Before starting with RecyclerView we have to add the RecyclerView dependency in our adle code file of the application. Android Studio will create two files in the project MainActivity.java and activitymain.xml. Import .floatingactionbutton. First, we will create an Android Studio project named RecyclerView Example. : Attempt to invoke virtual method ' .QuerySnapshot.getDocumentChanges()' on a null object referenceĪt _mini_app_Activity$3.onEvent(Tasks_mini_app_Activity.java:86)Īt _mini_app_Activity$3.onEvent(Tasks_mini_app_Activity.java:82)Īt .Query.lambda$addSnapshotListenerInternal$2$com-google-firebase-firestore-Query(Query.java:1131)Īt .Query$$ExternalSyntheticLambda2.onEvent(Unknown Source:6)Īt .$onEvent$0$com-google-firebase-firestore-core-AsyncEventListener(AsyncEventListener.java:42)Īt .core.AsyncEventListener$$n(Unknown Source:6)Īt android.os.Handler.handleCallback(Handler.java:938)Īt android.os.Handler.dispatchMessage(Handler.java:99)Īt android.os.Looper.loop(Looper.java:246)Īt (ActivityThread.java:8653)Īt .invoke(Native Method)Īt .RuntimeInit$n(RuntimeInit.java:602)Īt .ZygoteInit.main(ZygoteInit.java:1130) Выдает ошибку : : Attempt to invoke virtual method ' .QuerySnapshot.getDocumentChanges()' on a null object reference Public class CustomerDB extends SQLiteOpenHelper i have added a button to each of the customers that will be used to delete them. It has been created to make possible construction of any lists with XML layouts as an item which can be customized.
It is an improvement on both of them and can be found in the latest v-7 support packages. I am creating a basic app where i can add customers to a database and display them on another screen, i have set up everything using recyclerview and card views to display the customers and that works fine, but im not sure how i set it up so that i can delete the customers. RecyclerView is a ViewGroup added to the android studio as a successor of the GridView and ListView.
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