JList


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Thread: JList

  1. #1
    Pelle Henriksson Guest

    JList

    Hi !!

    Can someone please help me with this:
    I store objects in a Vector, and then i store the Vector in a file, here is that object:

    import java.io.*;
    import java.util.*;

    public class tblQuery implements Serializable {
    public String fldSuggestionTitle = null;
    public String fldSuggestionText = null;
    public Date fldSuggestionDate = null;
    public int fldUserID;

    }

    I would like to display these objects in a JList but only fldSuggestionTitle and then fldUserID as a hidden value,
    db is my vector with the tblQury objects. I dont understand how to hide an id and only show the title.

    private void test() {
    m = new DefaultListModel();

    db = clsDBHandler.readData("tblQuery.dat");
    for(int i =0; i < db.size(); i++){
    qry = (tblQuery) db.elementAt(i);
    m.addElement(qry.fldSuggestionTitle);

    }
    JList lstQuery = new JList(m);
    lstQuery.setBounds(10,10,100,100);
    getContentPane().add(lstQuery);
    }


    This one fetches the vector from file.

    import java.io.*;
    import java.util.*;

    public class clsDBHandler {

    public static Vector readData(String strFile) {
    Vector db = null;

    try {
    ObjectInputStream in = new ObjectInputStream(new FileInputStream(strFile));
    db = (Vector) in.readObject();
    in.close();
    }

    catch(FileNotFoundException e) {
    db = new Vector();
    }

    catch(Exception e) {
    }

    finally {
    return db;
    }
    }

    Chees and thanx Pelle


  2. #2
    Paul Clapham Guest

    Re: JList

    You can put any object into a JList, not only Strings. Whatever object you use, the default behaviour of JList should be to display the result of its "toString()" method. So change your class to include a method "toString()" that returns fldSuggestionTitle, and add the objects directly to the JList.

    PC2
    Pelle Henriksson <pelle_henriksson@home.se> wrote in message news:3a067ee7@news.devx.com...
    Hi !!

    Can someone please help me with this:
    I store objects in a Vector, and then i store the Vector in a file, here is that object:

    ...

    I would like to display these objects in a JList but only fldSuggestionTitle and then fldUserID as a hidden value,
    db is my vector with the tblQury objects. I dont understand how to hide an id and only show the title.



  3. #3
    Pelle Henriksson Guest

    Re: JList

    Thanx !!

    How should that method be implemented?, I tried

    public String toString() {

    retutrn fldSuggestionTitle;

    }

    but then I got a nullpointerexcepiton, if I remove this method it works ok, but I get tblQuery@484234 in the list.
    Do I need to change anything else in the class??

    pelle
    "Paul Clapham" <pclapham@core-mark
    .com> wrote in message news:3a06d5ae$1@news.devx.com...
    You can put any object into a JList, not only Strings. Whatever object you use, the default behaviour of JList should be to display the result of its "toString()" method. So change your class to include a method "toString()" that returns fldSuggestionTitle, and add the objects directly to the JList.

    PC2
    Pelle Henriksson <pelle_henriksson@home.se> wrote in message news:3a067ee7@news.devx.com...
    Hi !!

    Can someone please help me with this:
    I store objects in a Vector, and then i store the Vector in a file, here is that object:

    ...

    I would like to display these objects in a JList but only fldSuggestionTitle and then fldUserID as a hidden value,
    db is my vector with the tblQury objects. I dont understand how to hide an id and only show the title.



  4. #4
    Paul Clapham Guest

    Re: JList

    Yes, that's the correct implementation. But you need to set fldSuggestionTitle to something other than null -- I didn't see any code in your original post that does that.

    PC2
    Pelle Henriksson <pelle_henriksson@home.se> wrote in message news:3a07dd74$1@news.devx.com...
    Thanx !!

    How should that method be implemented?, I tried

    public String toString() {

    retutrn fldSuggestionTitle;

    }

    but then I got a nullpointerexcepiton, if I remove this method it works ok, but I get tblQuery@484234 in the list.
    Do I need to change anything else in the class??

    pelle


  5. #5
    Madani Guest

    Re: JList


    the toString method should be in another meothd that take your object as an
    argument and return a string

    public String thismethod (fldSuggestionTitle f) {

    return f.toString();

    }









    "Pelle Henriksson" <pelle_henriksson@home.se> wrote:
    >This is a multi-part message in MIME format.
    >
    >------=_NextPart_000_0026_01C048B0.2D0AF270
    >Content-Type: text/plain;
    > charset="iso-8859-1"
    >Content-Transfer-Encoding: quoted-printable
    >
    >Thanx !!
    >
    >How should that method be implemented?, I tried
    >
    >public String toString() {
    >
    > retutrn fldSuggestionTitle;
    >
    >}
    >
    >but then I got a nullpointerexcepiton, if I remove this method it works

    =
    >ok, but I get tblQuery@484234 in the list.
    >Do I need to change anything else in the class??
    >
    >pelle
    > "Paul Clapham" <pclapham@core-mark
    > .com> wrote in message news:3a06d5ae$1@news.devx.com...
    > You can put any object into a JList, not only Strings. Whatever =
    >object you use, the default behaviour of JList should be to display the

    =
    >result of its "toString()" method. So change your class to include a =
    >method "toString()" that returns fldSuggestionTitle, and add the objects

    =
    >directly to the JList.
    >
    > PC2
    > Pelle Henriksson <pelle_henriksson@home.se> wrote in message =
    >news:3a067ee7@news.devx.com...
    > Hi !!
    >
    > Can someone please help me with this:
    > I store objects in a Vector, and then i store the Vector in a file,

    =
    >here is that object:
    >
    > ...
    >
    > I would like to display these objects in a JList but only =
    >fldSuggestionTitle and then fldUserID as a hidden value,
    > db is my vector with the tblQury objects. I dont understand how to =
    >hide an id and only show the title.
    >
    >
    >------=_NextPart_000_0026_01C048B0.2D0AF270
    >Content-Type: text/html;
    > charset="iso-8859-1"
    >Content-Transfer-Encoding: quoted-printable
    >
    ><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
    ><HTML><HEAD>
    ><META content=3D"text/html; charset=3Diso-8859-1" =
    >http-equiv=3DContent-Type>
    ><META content=3D"MSHTML 5.00.3103.1000" name=3DGENERATOR>
    ><STYLE></STYLE>
    ></HEAD>
    ><BODY bgColor=3D#ffffff>
    ><DIV><FONT face=3DArial size=3D2>Thanx !!</FONT></DIV>
    ><DIV>*</DIV>
    ><DIV><FONT face=3DArial size=3D2>How should that method be =
    >implemented?,*I=20
    >tried</FONT></DIV>
    ><DIV>*</DIV>
    ><DIV><FONT face=3DArial size=3D2>public String toString() {</FONT></DIV>
    ><DIV>*</DIV>
    ><DIV><FONT face=3DArial size=3D2>*** retutrn=20
    >fldSuggestionTitle;</FONT></DIV>
    ><DIV>*</DIV>
    ><DIV><FONT face=3DArial size=3D2>}</FONT></DIV>
    ><DIV>*</DIV>
    ><DIV><FONT face=3DArial size=3D2>but then I got a nullpointerexcepiton,

    =
    >if*I=20
    >remove this method it works ok, but*I get tblQuery@484234 in the=20
    >list.</FONT></DIV>
    ><DIV><FONT face=3DArial size=3D2>Do I need to change anything else in =
    >the=20
    >class??</FONT></DIV>
    ><DIV>*</DIV>
    ><DIV><FONT face=3DArial size=3D2>pelle</FONT></DIV>
    ><BLOCKQUOTE=20
    >style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT:

    =
    >0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
    > <DIV>"Paul Clapham" <<A=20
    > href=3D"mailtoclapham@core-mark.com">pclapham@core-mark</A></DIV>
    > <DIV>.com> wrote in message <A=20
    > =
    >href=3D"news:3a06d5ae$1@news.devx.com">news:3a06d5ae$1@news.devx.com</A>.=
    >...</DIV>
    > <DIV><FONT face=3DArial size=3D2>You can put any object into a JList,

    =
    >not only=20
    > Strings.* Whatever object you use, the default behaviour of JList =
    >should=20
    > be to display the result of its "toString()" method.* So change =
    >your=20
    > class to include a method "toString()" that returns =
    >fldSuggestionTitle, and=20
    > add the objects directly to the JList.</FONT></DIV>
    > <DIV>*</DIV>
    > <DIV><FONT face=3DArial size=3D2>PC2</FONT></DIV>
    > <BLOCKQUOTE=20
    > style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; =
    >MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
    > <DIV>Pelle Henriksson <<A=20
    > =
    >href=3D"mailtoelle_henriksson@home.se">pelle_henriksson@home.se</A>>=
    >=20
    > wrote in message <A=20
    > =
    >href=3D"news:3a067ee7@news.devx.com">news:3a067ee7@news.devx.com</A>...</=
    >DIV>
    > <DIV><FONT face=3DArial size=3D2>Hi !!</FONT></DIV>
    > <DIV>*</DIV>
    > <DIV><FONT face=3DArial size=3D2>Can someone please help me with=20
    > this:</FONT></DIV>
    > <DIV><FONT face=3DArial size=3D2>I store objects in a Vector, and =
    >then i store=20
    > the Vector in a file, here is that object:</FONT></DIV>
    > <DIV>*</DIV>
    > <DIV><FONT face=3D"Courier New" size=3D2>...</FONT></DIV>
    > <DIV>*</DIV>
    > <DIV><FONT face=3DArial size=3D2>I would like to display these =
    >objects in a=20
    > JList but only fldSuggestionTitle* and then fldUserID as a =
    >hidden=20
    > value,</FONT></DIV>
    > <DIV><FONT face=3DArial size=3D2>db is my vector with the tblQury =
    >objects. I=20
    > dont understand how to hide an id and only show the =
    >title.</FONT></DIV>
    > <DIV>*</DIV>
    > <DIV><FONT =
    >size=3D2></DIV></BLOCKQUOTE></BLOCKQUOTE></FONT></BODY></HTML>
    >
    >------=_NextPart_000_0026_01C048B0.2D0AF270--
    >



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