spinner的使用

item.xml:

<?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>

main.xml:

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

strings.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello World, MainActivity!</string>
    <string name="app_name">spinner</string>
    <string-array name="planets_array">
        <item>Mercury</item>
        <item>Venus</item>
        <item>Earth</item>
        <item>Mars</item>
        <item>Jupiter</item>
        <item>Saturn</item>
        <item>Uranus</item>
        <item>Neptune</item>
    </string-array>
</resources>

MainActivity.java:

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");
        }
         
    }
}

效果图如下:

posted on   leihupqrst  阅读(225)  评论(0编辑  收藏  举报

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