无涯教程-Android - Spinner函数

Spinner允许您从下拉菜单中选择一个项目

例如。使用Gmail应用程序时,将显示如下所示的下拉菜单,您需要从下拉菜单中选择一个项目。

Spinner Example

示例

本示例演示计算机的类别,您需要从类别中选择一个类别。

以下是修改后的主要Activity文件src/com.example.spinner/AndroidSpinnerExampleActivity.java的内容。

package com.example.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.Toast;
import android.widget.AdapterView.OnItemSelectedListener;class AndroidSpinnerExampleActivity extends Activity implements OnItemSelectedListener{@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);//Spinner elementSpinner spinner = (Spinner) findViewById(R.id.spinner);//Spinner click listenerspinner.setOnItemSelectedListener(this);//Spinner Drop down elementsList<String> categories = new ArrayList<String>();categories.add("Automobile");categories.add("Business Services");categories.add("Computers");categories.add("Education");categories.add("Personal");categories.add("Travel");//Creating adapter for spinnerArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, categories);//Drop down layout style - list view with radio buttondataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);//attaching data adapter to spinnerspinner.setAdapter(dataAdapter);}@Overridepublic void onItemSelected(AdapterView<?> parent, View view, int position, long id) {//On selecting a spinner itemString item = parent.getItemAtPosition(position).toString();//Showing selected spinner itemToast.makeText(parent.getContext(), "Selected: " + item, Toast.LENGTH_LONG).show();}public void onNothingSelected(AdapterView<?> arg0) {//TODO Auto-generated method stub}
}

将 res/layout/activity_main.xml 的内容修改为以下内容

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:orientation="vertical"android:padding="10dip"android:layout_width="fill_parent"android:layout_height="wrap_content"><TextViewandroid:layout_width="fill_parent"android:layout_height="wrap_content"android:layout_marginTop="10dip"android:text="Category:"android:layout_marginBottom="5dp"/><Spinnerandroid:id="@+id/spinner"android:layout_width="fill_parent"android:layout_height="wrap_content"android:prompt="@string/spinner_title"/></LinearLayout>

将 res/values/string.xml 修改为以下内容

<?xml version="1.0" encoding="utf-8"?>
<resources><string name="app_name">AndroidSpinnerExample</string>
</resources>

这是默认的 AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"package="com.example.spinner" ><applicationandroid:allowBackup="true"android:icon="@drawable/ic_launcher"android:label="@string/app_name"android:theme="@style/AppTheme" ><activityandroid:name="com.example.spinner.AndroidSpinnerExampleActivity"android:label="@string/app_name" ><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity></application>
</manifest>