最近项目要做一个,类似淘宝手机客户端的,选择收货地址的三级联动滚动选择组件,下面是它的大致界面截图:
在IOS中有个叫UIPickerView的选择器,并且在dataSource中定义了UIPickerView的数据源和定制内容,所以用只要熟悉它的基本用法,要实现这么个三级联动滑动选择是挺简单的。
言归正传,今天讨论的是在Android里面如何来实现这么个效果,那么如何实现呢??? 相信部分童鞋首先想到的是android.widget.DatePicker和android.widget.TimePicker,因为它们的样子长得很像,事实就是它们仅仅是长得相而已,Google在设计这个两个widget的时候,并没有提供对外的数据源适配接口,带来的问题就是,我们只能通过它们来选择日期和时间,至于为什么这样设计,如果有童鞋知道,请给我留言,Thanks~
DatePicker.class包含的方法截图:
全都是关于时间获取用的方法.
好了,既然在Android中没办法偷懒的用一个系统widget搞定,那么只能自己来自定义view来实现了,这篇就围绕这个来展开分享一下,我在项目中实现这个的全过程。首先是做了下开源代码调研,在github上面有一个叫做 android-wheel 的开源控件, 代码地址https://github.com/maarek/android-wheel
是一个非常好用的组件,对于数据适配接口的抽取和事件的回调都做了抽取,代码的耦合度低,唯一不足就是在界面的定制这块,如果你需要做更改,需要去动源代码的。我这里在界面的代码做了改动,放在我的项目src目录下了:
在此次项目中,省市区及邮编的数据是放在了assets/province_data.xml里面,是产品经理花了好几天时间整理的,绝对是最齐全和完善了,辛苦辛苦!!!
关于XML的解析,一共有SAX、PULL、DOM三种解析方式,这里就不讲了,可以看我的前面的几篇学习的文章:
Android解析XML方式(一)使用SAX解析
Android解析XML方式(二)使用PULL解析XML
Android解析XML方式(三)使用DOM解析XML
此次项目中使用的是SAX解析方式,因为它占用内存少,并且速度快,数据解析代码写在了 com.mrwujay.cascade.service/XmlParserHandler.java中,代码如下:
- package com.mrwujay.cascade.service;
-
- import java.util.ArrayList;
- import java.util.List;
- import org.xml.sax.Attributes;
- import org.xml.sax.SAXException;
- import org.xml.sax.helpers.DefaultHandler;
-
- import com.mrwujay.cascade.model.CityModel;
- import com.mrwujay.cascade.model.DistrictModel;
- import com.mrwujay.cascade.model.ProvinceModel;
-
- public class XmlParserHandler extends DefaultHandler {
-
-
-
-
- private List<ProvinceModel> provinceList = new ArrayList<ProvinceModel>();
-
- public XmlParserHandler() {
-
- }
-
- public List<ProvinceModel> getDataList() {
- return provinceList;
- }
-
- @Override
- public void startDocument() throws SAXException {
-
- }
-
- ProvinceModel provinceModel = new ProvinceModel();
- CityModel cityModel = new CityModel();
- DistrictModel districtModel = new DistrictModel();
-
- @Override
- public void startElement(String uri, String localName, String qName,
- Attributes attributes) throws SAXException {
-
- if (qName.equals("province")) {
- provinceModel = new ProvinceModel();
- provinceModel.setName(attributes.getValue(0));
- provinceModel.setCityList(new ArrayList<CityModel>());
- } else if (qName.equals("city")) {
- cityModel = new CityModel();
- cityModel.setName(attributes.getValue(0));
- cityModel.setDistrictList(new ArrayList<DistrictModel>());
- } else if (qName.equals("district")) {
- districtModel = new DistrictModel();
- districtModel.setName(attributes.getValue(0));
- districtModel.setZipcode(attributes.getValue(1));
- }
- }
-
- @Override
- public void endElement(String uri, String localName, String qName)
- throws SAXException {
-
- if (qName.equals("district")) {
- cityModel.getDistrictList().add(districtModel);
- } else if (qName.equals("city")) {
- provinceModel.getCityList().add(cityModel);
- } else if (qName.equals("province")) {
- provinceList.add(provinceModel);
- }
- }
-
- @Override
- public void characters(char[] ch, int start, int length)
- throws SAXException {
- }
-
- }
通过XmlParserHandler.java提供的getDataList()方法获取得到,之后再进行拆分放到省、市、区不同的HashMap里面方便做数据适配。
这里是它的具体实现代码:
- protected void initProvinceDatas()
- {
- List<ProvinceModel> provinceList = null;
- AssetManager asset = getAssets();
- try {
- InputStream input = asset.open("province_data.xml");
-
- SAXParserFactory spf = SAXParserFactory.newInstance();
-
- SAXParser parser = spf.newSAXParser();
- XmlParserHandler handler = new XmlParserHandler();
- parser.parse(input, handler);
- input.close();
-
- provinceList = handler.getDataList();
-
- if (provinceList!= null && !provinceList.isEmpty()) {
- mCurrentProviceName = provinceList.get(0).getName();
- List<CityModel> cityList = provinceList.get(0).getCityList();
- if (cityList!= null && !cityList.isEmpty()) {
- mCurrentCityName = cityList.get(0).getName();
- List<DistrictModel> districtList = cityList.get(0).getDistrictList();
- mCurrentDistrictName = districtList.get(0).getName();
- mCurrentZipCode = districtList.get(0).getZipcode();
- }
- }
-
- mProvinceDatas = new String[provinceList.size()];
- for (int i=0; i< provinceList.size(); i++) {
- mProvinceDatas[i] = provinceList.get(i).getName();
- List<CityModel> cityList = provinceList.get(i).getCityList();
- String[] cityNames = new String[cityList.size()];
- for (int j=0; j< cityList.size(); j++) {
- cityNames[j] = cityList.get(j).getName();
- List<DistrictModel> districtList = cityList.get(j).getDistrictList();
- String[] distrinctNameArray = new String[districtList.size()];
- DistrictModel[] distrinctArray = new DistrictModel[districtList.size()];
- for (int k=0; k<districtList.size(); k++) {
- DistrictModel districtModel = new DistrictModel(districtList.get(k).getName(), districtList.get(k).getZipcode());
- mZipcodeDatasMap.put(districtList.get(k).getName(), districtList.get(k).getZipcode());
- distrinctArray[k] = districtModel;
- distrinctNameArray[k] = districtModel.getName();
- }
- mDistrictDatasMap.put(cityNames[j], distrinctNameArray);
- }
- mCitisDatasMap.put(provinceList.get(i).getName(), cityNames);
- }
- } catch (Throwable e) {
- e.printStackTrace();
- } finally {
-
- }
- }
在使用wheel组件时,数据适配起来也很方便,只需要做些数据、显示数量的配置即可,我这边设置了一行显示7条数据
- initProvinceDatas();
- mViewProvince.setViewAdapter(new ArrayWheelAdapter<String>(MainActivity.this, mProvinceDatas));
-
- mViewProvince.setVisibleItems(7);
- mViewCity.setVisibleItems(7);
- mViewDistrict.setVisibleItems(7);
- updateCities();
- updateAreas();
要监听wheel组件的滑动、点击、选中改变事件,可以通过实现它的三个事件监听接口来实现,分别是:
1、OnWheelScrollListener 滑动事件:
-
-
-
- public interface OnWheelScrollListener {
-
-
-
-
- void onScrollingStarted(WheelView wheel);
-
-
-
-
-
- void onScrollingFinished(WheelView wheel);
- }
2、OnWheelClickedListener 条目点击事件:
-
-
-
-
-
-
- public interface OnWheelClickedListener {
-
-
-
-
-
- void onItemClicked(WheelView wheel, int itemIndex);
- }
3、OnWheelChangedListener 被选中项的positon变化事件:
-
-
-
-
-
-
- public interface OnWheelChangedListener {
-
-
-
-
-
-
- void onChanged(WheelView wheel, int oldValue, int newValue);
- }
这里只要知道哪个省、市、区被选中了,实现第三个接口就行,在方法回调时去作同步和更新数据,比如省级条目滑动的时候,市级和县级数据都要做对应的适配、市级滑动时需要去改变县级(区)的数据,这样才能实现级联的效果,至于如何改变,需要三个HashMap来分别保存他们的对应关系:
-
-
-
- protected Map<String, String[]> mCitisDatasMap = new HashMap<String, String[]>();
-
-
-
- protected Map<String, String[]> mDistrictDatasMap = new HashMap<String, String[]>();
-
-
-
-
- protected Map<String, String> mZipcodeDatasMap = new HashMap<String, String>();
在onChanged()回调方法中,对于省、市、区/县的滑动,分别做数据的适配,代码如下:
- @Override
- public void onChanged(WheelView wheel, int oldValue, int newValue) {
-
- if (wheel == mViewProvince) {
- updateCities();
- } else if (wheel == mViewCity) {
- updateAreas();
- } else if (wheel == mViewDistrict) {
- mCurrentDistrictName = mDistrictDatasMap.get(mCurrentCityName)[newValue];
- mCurrentZipCode = mZipcodeDatasMap.get(mCurrentDistrictName);
- }
- }
-
-
-
-
- private void updateAreas() {
- int pCurrent = mViewCity.getCurrentItem();
- mCurrentCityName = mCitisDatasMap.get(mCurrentProviceName)[pCurrent];
- String[] areas = mDistrictDatasMap.get(mCurrentCityName);
-
- if (areas == null) {
- areas = new String[] { "" };
- }
- mViewDistrict.setViewAdapter(new ArrayWheelAdapter<String>(this, areas));
- mViewDistrict.setCurrentItem(0);
- }
-
-
-
-
- private void updateCities() {
- int pCurrent = mViewProvince.getCurrentItem();
- mCurrentProviceName = mProvinceDatas[pCurrent];
- String[] cities = mCitisDatasMap.get(mCurrentProviceName);
- if (cities == null) {
- cities = new String[] { "" };
- }
- mViewCity.setViewAdapter(new ArrayWheelAdapter<String>(this, cities));
- mViewCity.setCurrentItem(0);
- updateAreas();
- }
综上代码,最终实现的界面截图:
源码下载地址:http://download.csdn.net/detail/wulianghuan/8205211