JetPack Compose主题配色太少怎么办，来设计自己的颜色系统吧（上）

enum class ColorPallet {
    // 默认就给两个颜色，根据需求可以定义多个
    DARK, LIGHT
}

object ColorsManager {
    /** 使用一个变量维护当前主题 */
    var pallet by mutableStateOf(ColorPallet.LIGHT)
}

/** 共用的颜色 */
val Purple200 = Color(0xFFBB86FC)
val Purple500 = Color(0xFF6200EE)
val Purple700 = Color(0xFF3700B3)
val Teal200 = Color(0xFF03DAC5)
/** 业务颜色配置,如果需要增加其他主题业务色,直接定义相应的下述对象即可,如果某个颜色共用,则增加默认值 */
open class CkColor(val homeBackColor: Color, val homeTitleTvColor: Color = Color.Gray)
/** 提前定义好的业务颜色模板对象 */
private val CkDarkColor = CkColor(
    homeBackColor = Color.Black
)
private val CkLightColor = CkColor(
    homeBackColor = Color.White
)
/** 默认的颜色配置,即Md的默认配置颜色 */
private val DarkColorPalette = darkColors(
    primary = Purple200,
    primaryVariant = Purple700,
    secondary = Teal200
)
private val LightColorPalette = lightColors(
    primary = Purple500,
    primaryVariant = Purple700,
    secondary = Teal200
)

/** 增加扩展 */
val MaterialTheme.ckColor: CkColor
    get() = when (ColorsManager.pallet) {
        ColorPallet.DARK -> CkDarkColor
        ColorPallet.LIGHT -> CkLightColor
    }

@Composable
fun CkTheme(
    pallet: ColorPallet = ColorsManager.pallet,
    content: @Composable() () -> Unit
) {
    val colors = when (pallet) {
        ColorPallet.DARK -> DarkColorPalette
        ColorPallet.LIGHT -> LightColorPalette
    }
    MaterialTheme(
        colors = colors,
        typography = Typography,
        shapes = Shapes,
        content = content
    )
}

// 示例，正确做法是放到color.kt下
val Blue50 = Color(0xFFE3F2FD)
val Blue200 = Color(0xFF90CAF9)
val A900 = Color(0xFF0D47A1)
/**
 * 实际主题的颜色集,所有颜色都需要添加到其中,并使用相应的子类覆盖颜色。
 * 每一次的更改都需要将颜色配置在下方 [CkColors] 中,并同步 [CkDarkColor] 与 [CkLightColor]
 * */
@Stable
class CkColors(
    homeBackColor: Color,
    homeTitleTvColor: Color
) {
    var homeBackColor by mutableStateOf(homeBackColor)
        private set
    var homeTitleTvColor by mutableStateOf(homeTitleTvColor)
        private set
    fun update(colors: CkColors) {
        this.homeBackColor = colors.homeBackColor
        this.homeTitleTvColor = colors.homeTitleTvColor
    }
    fun copy() = CkColors(homeBackColor, homeTitleTvColor)
}
/** 提前定义好的颜色模板对象 */
private val CkDarkColors = CkColors(
    homeBackColor = A900,
    homeTitleTvColor = Blue50,
)
private val CkLightColors = CkColors(
    homeBackColor = Blue200,
    homeTitleTvColor = Color.White,
)

@Composable
fun ProvideLcColors(colors: CkColors, content: @Composable () -> Unit) {
    val colorPalette = remember {
        colors.copy()
    }
    colorPalette.update(colors)
    CompositionLocalProvider(LocalLcColors provides colorPalette, content = content)
}

// 创建静态 CompositionLocal ,通常情况下主题改动不会很频繁
private val LocalLcColors = staticCompositionLocalOf {
    CkLightColors
}

enum class StylePallet {
    // 默认就给两个颜色，根据需求可以定义多个
    DARK, LIGHT
}
/* 针对当前主题配置颜色板扩展属性 */
private val StylePallet.colors: Pair<Colors, CkColors>
    get() = when (this) {
        StylePallet.DARK -> DarkColorPalette to CkDarkColors
        StylePallet.LIGHT -> LightColorPalette to CkLightColors
    }
/** CkX-Compose主题管理者 */
object CkXTheme {
    /** 从CompositionLocal中取出相应的Local */
    val colors: CkColors
        @Composable
        get() = LocalLcColors.current
    /** 使用一个state维护当前主题配置,这里的写法取决于具体业务，如果你使用了深色模式默认配置，则无需这个变量，即app只支持深色与亮色，那么只需要每次读系统配置即可。但是compose本身可以做到快速切换主题，那么维护一个变量是肯定没法避免的 */
    var pallet by mutableStateOf(StylePallet.LIGHT)
}

@Composable
fun CkXTheme(
    pallet: StylePallet = CkXTheme.pallet,
    content: @Composable () -> Unit
) {
    val (colorPalette, lcColors) = pallet.colors
    ProvideLcColors(colors = lcColors) {
        MaterialTheme(
            colors = colorPalette,
            typography = Typography,
            shapes = Shapes,
            content = content
        )
    }
}