Showing Null Pointer Exception Calling From Static Method Android

Question

There are three class History, Databasehandlreone, DatabaseHandler. In History call there is one static method named addHistory(Record record). it calling the non static method which is in same class named calling(String u).

History

    class History extends Activity{
    public static long addHistory(Record record) {
    String u=record.getURL();
    History ss=new History();
    ss.calling(u);
    }
    private void calling(String u) {
            DatabaseHandlerone db=new DatabaseHandlerone(History.this);
            try{
            db.good(u); 
            }catch(Exception e){
                Log.v("Error",e.toString());
            }}}

In calling function, it calls the function named good which is in another class name Databasehandlerone.

DatabaseHandlerone.java

    public class DatabaseHandlerone {
        public DatabaseHandlerone(History history) {
            // TODO Auto-generated constructor stub
        }

    public void good(String s){
            try{
            DatabaseHandler db=new DatabaseHandler(DatabaseHandlerone.this);
            db.deleteall(s); 
            }catch(Exception e){
                Log.v("Calling from DatabseHandler1",e.toString());
            }   }

In good function, deleteall function will be called which is another class called DatabaseHandler.

When I am calling db.deleteall(s). It showing Java.NullPointerException error. can anyone pls Help.

DatabseHandler.this

    public class DatabaseHandler extends SQLiteOpenHelper {
         public void deleteall(String s){
          Log.v("value",s);
         }

Logcat

            02-21 11:46:35.941: D/libc-netbsd(22197): getaddrinfo: stackoverflow.com get result from proxy >>
            02-21 11:46:35.943: D/ID Safe Utils(22197): leave sendOpenUrlBroadcast
            02-21 11:46:35.959: V/Good(22197): http://stackoverflow.com/users
            02-21 11:46:35.959: V/Calling(22197): http://stackoverflow.com/users
            02-21 11:46:35.959: V/After Databse(22197): After DatabseHandler Calling
            02-21 11:46:35.959: V/Value(22197): http://stackoverflow.com/users
            02-21 11:46:35.959: V/String(22197): http://stackoverflow.com/users
            02-21 11:46:35.960: V/DatabaseHandler()(22197): Afert SdCard
            02-21 11:46:35.960: V/Calling from DatabseHandler1(22197): java.lang.NullPointerException
            02-21 11:46:35.960: V/DatabaseHandler()(22197): Afert SdCard
            02-21 11:46:35.960: V/Retreiving Values:(22197): java.lang.NullPointerException

where is the `return` statement of `long addHistory()` method? — Apurva, Feb 21 '15 at 07:10
Why not print the exception's stack trace somewhere? (Or log the whole exception) — user253751, Feb 21 '15 at 07:10
Post more code.. e.g constructor of `DatabaseHandler`, what you do in `deleteall(String s)`, etc.. — Hemanth, Feb 21 '15 at 07:15
Constructor and all working fine when call deleteall then it shows null pointer exception — user2858029, Feb 21 '15 at 07:17
`public static long addHistory` why did you put this in an `Activity`? Are you aware of why this can be dangerous? You should not try to treat activities like POJOs. Instead, create a separate class to handle the history. — Simon, Feb 21 '15 at 07:31
You posted some random part of logcat. Please learn a) how to use the debugger. It is madness to try to develop apps without it b) what a stack trace is, c) how to find it in the logcat d) how to read it — Simon, Feb 21 '15 at 07:33

Showing Null Pointer Exception Calling From Static Method Android

0 Answers0