Android Learning Note-listview implementation method of Baseadapter

The ListView is the most commonly used component in Android development, and here we learn to implement the ListView in a Baseadapter way,

The main layout activity_main.xml is this:

<linearlayout xmlns:android= "http://schemas.android.com/apk/res/android"    xmlns:tools= "http// Schemas.android.com/tools "    android:id=" @+id/ll_root "    android:layout_width=" Match_parent "    android: layout_height= "Match_parent"    android:orientation= "vertical" >    <listview android:id=        "@+id/lv"        android:layout_width= "match_parent"        android:layout_height= "match_parent"        android:orientation= " Vertical ">    </ListView></LinearLayout>

Defines a listitem.xml, which is used to display in a ListView component.

<?xml version= "1.0" encoding= "Utf-8"? ><linearlayout xmlns:android= "http://schemas.android.com/apk/res/ Android "Android:layout_width=" Match_parent "android:layout_height=" 60dip "android:gravity=" center_vertical "a ndroid:orientation= "Horizontal" > <textview android:id= "@+id/tv_id" android:layout_width= "Wrap_cont Ent "android:layout_height=" wrap_content "android:layout_marginleft=" 5dip "android:text=" ID "a" Ndroid:textcolor= "#ff0000" android:textsize= "18sp"/> <linearlayout android:layout_marginleft= "20di         P "android:layout_width=" Fill_parent "android:layout_height=" 60dip "android:gravity=" center_vertical " android:orientation= "vertical" > <textview android:id= "@+id/tv_name" Android:la            Yout_width= "Wrap_content" android:layout_height= "wrap_content" android:layout_marginleft= "5dip"           android:text= "Name" Android:textcolor= "#000000" android:textsize= "18sp"/> <textview android:id= "@+id/tv_n Umber "android:layout_width=" wrap_content "android:layout_height=" Wrap_content "android:l ayout_marginleft= "5dip" android:text= "number" android:textcolor= "#880000" android:textsize= "1 8sp "/> </LinearLayout></LinearLayout>

So the implementation logic in the Activiy is this, because I am in the database to take the value, so, the definition of a DAO class, and the reader, can fully define a ArrayList for the data display,

What we're doing here is baseddapter, here, this is to implement the two methods within the class, GetCount (): Get the number of data to show, GetView (): The presentation of the data, there is an important way: inflate (context context, int resource, ViewGroup root)

Context: is contextual,

Resource:resource the resource ID to inflate, which is the ID of the resource file to display in the ListView,

Root:root A View group that'll be the parent. Used to properly inflate the * layout_* parameters, this can be set bit empty.

　　

public class Mainactivity extends Activity {private linearlayout ll;private ListView lv;private list<person> person    S        @Override protected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate);                Setcontentview (R.layout.activity_main);        ll = (linearlayout) Findviewbyid (r.id.ll_root);        LV = (ListView) Findviewbyid (r.id.lv);        Get data Persondao dao = new Persondao (this);                       The type of persons is list<person> persons = Dao.findall ();      Lv.setadapter (New Myadapter ());    }//default implementation class Simplexxx,defaultxxx,basexxx. When the integration excuse is more, you can inherit Base,simple,defaule, these start private class Myadapter extends baseadapter{private static final String TAG = "Myadapter";//control how many entries in the ListView are in total @overridepublic int GetCount () {//TODO auto-generated method Stubreturn Persons.size ();} @Overridepublic Object getItem (int position) {//TODO auto-generated method Stubreturn null;} @Overridepublic Long Getitemid (iNT position) {//TODO auto-generated method Stubreturn 0;} @Overridepublic view GetView (int position, view Convertview, ViewGroup parent) {//Gets the person object for a location. Person person = persons.get (position);//load the XML in view view = View.inflate (mainactivity.this, r.layout.listitem, NULL); /Be sure to look for the child's Idtextview tv_id = (TextView) View.findviewbyid (r.id.tv_id) in the View object; TextView tv_name = (TextView) View.findviewbyid (r.id.tv_name); TextView Tv_number = (TextView) View.findviewbyid (R.id.tv_number),//person.getid (), int, + "", int must be converted to string type. Tv_id.settext (Person.getid ()); Tv_id.settext ("ID:" +person.getid ()); Tv_name.settext ("Name:" +person.getname ()); Tv_number.settext ("Phone:" +        Person.getnumber ()); return view;} }}

Android Learning Note-listview implementation method of Baseadapter