BEIJING — Chinese leader Xi Jinping on Thursday pledged $50 billion in loans, aid and investment for Africa over the next three years, and the creation of 1 million jobs, as he laid out a plan to expand Beijing’s already extensive political, military and economic ties with the continent.

       Portraying China as a champion of the developing world, Xi presented the Forum on China-Africa Cooperation with a vision of growth that is distinct from that offered by liberal Western governments.