伸展水平填充行xml

I'm probably missing something obvious here but I can't seem to figure this out. I am looking for a result like 1, 5, or 6, a single row of 3 evenly distributed buttons that fill the width of the screen. Unfortunately however, each of these methods seem to have something wrong with them. 1 gives me a warning that "This TableRow layout or its TableLayout parent is possibly useless" and 5 and 6 give "Nested weights are bad for performance". So basically I'm wondering what the best way to do this is. Should I ignore the warning on no.1 or can I get them to display properly with just a TableRow or TableLayoutI'm probably missing something obvious here but