java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
	at android.app.Dialog.<init>(Dialog.java:226)
	at android.app.AlertDialog.<init>(AlertDialog.java:201)
	at android.app.AlertDialog.<init>(AlertDialog.java:197)
	at android.app.ProgressDialog.<init>(ProgressDialog.java:129)
	at com.entitcs.office_attendance.fragments.Add_Task.showDialog(Add_Task.java:1987)
	at com.entitcs.office_attendance.fragments.Add_Task.cancelTaskRetrofit(Add_Task.java:942)
	at com.entitcs.office_attendance.fragments.Add_Task.access$1000(Add_Task.java:121)
	at com.entitcs.office_attendance.fragments.Add_Task$9.onClick(Add_Task.java:925)
	at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:184)
	at android.os.Handler.dispatchMessage(Handler.java:106)
	at android.os.Looper.loop(Looper.java:214)
	at android.app.ActivityThread.main(ActivityThread.java:7156)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)