Discrete SeekBar in Kotlin

A discrete SeekBar is one that jumps in fixed steps rather than smoothly transitioning between values. Android added support for a discrete SeekBar via the android:tickMark attribute, which was introduced in API level 24.

Here's a guide on how to create a discrete SeekBar in Kotlin:

Layout Definition (XML)

Create a layout file, e.g., activity_main.xml:

<SeekBar
    android:id="@+id/discreteSeekBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:max="10"  <!-- maximum value -->
    android:progress="5"  <!-- initial value -->
    android:tickMark="@drawable/tick_mark" />

Tick Mark Drawable

Create a drawable resource for the tick mark, e.g., tick_mark.xml in the res/drawable directory:

<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <size android:width="1dp" android:height="10dp" />
    <solid android:color="#000" />
</shape>

Kotlin Code

In your MainActivity.kt or corresponding Kotlin file:

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.widget.SeekBar
import android.widget.Toast

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val seekBar = findViewById<SeekBar>(R.id.discreteSeekBar)
        seekBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
            override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
                Toast.makeText(this@MainActivity, "Selected value: $progress", Toast.LENGTH_SHORT).show()
            }

            override fun onStartTrackingTouch(seekBar: SeekBar?) {}

            override fun onStopTrackingTouch(seekBar: SeekBar?) {}
        })
    }
}

Using a Third-party Library

If you're looking for more customization, there are third-party libraries like DiscreteSeekBar which offer additional features for discrete SeekBars.

With the basic Android SDK, this approach gives you a discrete SeekBar with fixed intervals. If you need custom intervals or more advanced features, you'll either have to extend the base SeekBar and implement custom behavior or use a third-party library tailored to your needs.

Implementing Discrete SeekBar example code in Kotlin:

Description: Discrete SeekBar is a SeekBar with discrete steps. Implement it in Kotlin by adding the DiscreteSeekBar library to your project and configuring it in the layout file or programmatically.

Code:

// Add DiscreteSeekBar library to your build.gradle
implementation 'org.adw.library:discrete-seekbar:1.0.1'

// In your activity or fragment
val discreteSeekBar = findViewById<DiscreteSeekBar>(R.id.discreteSeekBar)

// Set up DiscreteSeekBar
discreteSeekBar.progress = 50
discreteSeekBar.setOnProgressChangeListener(object : DiscreteSeekBar.OnProgressChangeListener {
    override fun onProgressChanged(seekBar: DiscreteSeekBar?, value: Int, fromUser: Boolean) {
        // Handle progress change
    }

    override fun onStartTrackingTouch(seekBar: DiscreteSeekBar?) {
        // Handle start tracking touch
    }

    override fun onStopTrackingTouch(seekBar: DiscreteSeekBar?) {
        // Handle stop tracking touch
    }
})

Setting up Discrete SeekBar in XML layout using Kotlin:

Description: Add Discrete SeekBar to your XML layout file using the following code snippet:

XML Layout:

<org.adw.library.widgets.discreteseekbar.DiscreteSeekBar
    android:id="@+id/discreteSeekBar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:dsb_max="100"
    app:dsb_min="0"
    app:dsb_progress="50"
    app:dsb_trackColor="@color/colorPrimary"
    app:dsb_thumbColor="@color/colorAccent"/>