Develop Reference

jetpack compose shadow strange behaviour

I am trying to build an text field with shadow outside
This is the result I achieved so on.
But if you zoom in the picture you will see some rectangle background under white text field (please look at the corners outside of text field, there is a background)
How can I remove that background ?
#Composable
fun MyTextField() {
var text by remember {
mutableStateOf("")
}
Box(
modifier = Modifier
.padding(15.dp)
.shadow(5.dp)
.background(color = Color.White, shape = RoundedCornerShape(10.dp))
.fillMaxWidth()
.height(50.dp),
contentAlignment = Alignment.Center,
) {
TextField(
value = text,
onValueChange = { text = it },
label = { Text(text = "Phone number", color = Color.Gray, fontSize = 14.sp) },
modifier = Modifier
.fillMaxSize()
.background(color = Color.Transparent, shape = RoundedCornerShape(10.dp)),
colors = TextFieldDefaults.textFieldColors(
backgroundColor = Color.Transparent,
focusedIndicatorColor = Color.Transparent,
unfocusedIndicatorColor = Color.Transparent
),
)
}
}

As default the shadow modifier uses a RectangleShape, it is the reason of your issue:
Apply the same shape to the shadow and background modifiers:
val shape = RoundedCornerShape(10.dp)
Box(
modifier = Modifier
.padding(15.dp)
.shadow(
elevation = 5.dp,
shape = shape
)
.background(color = Color.White, shape = shape)
.fillMaxWidth()
.height(50.dp),
contentAlignment = Alignment.Center,
)

Border radius is not changing based on shape when user click on it jetpack compose

Hey guys I am using RoundedCornerShape(4.dp) to my Surface which looks fine. When I tried to click on the item it not showing me 4dp corner in Surface. I tried this stack overflow 1 and stack overflow 2 but nothing works.
binding.itemComposable.setContent {
Column(modifier = Modifier.fillMaxSize(), verticalArrangement = Arrangement.spacedBy(12.dp)) {
val options = getOptions()
options.forEachIndexed { _, optionText ->
val interactionSource = remember { MutableInteractionSource() }
val isPressed by interactionSource.collectIsPressedAsState()
val backgroundColor = if (isPressed) DuckEggBlue else OffWhite
val textColor = if (isPressed) TealBlue else Slate
val borderWidth = if (isPressed) 1.dp else 0.dp
val borderColor = if (isPressed) Aqua else OffWhite
val clickable = Modifier.clickable(
interactionSource = interactionSource,
indication = rememberRipple(true)
) {
println("Item Click")
}
Surface(
modifier = Modifier
.then(clickable)
.border(borderWidth, borderColor),
shape = RoundedCornerShape(4.dp)
) {
Text(
modifier = Modifier
.fillMaxWidth()
.background(backgroundColor)
.padding(16.dp),
text = optionText,
style = Typography.h3,
fontWeight = FontWeight.Medium,
color = textColor
)
}
}
}
}
Without click on item corner is 4 dp
When I click it's not changing corner

If you want to handle the click on a Surface you have to use the function that accepts an onClick():
Surface(
onClick = {},
shape = RoundedCornerShape(4.dp),
border = BorderStroke(borderWidth,borderColor),
interactionSource = interactionSource
)

Create a variable for shape
val shape = RoundedCornerShape(4.dp)
Use it in Modifier.clip() and Modifier.border() like this,
Surface(
modifier = Modifier
.clip(shape)
.border(
width = borderWidth,
color = borderColor,
shape = shape,
)
.then(clickable),
// shape = shape,
)
shape in border() specifies the shape of the border which by default is RectangleShape. Hence, you are seeing the rectangle border.
shape in clip() changes the shape of the composable before the click action is added. This is to make the ripple effect appear only on the given shape.
Note: Order of modifiers are important.
The shape in the Surface may not be needed after these changes.

If youre using Surface to wrapping the content, try to add a container inside the content for example Box or Column. Then use your Surface only as a shape mask, the background and other content will be flexible as you want.
This is the example
Surface(
modifier = Modifier
.then(clickable)
.border(borderWidth, borderColor),
shape = RoundedCornerShape(4.dp)
) {
Box(modifier = Modifier
.fillMaxWidth()
.fillMaxHeight()
.background(Color.Green)){
Text(
modifier = Modifier
.fillMaxWidth()
.padding(16.dp),
text = optionText,
style = Typography.h3,
fontWeight = FontWeight.Medium,
color = textColor
)
}
}

Transparent checkmark in checkBox in Jetpack Compose

In my Compose app I need to create a circle checkboxes. I've already achieved that with the code below:
#Composable
fun CircleCheckBox(
isChecked: Boolean,
modifier: Modifier = Modifier,
onChecked: () -> Unit = {},
checkedBackgroundColor: Color,
unCheckedBackgroundColor: Color,
checkedIconColor: Color,
unCheckedIconColor: Color
) {
Box(
modifier = modifier
.clip(CircleShape)
.clickable { onChecked() }
.border(
width = if (!isChecked) 1.dp else 0.dp,
color = if (!isChecked) checkedBackgroundColor else Color.Transparent,
shape = CircleShape
)
.background(
color = if (isChecked) checkedBackgroundColor else unCheckedBackgroundColor,
shape = CircleShape
),
contentAlignment = Alignment.Center
) {
Icon(
imageVector = Icons.Default.Check,
contentDescription = stringResource(R.string.icon_check),
modifier = Modifier.padding(3.dp),
tint = if (isChecked) checkedIconColor else unCheckedIconColor
)
}
}
But in my app I have a gradient backgrounds on cards, so I want to make checkmarks transparent, but in this realization it's impossible because of the background of the Box. Is there any way to achieve it, like on image below?

You can find an appropriate default icons instead of drawing on your own. Icons.Default.CheckCircle is what you're looking for - it has transparent checkmark inside a filled circle. And you can use Icons.Outlined.Circle instead of border modifier:
#Composable
fun CircleCheckBox(
isChecked: Boolean,
modifier: Modifier = Modifier,
onChecked: () -> Unit = {},
color: Color,
) {
Box(
contentAlignment = Alignment.Center,
modifier = modifier
.clip(CircleShape)
.clickable { onChecked() }
) {
Icon(
imageVector = if (isChecked) Icons.Default.CheckCircle else Icons.Outlined.Circle,
contentDescription = stringResource(R.string.icon_check),
tint = color
)
}
}
Result:

I think you can achieve this by importing custom icon vector like this
Here, the check is transparent so, it will show the gradient background.

Android compose Card has a border when semi-transparent colors used

Android Jetpack compose Card draws a border around the card when background color has some transparency. This is how it looks in AS:
But this is how it looks in the app:
If I set background to a solid color it works, but by default backgroundColor is a surface color from material (in my app val white850 = Color(0xD9FFFFFF)) and it looks like on the picture above.
#Composable
fun TraitCard(trait: Trait) {
Card(
shape = MaterialTheme.shapes.small,
modifier = Modifier.size(width = 192.dp, height = 56.dp)
) {
Row(
verticalAlignment = Alignment.CenterVertically,
horizontalArrangement = Arrangement.Start
) {
Icon(
imageVector = Icons.Rounded.ChildFriendly,
contentDescription = "",
modifier = Modifier
.fillMaxHeight()
.background(color = MaterialTheme.colors.background)
.aspectRatio(1f)
.padding(8.dp),
tint = MaterialTheme.colors.onBackground
)
Text(
text = trait.name,
style = MaterialTheme.typography.h3,
modifier = Modifier.padding(horizontal = 16.dp),
)
}
}
}
Does anyone have a clue why it's happening?

This is because of the elevation that Card has by default (and how shadows are drawn), if you remove the elevation this won't happen.
You can try to convert the semitransparent color to the non transparent one with something like:
backgroundColor = Color(0xD9FFFFFF).compositeOver(Color.White),

When should I use Android Jetpack Compose Surface composable?

There's Surface composable in Jetpack Compose which represents a material surface. A surface allows you to setup things like background color or border but it seems that the same might be done using modifiers. When should I use the Surface composable and what the benefits it gives me?

Surface composable makes the code easier as well as explicitly indicates that the code uses a material surface. Let's see an example:
Surface(
color = MaterialTheme.colors.primarySurface,
border = BorderStroke(1.dp, MaterialTheme.colors.secondary),
shape = RoundedCornerShape(8.dp),
elevation = 8.dp
) {
Text(
text = "example",
modifier = Modifier.padding(8.dp)
)
}
and the result:
The same result can be achieved without Surface:
val shape = RoundedCornerShape(8.dp)
val shadowElevationPx = with(LocalDensity.current) { 2.dp.toPx() }
val backgroundColor = MaterialTheme.colors.primarySurface
Text(
text = "example",
color = contentColorFor(backgroundColor),
modifier = Modifier
.graphicsLayer(shape = shape, shadowElevation = shadowElevationPx)
.background(backgroundColor, shape)
.border(1.dp, MaterialTheme.colors.secondary, shape)
.padding(8.dp)
)
but it has a few drawbacks:
The modifiers chain is pretty big and it isn't obvious that it implements a material surface
I have to declare a variable for the shape and pass it into three different modifiers
It uses contentColorFor to figure out the content color while Surface does it under the hood. As a result the backgroundColor is used in two places as well.
I have to calculate the elevation in pixels
Surface adjusts colors for elevation (in case of dark theme) according to the material design. If you want the same behavior, it should be handled manually.
For the full list of Surface features it's better to take a look at the documentation.

Surface is a Box with a Modifier.surface() and material colors and elevation, it checks elevation of ancestors to be always on top of them, and only overload below blocking touch propagation behind the surface with pointerInput(Unit) {}.
#Composable
fun Surface(
modifier: Modifier = Modifier,
shape: Shape = RectangleShape,
color: Color = MaterialTheme.colors.surface,
contentColor: Color = contentColorFor(color),
border: BorderStroke? = null,
elevation: Dp = 0.dp,
content: #Composable () -> Unit
) {
val absoluteElevation = LocalAbsoluteElevation.current + elevation
CompositionLocalProvider(
LocalContentColor provides contentColor,
LocalAbsoluteElevation provides absoluteElevation
) {
Box(
modifier = modifier
.surface(
shape = shape,
backgroundColor = surfaceColorAtElevation(
color = color,
elevationOverlay = LocalElevationOverlay.current,
absoluteElevation = absoluteElevation
),
border = border,
elevation = elevation
)
.semantics(mergeDescendants = false) {}
.pointerInput(Unit) {},
propagateMinConstraints = true
) {
content()
}
}
}
And Modifier.surface()
private fun Modifier.surface(
shape: Shape,
backgroundColor: Color,
border: BorderStroke?,
elevation: Dp
) = this.shadow(elevation, shape, clip = false)
.then(if (border != null) Modifier.border(border, shape) else Modifier)
.background(color = backgroundColor, shape = shape)
.clip(shape)
Another interesting thing is it is Box with propagateMinConstraints = true parameter which forces first descendant to have same minimum constraints or dimensions
Surface(
modifier = Modifier.size(200.dp),
onClick = {}) {
Column(
modifier = Modifier
.size(50.dp)
.background(Color.Red, RoundedCornerShape(6.dp))
) {}
}
Spacer(modifier = Modifier.height(20.dp))
Surface(
modifier = Modifier.size(200.dp),
onClick = {}) {
Column(
modifier = Modifier
.size(50.dp)
.background(Color.Red, RoundedCornerShape(6.dp))
) {
Box(
modifier = Modifier
.size(50.dp)
.background(Color.Green, RoundedCornerShape(6.dp))
)
}
}
Spacer(modifier = Modifier.height(20.dp))
Box(
modifier = Modifier.size(200.dp)
) {
Column(
modifier = Modifier
.size(50.dp)
.background(Color.Red, RoundedCornerShape(6.dp))
) {
Box(
modifier = Modifier
.size(50.dp)
.background(Color.Green, RoundedCornerShape(6.dp))
)
}
}
In first example on Surface forces Column to have 200.dp size even though it has Modifier.size(50.dp).
In second example Box inside Column has 50.dp size because it's not a direct descendant of Surface.
In third example if we replace Surface(Box with propagateMinConstraints true) with Box it allows direct descendant to use its own constraints or dimensions.

Surface is the equivalent of CardView in view system.
By Surface, you can set elevation for the view (note that this is not the same with Modifier.shadow)