填充列表视图片段选项卡 android

Question

我的问题是 activity 加载时我的列表视图不显示。

这是我的 activity 代码：

protected void onCreate(Bundle savedInstanceState) {
...
 TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.addTab(tabLayout.newTab().setText("A"));
        tabLayout.addTab(tabLayout.newTab().setText("B"));
        tabLayout.addTab(tabLayout.newTab().setText("C"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

        getServices();

        final ViewPager viewPager = (ViewPager)       findViewById(R.id.pager);
        final PagerAdapter adapter = new PagerAdapter
                (getSupportFragmentManager(), tabLayout.getTabCount());
        viewPager.setAdapter(adapter);
        adapter.notifyDataSetChanged();
        viewPager.addOnPageChangeListener(new        TabLayout.TabLayoutOnPageChangeListener(tabLayout));

        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
        adapter.notifyDataSetChanged();
  }





   public void getServices(){
    RequestQueue queue;
    queue = Volley.newRequestQueue(this);


    String url = "http://..."

    JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.GET,url,
            new Response.Listener<JSONArray>() {
                @Override
                public void onResponse(JSONArray response) {
                    for(int i=0;i<response.length();i++){
                        try{

                            JSONObject jsonObjectService =        response.getJSONObject(i);
                            Service service = new Service(jsonObjectService);
                            serviceList.add(service);
                        }
                        catch(JSONException e){
                            e.printStackTrace();
                        }
                    }
                }
            }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

        }
    });

    queue.add(jsonArrayRequest);
}

这是我的片段：

 @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

    v = inflater.inflate(R.layout.fragment_tab_fragment1, container, false);

    activity = (SalonInformationsActivity) getActivity();
    listView = (ListView) v.findViewById(R.id.list_service);
    serviceList = activity.getServiceList();
    adapter = new ServiceListAdapter(activity, serviceList);
    listView.setAdapter(adapter);
    adapter.notifyDataSetChanged();
    activity.runOnUiThread(new Runnable() {
        @Override
        public void run() {
            adapter.notifyDataSetChanged();
        }
    });

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> arg0, View arg1, int position, long arg3) {
            ((SalonInformationsActivity)getActivity()).callSalon(v.findFocus());
            //Toast.makeText(getApplicationContext(), salonArrayList.get(position).getTel(), Toast.LENGTH_SHORT).show();
        }
    });
    return v;
}

我是 android 的新手，我不知道为什么列表视图不显示。但是，如果我点击其他选项卡，然后 return 到 tabA，列表视图会出现，我的列表视图已更新。启动时获取列表视图填充的任何解决方案？

Answer 1

您的网络调用需要时间来 return 您添加到数组列表的数据以片段而不是 activity 的形式执行该网络调用，一旦它被添加到数组列表就执行 notifyDataSetChanged()在适配器上

在您当前的案例中，片段是在 returned newtwork 数据之前创建的，因此 arraylist 大小为 0

而且不需要这个

 activity.runOnUiThread(new Runnable() {
        @Override
        public void run() {
            adapter.notifyDataSetChanged();
        }
    });

你可以直接调用 adapter.notifyDataSetChanged();

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