android > Spinner ( 下拉列表 )

先是在 layout 里面 建议个 Spinner 控件

<?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/spnner"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />
    
</LinearLayout>

然后在 主activity 里

package so.com;

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

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

public class SoActivity extends Activity {
    /** Called when the activity is first created. */
	private List<String> list = new ArrayList<String>();
	private Spinner spinner;
	private ArrayAdapter<String> adapter;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        spinner = (Spinner)findViewById(R.id.spnner);
                
        list.add("北京");
        list.add("上海");
        list.add("天津");
        list.add("南京");
        
      
        adapter = new ArrayAdapter<String>(SoActivity.this, android.R.layout.simple_spinner_item, list);   
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); 
        spinner.setAdapter(adapter);
        
        ///增加监听事件，其实在程序启动时就调用了该监听
        spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
        	public void onItemSelected(AdapterView<?> arg0, View arg1,
        			int arg2, long arg3) {
        		// TODO Auto-generated method stub
        		
        		Toast.makeText(SoActivity.this, adapter.getItem(arg2), Toast.LENGTH_LONG).show();
        		
        	}

			public void onNothingSelected(AdapterView<?> arg0) {
				// TODO Auto-generated method stub
				Toast.makeText(SoActivity.this, "Selected None", Toast.LENGTH_LONG).show();
			}
		});
        
        
        
      
    }
}