02_01_spinner的使用

02_01_spinner的使用

布局activity_main.xml

<RelativeLayout xmlns:android=""
    xmlns:tools=""
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

<Spinner
    android:id="@+id/spinnerId"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
</RelativeLayout>

Strings.xml文件

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">spinner</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>

    <string-array name="cities_array">
        <item>北京</item>
        <item>广州</item>
        <item>深圳</item>
        <item>上海</item>
        <item >香港</item>
        <item>成都</item>
    </string-array>
</resources>

item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=""
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
    <TextView
        android:id="@+id/textViewId"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        />
</LinearLayout>

//mainActivity.java
package com.lwb.spinner;

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

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
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 {
    private Spinner spinner = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        spinner = (Spinner)findViewById(R.id.spinnerId);
        /*1、通过createFromResource方法创建ArrayAdater对象
         *   adapter = ArrayAdapter.createFromResource(this
                , R.array.planets_array,android.R.layout.simple_spinner_item);
         * this:表上下文对象
         * R.array.planets_arry:表引用了在strings.xml文件当红定义的的String数组
         * android.R.layout.simple_spinner_dropdown_item：用于指定Spinner的样式，是一个布局文件的ID，该布局
         * 有Android系统提供，也可以替换为自定义的布局文件
         * */
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this
                , R.array.cities_array,android.R.layout.simple_spinner_item);
        /*2、设置Spinner当中每一个条目的样式，同样是引用Android系统提供的布局文件*/
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        /*22、*/
        List<String> list = new ArrayList<String>();
        list.add("纽约");
        list.add("旧金山");
    //    ArrayAdapter adapter = new ArrayAdapter(this,R.layout.item,R.id.textViewId,list);

        /*3、为spinner设置Adater*/
        spinner.setAdapter(adapter);
        /*4、为spinner的标题*/
        spinner.setPrompt("城市");
        /*5/为spinner对象绑定监听器*/
        spinner.setOnItemSelectedListener(new SpinnerOnSelectedListenner());
    }

     class SpinnerOnSelectedListenner implements OnItemSelectedListener{
        @Override
        public void onItemSelected(AdapterView<?> adapterView, View view, int position,
                long id) {
            System.out.println("onItemSelected*******");
            String selected = adapterView.getItemAtPosition(position).toString();
            System.out.println(selected);
            Toast.makeText(MainActivity.this, selected , Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
            System.out.println("nothingSelected*********");
            Toast.makeText(MainActivity.this, "nothingSelected*********" , Toast.LENGTH_SHORT).show();
        }
    }
 }