Fallback default values for View styles

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="SimpleView">
        <attr name="android:color" />
    </declare-styleable>

    <attr name="SimpleViewStyle" format="reference" />
</resources>

SimpleView.java

public class SimpleView extends View {
  final Paint paint = new Paint();

  public SimpleView(Context context) {
    this(context, null);
  }

  public SimpleView(Context context, AttributeSet attrs) {
    this(context, attrs, R.attr.SimpleViewStyle);
  }

  public SimpleView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

    TypedArray ta = context.obtainStyledAttributes(
        attrs, R.styleable.SimpleView, defStyleAttr, R.style.SimpleViewDefaultStyle);
    int color = ta.getColor(R.styleable.SimpleView_android_color, 0);
    paint.setColor(color);
    ta.recycle();
  }

  @Override
  protected void onDraw(Canvas canvas) {
    boolean isRtl = ViewCompat.getLayoutDirection(this) == ViewCompat.LAYOUT_DIRECTION_RTL;
    if (isRtl) {
      canvas.save();
      canvas.translate(getWidth(), 0);
      canvas.scale(-1.0f, 1.0f);
    }
    canvas.drawRect(0, 0, 100, 100, paint);
    if (isRtl) { canvas.restore(); }
  }
}

SimpleView.xml

<?xml version="1.0" encoding="utf-8"?>
<com.cafesalam.experiments.app.ui.SimpleView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

styles.xml

<resources>
    <style name="SimpleViewDefaultStyle">
        <item name="android:color">#ffff0000</item>
    </style>
</resources>