Android 轻松实现仿淘宝地区选择

介绍

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

如果对你有帮助的话，动动手点个赞给个评论支持一下。

期待你的关注