I have a button as in the following:

<Button android:text="Submit" android:id="@+id/Button01" android:layout_width="fill_parent" android:layout_height="wrap_content"></Button>

In my onCreate event, I am calling Button01 like this:

setContentView(R.layout.main);

View Button01 = this.findViewById(R.id.Button01);
Button01.setOnClickListener(this);

There is a background in the application, and I want to set an opacity on this submit button. How can I set an opacity for this view? Is it something that I can set on the java side, or can I set in the main.xml file?

On the java side I tried Button01.mutate().SetAlpha(100), but it gave me an error.

Thank you.