轻松实现Android仿淘宝地区选择功能

最近用淘宝客户端的时候，编辑地址的时候有个地区选择的功能。看上面的效果觉得挺酷，滚动的时候，是最后一个从下面飞上来挨着前一个。就自己鼓捣一个出来玩玩。

说了效果可能不太直观，下面上两张图看看效果

淘宝地区选择效果

再来一张自己的效果

gif的效果可能不太好，大家自己用Android手机打开淘宝看看

实现分析

展示很简单，ListView就可以了。对于动画效果，只需要在getView的时候获取到要展示的View，通过属性动画修改translationY就ok啦。由于地区选择是一个界面，所以这里还用到了Fragment的 addToBackStack知识

1、用来展示的Fragment

用一个Fragment来接受parentCode参数来获取父地区的所有子地区，然后进行显示。这里用Fragment来做是因为用Activity的话，这样的连续点击都是同一类的界面不太适合。

public class AreaFragment extends Fragment implements AdapterView.OnItemClickListener {

 private static final String ARG_PARAM1 = "parentCode";
 @Bind(R.id.refresh_list_view)
 ListView mRefreshListView;
 @Bind(R.id.loadingBar)
 ProgressBar mLoadingBar;

 private String mParam1;//parentCode参数

 OkHttpClient mOkHttpClient = new OkHttpClient();

 private OnFragmentInteractionListener mListener;

 private AreaAdapter adapter;//地区adapter

 public AreaFragment() {
 }

 /**
 * Use this factory method to create a new instance of
 * this fragment using the provided parameters.
 *
 * @param param1 Parameter 1.
 * @return A new instance of fragment AreaFragment.
 */
 public static AreaFragment newInstance(String param1) {
 AreaFragment fragment = new AreaFragment();
 Bundle args = new Bundle();
 args.putString(ARG_PARAM1, param1);
 fragment.setArguments(args);
 return fragment;
 }

 @Override
 public void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 if (getArguments() != null) {
  //获取父地区的code，用来查询子地区
  mParam1 = getArguments().getString(ARG_PARAM1);

 }
 }

 @Override
 public View onCreateView(LayoutInflater inflater, ViewGroup container,
    Bundle savedInstanceState) {
 // Inflate the layout for this fragment
 View view = inflater.inflate(R.layout.fragment_area, container, false);
 ButterKnife.bind(this, view);
 mRefreshListView.setOnItemClickListener(this);

 FormEncodingBuilder builder = new FormEncodingBuilder();
 builder.add(ARG_PARAM1,mParam1);

 //通过parentCode来请求地区，如果parentCode不存在就是第一级
 final Request request = new Request.Builder()
  .url("http://123.184.16.19:8008/area/list")
  .post(builder.build())
  .build();
 mOkHttpClient.newCall(request).enqueue(new Callback(){
  @Override
  public void onFailure(Request request, IOException e) {

  }

  @Override
  public void onResponse(Response response) throws IOException {
  final String res = response.body().string();
  if (res!=null){
   Gson gson = new Gson();
   JsonResult jsonResult = gson.fromJson(res, JsonResult.class);
   if (jsonResult.isSuccess()){
   List list = (List) jsonResult.getResult();

   List newList = new ArrayList();
   Iterator iterator = list.iterator();
   while (iterator.hasNext()){
    Map map = (Map) iterator.next();
    AreaInfo areaInfo = gson.fromJson(gson.toJson(map),AreaInfo.class);
    newList.add(areaInfo);
   }
   adapter = new AreaAdapter(getContext(),newList);
   getActivity().runOnUiThread(new Runnable() {
    @Override
    public void run() {
   //拿到数据进行展示  
   mRefreshListView.setAdapter(adapter);
    }
   });
   }
  }
  }
 });

 return view;
 }

 @Override
 public void onAttach(Context context) {
 super.onAttach(context);
 if (context instanceof OnFragmentInteractionListener) {
  mListener = (OnFragmentInteractionListener) context;
 } else {
  throw new RuntimeException(context.toString()
   + " must implement OnFragmentInteractionListener");
 }
 }

 @Override
 public void onDetach() {
 super.onDetach();
 mListener = null;
 }

 @Override
 public void onDestroyView() {
 super.onDestroyView();
 ButterKnife.unbind(this);
 }


 @Override
 public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
 //单击的时候需要处理地区点击事件，统一交给Activity处理
 AreaInfo areaInfo = (AreaInfo) parent.getAdapter().getItem(position);
 if (areaInfo==null) return;
 if (mListener!=null){
  mListener.onFragmentInteraction(areaInfo);
 }
 }


 //用来和Activity交互的回调接口
 public interface OnFragmentInteractionListener {
 void onFragmentInteraction(AreaInfo areaInfo);
 }

我们用了一个Fragment来接受parentCode，用于请求下一级的地区，获取成功之后进行了展示。并且提供了一个OnFragmentInteractionListener用来在onItemClick时与Activity交互。

接下来看adapter,最开始我们提到了要实现淘宝的效果我们只需要拿到即将显示的View，设置动画就可以了。

2、处理显示效果的adapter

class AreaAdapter extends BaseAdapter {

 private List list;

 private int lastPosition;

 public AreaAdapter(Context context, List<AreaInfo> list) {
  this.list = list;
 }


 @Override
 public int getCount() {
  return list.size();
 }

 @Override
 public Object getItem(int position) {
  return list.get(position);
 }

 @Override
 public long getItemId(int position) {
  return 0;
 }

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
  ViewHolder viewHolder = null;
  if (convertView==null){
  convertView = LayoutInflater.from(getContext()).inflate(R.layout.area_list_item,parent,false);
  viewHolder = new ViewHolder();
  viewHolder.textView = (TextView) convertView.findViewById(android.R.id.text1);
  convertView.setTag(viewHolder);
  }
  viewHolder = (ViewHolder) convertView.getTag();
  AreaInfo item = (AreaInfo) list.get(position);
  viewHolder.textView.setText(item.getAreaName());
  if (lastPosition<position&&lastPosition!=0){
  ObjectAnimator.ofFloat(convertView,"translationY",convertView.getHeight()*2,0).setDuration(500).start();

  }
  lastPosition = position;
  return convertView;
 }

 class ViewHolder{
  TextView textView;
 }
 }

很常见的一个Adapter写法，只是在getView当中获取到了要显示的view，通过
ObjectAnimator.ofFloat(convertView,”translationY”,convertView.getHeight()*2,0).setDuration(500).start()为veiw设置了动画，

这里还用了个变量position来区别只有在向上滚动的时候才会有动画。不过我觉得不加position区别的效果也不错，大家可以试试。

其实这样已经实现了效果，接下来顺便提一下Activity对Framgnet中onItemClick的处理。

3、Activity和fragment的交互处理

public class AreaSelectActivity extends AppCompatActivity implements AreaFragment.OnFragmentInteractionListener{

 private Fragment oneFragment;
 private Fragment twoFragment;


 private Map map = new HashMap();
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_area_select);
 ButterKnife.bind(this);
 //新建第一级地区，parentCode参数为null
 oneFragment = AreaFragment.newInstance("");
 FragmentManager fragmentManager = getSupportFragmentManager();
 fragmentManager.beginTransaction().replace(R.id.content,oneFragment).commit();
 }


 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
 switch (item.getItemId()){
  case android.R.id.home:
  FragmentManager fragmentManager = getSupportFragmentManager();
  if (fragmentManager.getBackStackEntryCount()>0){
   fragmentManager.popBackStack();
  }else{
   finish();
  }
  break;
 }
 return true;
 }


 /**
 * 处理交互，hide前一个fragment，并且调用addToBackStack让Fragment可以点击back的时候显示前一个fragment
 * 如果是第三级地区则直接返回地区选择数据给上个Activity
 * @param areaInfo 被点击的地区信息
 */
 @Override
 public void onFragmentInteraction(AreaInfo areaInfo) {
 if (areaInfo==null){
  return;
 }
 FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
 int level = areaInfo.getLevel();
 switch (level){
  case 1:
  map.put("provId",areaInfo.getId());
  map.put("provName",areaInfo.getAreaName());
  if (areaInfo.isLeaf()){
   Intent intent = new Intent();
   intent.putExtra("addressInfo", (Serializable) map);
   setResult(RESULT_OK,intent);
   finish();
  }else{
   transaction.hide(oneFragment);
   transaction.add(R.id.content,twoFragment=AreaFragment.newInstance(areaInfo.getAreaCode()+"")).addToBackStack(null).commit();
  }
  break;
  case 2:
  map.put("cityId",areaInfo.getId());
  map.put("cityName",areaInfo.getAreaName());
  if (areaInfo.isLeaf()){
   Intent intent = new Intent();
   intent.putExtra("addressInfo", (Serializable) map);
   setResult(RESULT_OK,intent);
   finish();
  }else {
   transaction.hide(twoFragment);
   transaction.add (R.id.content, AreaFragment.newInstance(areaInfo.getAreaCode()+"")).addToBackStack(null).commit();
  }
  break;
  case 3:
  map.put("districtId",areaInfo.getId());
  map.put("districtName",areaInfo.getAreaName());
  Intent intent = new Intent();
  intent.putExtra("addressInfo", (Serializable) map);
  setResult(RESULT_OK,intent);
  finish();
  break;
 }

 }
}

这样仿淘宝地区选择就实现啦！

结语

大家可以自己写测试接口，也可以直接调用我写好的接口： http://123.184.16.19:8008/area/list

源码提供给大家参考：Android仿淘宝地区选择

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持小牛知识库。