✨ Complete Library implementation

Author: emkayDauda

colorslider/src/main/java/com/emkaydauda/colorslider/ColorSlider.kt

@@ -1,2 +1,132 @@
 package com.emkaydauda.colorslider
 
+
+import android.content.Context
+import android.graphics.Canvas
+import android.graphics.Color
+import android.graphics.Paint
+import android.graphics.drawable.Drawable
+import androidx.core.content.ContextCompat
+import android.util.AttributeSet
+import android.util.TypedValue
+import android.widget.SeekBar
+
+class ColorSlider @JvmOverloads
+constructor(
+    context: Context,
+    attributeSet: AttributeSet? = null,
+    styleAttr: Int = R.attr.seekBarStyle,
+    styleRes: Int = 0
+) : SeekBar(context, attributeSet, styleAttr, styleRes) {
+
+    private var colors: ArrayList<Int> = arrayListOf(Color.RED, Color.GREEN, Color.DKGRAY)
+
+    private val w = 16f.toDip(context)
+    private val h = 16f.toDip(context)
+
+    private val halfW = if (w >= 0) w / 2f else 1f
+    private val halfH = if (h >= 0) h / 2f else 1f
+
+    private val paint = Paint()
+
+    private var noColorDrawable: Drawable? = null
+        set(value) {
+            w2 = value?.intrinsicWidth ?: 0
+            h2 = value?.intrinsicHeight ?: 0
+            halfW2 = if (w2 >= 0) w2 / 2 else 1
+            halfH2 = if (h2 >= 0) h2 / 2 else 1
+
+            value?.setBounds(-halfW2, -halfH2, halfW2, halfH2)
+            field = value
+        }
+
+    var w2 = 0
+    var h2 = 0
+    var halfW2 = 1
+    var halfH2 = 1
+
+    init {
+        val typedArray = context.obtainStyledAttributes(attributeSet, R.styleable.ColorSlider)
+        try {
+            colors = typedArray.getTextArray(R.styleable.ColorSlider_colors).map {
+                Color.parseColor(it.toString())
+            } as ArrayList<Int>
+        } finally {
+            typedArray.recycle()
+        }
+
+        noColorDrawable = context.getDrawable(R.drawable.ic_clear_red_24dp)
+
+
+        colors.add(0, android.R.color.transparent)
+        max = colors.size - 1
+        progressTintList = ContextCompat.getColorStateList(context, android.R.color.transparent)
+        progressBackgroundTintList = ContextCompat.getColorStateList(context, android.R.color.transparent)
+        splitTrack = false
+
+        setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom + 16f.toDip(context).toInt())
+
+        thumb = context.getDrawable(R.drawable.ic_arrow_drop_down_black_24dp)
+
+        setOnSeekBarChangeListener(object : OnSeekBarChangeListener {
+            override fun onProgressChanged(p0: SeekBar?, position: Int, p2: Boolean) {
+                listeners.forEach {
+                    it(colors[position])
+                }
+            }
+
+            override fun onStartTrackingTouch(p0: SeekBar?) {
+
+            }
+
+            override fun onStopTrackingTouch(p0: SeekBar?) {
+
+            }
+        })
+
+    }
+
+    override fun onDraw(canvas: Canvas?) {
+        super.onDraw(canvas)
+        drawTickMarks(canvas)
+    }
+
+    private var listeners: ArrayList<(Int) -> Unit> = arrayListOf()
+
+    var selectedColorValue: Int = android.R.color.transparent
+        set(value) {
+            var index = colors.indexOf(value)
+            progress = if (index == -1) 0 else index
+        }
+
+    fun addListener(function: (Int) -> Unit) {
+        listeners.add(function)
+    }
+
+    private fun drawTickMarks(canvas: Canvas?) {
+        canvas?.let {
+            val count = colors.size
+            val saveCount = canvas.save()
+            canvas.translate(paddingLeft.toFloat(), (height / 2f) + 8f.toDip(context))
+            if (count > 1) {
+
+                for (i in 0 until count) {
+                    val spacing = (width - paddingLeft - paddingRight) / (count - 1).toFloat()
+
+                    if (i == 0) {
+                        noColorDrawable?.draw(canvas)
+                    } else {
+                        paint.color = colors[i]
+                        canvas.drawRoundRect(-halfW, -halfH, halfW, halfH, 2f.toDip(context), 2f.toDip(context), paint)
+                    }
+                    canvas.translate(spacing, 0f)
+                }
+                canvas.restoreToCount(saveCount)
+            }
+        }
+    }
+}
+
+private fun Float.toDip(context: Context): Float {
+    return TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, this, context.resources.displayMetrics)
+}