CustomSeekbar.java

package com.kdt;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.util.AttributeSet;
import android.widget.SeekBar;

import androidx.annotation.Nullable;

import net.kdt.pojavlaunch.R;

/**
 * Seekbar with ability to handle ranges and increments
 */
@SuppressLint("AppCompatCustomView")
public class CustomSeekbar extends SeekBar {
    private int mMin = 0;
    private int mIncrement = 1;
    private SeekBar.OnSeekBarChangeListener mListener;

    private final OnSeekBarChangeListener mInternalListener = new OnSeekBarChangeListener() {
        /** When using increments, this flag is used to prevent double calls to the listener */
        private boolean internalChanges = false;
        /** Store the previous progress to prevent double calls with increments */
        private int previousProgress = 0;
        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
            if (internalChanges) return;
            internalChanges = true;

            progress += mMin;
            progress = applyIncrement(progress);

            if (progress != previousProgress) {
                if (mListener != null) {
                    previousProgress = progress;
                    mListener.onProgressChanged(seekBar, progress, fromUser);
                }
            }

            // Forces the thumb to snap to the increment
            setProgress(progress);
            internalChanges = false;
        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
            if (internalChanges) return;

            if (mListener != null) {
                mListener.onStartTrackingTouch(seekBar);
            }
        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            if (internalChanges) return;
            internalChanges = true;

            setProgress(seekBar.getProgress());

            if (mListener != null) {
                mListener.onStopTrackingTouch(seekBar);
            }
            internalChanges = false;
        }
    };

    public CustomSeekbar(Context context) {
        super(context);
        setup(null);
    }

    public CustomSeekbar(Context context, AttributeSet attrs) {
        super(context, attrs);
        setup(attrs);
    }

    public CustomSeekbar(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setup(attrs);
    }

    public void setIncrement(int increment) {
        mIncrement = increment;
    }

    public void setRange(int min, int max) {
        mMin = min;
        setMax(max - min);
    }

    @Override
    public synchronized void setProgress(int progress) {
        super.setProgress(applyIncrement(progress - mMin));
    }

    @Override
    public void setProgress(int progress, boolean animate) {
        super.setProgress(applyIncrement(progress - mMin), animate);
    }

    @Override
    public synchronized int getProgress() {
        return applyIncrement(super.getProgress() + mMin);
    }

    @Override
    public synchronized void setMin(int min) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            super.setMin(0);
        }
        mMin = min;
        //todo perform something to update the progress ?
    }



    /**
     * Wrapper to allow for a listener to be set around the internal listener
     */
    @Override
    public void setOnSeekBarChangeListener(OnSeekBarChangeListener l) {
        mListener = l;
    }

    public void setup(@Nullable AttributeSet attrs) {
        try (TypedArray attributes = getContext().obtainStyledAttributes(attrs, R.styleable.CustomSeekbar)) {
            setIncrement(attributes.getInt(R.styleable.CustomSeekbar_seekBarIncrement, 1));
            int min = attributes.getInt(R.styleable.CustomSeekbar_android_min, 0);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                super.setMin(0);
            }
            setRange(min, super.getMax());
        }

        // Due to issues with negative progress when setting up the seekbar
        // We need to set a random progress to force the refresh of the thumb
        if(super.getProgress() == 0) {
            super.setProgress(super.getProgress() + 1);
            post(() -> {
                super.setProgress(super.getProgress() - 1);
                post(() -> super.setOnSeekBarChangeListener(mInternalListener));
            });
        } else {
            super.setOnSeekBarChangeListener(mInternalListener);
        }
    }

    /**
     * Apply increment to the progress
     * @param progress Progress to apply increment to
     * @return Progress with increment applied
     */
    private int applyIncrement(int progress) {
        if (mIncrement < 1) return progress;

        progress = progress / mIncrement;
        progress = progress * mIncrement;
        return progress;
    }
}