Use expandablelistview in Android to implement Layer 2 and Layer 3 list source code

The L2 list can be directly implemented using the expandablelistview in androidapi. the L3 list is actually a nesting of the L2 list, which is relatively cumbersome to implement.

PartCode:

Supertreeviewadapter. Java

 Public   Class Supertreeviewadapter Extends  Baseexpandablelistadapter {  Static   Public   Class  Supertreenode {object parent;  //  Structure of level 2 tree menu List <treeviewadapter. treenode> Childs = New Arraylist <treeviewadapter. treenode> ();}  Private List <supertreenode> supertreenodes = New Arraylist <supertreenode> ();  Private  Context parentcontext;  Private Onchildclicklistener stvclickevent; //  External callback function          Public  Supertreeviewadapter (context view, onchildclicklistener stvclickevent) {parentcontext =View;  This . Stvclickevent = Stvclickevent ;}  Public List <supertreenode> Gettreenode (){  Return  Supertreenodes ;}  Public   Void Updatetreenode (list <supertreenode> Node) {supertreenodes = Node ;}  Public   Void Removeall () {supertreenodes. Clear ();}  Public Object getchild ( Int Groupposition, Int  Childposition ){  Return  Supertreenodes. Get (groupposition). Childs. Get (childposition );}  Public   Int Getchildrencount ( Int  Groupposition ){  Return Supertreenodes. Get (groupposition). Childs. Size ();}  Public  Expandablelistview getexpandablelistview () {abslistview. layoutparams lp = New  Abslistview. layoutparams (viewgroup. layoutparams. fill_parent, treeviewadapter. itemheight); expandablelistview supertreeview = New  Expandablelistview (parentcontext); supertreeview. setlayoutparams (LP );  Return  Supertreeview ;}  /** * The second layer in the layer-3 tree structure is an expandablelistview.  */          Public View getchildview ( Int Groupposition, Int  Childposition,  Boolean  Islastchild, view convertview, viewgroup parent ){  //  Yes          Final Expandablelistview Treeview = Getexpandablelistview ();  Final Treeviewadapter = New Treeviewadapter ( This . Parentcontext, 0 ); List <Treenode> TMP = treeviewadapter. gettreenode (); //  The temporary variable obtains the treenode set of the treeviewadapter. It can be empty.          Final Treenode = (Treenode) getchild (groupposition, childposition); TMP. Add (treenode); treeviewadapter. updatetreenode (TMP); Treeview. setadapter (treeviewadapter );  //  Key Point: Obtain the Parent and Child Nodes of the selected secondary tree menu and return the result to the external callback function. Treeview. setonchildclicklistener ( This  . Stvclickevent );  /**  * Key point: when the level-2 menu is expanded, the size of the level-3 menu is set by obtaining the number of nodes.  */  Treeview. setongroupexpandlistener (  New  Ongroupexpandlistener () {@ override  Public   Void Ongroupexpand ( Int  Groupposition) {abslistview. layoutparams lp =New  Abslistview. layoutparams (viewgroup. layoutparams. fill_parent, (treenode. Childs. Size () + 1) * treeviewadapter. itemheight + 10 ); Treeview. setlayoutparams (LP );}});  /**  * When the level-2 menu is recycled, it is set to the standard item size.  */  Treeview. setongroupcollapselistener (  New  Ongroupcollapselistener () {@ override  Public   Void Ongroupcollapse ( Int  Groupposition) {abslistview. layoutparams lp = New  Abslistview. layoutparams (viewgroup. layoutparams. fill_parent, treeviewadapter. itemheight); Treeview. setlayoutparams (LP) ;}}); Treeview. setpadding (treeviewadapter. paddingleft * 2, 0, 0, 0 );  Return  Treeview ;}  /**  * The first layer in the Three-Level tree structure is textview, which is used as the title  */     Public View getgroupview ( Int Groupposition, Boolean  Isexpanded, view convertview, viewgroup parent) {textview = Treeviewadapter. gettextview ( This  . Parentcontext); textview. settext (getgroup (groupposition). tostring (); textview. setpadding (treeviewadapter. paddingleft * 2, 0, 0, 0 );  Return  Textview ;}  Public   Long Getchildid ( Int Groupposition, Int  Childposition ){  Return  Childposition ;}  Public Object getgroup ( Int  Groupposition ){  Return  Supertreenodes. Get (groupposition). parent ;}  Public   Int  Getgroupcount (){  Return Supertreenodes. Size ();}  Public   Long Getgroupid ( Int  Groupposition ){  Return  Groupposition ;}  Public   Boolean Ischildselectable ( Int Groupposition, Int  Childposition ){  Return   True ;}  Public   Boolean  Hasstableids (){  Return   True  ;}} 

Expandablelistviewactivity. Java

List <supertreeviewadapter. supertreenode> supernodetree = Superadapter. gettreenode ();  For ( Int I = 0; I <parent. length; I ++ ) {Supertreeviewadapter. supertreenode Supernode =New  Supertreeviewadapter. supertreenode (); Supernode. Parent = Parent [I];  For ( Int J = 0; j <child_grandchild.length; j ++ ) {Treeviewadapter. treenode Node = New  Treeviewadapter. treenode (); node. Parent = Child_grandchild [J] [0] [0 ];  For ( Int K = 0; k <child_grandchild [J] [1]. length; k ++ ) {Node. Childs. Add (child_grandchild [J] [ 1 ] [K]);} Supernode. Childs. Add (node);} supernodetree. Add (Supernode);} superadapter. updatetreenode (supernodetree); expandablelistview. setadapter (superadapter ); 

Main. xml

< Linearlayout Android: ID = "@ + ID/linearlayout1" Android: layout_width = "Match_parent" Android: layout_height = "Wrap_content" Android: layout_gravity = "Center" Android: gravity = "Center"> < Button Android: ID = "@ + ID/button1" Android: layout_width = "100dip" Android: layout_height = "Wrap_content" Android: Text = "L2 structure"/> < Button Android: ID = "@ + ID/button2" Android: layout_width = "100dip" Android: layout_height = "Wrap_content" Android: Text = "Three-tier structure"/> </linearlayout> < Expandablelistview Android: ID = "@ + ID/expandablelistview" Android: layout_width = "Fill_parent" Android: layout_height = "Fill_parent"> </expandablelistview>

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L3 list

 

Layer 2 list

Download source code: expandablelistview.rar