Android's ListView related

A ListView is a list view that displays the various controls provided by ListAdapter in a vertical and scrollable list. Note that you create the adapter and set it to the ListView.

1.ArrayAdapter

The Arrayadapter is constructed from 3 parameters, the first is the context, the second is the layout defined in the R file, the system's R file is available, and the third parameter is an array with no restrictions on the type of each item in the array.

The default layout of the system is available via Android. r.layout.xx definition.

private static string[] data={"A", "B", "C", "D"};
@Override
public void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Setcontentview (R.layout.main);

ListView listview=new ListView (This);
Arrayadapter adapter=new arrayadapter<string> (this, Android. R.layout.simple_list_item_1,data);
Listview.setadapter (adapter);
Setcontentview (listview);
}

If you customize each item in the ListView, the style of TextView Arraylayout.xml is as follows:

<?xml version= "1.0" encoding= "Utf-8"?>
<textview xmlns:android= "Http://schemas.android.com/apk/res/android"
Android:layout_width= "Fill_parent" android:layout_height= "Wrap_content"
android:gravity= "Center_horizontal"/>

Activity, specify arrayadapter the second parameter is arraylayout.xml:

private static string[] data={"A", "B", "C", "D"};
@Override
public void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Setcontentview (R.layout.main);

ListView listview=new ListView (This);
Arrayadapter adapter=new arrayadapter<string> (this,r.layout.arraylayout, data);
Listview.setadapter (adapter);
Setcontentview (listview);
}

2 Simpleadapter

Each item in the Simpleadapter ArrayList is a map<string,?> type, and each map object corresponds to a data-bound one by one in Listv.

Private ListView ListView;
@Override
public void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Listview=new ListView (this);
Data2 = new arraylist<map<string, object>> ();
Map<string, object> item;
item = new hashmap<string, object> ();
Item.put ("name", "Zhang San");
Item.put ("Gender", "male");
Item.put ("Age", "25");
Data2.add (item);
item = new hashmap<string, object> ();
Item.put ("name", "John Doe");
Item.put ("Gender", "male");
Item.put ("Age", "33");
Data2.add (item);
item = new hashmap<string, object> ();
Item.put ("name", "Xiao Wang");
Item.put ("Gender", "female");
Item.put ("Age", "31");
Data2.add (item);
Simpleadapter adapter =New Simpleadapter (This, data2,
R.layout.simplelayout, new string[] {"Name", "Gender", "Age"}, new int[] {
R.ID.TV01, r.id.tv02,r.id.tv03});
Listview.setadapter (adapter);
Setcontentview (listview);

The layout file for each item in the ListView is as follows:

<?xml version= "1.0" encoding= "Utf-8"?>
<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"
Android:layout_width= "Fill_parent" android:layout_height= "Fill_parent"
android:orientation= "Horizontal" >
<textview android:id= "@+id/tv01" android:layout_width= "Wrap_content"
android:layout_height= "Wrap_content" android:width= "150DP"/>
<textview android:id= "@+id/tv02" android:layout_width= "Wrap_content"
android:layout_height= "Wrap_content" android:width= "150DP"/>
<textview android:id= "@+id/tv03" android:layout_width= "Wrap_content"
android:layout_height= "Wrap_content" android:width= "150DP"/>
</LinearLayout>

If you set the activity's layout file to contain not only the ListView, as follows:

<?xml version= "1.0" encoding= "Utf-8"?>
<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"
android:orientation= "vertical" android:layout_width= "fill_parent"
android:layout_height= "Fill_parent" >
<imageview android:layout_width= "fill_parent" android:layout_height= "Wrap_content"
android:src= "@drawable/img01"/>
<ListView android:id= "@+id/listview01" android:layout_width= "Fill_parent"
android:layout_height= "Wrap_content" android:choicemode= "Singlechoice"/>
</LinearLayout>

In the activity:

Setcontentview (R.layout.main);
listview= (ListView) Findviewbyid (R.ID.LISTVIEW01);
Listview.setadapter (adapter);

3 Baseadapter

public class Mainactivity extends Activity {
/** called when the activity is first created. */
int []Drawableids={R.DRAWABLE.IMG01,R.DRAWABLE.IMG02,R.DRAWABLE.IMG03};
int []Msgids={R.STRING.STR1,R.STRING.STR2,R.STRING.STR3};
@Override
public void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);

Setcontentview (R.layout.main);
ListviewListView= (ListView) Findviewbyid (R.ID.LISTVIEW01);
Baseadapter ba=newBaseadapter() {

@Override
PublicView GetView(int position, View Convertview, ViewGroup parent) {
TODO auto-generated Method Stub
LinearLayout ll=new LinearLayout (mainactivity.this);
Ll.setorientation (linearlayout.horizontal);
Ll.setpadding (5, 5, 5, 5);
ImageView ii=new ImageView (mainactivity.this);
Ii.setimagedrawable (Getresources (). getdrawable (Drawableids[position]));
Ii.setscaletype (ImageView.ScaleType.FIT_XY);
Ii.setlayoutparams (New Gallery.layoutparams (50,50));
Ll.addview (ii);
TextView tv=new TextView (mainactivity.this);
Tv.settext (Getresources (). GetText (Msgids[position]));
Tv.settextsize (24);
Tv.settextcolor (MainActivity.this.getResources (). GetColor (R.color.white));
Tv.setpadding (5, 5, 5, 5);
Tv.setgravity (Gravity.left);
Ll.addview (TV);
Returnll;
}

@Override
public long getitemid (int position) {
TODO auto-generated Method Stub
return 0;
}

@Override
Public Object getItem (int position) {
TODO auto-generated Method Stub
return null;
}

@Override
public int GetCount () {
TODO auto-generated Method Stub
return 3;
}
};
listview.setadapter (BA);
}
}

4 listactivity

If you use Listactivity, the ListView in the activity will fill the screen.

In a layout file, you must define a ListView whose ID is @id/android:list, and another that needs to be defined but not necessarily a textview with an ID of @id/android:empty, which is what is displayed when there is no data in the ListView.

<?xml version= "1.0" encoding= "Utf-8"?>
<linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"
Android:layout_width= "Fill_parent" android:layout_height= "Fill_parent" >
<listview android:id= "@id/android:list" android:layout_width= "Fill_parent"
android:layout_height= "Fill_parent"/>
<textview android:id= "@id/android:empty" android:layout_width= "Fill_parent"
android:layout_height= "Fill_parent" android:text= "no Data"/>
</LinearLayout>

Activity, the ListView is set to the same row as the previous method.

String [] data={"A", "B", "C", "D"};
@Override
public void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);

Setcontentview (R.layout.main);
Setlistadapter (New arrayadapter<string> (this, Android. R.layout.simple_list_item_1,data));

}

Android's ListView related