无法在LinearLayout中动态添加子视图

Question

我正在填充线性布局，其中包含从API获取的一些数据。每次执行代码时，我都会在我的模型类中保存数据，但之后不会将视图添加到线性布局中。

我在tabLayout中使用的另一个选项卡使用相同的代码，它正在工作，但为此它不起作用。我也在这里附上我的调试器截图。下面是片段的代码，它正在发生。

Sent.java

    package fragments;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.design.widget.Snackbar;
import android.support.v4.app.Fragment;
import android.support.v4.widget.SwipeRefreshLayout;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.android.volley.AuthFailureError;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import com.mranuran.pehchankaun.R;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.util.HashMap;
import java.util.Map;

import fr.castorflex.android.smoothprogressbar.SmoothProgressBar;
import models.SentMessage;
import utils.SharedPrefManager;

public class Sent extends android.app.Fragment implements SwipeRefreshLayout.OnRefreshListener {
    LinearLayout msgHolder,sentLinearLayout;
    LayoutInflater inflater;
    SmoothProgressBar progressBar;
    SwipeRefreshLayout swipeRefreshLayout;
    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view=inflater.inflate(R.layout.sent,container,false);
        sentLinearLayout=(LinearLayout)view.findViewById(R.id.sentLinearLayout);
        msgHolder=(LinearLayout)view.findViewById(R.id.sentMsgHolder);
        progressBar=(SmoothProgressBar)view.findViewById(R.id.progressBar);
        swipeRefreshLayout=(SwipeRefreshLayout)view.findViewById(R.id.swipe_refresh_layout);
        return view;
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        swipeRefreshLayout.setOnRefreshListener(this);
        swipeRefreshLayout.post(new Runnable() {
            @Override
            public void run() {
                swipeRefreshLayout.setRefreshing(true);
                populateSent();
            }
        });
    }

    private void populateSent() {
        msgHolder.removeAllViews();
        progressBar.setVisibility(View.VISIBLE);
        progressBar.progressiveStart();
        inflater=(LayoutInflater)getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        RequestQueue rq= Volley.newRequestQueue(getActivity());
        StringRequest sr=new StringRequest(Request.Method.POST, "http://mranuran.com/pehchan_kaun/getSent.php", new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                try {
                    JSONObject json=new JSONObject(response);
                    JSONArray userArray=json.optJSONArray("messages");
                    if(userArray.length()>0){
                        SentMessage msg;
                        View v;
                        for(int i=0;i<userArray.length();i++){
                            JSONObject singleMsgObj=userArray.getJSONObject(i);
                            msg=new SentMessage(singleMsgObj.getString("id"),singleMsgObj.getString("message"),singleMsgObj.getString("creation_date"),singleMsgObj.getString("receiver_name"));
                            v=inflater.inflate(R.layout.sent_msg_single_row,null,false);
                            TextView creationDate=(TextView) v.findViewById(R.id.creationDate);
                            TextView messageTV=(TextView)v.findViewById(R.id.msg);
                            TextView receivername=(TextView)v.findViewById(R.id.receiverName);
                            creationDate.setText(msg.getCreation_date());
                            messageTV.setText(msg.getMessage());
                            receivername.setText(msg.getReceiver_name());
                            msgHolder.addView(v);


                        }
                    }else{
                        Snackbar.make(sentLinearLayout,"You have not sent any messages to anyone.",Snackbar.LENGTH_SHORT).show();
                        progressBar.progressiveStop();
                        swipeRefreshLayout.setRefreshing(false);
                        return;
                    }

                    progressBar.progressiveStop();
                    swipeRefreshLayout.setRefreshing(false);

                } catch (JSONException e) {
                    e.printStackTrace();
                    progressBar.progressiveStop();
                    swipeRefreshLayout.setRefreshing(false);
                }
            }

        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {
                Snackbar.make(sentLinearLayout,"Something went wrong.Try again",Snackbar.LENGTH_SHORT).show();
                progressBar.progressiveStop();
                swipeRefreshLayout.setRefreshing(false);
                return;
            }
        }){
            @Override
            protected Map<String, String> getParams() throws AuthFailureError {
                Map<String,String> map=new HashMap<>();
                map.put("user_id",new SharedPrefManager(getActivity()).getUserID());
                return map;
            }
        };
        rq.add(sr);
    }

    @Override
    public void onRefresh() {
        populateSent();
    }
}

Answer 1

添加requestLayout进行更新

 msgHolder.addView(v);
 msgHolder.requestLayout();