Recursive unlimited tree drop-down menu

Java Code

2. /** 
4. * Tree menu Vo 
6. */
8.  Public ClassSelecttreeImplementsSerializable {
10. Private IntID;
12. PrivateString name;
14. PrivateList <selecttree> child =NewArraylist <selecttree> ();
16. // Getter & setter... omitted
18. }

 
/*** Tree menu VO */public class selecttree implements serializable {private int ID; private string name; private list <selecttree> child = new arraylist <selecttree> (); // getter & setter .... omitted}
 

Code snippet:

Java code

2. /** 
4. * Construct tree menu data 
6. */
8. PublicList <selecttree> buildnode (IntPID, list <ycchannel> channels ){
10. List <selecttree> result =NewArraylist <selecttree> ();
12. For(Ycchannel chlorophyll: channels ){
14. Selecttree node =NewSelecttree ();
16. If(Null! = Chlorophyll. getparentid () & chlorophyll. getparentid (). Equals (PID )){
18. Node. setid (chlorophyll. getchannelid ());
20. Node. setname (chlorophyll. getname ());
22. List <selecttree> Children = buildnode (chlorophyll. getchannelid (), channels );
24. If(Null! = Children &&0<Children. Size ()){
26. Node. setchild (children );
28. }
30. Result. Add (node );
32. }
34. }
36. ReturnResult;
38. }
42. PublicString querychannellist (){
44. Ycchannellist =This. Channelser. querychannellist ();
46. List <selecttree> trees =NewArraylist <selecttree> ();
48. For(Ycchannel YC: ycchannellist ){
50. If(Null= YC. getparentid ()){
52. Selecttree T =NewSelecttree ();
54. T. setid (YC. getchannelid ());
56. T. setname (YC. getname ());
58. T. setchild (buildnode (T. GETID (), ycchannellist ));
60. Trees. Add (t );
62. }
64. }
66. This. Setajaxdata (trees );
68. ReturnAjax_data;
70. }

/*** construct tree menu data */public list 
  
    buildnode (int pid, list 
   
     channels) {list 
    
      result = new arraylist 
     
       (); For (ycchannel chlorophyll: channels) {selecttree node = new selecttree (); If (null! = Chlorophyll. getparentid () & chlorophyll. getparentid (). equals (PID) {node. setid (chlorophyll. getchannelid (); node. setname (chlorophyll. getname (); List 
      
        Children = buildnode (chlorophyll. getchannelid (), channels); If (null! = Children & 0 
       
         trees = new arraylist 
        
          (); For (ycchannel YC: ycchannellist) {If (null = YC. getparentid () {selecttree T = new selecttree (); T. setid (YC. getchannelid (); T. setname (YC. getname (); T. setchild (buildnode (T. GETID (), ycchannellist); trees. add (t) ;}} this. setajaxdata (trees); Return ajax_data ;}
        
       
      
     
    
   
  

Front-end JS Code:

JS Code

2. // Recursive Tree node
4. FunctionBuildnode (Len, data ){
6. VaRPrefix ="|";
8. For(VaRI = 0; I <Len; I ++ ){
10. Prefix + ="-";
12. }
14. $. Each (data,Function(I, item ){
16. If(0 <item. Child. Length ){
18. $ ('# Typeid'). Append ("<Option value ="+ Item. ID +">"+ Prefix + item. Name +"</Option>");
20. Buildnode (LEN + 1, item. Child );
22. }Else{
24. $ ('# Typeid'). Append ("<Option value ="+ Item. ID +">"+ Prefix + item. Name +"</Option>");
26. }
28. });
30. }
34. $. Ajax ({
36. URL:'$ {Base}/channel/channelaction! Querychannellist. action',
38. Type:'Get',
40. Datatype:'Json',
42. Contenttype:'Application/json',
44. Success:Function(JSON ){
46. If(JSON. Success ){
48. $ ('# Typeid'). Empty ();
50. $ ('# Typeid'). Append ("<Option value = '0'> select a topic... </option>");
52. $. Each (JSON. Data,Function(I, item ){
54. If(Null= Item. parentid ){
56. $ ('# Typeid'). Append ("<Option value ="+ Item. ID +">"+ Item. Name +"</Option>");
58. Buildnode (1, item. Child );
60. }
62. });
64. }
66. },
68. Error:Function(){
70. Alert ("An error occurred while loading the topic! ");
72. }
74. });
78. });