子类如何调用父类的protected方法？?报错

我尝试的方法：

1.直接调用，行不通。

2.强转，反射，也报错。

ProgressBar instance = (ProgressBar) this;
@SuppressWarnings("unchecked")
Class<ProgressBar> clazz = (Class<ProgressBar>) instance.getClass();
try {
    progressBarOnDraw = clazz.getDeclaredMethod("onDraw", Canvas.class);
			progressBarOnDraw.setAccessible(true);
} catch (NoSuchMethodException e) {
    e.printStackTrace();

		}

 if (progressBarOnDraw != null) {
    try {
	progressBarOnDraw.invoke((ProgressBar) this, canvas);
    } catch (IllegalAccessException | IllegalArgumentException
		 | InvocationTargetException e) {
	e.printStackTrace();
        }
} else {
    super.onDraw(canvas);
}