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查字典教程网。
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