Employing a thermodynamic variational method, we propose sharp interface models combined with relaxed contact angle boundary conditions for simulating solid-state dewetting of thin films on rigid flat and curved substrates. In the models, film-vapor interfacial anisotropy is easily included, and the movement of the contact line can be explicitly described by the relaxed boundary conditions. We apply the models to study the equilibrium configuration of small islands and the pinch-off of large island, the migration of tiny particles and the templated solid-state dewetting on inverted pyramidal pits. The simulation results capture many of the complexities associated with solid-state dewetting experiments.