackNavigator TabNavigator DrawerNavigator Or combine them
Several options
StackNavigator TabNavigator DrawerNavigator Or combine them
Several options
StackNavigator TabNavigator DrawerNavigator Or combine them
Let’s do it
git checkout navigation
(To discard your changes)
git reset HEAD --hard
Let’s do it
const App = createStackNavigator({
Home: { screen: MovieList },
Movie: { screen: Movie },
}, {
navigationOptions: {
headerTintColor: Colors.accent,
headerStyle: Styles.header,
}
})
app/App.js
Let’s do it
const App = createStackNavigator({
Home: { screen: MovieList },
Movie: { screen: Movie },
}, {
navigationOptions: {
headerTintColor: Colors.accent,
headerStyle: Styles.header,
}
})
app/App.js
export default class MovieList extends Component {
static navigationOptions = {
title: 'Movies',
}
//…
app/components/MovieList.js
Let’s do it
const App = createStackNavigator({
Home: { screen: MovieList },
Movie: { screen: Movie },
}, {
navigationOptions: {
headerTintColor: Colors.accent,
headerStyle: Styles.header,
}
})
app/App.js
export default class MovieList extends Component {
static navigationOptions = {
title: 'Movies',
}
//…
app/components/MovieList.js
<FlatList
data={this.state.movies}
ListHeaderComponent={<MainHeader/>}
keyExtractor={item => item.name}
renderItem={({item}) =>
<TouchableHighlight
underlayColor={Colors.subtleAccent}
activeOpacity={0.5}
onPress={() => navigate('Movie', {name: item.name})}
>
<View>
<ListItem name={item.name} image={item.image}/>
</View>
</TouchableHighlight>
}
/>
In render()
Let’s do it
const App = createStackNavigator({
Home: { screen: MovieList },
Movie: { screen: Movie },
}, {
navigationOptions: {
headerTintColor: Colors.accent,
headerStyle: Styles.header,
}
})
app/App.js
export default class MovieList extends Component {
static navigationOptions = {
title: 'Movies',
}
//…
app/components/MovieList.js
<FlatList
data={this.state.movies}
ListHeaderComponent={<MainHeader/>}
keyExtractor={item => item.name}
renderItem={({item}) =>
<TouchableHighlight
underlayColor={Colors.subtleAccent}
activeOpacity={0.5}
onPress={() => navigate('Movie', {name: item.name})}
>
<View>
<ListItem name={item.name} image={item.image}/>
</View>
</TouchableHighlight>
}
/>
In render()
Exercise
Can you make a navigation transition from Movie to
app/components/Actor ?
Steps:
- Declare the screen in app/App.js
- Use a TouchableHighlight to capture onPress in the actors
list of <Movie/>
- Provide an appropriate title in <Actor/>
- Make the actor displayed based on
props.navigation.state.params.name
Optional: have a look at
https://reactnavigation.org/docs/en/stack-navigator.html
And tweak the navigation (Ideas: mode modal, add something to headerRight)
Networking
Networking
React-native uses the Fetch API
If you already know it, you are all set 🎉 
Let’s do it
componentDidMount() {
return fetch(baseUrl + '/movies')
.then((response) => response.json())
.then((responseJson) => {
this.setState({
isLoading: false,
movies: responseJson,
})
})
.catch((error) => {
console.error(error);
})
}
app/components/MovieList.js
Let’s do it
git checkout networking
yarn start-server
(or npm run start-server)
(To discard your changes)
git reset HEAD --hard
Further reading
https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch
Docs:
https://github.com/mzabriskie/axios
Additional libraries:
Interactive
Our goal
Working with state
Not specific of React Native,
we just use what we know of React 
Let’s do it
git checkout interactive
(To discard your changes)
git reset HEAD --hard
Modify the native side
Cases where it is needed
Installing packages that have a native side
Making our own changes or components
Installing assets, such as fonts
…
Simple case
Install this font
Let’s do it
"rnpm": {
"assets": ["./assets/fonts/"]
}
package.json
git checkout mod-native
(To discard your changes)
git reset HEAD --hard
(Expo users: https://docs.expo.io/versions/latest/guides/using-custom-fonts)
Let’s do it
"rnpm": {
"assets": ["./assets/fonts/"]
}
package.json
react-native link
git checkout mod-native
(To discard your changes)
git reset HEAD --hard
(Expo users: https://docs.expo.io/versions/latest/guides/using-custom-fonts)
Assets linked
Changes to be committed:
(use "git reset HEAD <file>..." to unstage)
new file: android/app/src/main/assets/fonts/OleoScript-Bold.ttf
new file: android/app/src/main/assets/fonts/OleoScript-Regular.ttf
modified: ios/travolta.xcodeproj/project.pbxproj
modified: ios/travolta/Info.plist
modified: package.json
Summary:
What is React Native
Starting a project
Working with Styles
Layout
Lists
Navigation
Networking
Touching the native side
Thanks! @nacmartin
nacho@limenius.com

Introduction to React Native Workshop

  • 1.
  • 2.
    Nacho Martin I writecode at Limenius. We build tailor-made projects, and provide consultancy and formation. We are very happy with React and React Native.
  • 3.
    https://github.com/Limenius/workshop-react-native.git Before we start 🙏 Pleasego to where you have cloned the repo of the project And run git fetch
  • 4.
    Goal of theworkshop To be able to estimate how long would it take you to create a first React Native project (and if you would enjoy it)
  • 5.
    Roadmap: What is ReactNative Starting a project Working with Styles Layout Lists Navigation Networking Touching the native side
  • 6.
  • 7.
    Fundamental premise ofReact Give me a state and a render() method that depends on it and forget about how and when to render.
  • 8.
    render() { return ( <divclassName="App"> <button onClick={this.tick}>Click me!</button> <span>Clicks: {this.state.count}</span> </div> ) }
  • 9.
    render() { return ( <divclassName="App"> <button onClick={this.tick}>Click me!</button> <span>Clicks: {this.state.count}</span> </div> ) } render() { return ( <View style={…}> <Button onPress={this.tick}>Click me!</Button> <Text>Clicks: {this.state.count}</Text> </View> ) }
  • 10.
    render() { return ( <divclassName="App"> <button onClick={this.tick}>Click me!</button> <span>Clicks: {this.state.count}</span> </div> ) } render() { return ( <View style={…}> <Button onPress={this.tick}>Click me!</Button> <Text>Clicks: {this.state.count}</Text> </View> ) }
  • 11.
    render() { return ( <divclassName="App"> <button onClick={this.tick}>Click me!</button> <span>Clicks: {this.state.count}</span> </div> ) } render() { return ( <View style={…}> <Button onPress={this.tick}>Click me!</Button> <Text>Clicks: {this.state.count}</Text> </View> ) } React Native
  • 12.
    How is thispossible Reconciliation Determines what parts of the tree have changed
  • 13.
    How is thispossible Reconciliation Determines what parts of the tree have changed Rendering Actually updates the app
  • 14.
    How is thispossible Reconciliation Determines what parts of the tree have changed Rendering Actually updates the app We can have several renderers
  • 15.
  • 16.
  • 17.
    React targets Main react-dom react-native WebiOS android But also react-art  react-canvas react-three ReactLibertyreact-worker-dom
  • 18.
    React targets Main react-dom react-native WebiOS android But also react-art  react-canvas react-three ReactLibertyreact-worker-dom react-konsul raxreact-native  react-blessedreact-tvml
  • 19.
    React targets Main react-dom react-native WebiOS android But also react-art  react-canvas react-three ReactLibertyreact-worker-dom react-konsul raxreact-native  react-blessedreact-tvml React-GLreact-vr  react-hardware react-fs-renderer react-x11
  • 20.
    React targets Main react-dom react-native WebiOS android But also react-art  react-canvas react-three ReactLibertyreact-worker-dom react-konsul raxreact-native  react-blessedreact-tvml React-GLreact-vr  react-hardware react-fs-renderer react-x11 redocx react-titanium  React-Gibbon react-pdf  react-test-renderer
  • 21.
    React targets Main react-dom react-native WebiOS android But also react-art  react-canvas react-three ReactLibertyreact-worker-dom react-konsul raxreact-native  react-blessedreact-tvml React-GLreact-vr  react-hardware react-fs-renderer react-x11 redocx react-titanium  React-Gibbon react-pdf  react-test-renderer ink  react-sketchapp 
  • 22.
    React targets Main react-dom react-native WebiOS android But also react-art  react-canvas react-three ReactLibertyreact-worker-dom react-konsul raxreact-native  react-blessedreact-tvml React-GLreact-vr  react-hardware react-fs-renderer react-x11 redocx react-titanium  React-Gibbon react-pdf  react-test-renderer ink  react-sketchapp  And more
  • 23.
  • 24.
  • 25.
  • 26.
  • 27.
    How Native isReact Native? JS Thread Business logic & Description of what components to render
  • 28.
    How Native isReact Native? JS Thread Main Thread UI manipulation with native components Business logic & Description of what components to render
  • 29.
    How Native isReact Native? JS Thread Main Thread UI manipulation with native components Business logic & Description of what components to render Bridge
  • 30.
    How much codecan we reuse? Tip: if you develop in one platform, test the app in the other from time to time 70%? 80%? 90%?
  • 31.
    How to starta project
  • 32.
    Option 1: create-react-native-app $npm install -g create-react-native-app $ create-react-native-app AwesomeProject
  • 33.
    Option 1: create-react-native-app OnlyJS, no iOS or Android code (outside node_modules) If you want to modify native code, $ npm run eject Uses the Expo app to test in real device Meant to have a quick way of trying react-native
  • 34.
    Option 2: react-nativeinit $ npm install -g react-native-cli $ react-native init AwesomeProject
  • 35.
    Option 2: react-nativeinit Complete project with native code More control Needed to use things like CodePush Doesn’t need external tools to publish to the store
  • 36.
  • 37.
    git clone https://github.com/Limenius/workshop-react-native.git Youare supposed to have done this 🙏 And then yarn install
  • 38.
    git checkout master react-nativerun-ios And then Or react-native run-android
  • 39.
    Debug tools Cmd+ d (Cmd + r) ctrl+m / cmd+m
  • 40.
    Play around Open app/App.jswith an editor <Text style={styles.welcome}>Hi there!</Text>Change the text in Try nesting <Text> <Text style={styles.welcome}>Hi there!</Text> Amigo </Text> Try changing some styles welcome: { fontSize: 100, textAlign: 'center', margin: 10, }, Try placing a console.log(‘hi’) before return(… and see it in Chrome dev tools https://www.slideshare.net/nachomartin/react-native-workshop-react-alicante
  • 41.
    Familiarize with errors Whathappens if we… remove a closing tag (</View>) <View style={styles.container}> Hi there! </View> put text not wrapped in <Text/> try to comment a JSX line with // return ( <View style={styles.container}> <Text style={styles.welcome}>Hi there!</Text> </View> <View/> ) have two root elements use wrong properties for styles ( rename flex -> flexo ) remove the words export default
  • 42.
  • 43.
    git checkout elements gitreset HEAD --hard (To discard your changes)
  • 44.
    Exercise: Play with thebasic components app/App.js
  • 45.
    Exercise: Build newcomponents Can you build a new component combining others? Ideas: Image with footer (<Text/>), two buttons that display different alerts Can you pass props to that component? Ideas: Pass the text of the footer with props, pass also the image, pass the titles of the buttons Can your build a component with local state? Ideas: Modify the counter to have a “minus 1” button
  • 46.
  • 47.
    No CSS. Everythingis JS <View style={{ borderLeftColor: Colors.accent, borderLeftWidth: 9, backgroundColor: Colors.backgroundSection, padding: 18, paddingVertical: 9, }}> No class No dimensions in pixels No things like padding: 19 9 3 1 camelCased Use constants
  • 48.
    StyleSheet <View style={Styles.headline}> const Styles= StyleSheet.create({ headline: { borderLeftColor: Colors.accent, borderLeftWidth: 9, backgroundColor: Colors.backgroundSection, paddingLeft: 18, paddingRight: 18, paddingTop: 9, paddingBottom: 9, }, })
  • 49.
    Combination <View style={[Styles.headline, {backgroundColor:'red'}]}> const Styles = StyleSheet.create({ headline: { borderLeftColor: Colors.accent, borderLeftWidth: 9, paddingLeft: 18, paddingRight: 18, paddingTop: 9, paddingBottom: 9, }, })
  • 50.
    git checkout styles (Todiscard your changes) git reset HEAD --hard
  • 51.
    We want tobuild this
  • 52.
    Our first goalis to get this (We will practice layouts in the next section)
  • 53.
    components/MovieHeader.js height: 210 fontWeight:‘bold’ fontSize: FontSizes.LargeTitle 48x48,rounded backgroundColor: Colors.highlight color: Colors.text color: Colors.text fontWeight:‘bold’ border: left, size 9, Colors.accent padding: 9, 18 backgroundColor: Colors.backgroundSection
  • 54.
    Exercise 1 84x84 Colors.text, bold Containerhas: border at bottom size 1, Colors.subtleAccent and background is 'white' components/ListItemActor.js
  • 55.
    Exercise 2 FontSizes.gigantic Colors.background Container has:a background with color: Colors.highlight components/MainHeader.js Image is 40x90 FontSizes.subhead With weight ‘200’ Colors.background Pro exercise:Think how would you add support for themes
  • 56.
    Dimensions import { Dimensions, } from'react-native' const windowSize = Dimensions.get('window') mainImage: { height: windowSize.height /3, width: undefined }, components/MovieHeader.js
  • 57.
    Dimensions import { Dimensions, } from'react-native' const windowSize = Dimensions.get('window') mainImage: { height: windowSize.height /3, width: undefined }, Our image height depends on the Height of the window Use sparingly components/MovieHeader.js
  • 58.
    Dimensions import { Dimensions, } from'react-native' const windowSize = Dimensions.get('window') mainImage: { height: windowSize.height /3, width: undefined }, Our image height depends on the Height of the window Use sparingly Exercise: Can you make another style dependant of Dimensions? What will happen if the device is rotated? Can you find anything in the documentation to fix it? components/MovieHeader.js
  • 59.
  • 60.
  • 61.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap
  • 62.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flexDirection: ‘column' flexDirection: ‘row’ (Default)
  • 63.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flexDirection: ‘column' flexDirection: ‘row’ (Default) main direction crossdirection
  • 64.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flexDirection: ‘column' flexDirection: ‘row’ (Default) main direction crossdirection cross direction maindirection
  • 65.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flexDirection: ‘column’ (Default) ‘flex-start’ ‘flex-end’ ‘center' ‘space-around’ ‘space-between’ flexDirection: ‘row’ (Default) ‘flex-start’ ‘flex-end’ ‘center' ‘space-around’ ‘space-between’
  • 66.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flexDirection: ‘column’ (Default) ‘flex-start’ ‘flex-end’ ‘center' ‘stretch’ ‘baseline’ flexDirection: ‘row’ (Default) ‘flex-start’ ‘flex-end’ ‘center' ‘stretch’ ‘baseline’
  • 67.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flexDirection: ‘row’ ‘baseline’
  • 68.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flexDirection: ‘column’ alignSelf: ’end’
  • 69.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flex: 1 flex: 0 flex: 0
  • 70.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flex: 5 flex: 2 flex: 3
  • 71.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flex: 0.5 flex: 0.2 flex: 0.3
  • 72.
    This is flexboxrealm flexDirection justifyContent alignItems alignSelf flex alignContent flexBasis flexGrow flexShrink flexWrap flex: 25 flex: 10 flex: 15
  • 73.
    git checkout layout (Todiscard your changes) git reset HEAD --hard
  • 74.
  • 75.
  • 76.
  • 77.
  • 78.
    Exercise 2 Hint: createsubviews if you need them Optional: can you come up with a different layout for any of our three components? app/components/MainHeader.js
  • 79.
  • 80.
  • 81.
  • 82.
    Naive lists, asin the web export default class Movie extends Component { constructor(props) { super(props) this.state = { movie: movies.find((movie) => movie.name === 'Pulp Fiction') } } render() { return ( <View> <MovieHeader movie={this.state.movie}/> { this.state.movie.actors.map(actor => ( <ListItem key={actor} name={actor} image={actors[actor].image}/> ))} </View> ) } } app/components/Movie.js
  • 83.
    Naive lists, asin the web export default class Movie extends Component { constructor(props) { super(props) this.state = { movie: movies.find((movie) => movie.name === 'Pulp Fiction') } } render() { return ( <View> <MovieHeader movie={this.state.movie}/> { this.state.movie.actors.map(actor => ( <ListItem key={actor} name={actor} image={actors[actor].image}/> ))} </View> ) } } Important to help the reconciler do its work app/components/Movie.js
  • 84.
    Exercise git checkout lists Canyou build a list of movies in app/components/MovieList.js ? (To discard your changes) git reset HEAD --hard
  • 85.
    FlatList Highly optimized Listcomponent Features: • Scroll loading (onEndReached). • Pull to refresh (onRefresh / refreshing). • Configurable viewability (VPV) callbacks (onViewableItemsChanged / viewabilityConfig). • Horizontal mode (horizontal). • Intelligent item and section separators. • Multi-column support (numColumns) • scrollToEnd, scrollToIndex, and scrollToItem • Better Flow typing.
  • 86.
    FlatList render() { return ( <View> <MovieHeadermovie={this.state.movie}/> <FlatList data={this.state.movie.actors} renderItem={({item}) => <ListItem name={item} image={this.state.actors[item].image}/> } /> </View> ) } app/components/Movie.js
  • 87.
  • 88.
  • 89.
    FlatList What about thekeys? <FlatList data={this.state.movie.actors} keyExtractor={item => item} renderItem={({item}) => <ListItem name={item} image={this.state.actors[item].image}/> } />
  • 90.
    FlatList What about thekeys? <FlatList data={this.state.movie.actors} keyExtractor={item => item} renderItem={({item}) => <ListItem name={item} image={this.state.actors[item].image}/> } />
  • 91.
    FlatList Scrolleable area <FlatList data={this.state.movie.actors} keyExtractor={item =>item} renderItem={({item}) => <ListItem name={item} image={this.state.actors[item].image}/> } /> <MovieHeader movie={this.state.movie}/>
  • 92.
  • 93.
    FlatList Desired scrolleable area <FlatList data={this.state.movie.actors} ListHeaderComponent={<MovieHeadermovie={this.state.movie}/>} keyExtractor={item => item} renderItem={({item}) => <ListItem name={item} image={this.state.actors[item].image}/> } />
  • 94.
    FlatList Desired scrolleable area <FlatList data={this.state.movie.actors} ListHeaderComponent={<MovieHeadermovie={this.state.movie}/>} keyExtractor={item => item} renderItem={({item}) => <ListItem name={item} image={this.state.actors[item].image}/> } />
  • 95.
    Exercise Can you useFlatList in app/components/MovieList.js ? git checkout flatLists item => item reminder In this case works as function(item) { return item } git reset HEAD —hard (To discard your changes)
  • 96.
  • 97.
  • 98.
  • 99.
  • 100.
    Several options StackNavigator TabNavigatorDrawerNavigator Or combine them
  • 101.
    Several options StackNavigator TabNavigatorDrawerNavigator Or combine them
  • 102.
    Several options StackNavigator TabNavigatorDrawerNavigator Or combine them
  • 103.
    Several options StackNavigator TabNavigatorDrawerNavigator Or combine them
  • 104.
    Let’s do it gitcheckout navigation (To discard your changes) git reset HEAD --hard
  • 105.
    Let’s do it constApp = createStackNavigator({ Home: { screen: MovieList }, Movie: { screen: Movie }, }, { navigationOptions: { headerTintColor: Colors.accent, headerStyle: Styles.header, } }) app/App.js
  • 106.
    Let’s do it constApp = createStackNavigator({ Home: { screen: MovieList }, Movie: { screen: Movie }, }, { navigationOptions: { headerTintColor: Colors.accent, headerStyle: Styles.header, } }) app/App.js export default class MovieList extends Component { static navigationOptions = { title: 'Movies', } //… app/components/MovieList.js
  • 107.
    Let’s do it constApp = createStackNavigator({ Home: { screen: MovieList }, Movie: { screen: Movie }, }, { navigationOptions: { headerTintColor: Colors.accent, headerStyle: Styles.header, } }) app/App.js export default class MovieList extends Component { static navigationOptions = { title: 'Movies', } //… app/components/MovieList.js <FlatList data={this.state.movies} ListHeaderComponent={<MainHeader/>} keyExtractor={item => item.name} renderItem={({item}) => <TouchableHighlight underlayColor={Colors.subtleAccent} activeOpacity={0.5} onPress={() => navigate('Movie', {name: item.name})} > <View> <ListItem name={item.name} image={item.image}/> </View> </TouchableHighlight> } /> In render()
  • 108.
    Let’s do it constApp = createStackNavigator({ Home: { screen: MovieList }, Movie: { screen: Movie }, }, { navigationOptions: { headerTintColor: Colors.accent, headerStyle: Styles.header, } }) app/App.js export default class MovieList extends Component { static navigationOptions = { title: 'Movies', } //… app/components/MovieList.js <FlatList data={this.state.movies} ListHeaderComponent={<MainHeader/>} keyExtractor={item => item.name} renderItem={({item}) => <TouchableHighlight underlayColor={Colors.subtleAccent} activeOpacity={0.5} onPress={() => navigate('Movie', {name: item.name})} > <View> <ListItem name={item.name} image={item.image}/> </View> </TouchableHighlight> } /> In render()
  • 109.
    Exercise Can you makea navigation transition from Movie to app/components/Actor ? Steps: - Declare the screen in app/App.js - Use a TouchableHighlight to capture onPress in the actors list of <Movie/> - Provide an appropriate title in <Actor/> - Make the actor displayed based on props.navigation.state.params.name Optional: have a look at https://reactnavigation.org/docs/en/stack-navigator.html And tweak the navigation (Ideas: mode modal, add something to headerRight)
  • 110.
  • 111.
    Networking React-native uses theFetch API If you already know it, you are all set 🎉 
  • 112.
    Let’s do it componentDidMount(){ return fetch(baseUrl + '/movies') .then((response) => response.json()) .then((responseJson) => { this.setState({ isLoading: false, movies: responseJson, }) }) .catch((error) => { console.error(error); }) } app/components/MovieList.js
  • 113.
    Let’s do it gitcheckout networking yarn start-server (or npm run start-server) (To discard your changes) git reset HEAD --hard
  • 114.
  • 115.
  • 116.
  • 117.
    Working with state Notspecific of React Native, we just use what we know of React 
  • 118.
    Let’s do it gitcheckout interactive (To discard your changes) git reset HEAD --hard
  • 119.
  • 120.
    Cases where itis needed Installing packages that have a native side Making our own changes or components Installing assets, such as fonts …
  • 121.
  • 122.
    Let’s do it "rnpm":{ "assets": ["./assets/fonts/"] } package.json git checkout mod-native (To discard your changes) git reset HEAD --hard (Expo users: https://docs.expo.io/versions/latest/guides/using-custom-fonts)
  • 123.
    Let’s do it "rnpm":{ "assets": ["./assets/fonts/"] } package.json react-native link git checkout mod-native (To discard your changes) git reset HEAD --hard (Expo users: https://docs.expo.io/versions/latest/guides/using-custom-fonts)
  • 124.
    Assets linked Changes tobe committed: (use "git reset HEAD <file>..." to unstage) new file: android/app/src/main/assets/fonts/OleoScript-Bold.ttf new file: android/app/src/main/assets/fonts/OleoScript-Regular.ttf modified: ios/travolta.xcodeproj/project.pbxproj modified: ios/travolta/Info.plist modified: package.json
  • 125.
    Summary: What is ReactNative Starting a project Working with Styles Layout Lists Navigation Networking Touching the native side
  • 126.