android handler 没有接收到消息

Question

从log里面可以看出message是确确实实发送了

但是 上面的handler也没办法执行handlemessage的方法

package czl.baoleme.Fragment;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import czl.baoleme.HttpClient.MyHttpClient;
import czl.baoleme.Other.JSONAnalys;
import czl.baoleme.R;

/**

• Created by LeoChen on 2017/5/15. */

public class HomePageFragment extends Fragment {
private static final int JSONSTR_MESSAGE=666;
private ListView list;

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    final View view = inflater.inflate(R.layout.fragment_homepage,container,false);
    Thread restaurantThread = new Thread(new RestaurantThread());
    restaurantThread.start();

    //问题是这里 这个handlemessage方法里面并没有执行
    //但是message是确确实实发送了
    Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            switch (msg.what){
                case JSONSTR_MESSAGE:
                    List<Map<String,Object>> data = (List<Map<String,Object>>)msg.obj;
                    getListView(view,data);
                    break;
                default:
                    break;
            }
        }
    };
    return view;
}


public void getListView(View view,List<Map<String,Object>> data){
    list = (ListView) view.findViewById(R.id.resraurantListView) ;
    SimpleAdapter simpleAdapter = new SimpleAdapter(this.getActivity(), data, R.layout.item_hplistview,
            new String[]{"restaurant_list_item_logo",
                    "restaurant_list_item_name",
                    "restaurant_list_item_score",
                    "restaurant_list_item_distribution",
                    "restaurant_list_item_discount"},
            new int[]{R.id.restaurant_list_item_logo,
                    R.id.restaurant_list_item_name,
                    R.id.restaurant_list_item_score,
                    R.id.restaurant_list_item_distribution,
                    R.id.restaurant_list_item_discount}
    );
    list.setAdapter(simpleAdapter);
    setListViewHeightBasedOnChildren(list);
}

//这个方法是从解析json得到的列表里取出图片url然后请求图片并放入新的列表
public List> getData(String jsonStr){
List> list = JSONAnalys.getJSON(jsonStr);
List> dataList = new ArrayList<>();
for(Map item:list){
Map map = new HashMap<>();

        String url=item.get("reslogo");
        Log.d("url",url);
        Bitmap pic = getImage(url);

        map.put("restaurant_list_item_logo",pic);
        map.put("restaurant_list_item_name",item.get("name"));
        map.put("restaurant_list_item_score","33333");
        map.put("restaurant_list_item_distribution",item.get("jianjie"));
        map.put("restaurant_list_item_discount","55555");
        dataList.add(map);
    }

    return dataList;
}

//请求图片方法
public Bitmap getImage(String url){

    HttpGet get = new HttpGet(url);

    HttpClient client= new DefaultHttpClient();
    Bitmap pic = null;
    try{
        HttpResponse response = client.execute(get);
        HttpEntity entity = response.getEntity();
        InputStream is = entity.getContent();
        pic = BitmapFactory.decodeStream(is);
    }catch (Exception e){
        e.printStackTrace();
    }
    return pic;
}

//执行网络请求 获取json 最终生成List 并发送List对象
class RestaurantThread implements Runnable{
Handler handler = new Handler();
@Override
public void run() {
MyHttpClient httpClient = new MyHttpClient();
String jsonStr = httpClient.getRestaurant();
List> list = getData(jsonStr);
try{
Message message = new Message();
message.what=JSONSTR_MESSAGE;
message.obj = list;
if(handler.sendMessage(message)){
Log.d("发送列表","成功");
}
}catch(Exception e){
e.printStackTrace();
}

    }
}



public static void setListViewHeightBasedOnChildren(ListView listView) {
    ListAdapter listAdapter = listView.getAdapter();
    if (listAdapter == null) {
        return;
    }

    int totalHeight = listView.getPaddingTop() + listView.getPaddingBottom();
    for (int i = 0; i < listAdapter.getCount(); i++) {
        View listItem = listAdapter.getView(i, null, listView);
        /**
         * listItem.measure(0,0) will throw a NPE if listItem is a ViewGroup
         * instance
         */
        if (listItem instanceof ViewGroup) {
            listItem.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
        }
        listItem.measure(0, 0);
        totalHeight += listItem.getMeasuredHeight();
    }

    LayoutParams params = listView.getLayoutParams();
    // listView.getDividerHeight()获取子项间分隔符占用的高度
    // params.height最后得到整个ListView完整显示需要的高度
    params.height = totalHeight + (listView.getDividerHeight() * (listAdapter.getCount() - 1));
    listView.setLayoutParams(params);
}

}

Answer 1

RestaurantThread里面的那个handler和onCreateView里面的handler是两个handler。
建议把handler自定义成一个class，

class MyHandler extends Handler {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
switch (msg.what){
case JSONSTR_MESSAGE:
List> data = (List>)msg.obj;
getListView(view,data);
break;
default:
break;
}
}
}

然后把RestaurantThread里面的handler类型换成MyHandler