问题
i have 2 database node one is friends and other User. In User node all the user which are using my app are registered but in friend node those keys are available which are friends. In friends node One key (parent key ) can have multiple child key (also present in User node). Now I want to access data of User node Using Friend child child (2times) key.
来源：https://stackoverflow.com/questions/47616054/how-to-access-child-node-using-parent-key-in-firebase-android