Android学习笔记之Spinner下拉列表使用案例

Posted 2020-09-17 yutingliuyl

（1）两种方法提冲Spinner中的数据源：通过list集合，或者是通过xml文件进行配置

（2）布局代码例如以下：

<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=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="46dp"
        android:text="所属城市"
        android:textSize="22sp" />

    <Spinner
        android:id="@+id/spinner1"
        android:layout_width="200sp"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginTop="44dp"
        android:layout_toRightOf="@+id/textView1" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/textView1"
        android:layout_centerVertical="true"
        android:text="所属星球" />

    <Spinner
        android:id="@+id/spinner2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/spinner1"
        android:layout_alignTop="@+id/textView2"
        android:layout_marginLeft="21dp" />

</RelativeLayout>

（2）

package com.example.spinners;

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

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;
/**
 * 通过继承OnItemSelectedListener接口来实现选择时的事件
 * @author xuliugen
 *
 */
public class MainActivity extends Activity implements OnItemSelectedListener {

	private Spinner spinner1;
	private Spinner spinner2;
	// private SpinnerAdapter spinnerAdapter;

	private ArrayAdapter<String> adapter;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		spinner1 = (Spinner) this.findViewById(R.id.spinner1);
		spinner2 = (Spinner) this.findViewById(R.id.spinner2);

		// 第一种手工输入的list
		adapter = new ArrayAdapter<String>(MainActivity.this,
				android.R.layout.simple_spinner_item, getDataSource());
		spinner1.setAdapter(adapter);

		//注冊监听器
		spinner1.setOnItemSelectedListener(this);
		// 另外一种：通过载入xml文件配置的数据源
		ArrayAdapter adapter2 = ArrayAdapter.createFromResource(this,
				R.array.planets_array, android.R.layout.simple_spinner_item);
		adapter2.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
		spinner2.setAdapter(adapter2);
	}

	/*
	 * 通过第一种方法：手工输入的list
	 */
	public List<String> getDataSource() {
		List<String> list = new ArrayList<String>();
		list.add("beijing");
		list.add("beida");
		list.add("shahai");
		list.add("shangjing");
		list.add("shanglian");
		list.add("chengdu");
		return list;
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public void onItemSelected(AdapterView<?
> parent, View view, int position,
			long id) {
		String itemString = spinner1.getItemAtPosition(position).toString();
		Toast.makeText(this, "你选中的是" + itemString, 1).show();
	}

	@Override
	public void onNothingSelected(AdapterView<?
> parent) {

	}

}

（4）资源文件里的配置例如以下：

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

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

（5）执行结果例如以下所看到的：