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Márton Braun
zsmb.co
zsmb13
It’s Compose
O'Clock on
Android
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React
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React
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React
React Native
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React
React Native
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React
React Native
Flutter
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React
React Native
Flutter
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React
React Native
Flutter
Flutter 2
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React
React Native
Flutter
Flutter 2
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React
React Native
Flutter
Flutter 2
SwiftUI
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React
React Native
Flutter
Flutter 2
SwiftUI
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React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
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React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
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Jetpack Compose announced
React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
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Jetpack Compose announced
React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
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Jetpack Compose announced
React
React Native
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SwiftUI
SwiftUI “2.0”
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Jetpack Compose alpha
Jetpack Compose announced
React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
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Jetpack Compose alpha
Jetpack Compose announced
React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
Jetpack Compose beta
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Jetpack Compose alpha
Jetpack Compose announced
React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
Jetpack Compose beta
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Jetpack Compose alpha
Jetpack Compose announced
React
React Native
Flutter
Flutter 2
SwiftUI
SwiftUI “2.0”
Jetpack Compose beta
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Common traits
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Common traits
› Declarative
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Common traits
› Declarative
› Component-based
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Common traits
› Declarative
› Component-based
› UI is a function of state
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Common traits
› Declarative
› Component-based
› UI is a function of state
› Mostly blue
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Common traits
› Declarative
› Component-based
› UI is a function of state
› Mostly blue
› Quick iteration, fast previews
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Common traits
› Declarative
› Component-based
› UI is a function of state
› Mostly blue
› Quick iteration, fast previews
› Multiplatform ambitions
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Jetpack Compose
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Jetpack Compose
› Built with Composable functions
› Eliminates the need to sync UI state
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Jetpack Compose
› Built with Composable functions
› Eliminates the need to sync UI state
› Unbundled
› Not tied to OS versions
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Jetpack Compose
› Built with Composable functions
› Eliminates the need to sync UI state
› Unbundled
› Not tied to OS versions
› All Kotlin
› Awesome!
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Jetpack Compose
› Built with Composable functions
› Eliminates the need to sync UI state
› Unbundled
› Not tied to OS versions
› All Kotlin
› Awesome!
› Two-way interoperability
› Works with existing UI code
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Let’s get ticking
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A single number
@Composable
fun Number(value: Int) {
}
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A single number
@Composable
fun Number(value: Int) {
Text(
text = value.toString(),
fontSize = 20.sp,
modifier = Modifier.size(40.dp)
)
}
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A single number
@Composable
fun Number(value: Int) {
Text(
text = value.toString(),
fontSize = 20.sp,
modifier = Modifier.size(40.dp)
)
}
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A single number
@Composable
fun Number(value: Int) {
Text(
text = value.toString(),
fontSize = 20.sp,
modifier = Modifier.size(40.dp)
)
}
Number(3)
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A single number
@Composable
fun Number(value: Int) {
Text(
text = value.toString(),
fontSize = 20.sp,
modifier = Modifier
)
}
3
Number(3)
.size(40.dp)
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A single number
@Composable
fun Number(value: Int) {
Text(
text = value.toString(),
fontSize = 20.sp,
modifier = Modifier
.background(Color.Black)
)
}
Number(3)
.size(40.dp)
3
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A single number
text = value.toString(),
fontSize = 20.sp,
)
}
Number(3)
modifier = Modifier
.size(40.dp)
.background(Color.Black)
Text(
@Composable
fun Number(value: Int) {
3
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A single number
Box(
) {
text = value.toString(),
fontSize = 20.sp,
)
}
}
Number(3)
modifier = Modifier
.size(40.dp)
.background(Color.Black)
Text(
@Composable
fun Number(value: Int) {
3
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A single number
Box(
contentAlignment = Alignment.Center,
) {
text = value.toString(),
fontSize = 20.sp,
)
}
}
Number(3)
3
modifier = Modifier
.size(40.dp)
.background(Color.Black)
Text(
@Composable
fun Number(value: Int) {
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backgroundColor
) {
Text(
text = value.toString(),
fontSize = 20.sp,
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.size(40.dp)
.background(
A single number
Number(3)
Color.Black
@Composable
fun Number(value: Int) {
)
}
}
) 3
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A single number
Number(3)
@Composable
fun Number(value: Int, active: Boolean) {
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.size(40.dp)
.background( )
val backgroundColor = if (active) {
MaterialTheme.colors.primary
} else {
MaterialTheme.colors.primaryVariant
}
)
}
}
) {
Text(
text = value.toString(),
fontSize = 20.sp,
backgroundColor
color = Color.White,
3
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A single number
Column {
Number(3, active = true)
Number(7, active = false)
}
@Composable
fun Number(value: Int, active: Boolean) {
val backgroundColor = if (active) {
MaterialTheme.colors.primary
} else {
MaterialTheme.colors.primaryVariant
}
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.size(40.dp)
.background(backgroundColor)
) {
Text(
text = value.toString(),
fontSize = 20.sp,
color = Color.White,
)
}
}
3
7
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A single number
Column {
Number(3, active = true)
Number(7, active = false)
}
@Composable
fun Number(value: Int, active: Boolean) {
val backgroundColor = if (active) {
MaterialTheme.colors.primary
} else {
MaterialTheme.colors.primaryVariant
}
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.size(40.dp)
.background(backgroundColor)
) {
Text(
text = value.toString(),
fontSize = 20.sp,
color = Color.White,
)
}
}
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7
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A column of digits
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
Column(
Modifier
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
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7
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A column of digits
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
Column(
Modifier
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
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A column of digits
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
Column(
Modifier
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
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7
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A column of digits
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
Column(
Modifier
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
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7
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A column of digits
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
Column(
Modifier
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
NumberColumn(range = 0..9, current = 5)
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A column of digits
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
Column(
Modifier
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
NumberColumn(range = 0..9, current = 5)
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A complete clock
@Composable
fun Clock(time: Time) {
Row(
modifier = Modifier.fillMaxSize(),
horizontalArrangement = Arrangement.Center,
verticalAlignment = Alignment.CenterVertically,
) {
NumberColumn(0..2, time.hours / 10)
NumberColumn(0..9, time.hours % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.minutes / 10)
NumberColumn(0..9, time.minutes % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.seconds / 10)
NumberColumn(0..9, time.seconds % 10)
}
}
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A complete clock
@Composable
fun Clock(time: Time) {
Row(
modifier = Modifier.fillMaxSize(),
horizontalArrangement = Arrangement.Center,
verticalAlignment = Alignment.CenterVertically,
) {
NumberColumn(0..2, time.hours / 10)
NumberColumn(0..9, time.hours % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.minutes / 10)
NumberColumn(0..9, time.minutes % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.seconds / 10)
NumberColumn(0..9, time.seconds % 10)
}
}
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A complete clock
@Composable
fun Clock(time: Time) {
Row(
modifier = Modifier.fillMaxSize(),
horizontalArrangement = Arrangement.Center,
verticalAlignment = Alignment.CenterVertically,
) {
NumberColumn(0..2, time.hours / 10)
NumberColumn(0..9, time.hours % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.minutes / 10)
NumberColumn(0..9, time.minutes % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.seconds / 10)
NumberColumn(0..9, time.seconds % 10)
}
}
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A complete clock
@Composable
fun Clock(time: Time) {
Row(
modifier = Modifier.fillMaxSize(),
horizontalArrangement = Arrangement.Center,
verticalAlignment = Alignment.CenterVertically,
) {
NumberColumn(0..2, time.hours / 10)
NumberColumn(0..9, time.hours % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.minutes / 10)
NumberColumn(0..9, time.minutes % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.seconds / 10)
NumberColumn(0..9, time.seconds % 10)
}
}
Clock(Time(14, 15, 59))
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A complete clock
@Composable
fun Clock(time: Time) {
Row(
modifier = Modifier.fillMaxSize(),
horizontalArrangement = Arrangement.Center,
verticalAlignment = Alignment.CenterVertically,
) {
NumberColumn(0..2, time.hours / 10)
NumberColumn(0..9, time.hours % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.minutes / 10)
NumberColumn(0..9, time.minutes % 10)
Spacer(Modifier.size(16.dp))
NumberColumn(0..5, time.seconds / 10)
NumberColumn(0..9, time.seconds % 10)
}
}
Clock(Time(14, 15, 59))
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Aligning digits
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Clock(Time(14, 15, 59))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
Column(
Modifier.clip(RoundedCornerShape(percent = 25))
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
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Aligning digits
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Clock(Time(14, 15, 59))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
Column(
Modifier
.clip(RoundedCornerShape(percent = 25))
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
val mid = (range.last - range.first) / 2f
val offset = 40.dp * (mid - current)
.offset(y = offset)
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Aligning digits
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
val mid = (range.last - range.first) / 2f
val offset = 40.dp * (mid - current)
Column(
Modifier
.offset(y = offset)
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
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Clock(Time(14, 15, 59))
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Driving the clock
fun currentTime(): Time {
val cal = Calendar.getInstance()
return Time(
hours = cal.get(Calendar.HOUR_OF_DAY),
minutes = cal.get(Calendar.MINUTE),
seconds = cal.get(Calendar.SECOND),
)
}
var time by remember { mutableStateOf(currentTime()) }
LaunchedEffect(0) {
while (true) {
time = currentTime()
delay(1000)
}
}
Clock(time)
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Driving the clock
fun currentTime(): Time {
val cal = Calendar.getInstance()
return Time(
hours = cal.get(Calendar.HOUR_OF_DAY),
minutes = cal.get(Calendar.MINUTE),
seconds = cal.get(Calendar.SECOND),
)
}
var time by remember { mutableStateOf(currentTime()) }
LaunchedEffect(0) {
while (true) {
time = currentTime()
delay(1000)
}
}
Clock(time)
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Driving the clock
fun currentTime(): Time {
val cal = Calendar.getInstance()
return Time(
hours = cal.get(Calendar.HOUR_OF_DAY),
minutes = cal.get(Calendar.MINUTE),
seconds = cal.get(Calendar.SECOND),
)
}
var time by remember { mutableStateOf(currentTime()) }
LaunchedEffect(0) {
while (true) {
time = currentTime()
delay(1000)
}
}
Clock(time)
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Driving the clock
fun currentTime(): Time {
val cal = Calendar.getInstance()
return Time(
hours = cal.get(Calendar.HOUR_OF_DAY),
minutes = cal.get(Calendar.MINUTE),
seconds = cal.get(Calendar.SECOND),
)
}
var time by remember { mutableStateOf(currentTime()) }
LaunchedEffect(0) {
while (true) {
time = currentTime()
delay(1000)
}
}
Clock(time)
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Driving the clock
fun currentTime(): Time {
val cal = Calendar.getInstance()
return Time(
hours = cal.get(Calendar.HOUR_OF_DAY),
minutes = cal.get(Calendar.MINUTE),
seconds = cal.get(Calendar.SECOND),
)
}
var time by remember { mutableStateOf(currentTime()) }
LaunchedEffect(0) {
while (true) {
time = currentTime()
delay(1000)
}
}
Clock(time)
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Animations
@Composable
fun Number(value: Int, active: Boolean) {
val backgroundColor =
if (active) MaterialTheme.colors.primary
else MaterialTheme.colors.primaryVariant
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.size(40.dp)
.background(backgroundColor),
) {
Text(
text = value.toString(),
fontSize = 20.sp,
color = Color.White,
)
}
}
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Animations
@Composable
fun Number(value: Int, active: Boolean) {
val backgroundColor by animateColorAsState(
if (active) MaterialTheme.colors.primary
else MaterialTheme.colors.primaryVariant
)
Box(
contentAlignment = Alignment.Center,
modifier = Modifier
.size(40.dp)
.background(backgroundColor),
) {
Text(
text = value.toString(),
fontSize = 20.sp,
color = Color.White,
)
}
}
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Animations
=
Column(
Modifier
.offset(y = offset)
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
40.dp * (mid - current)
val mid = (range.last - range.first) / 2f
val offset
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Animations
Column(
Modifier
.offset(y = offset)
.clip(RoundedCornerShape(percent = 25))
) {
range.forEach { num ->
Number(num, num == current)
}
}
}
@Composable
fun NumberColumn(
range: IntRange,
current: Int,
) {
40.dp * (mid - current)
val mid = (range.last - range.first) / 2f
val offset by animateDpAsState(
targetValue =
)
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Animated
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Polished
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Resources
• Compose O’Clock
https://zsmb.co/compose-o-clock/
• Source code on GitHub
https://github.com/zsmb13/ComposeClock
• Jetpack Compose First Impressions & Learning Resources
https://getstream.io/blog/jetpack-compose-impressions-resources/
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zsmb13
zsmb.co/talks
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zsmb.co/talks
zsmb13
Márton Braun
It's Compose
O'Clock on
Android
› Declarative,
component-based
› Quick iteration
› Future of Android UI
development