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Discovering Jetpack Compose

Gerard
February 28, 2020

Discovering Jetpack Compose

Jetpack Compose will be the new declarative UI to build Android apps. Based on this new paradigm, let's see how we can use it with some simple samples!

Gerard

February 28, 2020
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  1. @GerardPaligot
    DISCOVERING
    JETPACK COMPOSE

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  2. WHAT’S JETPACK COMPOSE?
    100% Kotlin
    Compiler Open Source
    Declarative UI toolkit
    Android Team

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  3. THINK DIFFERENT.

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  4. View Slide

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  6. MovieMetadata
    Rating
    TopAppBar
    Poster
    PosterNoted
    MovieItem

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  11. App
    MovieHome
    Home
    Section
    Home
    Section
    Home
    Section
    Data
    Events

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  12. App
    MovieHome
    Home
    Section
    Home
    Section
    Home
    Section
    Data
    Events

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  13. PLACING ELEMENTS

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  14. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    }

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  15. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Text(
    text = title
    )
    }

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  16. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Text(
    text = title,
    style = MaterialTheme.typography.h6
    )
    }

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  17. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Text(
    text = title,
    style = MaterialTheme.typography.h6,
    maxLines = 2,
    overflow = TextOverflow.Ellipsis
    )
    }

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  18. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(
    text = title,
    style = MaterialTheme.typography.h6,
    maxLines = 2,
    overflow = TextOverflow.Ellipsis
    )
    }
    }

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  19. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    }
    }

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  20. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    genres.forEach {
    Tag(text = it)
    }
    }
    }

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  21. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    Row {
    genres.forEach {
    Tag(text = it)
    }
    }
    }
    }

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  22. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    Row(modifier = Modifier.padding(top = 5.dp)) {
    genres.forEach {
    Tag(text = it)
    }
    }
    }
    }

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  23. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    Row(modifier = Modifier.padding(top = 5.dp)) {
    ...
    }
    }
    }

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  24. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    Row(modifier = Modifier.padding(top = 5.dp)) {
    ...
    }
    val year = releaseDate.getCalendar().get(Calendar.YEAR)
    val time = "${runtime / 60}h ${runtime % 60}min"
    Text(
    text ="$year - $time",
    modifier = Modifier.padding(top = 5.dp)
    )
    }
    }

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  25. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    Row(modifier = Modifier.padding(top = 5.dp)) {
    ...
    }
    val year = releaseDate.getCalendar().get(Calendar.YEAR)
    val time = "${runtime / 60}h ${runtime % 60}min"
    Text(
    text = if (runtime != 0) "$year - $time" else "$year",
    modifier = Modifier.padding(top = 5.dp)
    )
    }
    }

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  26. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    Row(modifier = Modifier.padding(top = 5.dp)) {
    ...
    }
    CompositionLocalProvider(
    LocalContentAlpha provides ContentAlpha.medium
    ) {
    val year = releaseDate.getCalendar().get(Calendar.YEAR)
    val time = "${runtime / 60}h ${runtime % 60}min"
    Text(
    text = if (runtime != 0) "$year - $time" else "$year",
    modifier = Modifier.padding(top = 5.dp)
    )
    }
    }
    }

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  27. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int
    ) {
    Column {
    Text(...)
    Row(modifier = Modifier.padding(top = 5.dp)) {
    ...
    }
    CompositionLocalProvider(
    LocalContentAlpha provides ContentAlpha.medium
    ) {
    ...
    }
    }
    }

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  28. @Composable
    fun MovieMetadata(
    title: String,
    genres: List,
    releaseDate: String,
    runtime: Int,
    modifier: Modifier = Modifier
    ) {
    Column(modifier = modifier) {
    Text(...)
    Row(modifier = Modifier.padding(top = 5.dp)) {
    ...
    }
    CompositionLocalProvider(
    LocalContentAlpha provides ContentAlpha.medium
    ) {
    ...
    }
    }
    }

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  29. LET’S CODE A LIST

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  30. @Composable
    fun PosterNoted(
    posterUrl: String,
    voteAverage: Int,
    ratingSize: Dp,
    ratingAlignment: Alignment,
    onClick: () -> Unit = {}
    )

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  31. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    }

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  32. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    PosterNoted(
    posterUrl = movie.pictureUrl,
    voteAverage = movie.percentage,
    ratingSize = 50.dp,
    ratingAlignment = Alignment.TopEnd
    )
    }

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  33. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    Box(
    modifier = Modifier
    .width(130.dp)
    .aspectRatio(0.7f)
    ) {
    PosterNoted(
    posterUrl = movie.pictureUrl,
    voteAverage = movie.percentage,
    ratingSize = 50.dp,
    ratingAlignment = Alignment.TopEnd
    )
    }
    }

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  34. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    Box(
    modifier = Modifier
    .width(130.dp)
    .aspectRatio(0.7f)
    ) {
    …
    }
    }

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  35. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    Box(modifier = modifier) {
    Box(
    modifier = Modifier
    .width(130.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  36. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    ) {
    }
    Box(
    modifier = Modifier
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  37. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .padding(top = 60.dp)
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    ) {
    }
    Box(
    modifier = Modifier
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  38. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .padding(top = 60.dp)
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    .clickable(onClick = { onClick(movie) })
    ) {
    }
    Box(
    modifier = Modifier
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  39. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .padding(top = 60.dp)
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    .clickable(onClick = { onClick(movie) }),
    shape = RoundedCornerShape(8.dp)
    ) {
    }
    Box(
    modifier = Modifier
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  40. @Composable
    fun MovieItem(
    movie: Movie,
    modifier: Modifier = Modifier,
    onClick: (movie: Movie) -> Unit
    ) {
    val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .padding(top = 60.dp)
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    .clickable(onClick = { onClick(movie) }),
    shape = RoundedCornerShape(8.dp),
    elevation = 5.dp
    ) {
    }
    Box(
    modifier = Modifier
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  41. val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .padding(top = 60.dp)
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    .clickable(onClick = { onClick(movie) }),
    shape = RoundedCornerShape(8.dp),
    elevation = 5.dp
    ) {
    }
    Box(
    modifier = Modifier
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  42. val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .padding(top = 60.dp)
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    .clickable(onClick = { onClick(movie) }),
    shape = RoundedCornerShape(8.dp),
    elevation = 5.dp
    ) {
    }
    Box(
    modifier = Modifier
    .padding(start = 30.dp)
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }
    }

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  43. val posterWidth = 130
    val height = (posterWidth / 0.7f).roundToInt()
    Box(modifier = modifier) {
    Surface(
    modifier = Modifier
    .padding(top = 60.dp)
    .fillMaxWidth()
    .preferredHeight((height - 30).dp)
    .clickable(onClick = { onClick(movie) }),
    shape = RoundedCornerShape(8.dp),
    elevation = 5.dp
    ) {
    MovieMetadata(
    title = movie.title, genres = movie.genres,
    releaseDate = movie.releaseDate, runtime = movie.runtime,
    modifier = Modifier.padding(start = (posterWidth + 15).dp)
    .align(alignment = Alignment.CenterStart)
    )
    }
    Box(
    modifier = Modifier
    .padding(start = 30.dp)
    .width(posterWidth.dp)
    .aspectRatio(0.7f)
    ) {
    ...
    }
    }

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  44. @Composable
    fun MovieList(
    title: String,
    movies: List,
    onClick: (movie: Movie) -> Unit
    ) {
    }

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  45. @Composable
    fun MovieList(
    title: String,
    movies: List,
    onClick: (movie: Movie) -> Unit
    ) {
    val state = rememberScrollState()
    Column(modifier = Modifier.verticalScroll(state = state)) {
    movies.forEach {
    MovieItem(
    movie = it,
    modifier = Modifier
    .padding(start = 10.dp, top = 10.dp, end = 10.dp),
    onClick = onClick
    )
    }
    }
    }

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  46. @Composable
    fun MovieList(
    title: String,
    movies: List,
    onClick: (movie: Movie) -> Unit
    ) {
    LazyColumn {
    items(movies) { movie ->
    MovieItem(
    movie = movie,
    modifier = Modifier
    .padding(start = 10.dp, top = 10.dp, end = 10.dp),
    onClick = onClick
    )
    }
    }
    }

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  47. @Composable
    fun MovieList(
    title: String,
    movies: List,
    onClick: (movie: Movie) -> Unit
    ) {
    MovieScaffold(title = title) {
    LazyColumn {
    items(movies) { movie ->
    MovieItem(
    movie = it,
    modifier = Modifier
    .padding(start = 10.dp, top = 10.dp, end = 10.dp),
    onClick = onClick
    )
    }
    }
    }
    }

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  48. @Composable
    fun Scaffold(
    modifier: Modifier = Modifier,
    scaffoldState: ScaffoldState = rememberScaffoldState(),
    topBar: @Composable () -> Unit = emptyContent(),
    bottomBar: @Composable () -> Unit = emptyContent(),
    snackbarHost: @Composable (SnackbarHostState) -> Unit = { SnackbarHost(it) },
    floatingActionButton: @Composable () -> Unit = emptyContent(),
    floatingActionButtonPosition: FabPosition = FabPosition.End,
    isFloatingActionButtonDocked: Boolean = false,
    drawerContent: @Composable (ColumnScope.() -> Unit)? = null,
    drawerGesturesEnabled: Boolean = true,
    drawerShape: Shape = MaterialTheme.shapes.large,
    drawerElevation: Dp = DrawerConstants.DefaultElevation,
    drawerBackgroundColor: Color = MaterialTheme.colors.surface,
    drawerContentColor: Color = contentColorFor(drawerBackgroundColor),
    drawerScrimColor: Color = DrawerConstants.defaultScrimColor,
    backgroundColor: Color = MaterialTheme.colors.background,
    contentColor: Color = contentColorFor(backgroundColor),
    bodyContent: @Composable (PaddingValues) -> Unit
    )

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  49. LET’S CODE A LIST
    WITH ACTUAL FRAMEWORK UI

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  50. xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" />

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  51. xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent" android:layout_height="80dp">
    android:layout_width="match_parent" android:layout_height="match_parent">
    android:layout_width="50dp" android:layout_height="50dp" android:layout_marginStart="20dp"
    app:layout_constraintBottom_toBottomOf="parent" app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent" tools:srcCompat="@tools:sample/avatars" />
    android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:orientation="vertical" app:layout_constraintGuide_begin="100dp" />

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  52. android:layout_width="0dp" android:layout_height="wrap_content"
    android:layout_marginEnd="20dp" android:orientation="vertical"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toStartOf="@+id/price"
    app:layout_constraintStart_toStartOf="@+id/guideline3"
    app:layout_constraintTop_toTopOf="parent">
    android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:textAppearance="@style/TextAppearance.Decathlon.Subtitle2"
    android:textColor="@color/colorOnSurface" />
    android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:textAppearance="@style/TextAppearance.Decathlon.Subtitle2"
    android:textColor="@color/grey" />

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  53. android:id="@+id/price"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginEnd="20dp"
    android:textAppearance="@style/TextAppearance.Decathlon.Subtitle2"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    tools:text="50$" />


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  54. data class Activity(
    @DrawableRes val picture: Int,
    val displayName: String,
    val type: String,
    val price: Int
    )
    class ActivityListAdapter(val items: MutableList) :
    RecyclerView.Adapter() {
    val onClick: LiveData
    get() = this._onClick
    private val _onClick: MutableLiveData by lazy {
    return@lazy MutableLiveData()
    }

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  55. override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ActivityViewHolder =
    ActivityViewHolder(LayoutInflater.from(parent.context).inflate(R.layout.item_activity, parent, false))
    override fun getItemCount(): Int = items.size
    override fun onBindViewHolder(holder: ActivityViewHolder, position: Int) {
    val activity = items[position]
    holder.bind(activity, View.OnClickListener {
    _onClick.value = activity
    })
    }
    fun update(items: List) {
    this.items.clear()
    this.items.addAll(items)
    notifyDataSetChanged()
    }

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  56. class ActivityViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
    fun bind(activity: Activity, onClickListener: View.OnClickListener) {
    itemView.setOnClickListener(onClickListener)
    itemView.picture.setImageDrawable(ContextCompat.getDrawable(itemView.context,
    activity.picture))
    itemView.name.text = activity.displayName
    itemView.type.text = activity.type
    val color = if (activity.price > 0)
    ContextCompat.getColor(itemView.context, R.color.green)
    else
    ContextCompat.getColor(itemView.context, R.color.red)
    itemView.price.setTextColor(color)
    }
    }
    }

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  57. LIGHT DARK

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  58. val orange800 = Color(255, 150, 29)
    val orange900 = Color(255, 118, 26)
    val blue400 = Color(26, 163, 255)
    private val LightColorPalette = lightColors(
    primary = orange900,
    primaryVariant = orange800,
    secondary = blue400,
    background = Color.White,
    surface = Color.White,
    onPrimary = Color.White,
    onSecondary = Color.Black,
    onBackground = Color.Black,
    onSurface = Color.Black,
    )

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  59. val orange400 = Color(255, 205, 56)
    val blue800 = Color(0, 98, 203)
    val blue900 = Color(0, 68, 171)
    val grayDark = Color(45, 47, 49)
    private val DarkColorPalette = darkColors(
    primary = blue900,
    primaryVariant = blue800,
    secondary = orange400,
    background = grayDark,
    surface = grayDark,
    onPrimary = Color.White,
    onSecondary = Color.Black,
    onBackground = Color.White,
    onSurface = Color.White
    )

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  60. val typography = Typography(
    h5 = TextStyle(
    fontFamily = FontFamily.Default,
    fontWeight = FontWeight.W700,
    fontSize = 24.sp
    ),
    subtitle1 = TextStyle(
    fontFamily = FontFamily.Default,
    fontWeight = FontWeight.W700,
    fontSize = 16.sp
    ),
    body1 = TextStyle(
    fontFamily = FontFamily.Default,
    fontWeight = FontWeight.Normal,
    fontSize = 16.sp
    ),
    caption = TextStyle(
    fontFamily = FontFamily.Default,
    fontWeight = FontWeight.W400,
    fontSize = 10.sp
    )
    )

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  61. val shapes = Shapes(
    small = RoundedCornerShape(2.dp),
    medium = RoundedCornerShape(4.dp),
    large = RoundedCornerShape(8.dp)
    )

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  62. @Composable
    fun MaterialTheme(
    colors: Colors = MaterialTheme.colors,
    typography: Typography = MaterialTheme.typography,
    shapes: Shapes = MaterialTheme.shapes,
    content: @Composable () -> Unit
    )

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  63. @Composable
    fun ExploringMoviesTheme(
    isDarkMode: Boolean = isSystemInDarkTheme(),
    content: @Composable() () -> Unit
    ) {
    }

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  64. @Composable
    fun ExploringMoviesTheme(
    isDarkMode: Boolean = isSystemInDarkTheme(),
    content: @Composable() () -> Unit
    ) {
    MaterialTheme(
    content = content
    )
    }

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  65. @Composable
    fun ExploringMoviesTheme(
    isDarkMode: Boolean = isSystemInDarkTheme(),
    content: @Composable() () -> Unit
    ) {
    MaterialTheme(
    colors =
    if (isDarkMode) DarkColorPalette else LightColorPalette,
    content = content
    )
    }

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  66. @Composable
    fun ExploringMoviesTheme(
    isDarkMode: Boolean = isSystemInDarkTheme(),
    content: @Composable() () -> Unit
    ) {
    MaterialTheme(
    colors =
    if (isDarkMode) DarkColorPalette else LightColorPalette,
    typography = typography,
    content = content
    )
    }

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  67. @Composable
    fun ExploringMoviesTheme(
    isDarkMode: Boolean = isSystemInDarkTheme(),
    content: @Composable() () -> Unit
    ) {
    MaterialTheme(
    colors =
    if (isDarkMode) DarkColorPalette else LightColorPalette,
    typography = typography,
    shapes = shapes,
    content = content
    )
    }

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  68. @Composable
    fun MovieList(
    title: String,
    movies: List,
    onClick: (movie: Movie) -> Unit
    ) {
    MovieScaffold(
    title = title
    ){
    LazyColumnFor(items = movies) {
    MovieItem(
    movie = it,
    modifier = Modifier
    .padding(start = 10.dp, top = 10.dp, end = 10.dp),
    onClick = onClick
    )
    }
    }
    }

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  69. @Composable
    fun MovieList(
    title: String,
    movies: List,
    isDarkModeActive: Boolean,
    switchDarkMode: () -> Unit = {},
    onClick: (movie: Movie) -> Unit
    ) {
    MovieScaffold(
    title = title,
    isDarkModeActive = isDarkModeActive,
    switchDarkMode = switchDarkMode
    ){
    LazyColumnFor(items = movies) {
    MovieItem(
    movie = it,
    modifier = Modifier
    .padding(start = 10.dp, top = 10.dp, end = 10.dp),
    onClick = onClick
    )
    }
    }
    }

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  70. setContent {
    val isSystemDark = isSystemInDarkTheme()
    }

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  71. setContent {
    val isSystemDark = isSystemInDarkTheme()
    val isDarkModeState = remember { mutableStateOf(isSystemDark) }
    }

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  72. setContent {
    val isSystemDark = isSystemInDarkTheme()
    val isDarkModeState = remember { mutableStateOf(isSystemDark) }
    ExploringMoviesTheme(isDarkMode = isDarkModeState.value) {
    }
    }

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  73. setContent {
    val isSystemDark = isSystemInDarkTheme()
    val isDarkModeState = remember { mutableStateOf(isSystemDark) }
    ExploringMoviesTheme(isDarkMode = isDarkModeState.value) {
    App(
    isDarkModeActive = isDarkModeState.value
    )
    }
    }

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  74. setContent {
    val isSystemDark = isSystemInDarkTheme()
    val isDarkModeState = remember { mutableStateOf(isSystemDark) }
    ExploringMoviesTheme(isDarkMode = isDarkModeState.value) {
    App(
    isDarkModeActive = isDarkModeState.value,
    switchDarkMode = {
    isDarkModeState.value = !isDarkModeState.value
    }
    )
    }
    }

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  75. OBSERVING DATA WITH
    VIEWMODEL

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  76. class MovieViewModel : ViewModel() {
    fun getPopulars() = flow {
    ...
    }
    fun getDailyTrending() = flow {
    ...
    }
    fun getUpComing() = flow {
    ...
    }
    fun getMovieDetail(movieId: Int) = flow {
    ...
    }
    }

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  77. ▸ LiveData.observeAsState()
    ▸ Flow.collectAsState()
    ▸ Observable.subscribeAsState()

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  78. @Composable
    fun MyExample() {
    // Returns the same instance as long as the activity is alive,
    // just as if you grabbed the instance from an Activity or
    // Fragment
    val viewModel: MovieViewModel = viewModel()
    }
    @Composable
    fun MyExample2() {
    // Same instance as in MyExample
    val viewModel: MovieViewModel = viewModel()
    }

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  79. @Composable
    fun MovieListViewModel(
    movieSection: MovieSection,
    isDarkModeActive: Boolean,
    switchDarkMode: () -> Unit = {},
    onClick: (movie: Movie) -> Unit
    ) {
    MovieList(
    title = title,
    movies = movies.value,
    isDarkModeActive = isDarkModeActive,
    switchDarkMode = switchDarkMode,
    onClick = onClick
    )
    }

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  80. @Composable
    fun MovieListViewModel(
    movieSection: MovieSection,
    isDarkModeActive: Boolean,
    switchDarkMode: () -> Unit = {},
    onClick: (movie: Movie) -> Unit
    ) {
    val viewModel: MovieViewModel = viewModel()
    MovieList(
    title = title,
    movies = movies.value,
    isDarkModeActive = isDarkModeActive,
    switchDarkMode = switchDarkMode,
    onClick = onClick
    )
    }

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  81. @Composable
    fun MovieListViewModel(
    movieSection: MovieSection,
    isDarkModeActive: Boolean,
    switchDarkMode: () -> Unit = {},
    onClick: (movie: Movie) -> Unit
    ) {
    val viewModel: MovieViewModel = viewModel()
    val movies = when (movieSection) {
    MovieSection.UPCOMING -> viewModel.getUpComing()
    .collectAsState(initial = emptyList())
    MovieSection.POPULAR -> viewModel.getPopulars()
    .collectAsState(initial = emptyList())
    MovieSection.TRENDING -> viewModel.getDailyTrending()
    .collectAsState(initial = emptyList())
    }
    MovieList(
    movies = movies.value,
    isDarkModeActive = isDarkModeActive,
    switchDarkMode = switchDarkMode,
    onClick = onClick
    )
    }

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  82. @GerardPaligot
    DISCOVERING
    JETPACK COMPOSE

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  83. @GerardPaligot
    DISCOVERING
    COMPOSE MULTIPLATFORM

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  84. UI/UX UI/UX UI/UX
    BUSINESS LOGIC AND CORE

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  85. UI/UX UI/UX UI/UX
    BUSINESS LOGIC AND CORE
    ACTUAL ACTUAL ACTUAL

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  86. BUSINESS LOGIC AND CORE
    ACTUAL ACTUAL ACTUAL
    COMPOSE MULTIPLATFORM

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  87. View Slide

  88. BUSINESS LOGIC AND CORE
    ACTUAL ACTUAL ACTUAL
    COMPOSE MULTIPLATFORM

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  89. UX UX UX
    BUSINESS LOGIC AND CORE
    ACTUAL ACTUAL ACTUAL
    COMPOSE MULTIPLATFORM

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  90. COMPILER
    RUNTIME
    UI
    FOUNDATION-LAYOUT
    ANIMATION
    FOUNDATION
    MATERIAL 3
    Transf m @C posable functi s Pro amming model, state
    management and runtime f
    the c pose c pil plugin
    Fundamental c p ents
    Basics lay ts like B , R
    and C umn
    C p ents animati s
    Basics c p ents and int acti s
    Implementati of Mat ial Design
    specificati s
    Implementati of Mat ial Y

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  91. COMPILER
    RUNTIME
    UI
    FOUNDATION-LAYOUT
    ANIMATION
    FOUNDATION
    MATERIAL 3
    Transf m @C posable functi s Pro amming model, state
    management and runtime f
    the c pose c pil plugin

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  92. COMPILER
    RUNTIME
    UI
    FOUNDATION-LAYOUT
    ANIMATION
    FOUNDATION
    MATERIAL 3
    Transf m @C posable functi s Pro amming model, state
    management and runtime f
    the c pose c pil plugin
    WEB-CORE-RUNTIME
    WEB-CORE
    WIDGETS
    Runtime dedicated to web apps
    to gen ate DOM tags
    Basics native web c p ents
    Modifi s and lay ts

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  93. UX UX UX
    BUSINESS LOGIC AND CORE
    ACTUAL ACTUAL ACTUAL
    COMPOSE MULTIPLATFORM

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  94. UX UX UX
    BUSINESS LOGIC AND CORE
    ACTUAL ACTUAL ACTUAL
    COMPOSE MULTIPLATFORM COMPOSE WEB

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  95. WHY COMPOSE WEB?
    ▸ Compose Canvas rendering not compatible (yet) with web technologies
    ▸ Compose Web emit DOM UI for NPM librairies compatibility and SEO

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  96. :android-app :desktop-app
    :data

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  97. :android-app :desktop-app
    :data

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  98. :android-app :desktop-app
    :data :components
    :theming

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  99. :android-app :desktop-app
    :data :components
    :theming

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  100. plugins {
    id("com.android.library")
    }
    android {
    ...
    }

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  101. plugins {
    id("com.android.library")
    kotlin("multiplatform")
    id("org.jetbrains.compose")
    }
    android {
    ...
    }

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  102. plugins {
    id("com.android.library")
    kotlin("multiplatform")
    id("org.jetbrains.compose")
    }
    android {
    ...
    }
    kotlin {
    android()
    jvm("desktop")
    }

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  103. import org.jetbrains.compose.compose
    plugins {
    id("com.android.library")
    kotlin("multiplatform")
    id("org.jetbrains.compose")
    }
    android {
    ...
    }
    kotlin {
    android()
    jvm("desktop")
    sourceSets {
    named("commonMain") {
    dependencies {
    implementation(compose.runtime)
    implementation(compose.foundation)
    implementation(compose.material)
    }
    }
    }
    }

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  104. SOURCE SET
    desktopMain
    SOURCE SET
    androidMain
    SOURCE SET
    commonMain

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  105. @Composable
    expect fun Font(
    fontName: String,
    weight: FontWeight,
    style: FontStyle
    ): Font
    SOURCE SET
    commonMain

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  106. @Composable
    actual fun Font(
    fontName: String,
    weight: FontWeight,
    style: FontStyle
    ): Font {
    val context = LocalContext.current
    val id = context.resources
    .getIdentifier(fontName, "font", context.packageName)
    return Font(id, weight, style)
    }
    SOURCE SET
    androidMain

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  107. @Composable
    actual fun Font(
    fontName: String,
    weight: FontWeight,
    style: FontStyle
    ): Font {
    return androidx.compose.ui.text.platform.Font(
    "font/${fontName}.ttf",
    weight,
    style
    )
    }
    SOURCE SET
    desktopMain

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  108. object Fonts {
    val roboto: FontFamily
    @Composable
    get() = FontFamily(
    Font(
    "roboto_bold",
    FontWeight.Bold,
    FontStyle.Normal
    ),
    Font(
    "roboto_italic",
    FontWeight.Normal,
    FontStyle.Italic
    ),
    Font(
    "roboto_regular",
    FontWeight.Normal,
    FontStyle.Normal
    )
    )
    }
    SOURCE SET
    commonMain

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  109. object Fonts {
    val roboto: FontFamily
    @Composable
    get() = ...
    }
    SOURCE SET
    commonMain

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  110. object Fonts {
    val roboto: FontFamily
    @Composable
    get() = ...
    }
    object Typographies {
    val roboto: Typography
    @Composable
    get() = Typography(defaultFontFamily = Fonts.roboto)
    }
    SOURCE SET
    commonMain

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  111. object Fonts {
    val roboto: FontFamily
    @Composable
    get() = ...
    }
    object Typographies {
    val roboto: Typography
    @Composable
    get() = Typography(defaultFontFamily = Fonts.roboto)
    }
    @Composable
    fun ExploringMoviesTheme(
    isDarkMode: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit
    ) {
    MaterialTheme(
    colors =
    if (isDarkMode) DarkColorPalette else LightColorPalette,
    typography = Typographies.roboto,
    shapes = shapes,
    content = content
    )
    }
    SOURCE SET
    commonMain

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  112. :android-app :desktop-app
    :data :components
    :theming

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  113. @Composable
    expect fun RemoteImage(
    url: String,
    contentDescription: String?,
    modifier: Modifier = Modifier,
    contentScale: ContentScale = ContentScale.Fit
    )
    SOURCE SET
    commonMain

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  114. import org.jetbrains.compose.compose
    plugins {
    ...
    }
    android {
    ...
    }
    kotlin {
    android()
    jvm("desktop")
    sourceSets {
    named("commonMain") {
    ...
    }
    named("androidMain") {
    dependencies {
    implementation(Dependencies.Accompanist.coil)
    }
    }
    }
    }

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  115. @Composable
    actual fun CrossRemoteImage(
    url: String,
    contentDescription: String?,
    modifier: Modifier,
    contentScale: ContentScale
    ) {
    Image(
    painter = rememberAsyncImagePainter(model = url),
    modifier = modifier,
    contentDescription = contentDescription,
    contentScale = ContentScale.Crop,
    )
    }
    SOURCE SET
    androidMain

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  116. import org.jetbrains.compose.compose
    plugins {
    ...
    }
    android {
    ...
    }
    kotlin {
    android()
    jvm("desktop")
    sourceSets {
    named("commonMain") {
    ...
    }
    named("androidMain") {
    ...
    }
    named("desktopMain") {
    dependencies {
    implementation(Dependencies.okhttp)
    }
    }
    }
    }

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  117. @Composable
    actual fun CrossRemoteImage(
    url: String,
    contentDescription: String?,
    modifier: Modifier,
    contentScale: ContentScale
    ) {
    val image = remember { mutableStateOf(null) }
    if (image.value != null) {
    Image(
    bitmap = image.value!!,
    contentDescription = contentDescription,
    modifier = modifier,
    contentScale = contentScale
    )
    }
    }
    SOURCE SET
    desktopMain

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  118. @Composable
    actual fun CrossRemoteImage(
    url: String,
    contentDescription: String?,
    modifier: Modifier,
    contentScale: ContentScale
    ) {
    val image = remember { mutableStateOf(null) }
    LaunchedEffect(url) {
    }
    if (image.value != null) {
    Image(
    bitmap = image.value!!,
    contentDescription = contentDescription,
    modifier = modifier,
    contentScale = contentScale
    )
    }
    }
    SOURCE SET
    desktopMain

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  119. @Composable
    actual fun CrossRemoteImage(
    url: String,
    contentDescription: String?,
    modifier: Modifier,
    contentScale: ContentScale
    ) {
    val image = remember { mutableStateOf(null) }
    LaunchedEffect(url) {
    ImageLoader.load(url)?.let {
    }
    }
    if (image.value != null) {
    Image(
    bitmap = image.value!!,
    contentDescription = contentDescription,
    modifier = modifier,
    contentScale = contentScale
    )
    }
    }
    SOURCE SET
    desktopMain

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  120. @Composable
    actual fun CrossRemoteImage(
    url: String,
    contentDescription: String?,
    modifier: Modifier,
    contentScale: ContentScale
    ) {
    val image = remember { mutableStateOf(null) }
    LaunchedEffect(url) {
    ImageLoader.load(url)?.let {
    image.value = org.jetbrains.skia.Image.makeFromEncoded(it)
    .toComposeImageBitmap()
    }
    }
    if (image.value != null) {
    Image(
    bitmap = image.value!!,
    contentDescription = contentDescription,
    modifier = modifier,
    contentScale = contentScale
    )
    }
    }
    SOURCE SET
    desktopMain

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  121. WHY SHOULD CARE
    ABOUT COMPOSE?

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  122. WHY SHOULD CARE ABOUT COMPOSE?
    ▸ Android UI framework never
    changed since 2008
    ▸ Need to wait very long time before
    bug fixes deployed in production
    ▸ Need to worry about keeping the
    View hierarchy as flat as possible
    ▸ Unbundled from OS
    ▸ Exit View and Fragment
    ▸ Clarify state ownership
    and event handling
    ▸ Writing less code

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  123. slack.kotlinlang.org
    #compose
    Open Source Project
    github.com/androidx/androidx

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  124. REFERENCES
    ▸ Discovering Movies, GitHub Repository of Gerard Paligot
    https://github.com/GerardPaligot/discovering-movies
    ▸ Official documentation about Jetpack Compose, Developer Android Website
    https://developer.android.com/jetpack/compose/documentation
    ▸ Pathways Compose
    https://developer.android.com/courses/pathways/compose
    ▸ Compose Academy
    https://compose.academy/
    ▸ Samples Compose app by community
    https://jetpackcompose.app/

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  125. THANK YOU!
    @GerardPaligot

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