TextColorSpan.java

package io.plaidapp.ui.span;

import android.support.annotation.ColorInt;
import android.support.annotation.FloatRange;
import android.text.TextPaint;
import android.text.style.ForegroundColorSpan;

import io.plaidapp.util.ColorUtils;

/**
 * An extension to {@link ForegroundColorSpan} which allows updating the color or alpha component.
 * Note that Spans cannot invalidate themselves so consumers must ensure that the Spannable is
 * refreshed themselves.
 */
public class TextColorSpan extends ForegroundColorSpan {

    private @ColorInt int color;

    public TextColorSpan(int color) {
        super(color);
        this.color = color;
    }

    public @ColorInt int getColor() {
        return color;
    }

    public void setColor(@ColorInt int color) {
        this.color = color;
    }

    public void setAlpha(@FloatRange(from = 0f, to = 1f) float alpha) {
        color = ColorUtils.modifyAlpha(color, alpha);
    }

    @Override
    public void updateDrawState(TextPaint ds) {
        ds.setColor(color);
    }
}