Spinner 的用法

package com.music.my.pk;


import java.util.ArrayList;
import java.util.List;


import com.utils.pk.MyFileTree;


import android.R.integer;
import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;


public class MainActivity extends Activity {
/** Called when the activity is first created. */
private Spinner spinner;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
spinner = (Spinner)findViewById(R.id.sp);

spinner.setOnItemSelectedListener(new SpLS());


spinner.setPrompt( "本机可用歌曲名" ); //设置头部
MyFileTree tree = new MyFileTree(); //此类返回的是SD卡上的所有文件名
//得到所有文件

String [ ] items = tree.getFileTree(Environment.getExternalStorageDirectory().toString());

ArrayAdapter array_adapter = new ArrayAdapter <String> ( this, android.R.layout.simple_spinner_item, items );
array_adapter.setDropDownViewResource ( android.R.layout.simple_spinner_dropdown_item );
spinner.setAdapter ( array_adapter );




}


//得到选择的spinner的值
private class SpLS implements OnItemSelectedListener{


@Override
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
String musicFile = MainActivity.this.spinner.getItemAtPosition(position).toString();
Toast.makeText(MainActivity.this, musicFile, 1).show();

}


@Override
public void onNothingSelected(AdapterView<?> parent) {
// TODO Auto-generated method stub

}

}

}

/////////////////////////////////////////////////////////////////////main,xml

<?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="vertical" >


<Spinner
android:id="@+id/sp"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
</LinearLayout>