content: package allen.town.podcast.ui.common;
  
  import android.content.Context;
  import android.content.res.TypedArray;
  import android.graphics.Canvas;
  import android.graphics.Color;
  import android.graphics.Paint;
  import android.graphics.RectF;
  import android.util.AttributeSet;
  import android.view.View;
  import androidx.annotation.Nullable;
  
  public class CircularProgressBar extends View {
      public static final float MINIMUM_PERCENTAGE = 0.005f;
      public static final float MAXIMUM_PERCENTAGE = 1 - MINIMUM_PERCENTAGE;
  
      private final Paint paintBackground = new Paint();
      private final Paint paintProgress = new Paint();
      private float percentage = 0;
      private float targetPercentage = 0;
      private Object tag = null;
      private final RectF bounds = new RectF();
  
      public CircularProgressBar(Context context) {
          super(context);
          setup(null);
      }
  
      public CircularProgressBar(Context context, @Nullable AttributeSet attrs) {
          super(context, attrs);
          setup(attrs);
      }
  
      public CircularProgressBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
          super(context, attrs, defStyleAttr);
          setup(attrs);
      }
  
      private void setup(@Nullable AttributeSet attrs) {
          paintBackground.setAntiAlias(true);
          paintBackground.setStyle(Paint.Style.STROKE);
  
          paintProgress.setAntiAlias(true);
          paintProgress.setStyle(Paint.Style.STROKE);
          paintProgress.setStrokeCap(Paint.Cap.ROUND);
  
          TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.CircularProgressBar);
          int color = typedArray.getColor(R.styleable.CircularProgressBar_foregroundColor, Color.GREEN);
          typedArray.recycle();
          paintProgress.setColor(color);
          paintBackground.setColor(color);
      }
  
      /**
       * Sets the percentage to be displayed.
       * @param percentage Number from 0 to 1
       * @param tag When the tag is the same as last time calling setPercentage, the update is animated
       */
      public void setPercentage(float percentage, Object tag) {
          targetPercentage = percentage;
  
          if (tag == null || !tag.equals(this.tag)) {
              // Do not animate
              this.percentage = percentage;
              this.tag = tag;
          }
          invalidate();
      }
  
      @Override
      protected void onDraw(Canvas canvas) {
          super.onDraw(canvas);
  
          float padding = getHeight() * 0.07f;
          paintBackground.setStrokeWidth(getHeight() * 0.02f);
          paintProgress.setStrokeWidth(padding);
          bounds.set(padding, padding, getWidth() - padding, getHeight() - padding);
          canvas.drawArc(bounds, 0, 360, false, paintBackground);
  
          if (MINIMUM_PERCENTAGE <= percentage && percentage <= MAXIMUM_PERCENTAGE) {
              canvas.drawArc(bounds, -90, percentage * 360, false, paintProgress);
          }
  
          if (Math.abs(percentage - targetPercentage) > MINIMUM_PERCENTAGE) {
              float speed = 0.02f;
              if (Math.abs(targetPercentage - percentage) < 0.1 && targetPercentage > percentage) {
                  speed = 0.006f;
              }
              float delta = Math.min(speed, Math.abs(targetPercentage - percentage));
              float direction = ((targetPercentage - percentage) > 0 ? 1f : -1f);
              percentage += delta * direction;
              invalidate();
          }
      }
  }
  