DoughnutDrawable.java

package com.github.genderquery;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.support.annotation.ColorInt;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;

public class DoughnutDrawable extends Drawable {

  private static final float STROKE_RATIO = 12f;
  private static final float PADDING_RATIO = 8f;
  private static final int MAX_LEVEL = 10000;

  private Paint primaryPaint;
  private Paint secondaryPaint;
  private RectF drawRect;

  public DoughnutDrawable() {
    primaryPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
    primaryPaint.setStyle(Style.STROKE);
    primaryPaint.setColor(0xff000000);
    secondaryPaint = new Paint(primaryPaint);
    secondaryPaint.setColor(0x80000000);
  }

  @Override
  public int getOpacity() {
    return PixelFormat.TRANSLUCENT;
  }

  @ColorInt
  public int getPrimaryColor() {
    return primaryPaint.getColor();
  }

  public void setPrimaryColor(@ColorInt int color) {
    primaryPaint.setColor(color);
    invalidateSelf();
  }

  @ColorInt
  public int getSecondaryColor() {
    return secondaryPaint.getColor();
  }

  public void setSecondaryColor(@ColorInt int color) {
    secondaryPaint.setColor(color);
    invalidateSelf();
  }

  @Override
  public void setAlpha(int alpha) {
    primaryPaint.setAlpha(alpha);
    secondaryPaint.setAlpha(alpha);
  }

  @Override
  public void setColorFilter(@Nullable ColorFilter colorFilter) {
    primaryPaint.setColorFilter(colorFilter);
    secondaryPaint.setColorFilter(colorFilter);
  }

  @Override
  public void draw(@NonNull Canvas canvas) {
    int level = getLevel();
    float sweepAngle = (float) level / (float) MAX_LEVEL * 360f;
    canvas.drawOval(drawRect, secondaryPaint);
    canvas.drawArc(drawRect, -90, sweepAngle, false, primaryPaint);
  }

  public void setPercent(int percent) {
    // 100 - 10000
    setLevel(percent * 100);
  }

  public Bitmap createBitmap(int width, int height) {
    setBounds(0, 0, width, height);
    Bitmap bitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    draw(canvas);
    return bitmap;
  }

  @Override
  protected void onBoundsChange(Rect bounds) {
    drawRect = new RectF(bounds);
    float width = drawRect.width();
    float height = drawRect.height();
    float size = Math.min(width, height);
    float padding = size / PADDING_RATIO;

    // center and pad
    drawRect.inset((width - size) / 2f, (height - size) / 2f);
    drawRect.inset(padding, padding);

    float stroke = size / STROKE_RATIO;
    primaryPaint.setStrokeWidth(stroke);
    secondaryPaint.setStrokeWidth(stroke / 2f);
  }

  @Override
  protected boolean onLevelChange(int level) {
    invalidateSelf();
    return true;
  }
}