ANDROID_MARS学习笔记_S02_001_Spinner

1.strings.xml

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

     <string name="app_name">S02_E01_SpinnerEtc</string>
     <string name="hello_world">Hello world!</string>
     <string name="action_settings">Settings</string>

     <string-array name="planets">
         <item>地球</item>
         <item>火星</item>
         <item>水星</item>
         <item>木星</item>
     </string-array>
 </resources>

2.activity_main.xml

 <RelativeLayout 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: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="com.example.s02_e01_spinneretc.MainActivity" >

     <Spinner
         android:id="@+id/mSpinner"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"/>

 </RelativeLayout>

3.item.xml自定义下拉项用

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/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>

4.java

 package com.example.s02_e01_spinneretc;

 import android.annotation.SuppressLint;
 import android.os.Bundle;
 import android.support.v7.app.ActionBarActivity;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemSelectedListener;
 import android.widget.ArrayAdapter;
 import android.widget.Spinner;

 @SuppressLint("NewApi")
 public class MainActivity extends ActionBarActivity implements OnItemSelectedListener{

     private Spinner mSpinner;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         mSpinner = (Spinner) findViewById(R.id.mSpinner);
         // Create an ArrayAdapter using the string array and a default spinner layout
         ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.planets, android.R.layout.simple_spinner_item);
         // Specify the layout to use when the list of choices appears
         adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
         // Apply the adapter to the spinner
         mSpinner.setAdapter(adapter);
         mSpinner.setPrompt("测试");
         mSpinner.setOnItemSelectedListener(this);
     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.main, menu);
         return true;
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         // Handle action bar item clicks here. The action bar will
         // automatically handle clicks on the Home/Up button, so long
         // as you specify a parent activity in AndroidManifest.xml.
         int id = item.getItemId();
         if (id == R.id.action_settings) {
             return true;
         }
         return super.onOptionsItemSelected(item);
     }

     @Override
     public void onItemSelected(AdapterView<?> parent, View view, int position,
             long id) {
         System.out.println(parent.getItemAtPosition(position));

     }

     @Override
     public void onNothingSelected(AdapterView<?> parent) {
         System.out.println(parent);

     }
 }

5.自定义下拉源

 package mars.spinner;

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

 import android.app.Activity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.ArrayAdapter;
 import android.widget.Spinner;
 import android.widget.AdapterView.OnItemSelectedListener;

 public class MainActivity extends Activity {
     /** Called when the activity is first created. */
     //声明Spinner对象
     private Spinner spinner = null;

     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         //通过ID，得到Spinner对象
         spinner = (Spinner) findViewById(R.id.spinnerId);
         List<String> list = new ArrayList<String>();
         list.add("test1");
         list.add("test2");
         //调用ArrayAdapter的构造函数来创建ArrayAdapter对象
         //第一个参数是指上下文对象
         //第二个参数指定了下拉菜单当中每一个条目的样式
         //第三个参数指定了TextView控件的ID
         //第四个参数为整个列表提供数据
         ArrayAdapter adapter = new ArrayAdapter(this,R.layout.item,R.id.textViewId,list);
         //通过createFromResource方法创建一个ArrayAdapter对象
         //第一个参数是指上下文对象
         //第二参数引用了在strings.xml文件当中定义的String数组
         //第三个参数是用来指定Spinner的样式，是一个布局文件ID，该布局文件由Android系统提供，也可替换为自己定义的布局文件
         /*ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
                 this, R.array.planets_array,
                 android.R.layout.simple_spinner_item);
 */        //设置Spinner当中每个条目的样式，同样是引用一个Android系统提供的布局文件
         //adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

         spinner.setAdapter(adapter);
         spinner.setPrompt("测试");
         //为spinner对象绑定监听器
         spinner.setOnItemSelectedListener(new SpinnerOnSelectedListener());
     }
     //这个监听器主要用来监听用户选择列表的动作
     class SpinnerOnSelectedListener implements OnItemSelectedListener{

         //当用户选定了一个条目时，就会调用该方法
         @Override
         public void onItemSelected(AdapterView<?> adapterView, View view, int position,
                 long id) {
             String selected = adapterView.getItemAtPosition(position).toString();
             System.out.println(selected);
         }

         @Override
         public void onNothingSelected(AdapterView<?> adapterView) {
             // TODO Auto-generated method stub
             System.out.println("nothingSelected");
         }

     }
 }