Android error when casting a interface in fragment?
<p>AndroidRuntime: FATAL EXCEPTION: main
                                                                                        Process: app.com.exam.administrator.healthcareapp, PID: 2663
                                                                                        java.lang.ClassCastException: app.com.exam.administrator.healthcareapp.MainActivity cannot be cast to app.com.exam.administrator.healthcareapp.SaveHealth
                                                                                            at app.com.exam.administrator.healthcareapp.BMI_Fragment.onActivityCreated(BMI_Fragment.java:43)
                                                                                            at android.app.Fragment.performActivityCreated(Fragment.java:2228)
                                                                                            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:992)
                                                                                            at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1148)
                                                                                            at android.app.BackStackRecord.run(BackStackRecord.java:793)
                                                                                            at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1535)
                                                                                            at android.app.FragmentManagerImpl$1.run(FragmentManager.java:482)
                                                                                            at android.os.Handler.handleCallback(Handler.java:739)
                                                                                            at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                                            at android.os.Looper.loop(Looper.java:148)
                                                                                            at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                                            at java.lang.reflect.Method.invoke(Native Method)
                                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)</p>