android学习笔记4-Spinner

功能上大致与ListView 不做赘述

java 文件

package com.example.spiner;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.*;

publicclass MainActivity extends Activity  {

    TextView selection;

    Spinner spin;

    String[] items={"a","b","c","e"};

    @Override

    protectedvoid onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //加载视图文件，类似于C#的窗体设计

        selection=(TextView)findViewById(R.id.selection);

        //查找对应xml文件中的部件

        spin=(Spinner)findViewById(R.id.spinner);

        ArrayAdapter<String> aa=new ArrayAdapter<String>(this,android.R.layout.simple_spinner_dropdown_item,items);

        //定义一个数组适配器《string》类型的，

        //对应的三个参数分别为  所有者，外观样式，数据源

        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        //定义下拉列表样式

        spin.setAdapter(aa);

        //定义适配器

        spin.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

        //定义下拉事件，先打入  new AdapterView.OnItemSelectedListener()后，会提示是否自动生成对应的代码

            @Override

            publicvoid onItemSelected(AdapterView<?> parent, View v,

                    int position, long id) {

                // TODO Auto-generated method stub

                selection.setText(parent.getItemAtPosition(position).toString());

            }

            @Override

            publicvoid onNothingSelected(AdapterView<?> parent) {

                // TODO Auto-generated method stub

                selection.setText("nothing select");

            }

        });

        }

    }

 xml文件

<LinearLayout xmlns: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">

    <TextView

        android:layout_width="fill_parent"

        android:layout_height="wrap_content"

        android:id="@+id/selection"

    />

    <Spinner

        android:id="@+id/spinner"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

         />

</LinearLayout>

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