Android scalable list listview (expandablelistview)

QQ chat is used every day. Today, I suddenly think, how does Android implement list grouping? I looked at the API and found that its implementation process is also very simple. Let's take a look at the final result first!

 

1. First, create our activity and inherit from Android. App. expandablelistactivity. Read the Code directly.

Package COM. ideasandroid. sample; import android. app. expandablelistactivity; import android. OS. bundle; import COM. ideasandroid. sample. adapter. ideasexpandablelistadapter;/*** @ author ideasandroid * example of a scalable list */public class extends expandablelistactivity {@ override public void oncreate (bundle savedinstancestate) {super. oncreate (savedinstancestate); // sets the list adapter ideasexpandablelistadapter setlistadapter (New ideasexpandablelistadapter (this ));}}

2. Create an adapter and inherit from Android. widget. baseexpandablelistadapter.

Package COM. ideasandroid. sample. adapter; import Java. util. arraylist; import Java. util. list; import android. content. context; import android. view. gravity; import android. view. view; import android. view. viewgroup; import android. widget. abslistview; import android. widget. baseexpandablelistadapter; import android. widget. textview;/*** @ author ideasandroid * example of a expanded (shrunk) list */public class ideasexpandablelistadapter extends baseexpandablelistadapter {private context mcontext = NULL; // test data, the development may come from the database, network .... private string [] groups = {"family", "friends", "colleagues"}; private string [] familis = {"dad", "Mom", "sister "}; private string [] Friends = {"Xiao Li", "Zhang San", "Li Si"}; private string [] colleagues = {"Chen Zong", "Li Gong ", "Li client"}; private list <string> grouplist = NULL; private list <string> itemlist = NULL; Public ideasexpandablelistadapter (context) {This. mcontext = context; grouplist = new arraylist <string> (); itemlist = new arraylist <list <string> (); initdata ();}/*** initialize data, put the relevant data in the list to facilitate processing */private void initdata () {for (INT I = 0; I <groups. length; I ++) {grouplist. add (groups [I]) ;}list <string> Item1 = new arraylist <string> (); For (INT I = 0; I <familis. length; I ++) {item1.add (familis [I]) ;}list <string> item2 = new arraylist <string> (); For (INT I = 0; I <friends. length; I ++) {item2.add (Friends [I]) ;}list <string> item3 = new arraylist <string> (); For (INT I = 0; I <colleagues. length; I ++) {item3.add (colleagues [I]);} itemlist. add (Item1); itemlist. add (item2); itemlist. add (item3);} public Boolean areallitemsenabled () {return false;}/** sets the subnode object, which is returned during event processing, some data can be stored */public object getchild (INT groupposition, int childposition) {return itemlist. get (groupposition ). get (childposition);} public long getchildid (INT groupposition, int childposition) {return childposition;}/** byte point view, here we display a Text object */public view getchildview (INT groupposition, int childposition, Boolean islastchild, view convertview, viewgroup parent) {textview text = NULL; If (convertview = NULL) {text = new textview (mcontext);} else {text = (textview) convertview;} // obtain the name string name = (string) itemlist to be displayed on the subnode. get (groupposition ). get (childposition); // sets the relevant attributes of the text view, abslistview. layoutparams Lp = new abslistview. layoutparams (viewgroup. layoutparams. fill_parent, 40); text. setlayoutparams (LP); text. settextsize (18); text. setgravity (gravity. center_vertical | gravity. left); text. setpadding (45, 0, 0, 0); text. settext (name); return text;}/** returns the number of vertices in the current group */Public int getchildrencount (INT groupposition) {return itemlist. get (groupposition ). size ();}/** return group object for data transmission. data related to the group can be directly obtained during event processing */public object getgroup (INT groupposition) {return grouplist. get (groupposition);}/** number of groups */Public int getgroupcount () {return grouplist. size () ;}public long getgroupid (INT groupposition) {return groupposition ;}/ ** group view, which is also a text view */public view getgroupview (INT groupposition, Boolean isexpanded, view convertview, viewgroup parent) {textview text = NULL; If (convertview = NULL) {text = new textview (mcontext);} else {text = (textview) convertview ;} string name = (string) grouplist. get (groupposition); abslistview. layoutparams Lp = new abslistview. layoutparams (viewgroup. layoutparams. fill_parent, 40); text. setlayoutparams (LP); text. settextsize (18); text. setgravity (gravity. center_vertical | gravity. left); text. setpadding (36, 0, 0, 0); text. settext (name); return text;}/** determines whether the group is empty. In this example, the data is fixed, so it is not empty. We return false * If the data comes from the database, when the network is used, you can write the judgment logic to this method. If it is null *, true */Public Boolean isempty () {return false;} is returned ;} /** place all the things to be processed during list shrinking */Public void ongroupcollapsed (INT groupposition) {}/** put all the items to be processed during list expansion */Public void ongroupexpanded (INT groupposition) {}/** indicates whether the child and group IDs are stable when SS changes to * the underlying data. */Public Boolean hasstableids () {return false;}/** whether the child at the specified position is selectable. */Public Boolean ischildselectable (INT groupposition, int childposition) {return true ;}}

Ideasexpandablelistview.rar

Turn: http://www.apkbus.com/android-54271-1-1.html