Slide 1

Slide 1 text

Compose Previews as a Power User Chennai Subhrajyoti Sen Motive

Slide 2

Slide 2 text

Simple Previews

Slide 3

Slide 3 text

@Composable fun BorrowedItemRowPreview() { BorrowedItemRow( item = BorrowItem( id = 0, itemName = "XBox Series X", borrowerName = "Steve", borrowDate = "2-11-2023" ) ) }

Slide 4

Slide 4 text

@Preview @Composable fun BorrowedItemRowPreview() { BorrowedItemRow( item = BorrowItem( id = 0, itemName = "XBox Series X", borrowerName = "Steve", borrowDate = "2-11-2023" ) ) }

Slide 5

Slide 5 text

@Preview @Composable fun BorrowedItemRowPreview() { BorrowedItemRow( item = BorrowItem( id = 0, itemName = "XBoz Series X", borrowerName = "Steve", borrowDate = "2-11-2023" ) ) }

Slide 6

Slide 6 text

No content

Slide 7

Slide 7 text

Available Arguments ● name ● group ● uiMode ● locale ● showSystemUi ● showBackground ● device ● apiLevel

Slide 8

Slide 8 text

Dark Mode

Slide 9

Slide 9 text

@Preview(uiMode = UI_MODE_NIGHT_YES) @Composable fun BorrowedItemRowDevicePreview() { BorrowTheme { BorrowedItemRow( item = //.. ) } }

Slide 10

Slide 10 text

No content

Slide 11

Slide 11 text

Multi Preview Annotation

Slide 12

Slide 12 text

@Preview(uiMode = UI_MODE_NIGHT_NO) @Preview(uiMode = UI_MODE_NIGHT_YES) @Composable fun BorrowedItemRowDevicePreview() { BorrowTheme { BorrowedItemRow( item = //.. ) } }

Slide 13

Slide 13 text

@Preview(uiMode = UI_MODE_NIGHT_NO) @Preview(uiMode = UI_MODE_NIGHT_YES) annotation class LightDarkThemePreview

Slide 14

Slide 14 text

@LightDarkThemePreview @Composable fun BorrowedItemRowDevicePreview() { BorrowTheme { BorrowedItemRow( item = //.. ) } }

Slide 15

Slide 15 text

@LightDarkThemePreview @Composable fun BorrowedItemRowDevicePreview() { BorrowTheme { BorrowedItemRow( item = //.. ) } }

Slide 16

Slide 16 text

No content

Slide 17

Slide 17 text

@Preview( showSystemUi = true, device = Devices.NEXUS_5X ) @Preview( showSystemUi = true, device = Devices.NEXUS_10 ) annotation class MultiDevicePreview

Slide 18

Slide 18 text

@Preview( showSystemUi = true, device = Devices.NEXUS_5X ) @Preview( showSystemUi = true, device = Devices.NEXUS_10 ) annotation class MultiDevicePreview

Slide 19

Slide 19 text

@Preview(locale = "en") @Preview(locale = "fr-rCA") @Preview(locale = "es-rUS") annotation class MultiLocalePreview Valid locale format: https://developer.android.com/guide/topics/resources/provid ing-resources#LocaleQualifier

Slide 20

Slide 20 text

@LightDarkThemePreview @MultiLocalePreview annotation class MultiLocaleLightDarkPreview

Slide 21

Slide 21 text

Dataset Driven Preview

Slide 22

Slide 22 text

No content

Slide 23

Slide 23 text

@Preview @Composable fun BorrowedItemRowPreview() { BorrowedItemRow( item = BorrowItem( id = 0, itemName = "XBox Series X", borrowerName = "Steve", borrowDate = "2-11-2023" ) ) } @Preview @Composable fun BorrowedItemRowPreview() { BorrowedItemRow( item = BorrowItem( id = 0, itemName = "PlayStation", borrowerName = "Steve", borrowDate = "2-11-2023" ) ) }

Slide 24

Slide 24 text

class BorrowItemsProvider : PreviewParameterProvider { override val values = sequenceOf( BorrowItem( id = 0, itemName = "PlayStation", borrowerName = "Steve", borrowDate = "2-11-2022" ), BorrowItem( id = 0, itemName = "XBox", borrowerName = "Steve", borrowDate = "2-11-2022" ) ) }

Slide 25

Slide 25 text

class BorrowItemsProvider : PreviewParameterProvider { override val values = sequenceOf( BorrowItem( id = 0, itemName = "PlayStation", borrowerName = "Steve", borrowDate = "2-11-2022" ), BorrowItem( id = 0, itemName = "XBox", borrowerName = "Steve", borrowDate = "2-11-2022" ) ) }

Slide 26

Slide 26 text

@Preview @Composable fun BorrowedItemRowPreview( @PreviewParameter(BorrowItemsProvider::class) item: BorrowItem ) { BorrowedItemRow( item ) }

Slide 27

Slide 27 text

@Preview @Composable fun BorrowedItemRowPreview( @PreviewParameter(BorrowItemsProvider::class) item: BorrowItem ) { BorrowedItemRow( item ) }

Slide 28

Slide 28 text

Declutter using Groups

Slide 29

Slide 29 text

@MultiLocaleLightDarkPreview @Composable fun BorrowedItemRowDevicePreview() { BorrowTheme { BorrowedItemRow( item = //.. ) } }

Slide 30

Slide 30 text

No content

Slide 31

Slide 31 text

@Preview(locale = "en", group = "English") @Preview(locale = "fr-rCA", group = "Canadian French") @Preview(locale = "es-rUS", group = "US Spanish") annotation class MultiLocalePreview

Slide 32

Slide 32 text

No content

Slide 33

Slide 33 text

Local Inspection

Slide 34

Slide 34 text

No content

Slide 35

Slide 35 text

@Composable fun BorrowedItemRow(item: BorrowItem) { var expanded by remember { mutableStateOf(false) } // this will only affect previews if (LocalInspectionMode.current) { expanded = true } //.. }

Slide 36

Slide 36 text

@Composable fun BorrowedItemRow(item: BorrowItem) { var expanded by remember { mutableStateOf(false) } // this will only affect previews if (LocalInspectionMode.current) { expanded = true } //.. }

Slide 37

Slide 37 text

Showkase

Slide 38

Slide 38 text

No content

Slide 39

Slide 39 text

@ShowkaseComposable(group = "Individual rows") @Preview @Composable fun BorrowedItemRowExpandedPreview() { BorrowTheme { BorrowedItemRow( //.. ) } }

Slide 40

Slide 40 text

@ShowkaseComposable(group = "Individual rows") @Preview @Composable fun BorrowedItemRowExpandedPreview() { BorrowTheme { BorrowedItemRow( //.. ) } }

Slide 41

Slide 41 text

@ShowkaseComposable(group = "Individual rows") @Composable @Preview fun BorrowedItemRowCollapsedPreview() { CompositionLocalProvider(LocalInspectionMode provides false) { BorrowTheme { BorrowedItemRow( //.. ) } } }

Slide 42

Slide 42 text

No content

Slide 43

Slide 43 text

No content

Slide 44

Slide 44 text

No content

Slide 45

Slide 45 text

Animation Previews

Slide 46

Slide 46 text

No content

Slide 47

Slide 47 text

No content

Slide 48

Slide 48 text

updateTransition Supported Animations AnimatedVisibility animate*AsState rememberInfiniteTransition CrossFade AnimatedContent

Slide 49

Slide 49 text

Screenshot Testing

Slide 50

Slide 50 text

Available Options

Slide 51

Slide 51 text

Paparazzi Available Options

Slide 52

Slide 52 text

Paparazzi Roborazzi Available Options

Slide 53

Slide 53 text

Paparazzi Roborazzi Compose Preview Available Options

Slide 54

Slide 54 text

Paparazzi

Slide 55

Slide 55 text

Works on JVM Paparazzi

Slide 56

Slide 56 text

Works on JVM Based on Layoutlib Paparazzi

Slide 57

Slide 57 text

Works on JVM Based on Layoutlib Needs JUnit tests Paparazzi

Slide 58

Slide 58 text

Works on JVM Based on Layoutlib Needs JUnit tests Paparazzi Supports Views

Slide 59

Slide 59 text

Works on JVM Based on Layoutlib Needs JUnit tests Paparazzi Supports Views Emulates Production

Slide 60

Slide 60 text

class PaparazziTests { @get:Rule val paparazzi = Paparazzi( deviceConfig = PIXEL_5.copy(nightMode = NightMode.NIGHT), renderingMode = RenderingMode.SHRINK ) }

Slide 61

Slide 61 text

class PaparazziTests { @get:Rule val paparazzi = Paparazzi( deviceConfig = PIXEL_5.copy(nightMode = NightMode.NIGHT), renderingMode = RenderingMode.SHRINK ) }

Slide 62

Slide 62 text

class PaparazziTests { //.. @Test fun launchComposable() { paparazzi.snapshot { BorrowTheme { BorrowedItemRow( item = //.. ) } } } }

Slide 63

Slide 63 text

class PaparazziTests { //.. @Test fun launchComposable() { paparazzi.snapshot { CompositionLocalProvider(LocalInspectionMode provides true) { BorrowTheme { BorrowedItemRow( item = //.. ) } } } } }

Slide 64

Slide 64 text

class PaparazziTests { //.. @Test fun launchComposable() { paparazzi.snapshot { CompositionLocalProvider(LocalInspectionMode provides true) { BorrowTheme { BorrowedItemRow( item = //.. ) } } } } }

Slide 65

Slide 65 text

Baseline

Slide 66

Slide 66 text

After changes

Slide 67

Slide 67 text

Failure Comparison

Slide 68

Slide 68 text

Compose Preview Screenshot

Slide 69

Slide 69 text

Works on JVM Compose Preview Screenshot

Slide 70

Slide 70 text

Works on JVM Based on Layoutlib Compose Preview Screenshot

Slide 71

Slide 71 text

Works on JVM Based on Layoutlib Fully Automated Compose Preview Screenshot

Slide 72

Slide 72 text

Works on JVM Based on Layoutlib Fully Automated Compose Preview Screenshot Needs a special directory

Slide 73

Slide 73 text

Works on JVM Based on Layoutlib Fully Automated Compose Preview Screenshot Needs a special directory Emulates Debug

Slide 74

Slide 74 text

Compose Preview Screenshot - Source

Slide 75

Slide 75 text

Compose Preview Screenshot - Source @LightDarkThemePreview @Composable fun BorrowedItemRowPreview( @PreviewParameter(BorrowItemsProvider::class) item: BorrowItem ) { BorrowedItemRow( item ) }

Slide 76

Slide 76 text

Compose Preview Screenshot - Destination

Slide 77

Slide 77 text

Screen Comparison

Slide 78

Slide 78 text

Screen Comparison

Slide 79

Slide 79 text

Can’t decide? sergio-sastre/ComposablePreviewScanner

Slide 80

Slide 80 text

Further Exploration https://github.com/takahirom/roborazzi Composable Preview Driven Development: TDD-fying your UI with ease!

Slide 81

Slide 81 text

Questions?

Slide 82

Slide 82 text

Thank You! Chennai