hola, tenés que borrar esto del activity_main.xml
<android.support.design.widget.FloatingActionButton android:id="@+id/fab"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="bottom|end" android:layout_margin="@dimen/fab_margin"
android:src="@android:drawable/ic_dialog_email" />
y esto del MainActivity.java
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.
setOnClickListener(new View.
OnClickListener() { @Override
public void onClick
(View view
) { Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
saludos!