Frame by frame #4

SpinnerLoaderView.java

public class SpinnerLoaderView extends View {

    private final RectF mArcBounds = new RectF();
    private final Paint mPaint = new Paint();
  
    // ...
  
    @Override
    protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) {
        super.onSizeChanged(width, height, oldWidth, oldHeight);

        final int smallestSide = Math.min(width, height);
        mPaint.setStrokeWidth(smallestSide * 0.05f);

        // When drawing a stroked line at an X,Y position it's always the
        // the center of the brush that's positioned there. This means that
        // if the position is set the one of view edges, half the stroke width
        // will be drawn outside of the view. To counter this, add half the
        // stroke width as a padding.
        final float paintPadding = mPaint.getStrokeWidth() / 2f;

        // Also apply any padding set in the XML/using setPadding(...)
        mArcBounds.set(
                paintPadding + getPaddingLeft(),
                paintPadding + getPaddingTop(),
                width - paintPadding - getPaddingRight(),
                height - paintPadding - getPaddingBottom()
        );
    }
}