Computational drug repositioning is nowadays a widely used approach for finding new uses for existing and experimental drugs. In this project, we developed a network-based method, namely HDR, as an app for the Cytoscape platform for drug repositioning. The task was approached in both drug- and disease-centric views. Besides, it can use both pre-installed and imported networks, thus making the user flexible in selecting datasets of interest. In addition, predicted and existing associations between drugs and diseases as well as involved pathways/protein complexes/genes/targets can be visualized intuitively, thus supporting evidence for the predicted ones. The ability of HDR was also shown by comparing its overall prediction performance and usage with some existing methods/tools and by identifying drugs that can be repurposed for COVID-19 as well as potential diseases that can be treated by Thalidomide.