commonMain.androidx.compose.material3.MaterialTheme.kt Maven / Gradle / Ivy
/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.material3
import androidx.compose.foundation.LocalIndication
import androidx.compose.foundation.text.selection.LocalTextSelectionColors
import androidx.compose.foundation.text.selection.TextSelectionColors
import androidx.compose.material.ripple.LocalRippleTheme
import androidx.compose.material.ripple.RippleAlpha
import androidx.compose.material.ripple.RippleTheme
import androidx.compose.material.ripple.rememberRipple
import androidx.compose.material3.tokens.StateTokens
import androidx.compose.runtime.Composable
import androidx.compose.runtime.CompositionLocalProvider
import androidx.compose.runtime.Immutable
import androidx.compose.runtime.ReadOnlyComposable
import androidx.compose.runtime.remember
// TODO: Create a sample androidx.compose.material3.samples.MaterialThemeSample
// TODO(b/197880751) Update to link M3 Material Theming page (i.e. a Material
// Theming M3 equivalent).
/**
* Material Theming refers to the customization of your Material Design app to better reflect your
* product’s brand.
*
* Material components such as [Button] and [Checkbox] use values provided here when retrieving
* default values.
*
* All values may be set by providing this component with the [colorScheme][ColorScheme],
* [typography][Typography] attributes. Use this to configure the overall
* theme of elements within this MaterialTheme.
*
* Any values that are not set will inherit the current value from the theme, falling back to the
* defaults if there is no parent MaterialTheme. This allows using a MaterialTheme at the top
* of your application, and then separate MaterialTheme(s) for different screens / parts of your
* UI, overriding only the parts of the theme definition that need to change.
*
* @param colorScheme A complete definition of the Material Color theme for this hierarchy
* @param typography A set of text styles to be used as this hierarchy's typography system
* @param shapes A set of corner shapes to be used as this hierarchy's shape system
*/
@Composable
fun MaterialTheme(
colorScheme: ColorScheme = MaterialTheme.colorScheme,
shapes: Shapes = MaterialTheme.shapes,
typography: Typography = MaterialTheme.typography,
content: @Composable () -> Unit
) {
val rememberedColorScheme = remember {
// Explicitly creating a new object here so we don't mutate the initial [colorScheme]
// provided, and overwrite the values set in it.
colorScheme.copy()
}.apply {
updateColorSchemeFrom(colorScheme)
}
val rippleIndication = rememberRipple()
val selectionColors = rememberTextSelectionColors(rememberedColorScheme)
CompositionLocalProvider(
LocalColorScheme provides rememberedColorScheme,
LocalIndication provides rippleIndication,
LocalRippleTheme provides MaterialRippleTheme,
LocalShapes provides shapes,
LocalTextSelectionColors provides selectionColors,
LocalTypography provides typography,
) {
ProvideTextStyle(value = typography.bodyLarge, content = content)
}
}
/**
* Contains functions to access the current theme values provided at the call site's position in
* the hierarchy.
*/
object MaterialTheme {
/**
* Retrieves the current [ColorScheme] at the call site's position in the hierarchy.
*/
val colorScheme: ColorScheme
@Composable
@ReadOnlyComposable
get() = LocalColorScheme.current
/**
* Retrieves the current [Typography] at the call site's position in the hierarchy.
*/
val typography: Typography
@Composable
@ReadOnlyComposable
get() = LocalTypography.current
/**
* Retrieves the current [Shapes] at the call site's position in the hierarchy.
*/
val shapes: Shapes
@Composable
@ReadOnlyComposable
get() = LocalShapes.current
}
@Immutable
private object MaterialRippleTheme : RippleTheme {
@Composable
override fun defaultColor() = LocalContentColor.current
@Composable
override fun rippleAlpha() = DefaultRippleAlpha
}
private val DefaultRippleAlpha = RippleAlpha(
pressedAlpha = StateTokens.PressedStateLayerOpacity,
focusedAlpha = StateTokens.FocusStateLayerOpacity,
draggedAlpha = StateTokens.DraggedStateLayerOpacity,
hoveredAlpha = StateTokens.HoverStateLayerOpacity
)
@Composable
/*@VisibleForTesting*/
internal fun rememberTextSelectionColors(colorScheme: ColorScheme): TextSelectionColors {
val primaryColor = colorScheme.primary
return remember(primaryColor) {
TextSelectionColors(
handleColor = primaryColor,
backgroundColor = primaryColor.copy(alpha = TextSelectionBackgroundOpacity),
)
}
}
/*@VisibleForTesting*/
internal const val TextSelectionBackgroundOpacity = 0.4f