Spinner学习

 今天学习了Spinner组件，使用Spinner相当于从下拉列表中选择项目，下面演示一下Spinner的使用(分别使用ArrayAdapter和自定义Adapter实现)

（一）:使用ArrayAdapter进行适配数据:

   ①:首先定义一个布局文件:

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< span style = "font-size:16px;" ><? 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/spinner1"          android:layout_width = "match_parent"          android:layout_height = "wrap_content"        /> </ LinearLayout ></ span >

  【注意:】上面的Spinner有两个属性1:prompt是初始的时候，Spinner显示的数据，是一个引用类型   2:entries是直接在xml布局文件中绑定数据源（可以不设置，即可以在Activity中动态绑定） 

         ②:建立数据源，使用数组,这些数据将会在Spinner下来列表中进行显示:

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< span style = "font-size:16px;" ><? xml version = "1.0" encoding = "utf-8" ?> < resources >      < string-array name = "spinnername" >          < item >北京</ item >          < item >上海 </ item >          < item >广州</ item >          < item >深圳</ item >      </ string-array > </ resources ></ span >

  ③:接着在Activity中加入如下的代码(使用了系统定义的下拉列表的布局文件，当然也可以自定义)

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// 初始化控件 mSpinner = (Spinner) findViewById(R.id.spinner1); // 建立数据源 String[] mItems = getResources().getStringArray(R.array.spinnername); // 建立Adapter并且绑定数据源 ArrayAdapter<String> _Adapter= new ArrayAdapter<String>( this ,android.R.layout.simple_spinner_item, mItems); //绑定 Adapter到控件 mSpinner.setAdapter(_Adapter);

以上代码初步完成，看下运行效果:

    下面是关于Spinner的点击事件(效果图如上图):

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mSpinner.setOnItemSelectedListener( new OnItemSelectedListener() {      @Override      public void onItemSelected(AdapterView<?> parent, View view,              int position,  long id) {          String str=parent.getItemAtPosition(position).toString();          Toast.makeText(SpinnerActivity. this ,  "你点击的是:" +str,  2000 ).show();      }      @Override      public void onNothingSelected(AdapterView<?> parent) {          // TODO Auto-generated method stub      } });

       （二）使用自定义的Adapter(重点)

           ①:定义每一个Item的布局文件

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<? xml version = "1.0" encoding = "utf-8" ?> < LinearLayout xmlns:android = "http://schemas.android.com/apk/res/android"      android:layout_width = "match_parent"      android:layout_height = "match_parent"      android:orientation = "horizontal" >        < TextView          android:id = "@+id/textView1"          android:layout_width = "wrap_content"          android:layout_height = "wrap_content"          android:drawableLeft = "@drawable/ic_launcher"          android:paddingRight = "8dip"          android:paddingTop = "8dip"          android:text = "TextView"          android:textSize = "25sp" />        < TextView          android:id = "@+id/textView2"          android:layout_width = "wrap_content"          android:layout_height = "wrap_content"          android:paddingLeft = "8dip"          android:paddingTop = "8dip"          android:text = "TextView"          android:textSize = "25sp" />   </ LinearLayout >

        ②:建立Person类：

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package com.jiangqq.csdn; public class Person {      private String personName;      private String personAddress;      public Person(String personName, String personAddress) {          super ();          this .personName = personName;          this .personAddress = personAddress;      }      public String getPersonName() {          return personName;      }      public void setPersonName(String personName) {          this .personName = personName;      }      public String getPersonAddress() {          return personAddress;      }      public void setPersonAddress(String personAddress) {          this .personAddress = personAddress;      }   }

     ③:创建MyAdapter继承与BaseAdapter,进行适配:

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package com.jiangqq.csdn;   import java.util.List; import android.content.Context; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.TextView;   /**   * 自定义适配器类   * @author jiangqq  <a href=http://blog.youkuaiyun.com/jiangqq781931404></a>   *   */ public class MyAdapter  extends BaseAdapter {      private List<Person> mList;      private Context mContext;        public MyAdapter(Context pContext, List<Person> pList) {          this .mContext = pContext;          this .mList = pList;      }        @Override      public int getCount() {          return mList.size();      }        @Override      public Object getItem( int position) {          return mList.get(position);      }        @Override      public long getItemId( int position) {          return position;      }      /**       * 下面是重要代码       */      @Override      public View getView( int position, View convertView, ViewGroup parent) {          LayoutInflater _LayoutInflater=LayoutInflater.from(mContext);          convertView=_LayoutInflater.inflate(R.layout.item,  null );          if (convertView!= null )          {              TextView _TextView1=(TextView)convertView.findViewById(R.id.textView1);              TextView _TextView2=(TextView)convertView.findViewById(R.id.textView2);              _TextView1.setText(mList.get(position).getPersonName());              _TextView2.setText(mList.get(position).getPersonAddress());          }          return convertView;      } }

④:在Activity中加入如下代码:

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// 初始化控件 mSpinner = (Spinner) findViewById(R.id.spinner1); // 建立数据源 List<Person>  persons= new ArrayList<Person>(); persons.add( new Person( "张三" ,  "上海 " )); persons.add( new Person( "李四" ,  "上海 " )); persons.add( new Person( "王五" ,  "北京" )); persons.add( new Person( "赵六" ,  "广州 " )); //  建立Adapter绑定数据源 MyAdapter _MyAdapter= new MyAdapter( this , persons); //绑定Adapter mSpinner.setAdapter(_MyAdapter);

运行效果如下截图:

  

      监听事件和第一种方法相同: