Android Spinner

 

(1)新建一個Android工程，名字爲SpinnerActy。修改layout下的main.xml，添加一個Textview和一個Spinner，文件內容如下：
<?xml version="1.0" encoding=”utf-8″?>
<LinearLayout
    android:id= "@+id/widget28"
    android:layout_width= "fill_parent"
    android:layout_height= "fill_parent"
    android:orientation= "vertical"
    xmlns:android= "http://schemas.android.com/apk/res/android" >
    <TextView
        android:id= "@+id/TextView_Show"
        android:layout_width= "fill_parent"
        android:layout_height= "wrap_content"
        android:text= "你選擇的是"
        android:textSize= "25sp" >
    </TextView>
    <Spinner
        android:id= "@+id/spinner_City"
        android:layout_width= "fill_parent"
        android:layout_height= "wrap_content" >
    </Spinner> <!– 定義一個下拉菜單–>
</LinearLayout>
(2)修改你的SpinnerActy類，在這裏我們就要記住五步來自定義一個Spinner了，完整代碼及五步註釋如下：
package com . xtlh . spinner;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;

public class SpinnerActy extends Activity {
    /** Called when the activity is first created. */
    private List<String> list = new ArrayList<String>();
    private TextView myTextView;
    private Spinner mySpinner;
    private ArrayAdapter<String> adapter;
    private Animation myAnimation;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        //第一步：添加一個下拉列表項的list，這裏添加的項就是下拉列表的菜單項
        list.add("北京");
        list.add("上海");
        list.add("深圳");
        list.add("南京");
        list.add("重慶");
        myTextView = (TextView)findViewById(R.id.TextView_Show);
        mySpinner = (Spinner)findViewById(R.id.spinner_City);
        //第二步：爲下拉列表定義一個適配器，這裏就用到裏前面定義的list。
        adapter = new ArrayAdapter<String>(this,android.R.layout.simple_spinner_item, list);
        //第三步：爲適配器設置下拉列表下拉時的菜單樣式。
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        //第四步：將適配器添加到下拉列表上
        mySpinner.setAdapter(adapter);
        //第五步：爲下拉列表設置各種事件的響應，這個事響應菜單被選中
        mySpinner.setOnItemSelectedListener(new Spinner.OnItemSelectedListener(){
            public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
                // TODO Auto-generated method stub
                /* 將所選mySpinner 的值帶入myTextView 中*/
                myTextView.setText("您選擇的是："+ adapter.getItem(arg2));
                /* 將mySpinner 顯示*/
                arg0.setVisibility(View.VISIBLE);
            }
            public void onNothingSelected(AdapterView<?> arg0) {
                // TODO Auto-generated method stub
                myTextView.setText("NONE");
                arg0.setVisibility(View.VISIBLE);
            }
        });
        /*下拉菜單彈出的內容選項觸屏事件處理*/
        mySpinner.setOnTouchListener(new Spinner.OnTouchListener(){
            public boolean onTouch(View v, MotionEvent event) {
                // TODO Auto-generated method stub
                /* 將mySpinner 隱藏，不隱藏也可以，看自己愛好*/
                v.setVisibility(View.INVISIBLE);
                return false;
            }
        });
        /*下拉菜單彈出的內容選項焦點改變事件處理*/
        mySpinner.setOnFocusChangeListener(new Spinner.OnFocusChangeListener(){
        public void onFocusChange(View v, boolean hasFocus) {
        // TODO Auto-generated method stub
            v.setVisibility(View.VISIBLE);
        }
        });
    }
}