Custom SeekBar for Android that treat its value as float type. floatMax and floatMin can be negative value.

attr.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="FloatSeekBar">
        <attr name="floatMax" format="float" />
        <attr name="floatMin" format="float" />
    </declare-styleable>

</resources>

FloatSeekBar.java

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.widget.SeekBar;

public class FloatSeekBar extends SeekBar {
	private float max = 1.0f;
	private float min = 0.0f;

	public FloatSeekBar(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		applyAttrs(attrs);
	}

	public FloatSeekBar(Context context, AttributeSet attrs) {
		super(context, attrs);
		applyAttrs(attrs);
	}

	public FloatSeekBar(Context context) {
		super(context);
	}

	public float getValue() {
		return (max - min) * ((float) getProgress() / (float) getMax()) + min;
	}

	public void setValue(float value) {
		setProgress((int) ((value - min) / (max - min) * getMax()));
	}

	private void applyAttrs(AttributeSet attrs) {
		TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.FloatSeekBar);
		final int N = a.getIndexCount();
		for (int i = 0; i < N; ++i) {
			int attr = a.getIndex(i);
			switch (attr) {
			case R.styleable.FloatSeekBar_floatMax:
				this.max = a.getFloat(attr, 1.0f);
				break;
			case R.styleable.FloatSeekBar_floatMin:
				this.min = a.getFloat(attr, 0.0f);
				break;
			}
		}
		a.recycle();
	}
}