Android uses spinner to implement a drop-down list

Course Objectives
1. Understand the use and functionality of the spinner drop-down list
2. Learn to use the system default spinner
3. Learn to use custom style spinner

Perform steps
First step: Add a list of drop-down list items, and the items you add here are the menu items for the drop-down list
Private list<string> List = new arraylist<string> ();
List.add ("background");
List.add ("Shanghai");
List.add ("Guangzhou");
List.add ("Shenzhen");
Step two: Define an array adapter (Arrayadapter) for the drop-down list, where the list defined above is used.
adapter = new Arrayadapter<string> (this, Android. R.layout.simple_spinner_item, list);
------> Define an adapter, add a data source
Step Three: Set the menu style for the adapter drop-down list.
Adapter.setdropdownresource (Android. R.layout.simple_spinner_dropdown_item);
Fourth step: Add the adapter to the drop-down list-spinner load Adapter
Myspinner.setadapter (adapter);
Fifth step: Set the response of various time for the drop-down list, this event response menu is selected
Myspinner.setonitemselectedlistener (New Spinner.onitemselectedlistener ())
--Set listener for Spiner

The city name can be obtained using Adapter.getitem (position) (of course, the city name can also be obtained by list.get (position) in this program).

<LinearLayoutxmlns:android= "Http://schemas.android.com/apk/res/android"Xmlns:tools= "Http://schemas.android.com/tools"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent"android:orientation= "vertical"    >    <TextViewAndroid:id= "@+id/textview1"Android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"android:textsize= "25SP"Android:textcolor= "#FF00FF"        />    <SpinnerAndroid:id= "@+id/spinner1"Android:layout_width= "Match_parent"Android:layout_height= "Wrap_content" /></LinearLayout>

Activity_main.xml

 PackageCom.example.spinner;Importjava.util.ArrayList;Importjava.util.List;ImportAndroid.os.Bundle;Importandroid.support.v7.app.ActionBarActivity;ImportAndroid.view.View;ImportAndroid.widget.AdapterView;ImportAndroid.widget.AdapterView.OnItemSelectedListener;ImportAndroid.widget.ArrayAdapter;ImportAndroid.widget.Spinner;ImportAndroid.widget.TextView; Public classMainactivityextendsActionbaractivityImplementsOnitemselectedlistener {PrivateTextView TextView; PrivateSpinner Spinner; PrivateArrayadapter<string>Arrayadapter; @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);                Setcontentview (R.layout.activity_main); TextView=(TextView) Findviewbyid (R.ID.TEXTVIEW1); Textview.settext ("The city you chose is Beijing"); Spinner=(Spinner) Findviewbyid (r.id.spinner1); List<String> list =NewArraylist<string>();  for(String s:NewString[] {"Beijing", "Shanghai", "Guangzhou", "Hangzhou"}) List.add (s); Arrayadapter=NewArrayadapter<string> ( This, Android.        R.layout.simple_spinner_item, list); Arrayadapter.setdropdownviewresource (Android.        R.layout.simple_dropdown_item_1line);        Spinner.setadapter (Arrayadapter); Spinner.setonitemselectedlistener ( This); } @Override Public voidOnitemselected (adapterview<?> Parent, view view,intposition,LongID) {String cityname=Arrayadapter.getitem (position); Textview.settext ("The city you selected is" +cityname); } @Override Public voidOnnothingselected (adapterview<?>parent) {            }}

Mainactivity.java

Effect:

Android uses spinner to implement a drop-down list