最近用淘寶客戶端的時候，編輯地址的時候有個地區選擇的功能。看上面的效果覺得挺酷，滾動的時候，是最后一個從下面飛上來挨著前一個。就自己鼓搗一個出來玩玩。
說了效果可能不太直觀，下面上兩張圖看看效果
淘寶地區選擇效果
再來一張自己的效果
gif的效果可能不太好，大家自己用Android手機打開淘寶看看
實現分析
展示很簡單，ListView就可以了。對于動畫效果，只需要在getView的時候獲取到要展示的View，通過屬性動畫修改translationY就ok啦。由于地區選擇是一個界面，所以這里還用到了Fragment的 addToBackStack知識
1、用來展示的Fragment
用一個Fragment來接受parentCode參數來獲取父地區的所有子地區，然后進行顯示。這里用Fragment來做是因為用Activity的話，這樣的連續點擊都是同一類的界面不太適合。
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參數 OkHttpClient mOkHttpClient = new OkHttpClient(); private OnFragmentInteractionListener mListener; private AreaAdapter adapter;//地區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) { //獲取父地區的code，用來查詢子地區 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); //通過parentCode來請求地區，如果parentCode不存在就是第一級 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() { //拿到數據進行展示 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) { //單擊的時候需要處理地區點擊事件，統一交給Activity處理 AreaInfo areaInfo = (AreaInfo) parent.getAdapter().getItem(position); if (areaInfo==null) return; if (mListener!=null){ mListener.onFragmentInteraction(areaInfo); } } //用來和Activity交互的回調接口 public interface OnFragmentInteractionListener { void onFragmentInteraction(AreaInfo areaInfo); }我們用了一個Fragment來接受parentCode，用于請求下一級的地區，獲取成功之后進行了展示。并且提供了一個OnFragmentInteractionListener用來在onItemClick時與Activity交互。
接下來看adapter,最開始我們提到了要實現淘寶的效果我們只需要拿到即將顯示的View，設置動畫就可以了。
2、處理顯示效果的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; } }很常見的一個Adapter寫法，只是在getView當中獲取到了要顯示的view，通過
ObjectAnimator.ofFloat(convertView,”translationY”,convertView.getHeight()*2,0).setDuration(500).start()為veiw設置了動畫，
這里還用了個變量position來區別只有在向上滾動的時候才會有動畫。不過我覺得不加position區別的效果也不錯，大家可以試試。
其實這樣已經實現了效果，接下來順便提一下Activity對Framgnet中onItemClick的處理。
3、Activity和fragment的交互處理
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); //新建第一級地區，parentCode參數為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; } /** * 處理交互，hide前一個fragment，并且調用addToBackStack讓Fragment可以點擊back的時候顯示前一個fragment * 如果是第三級地區則直接返回地區選擇數據給上個Activity * @param areaInfo 被點擊的地區信息 */ @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; } }}這樣仿淘寶地區選擇就實現啦！
結語
大家可以自己寫測試接口，也可以直接調用我寫好的接口： http://123.184.16.19:8008/area/list
源碼提供給大家參考：Android仿淘寶地區選擇
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持武林網。
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