In writing a project proposal,is it necessary to write the literature review before methodology or otherwise??

I would put the lit review first, because it leads nicely into the research questions and then you can describe how your methodology will help you answer the questions.

I agree with Chickpea. But if you are already familiar with the literature and the key elements of your argument (but just haven't yet shaped it up into fully written up literature review) I think it is fine to start on the methodology.

Addressing the literature will demonstrate that you have an understanding of the nature of the problem.