ui: more theming utilities (for Files)

ui/src/main/java/com/nextcloud/android/common/ui/color/ColorUtil.kt

@@ -51,16 +51,20 @@ class ColorUtil @Inject constructor(private val context: Context) {
 
     @ColorInt
     fun getForegroundColorForBackgroundColor(@ColorInt color: Int): Int {
-        val hsl = FloatArray(HSL_SIZE)
-        ColorUtils.RGBToHSL(Color.red(color), Color.green(color), Color.blue(color), hsl)
-
-        return if (hsl[INDEX_LIGHTNESS] < LIGHTNESS_DARK_THRESHOLD) {
+        return if (isDarkBackground(color)) {
             Color.WHITE
         } else {
             ContextCompat.getColor(context, R.color.grey_900)
         }
     }
 
+    fun isDarkBackground(@ColorInt color: Int): Boolean {
+        val hsl = FloatArray(HSL_SIZE)
+        ColorUtils.RGBToHSL(Color.red(color), Color.green(color), Color.blue(color), hsl)
+
+        return hsl[INDEX_LIGHTNESS] < LIGHTNESS_DARK_THRESHOLD
+    }
+
     fun setLightness(@ColorInt color: Int, lightness: Float): Int {
         require(lightness in 0.0..1.0) { "Lightness must be between 0 and 1" }
         val hsl = FloatArray(HSL_SIZE)
@@ -71,9 +75,17 @@ class ColorUtil @Inject constructor(private val context: Context) {
         return ColorUtils.HSLToColor(hsl)
     }
 
+    fun colorToHexString(@ColorInt color: Int): String {
+        return String.format(null, "#%06X", HEX_WHITE and color)
+    }
+
     @ColorInt
     private fun String?.parseColorOrFallback(fallback: () -> Int): Int {
-        return this?.let { Color.parseColor(this) } ?: fallback()
+        return if (this?.isNotBlank() == true) {
+            Color.parseColor(this)
+        } else {
+            fallback()
+        }
     }
 
     @ColorInt
@@ -90,5 +102,6 @@ class ColorUtil @Inject constructor(private val context: Context) {
         private const val HSL_SIZE: Int = 3
         private const val INDEX_LIGHTNESS: Int = 2
         private const val LIGHTNESS_DARK_THRESHOLD: Float = 0.6f
+        private const val HEX_WHITE = 0xFFFFFF
     }
 }

ui/src/main/java/com/nextcloud/android/common/ui/theme/MaterialSchemes.kt

@@ -21,6 +21,7 @@
 
 package com.nextcloud.android.common.ui.theme
 
+import androidx.annotation.ColorInt
 import scheme.Scheme
 
 interface MaterialSchemes {
@@ -36,5 +37,6 @@ interface MaterialSchemes {
 
     companion object {
         fun fromServerTheme(theme: ServerTheme): MaterialSchemes = MaterialSchemesImpl(theme)
+        fun fromColor(@ColorInt color: Int): MaterialSchemes = MaterialSchemesImpl(color)
     }
 }

ui/src/main/java/com/nextcloud/android/common/ui/theme/MaterialSchemesImpl.kt

@@ -21,15 +21,18 @@
 
 package com.nextcloud.android.common.ui.theme
 
+import androidx.annotation.ColorInt
 import scheme.Scheme
 
-internal class MaterialSchemesImpl(serverTheme: ServerTheme) :
+internal class MaterialSchemesImpl :
     MaterialSchemes {
     override val lightScheme: Scheme
     override val darkScheme: Scheme
 
-    init {
-        lightScheme = Scheme.light(serverTheme.primaryColor)
-        darkScheme = Scheme.dark(serverTheme.primaryColor)
+    constructor(@ColorInt primaryColor: Int) {
+        lightScheme = Scheme.light(primaryColor)
+        darkScheme = Scheme.dark(primaryColor)
     }
+
+    constructor(serverTheme: ServerTheme) : this(serverTheme.primaryColor)
 }

ui/src/main/java/com/nextcloud/android/common/ui/theme/ViewThemeUtilsBase.kt

@@ -28,7 +28,7 @@ import android.view.View
 import com.nextcloud.android.common.ui.util.PlatformThemeUtil
 import scheme.Scheme
 
-open class ViewThemeUtilsBase(val schemes: MaterialSchemes) {
+open class ViewThemeUtilsBase(private val schemes: MaterialSchemes) {
     /**
      * Scheme for painting elements
      */
@@ -40,20 +40,15 @@ open class ViewThemeUtilsBase(val schemes: MaterialSchemes) {
     fun getScheme(context: Context): Scheme = getSchemeInternal(context)
 
     @Suppress("MemberVisibilityCanBePrivate")
+    // TODO cache by context hashcode
     protected fun getSchemeInternal(context: Context): Scheme = when {
         PlatformThemeUtil.isDarkMode(context) -> schemes.darkScheme
         else -> schemes.lightScheme
     }
 
-    protected fun withScheme(view: View, block: (Scheme) -> Unit) {
-        block(getSchemeInternal(view.context))
-    }
+    protected fun <R> withScheme(view: View, block: (Scheme) -> R): R = block(getSchemeInternal(view.context))
 
-    protected fun withScheme(context: Context, block: (Scheme) -> Unit) {
-        block(getSchemeInternal(context))
-    }
+    protected fun <R> withScheme(context: Context, block: (Scheme) -> R): R = block(getSchemeInternal(context))
 
-    protected fun withSchemeDark(block: (Scheme) -> Unit) {
-        block(schemes.darkScheme)
-    }
+    protected fun <R> withSchemeDark(block: (Scheme) -> R): R = block(schemes.darkScheme)
 }