A library for Android that provides HSV Color Wheel and Linear Gradient Seek Bar

ColorWheel

ColorWheel is a library for Android that provides HSV Color Wheel and Linear Gradient Seek Bar UI elements that can be used to pick ARGB color.

Requirements

The minimal required Android API version is 19 (Android 4.4).

Screenshots

Installation

To add the library to your project simply add the following line to your app module build.gradle file:

implementation 'com.apandroid:colorwheel:1.0.3'

In case of problems make sure that jCenter repository is specified in your build.gradle file:

repositories {
    jcenter()
}

Getting Started

To start using the views just add ColorWheel or GradientSeekBar to your xml layout file:

<com.apandroid.colorwheel.ColorWheel
    android:id="@+id/colorWheel"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

<com.apandroid.colorwheel.gradientseekbar.GradientSeekBar
    android:id="@+id/gradientSeekBar"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

Basic Usage

ColorWheel

To set or get RGB color you can use ColorWheel.rgb property:

val colorWheel = findViewById<ColorWheel>(R.id.colorWheel)

colorWheel.rgb = Color.rgb(13, 37, 42)

val currentColor = colorWheel.rgb

Note: when you set RGB or ARGB color it is transformed to the closest HSV color with value(brightness) component of it set to 1
so the color can be correctly displayed on the ColorWheel because it is only 2 dimensional. Therefore currently displayed color
on the ColorWheel may differ from the original color that you have set. To allow a user to change brightness or alpha component
of a color picked from ColorWheel you can use GradientSeekBar view.

Also you can set colorChangeListener that will be called every time when currently selected color is changed:

colorWheel.colorChangeListener = { rgb: Int ->
    // Listener Code
}

GradientSeekBar

GradientSeekBar draws a vertical or horizontal bar filled with linear gradient of two colors.
You can use it to pick an intermediate color between these two.

Color

To pick intermediate ARGB color you can use GradientSeekBar.argb property:

val color = gradientSeekBar.argb

To set or get start or end colors to or from GradientSeekBar you can use the following properties and methods:

val startColor = Color.argb(0, 0, 0, 0)
val endColor = Color.argb(0xff, 0xff, 0xff, 0xff)

gradientSeekBar.startColor = startColor
gradientSeekBar.endColor = endColor
gradientSeekBar.setColors(startColor, endColor)

Also you can use listener property to set a listener that will be called every time an intermediate color is changed:

gradientSeekBar.currentColor = { offset: Float, argb: Int ->
    // Listener code
}

If you want to change an intermediate color programmatically you can use GradientSeekBar.offset property. This value is always within
the range from 0f to 1f and shows how close an intermediate color to a start or end color.

Alpha

If you want to use GradientSeekBar to pick alpha component of a color in range from 0 to 255
you can use the following extensions of GradientSeekBar:

• GradientSeekBar.setAlphaArgb(argb)
• GradientSeekBar.setAlphaRgb(rgb)

Both of these methods take RGB color and set transparent version of it as start color and opaque as end color.

The only difference between these two methods is that GradientSeekBar.setAlphaArgb(argb) also adjusts
position of the thumb based on the alpha value of the parameter while GradientSeekBar.setAlphaRgb(rgb) doesn't.

To get alpha component of a current intermediate color you can use GradientSeekBar.argbAlpha extension property.

Also you can use GradientSeekBar.setAlphaListener method to set a listener that will be called when
alpha value is changed.

gradientSeekBar.setAlphaListener { offset: Float, color: Int, alpha: Int ->
    // Listener code
}

Brightness

It is impossible to pick all different colors from HSV Color Wheel since it is 2 dimensional and value(brightness) component of it
is always set to 1f.

To compensate it you can use GradientSeekBar and it's setBlackToColor(color) extensions. This method sets black color as
start color and provided color as end color. This gives you a possibility to pick additional shades of a color selected from ColorWheel.

Additional Customazing

You can use the following XML attributes to additionally customize ColorWheel and GradientSeekBar.

ColorWheel

GradientSeekBar

GitHub