HashMap中不能被转换为java.lang.String转换为、HashMap、java、String

2023-09-06 14:42:06 作者:图、忘却沵╮

我想从列表视图中获取值。列表视图是由HashMap的类型的数组列表中设置。所以,如果我想获得一个字符串中,我得到了错误的值的HashMap不能转换为java.lang.String

details1.java

 包com.example.festipedia_logo;进口的java.util.ArrayList;进口的java.util.HashMap;进口的java.util.List;进口org.apache.http.NameValuePair;进口org.apache.http.message.BasicNameValuePair;进口org.json.JSONArray;进口org.json.JSONException;进口org.json.JSONObject;进口com.actionbarsherlock.app.SherlockFragment;进口com.actionbarsherlock.app.SherlockListFragment;//进口com.example.festipedia_logo.Searchpage.LoadAllProducts;//进口com.example.connection.disp;进口android.app.Activity;进口android.app.Fragment;进口android.app.ListActivity;进口android.app.ProgressDialog;进口android.content.Intent;进口android.os.AsyncTask;进口android.os.Bundle;进口android.support.v4.app.FragmentTransaction;进口android.util.Log;进口android.view.LayoutInflater;进口android.view.View;进口android.view.ViewGroup;进口android.widget.AdapterView;进口android.widget.AdapterView.OnItemClickListener;进口android.widget.ArrayAdapter;进口android.widget.Button;进口android.widget.EditText;进口android.widget.ListAdapter;进口android.widget.ListView;进口android.widget.SimpleAdapter;进口android.widget.Spinner;进口android.widget.TextView;进口android.widget.Toast;公共类扩展详情1 {SherlockFragment    ArrayAdapter<串GT;适配器;    的String []城市;    //进度对话框    私人ProgressDialog pDialog;    //创建JSON解析器对象    JSONParser jParser =新JSONParser();的EditText B:    ArrayList的<&HashMap的LT;字符串,字符串>>产品列表;    // URL获得所有产品清单    私人静态字符串url_all_products =htt​​p://192.168.43.77/festipedia/get_all_products.php;按钮;    // JSON节点名称    私有静态最后弦乐TAG_SUCCESS =成功;    私有静态最后弦乐TAG_PRODUCTS =产品;    私有静态最后弦乐TAG_NAME =eventname已;    //产品JSONArray    JSONArray产品= NULL;ListView控件升;微调微调;    @覆盖    公共查看onCreateView(LayoutInflater充气器,容器的ViewGroup,            捆绑savedInstanceState){        super.onCreate(savedInstanceState);        //setContentView(R.layout.second);        查看rootView = inflater.inflate(R.layout.home2,集装箱,FALSE);    //的setContentView(R.layout.all_products);        L =(ListView控件)rootView.findViewById(R.id.list);        //为哈希映射的ListView        产品列表=新的ArrayList<&HashMap的LT;字符串,字符串>>();        新LoadAllProducts()执行();        l.setOnItemClickListener(新OnItemClickListener(){            @覆盖            公共无效onItemClick(适配器视图<>母公司,观景,                    INT位置,长的id){                // 做一点事                //字符串itemValue =(字符串)l.getItemAtPosition(位置);                 //意向意图=新意图(getActivity()。getBaseContext()                 // MainActivity.class);                   // intent.putExtra(信息,itemValue);                 // getActivity()startActivity(意向)。               //捆绑ARGS =新包();             // args.putString(doctor_id,itemValue);           //点​​评详情newFragment =新点评详情();          // newFragment.setArguments(参数);                //字符串str =((的TextView)childView).getText()的toString()。                       // MainActivity OB =新MainActivity();                      // ListView中单击项目指标                      INT itemPosition =位置;                      // ListView中单击项目价值                      字符串itemValue =(字符串)l.getItemAtPosition(位置);                最后FragmentTransaction英尺= getFragmentManager()调用BeginTransaction()。                    ft.replace(R.id.content_frame,新SlidetabTesting(itemValue),巨星内容);                    ft.commit();            }        });        返回rootView;                    }    / **     *背景异步任务以通过HTTP请求负载的所有产品     * * /    类LoadAllProducts扩展的AsyncTask<字符串,字符串,字符串> {        @覆盖        在preExecute保护无效(){            super.on preExecute();            pDialog =新ProgressDialog(getActivity());            pDialog.setMessage(加载产品请稍候......);            pDialog.setIndeterminate(假);            pDialog.setCancelable(假);            pDialog.show();        }        / **         *让所有的产品网址         * * /        保护字符串doInBackground(字符串参数... args){            //大厦参数            清单<&的NameValuePair GT; PARAMS =新的ArrayList<&的NameValuePair GT;();            // URL从获取JSON字符串            JSONObject的JSON = jParser.makeHtt prequest(url_all_products,GET,则params);        // Log.d(所有产品,json.toString());            尝试{                //检查成功TAG                INT成功= json.getInt(TAG_SUCCESS);                如果(成功== 1){                    发现//产品                    //获取产品阵列                    产品= json.getJSONArray(TAG_PRODUCTS);                    //产品通过所有循环                    的for(int i = 0; I< products.length();我++){                        JSONObject的C = products.getJSONObject(I)                        //存储在变量中的每个JSON项目                        字符串名称= c.getString(TAG_NAME);                        //l.setFilterText(id);                        //创建新的HashMap                        HashMap的<字符串,字符串>地图=新的HashMap<字符串,字符串>();                        //将每个子节点的HashMap键=>值                        map.put(TAG_NAME,名);                        //添加HashList到ArrayList的                        productsList.add(地图);                    }                }其他{                    //没有发现产品                    //启动添加新产品活动                }            }赶上(JSONException E){                e.printStackTrace();            }            返回null;        }        / **         *在完成后台任务之后辞退进度对话框         * ** /        保护无效onPostExecute(字符串FILE_URL){            //让所有的产品后,关闭该对话框            pDialog.dismiss();            //从后台线程更新界面            getActivity()。runOnUiThread(新的Runnable(){                公共无效的run(){                    / **                     *更新解析JSON数据到ListView控件                     * * /                    ListAdapter适配器=新SimpleAdapter(                            getActivity(),产品列表,                            R.layout.list_item,新的String [] {                                    TAG_NAME},                            新的INT [] {R.id.name});                    //更新列表视图                    l.setAdapter(适配器);                }            });        }    }} 

logcat的

  20 03-30:03:43.341:E / ViewRootImpl(8395):sendUserActionEvent()== MView的空03-30 20:03:47.111:E / ViewRootImpl(8395):sendUserActionEvent()== MView的空03-30 20:03:49.416:E / AndroidRuntime(8395):致命异常:主要03-30 20:03:49.416:E / AndroidRuntime(8395):工艺:com.example.festipedia_logo,PID:839503-30 20:03:49.416:E / AndroidRuntime(8395):java.lang.ClassCastException:java.util.HashMap中不能转换为java.lang.String03-30 20:03:49.416:E / AndroidRuntime(8395):在com.example.festipedia_logo.details1 $ 1.onItemClick(details1.java:103)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.widget.AdapterView.performItemClick(AdapterView.java:308)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.widget.AbsListView.performItemClick(AbsListView.java:1483)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.widget.AbsListView $ PerformClick.run(AbsListView.java:3485)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.widget.AbsListView $ 3.run(AbsListView.java:4843)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.os.Handler.handleCallback(Handler.java:733)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.os.Handler.dispatchMessage(Handler.java:95)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.os.Looper.loop(Looper.java:157)03-30 20:03:49.416:E / AndroidRuntime(8395):在android.app.ActivityThread.main(ActivityThread.java:5356)03-30 20:03:49.416:E / AndroidRuntime(8395):在java.lang.reflect.Method.invokeNative(本机方法)03-30 20:03:49.416:E / AndroidRuntime(8395):在java.lang.reflect.Method.invoke(Method.java:515)03-30 20:03:49.416:E / AndroidRuntime(8395):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:1265)03-30 20:03:49.416:E / AndroidRuntime(8395):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)03-30 20:03:49.416:E / AndroidRuntime(8395):在dalvik.system.NativeStart.main(本机方法) 

有什么办法由我就能检索值

解决方案   

java.lang.ClassCastException:java.util.HashMap中不能被转换为  java.lang.String中

Java学习教程 Java基础 反射

这行是问题

 字符串itemValue =(字符串)l.getItemAtPosition(位置); 

更改为

  l.setOnItemClickListener(新OnItemClickListener(){@覆盖公共无效onItemClick(适配器视图<>母公司,观景,INT位置,长的id){HashMap的<字符串,字符串>地图=(HashMap的<字符串,字符串>)l.getItemAtPosition(位置);字符串值= map.get(TAG_SUCCESS);斯汀产品= map.get(TAG_PRODUCTS);字符串名称= map.get(TAG_NAME);... //在code休息} 

I am trying to get values from a list view. The list view is set by an array list of hashmap type. So , if I am trying to get the values in a string I get the error HashMap cannot be cast to java.lang.string

details1.java

package com.example.festipedia_logo;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import com.actionbarsherlock.app.SherlockFragment;
import com.actionbarsherlock.app.SherlockListFragment;
//import com.example.festipedia_logo.Searchpage.LoadAllProducts;


//import com.example.connection.disp;

import android.app.Activity;
import android.app.Fragment;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentTransaction;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

public class details1 extends SherlockFragment {
    ArrayAdapter<String> adapter;
    String[] city;
    // Progress Dialog
    private ProgressDialog pDialog;

    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();
EditText b;
    ArrayList<HashMap<String, String>> productsList;

    // url to get all products list
    private static String url_all_products = "http://192.168.43.77/festipedia/get_all_products.php";
Button a;

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCTS = "products";
    private static final String TAG_NAME = "eventname";

    // products JSONArray
    JSONArray products = null;
ListView l;
Spinner spinner;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.second);
        View rootView = inflater.inflate(R.layout.home2, container, false);

    //  setContentView(R.layout.all_products);
        l = (ListView) rootView.findViewById(R.id.list);

        // Hashmap for ListView
        productsList = new ArrayList<HashMap<String, String>>();
        new LoadAllProducts().execute();
        l.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // Do something   
                //  String  itemValue    = (String) l.getItemAtPosition(position);
                 // Intent intent = new Intent(getActivity().getBaseContext(),
                 //           MainActivity.class);
                   // intent.putExtra("message", itemValue);
                 //   getActivity().startActivity(intent);

               //     Bundle args = new Bundle();
             //       args.putString("doctor_id",itemValue);    
           //         details1 newFragment = new details1 ();
          //          newFragment.setArguments(args);
                //String str = ((TextView)childView).getText().toString();

                       //MainActivity ob=new MainActivity();
                      // ListView Clicked item index
                      int itemPosition     = position;

                      // ListView Clicked item value
                      String  itemValue    = (String) l.getItemAtPosition(position);  
                final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
                    ft.replace(R.id.content_frame,new SlidetabTesting(itemValue) , "Fest Content"); 
                    ft.commit();
            }

        });

        return rootView;
                    }

    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class LoadAllProducts extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

            pDialog = new ProgressDialog(getActivity());
            pDialog.setMessage("Loading products. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * getting All products from url
         * */
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();


            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);

        //  Log.d("All Products: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // products found
                    // Getting Array of Products
                    products = json.getJSONArray(TAG_PRODUCTS);

                    // looping through All Products
                    for (int i = 0; i < products.length(); i++) {
                        JSONObject c = products.getJSONObject(i);

                        // Storing each json item in variable

                        String name = c.getString(TAG_NAME);

                        //l.setFilterText(id);
                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        map.put(TAG_NAME, name);

                        // adding HashList to ArrayList
                        productsList.add(map);
                    }
                } else {
                    // no products found
                    // Launch Add New product Activity
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all products
            pDialog.dismiss();
            // updating UI from Background Thread
            getActivity().runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            getActivity(), productsList,
                            R.layout.list_item, new String[] {
                                    TAG_NAME},
                            new int[] {  R.id.name });
                    // updating listview
                    l.setAdapter(adapter);
                }
            });


        }

    }
}

LOGCAT

03-30 20:03:43.341: E/ViewRootImpl(8395): sendUserActionEvent() mView == null
03-30 20:03:47.111: E/ViewRootImpl(8395): sendUserActionEvent() mView == null
03-30 20:03:49.416: E/AndroidRuntime(8395): FATAL EXCEPTION: main
03-30 20:03:49.416: E/AndroidRuntime(8395): Process: com.example.festipedia_logo, PID: 8395
03-30 20:03:49.416: E/AndroidRuntime(8395): java.lang.ClassCastException: java.util.HashMap cannot be cast to java.lang.String
03-30 20:03:49.416: E/AndroidRuntime(8395):     at com.example.festipedia_logo.details1$1.onItemClick(details1.java:103)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.widget.AdapterView.performItemClick(AdapterView.java:308)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.widget.AbsListView.performItemClick(AbsListView.java:1483)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.widget.AbsListView$PerformClick.run(AbsListView.java:3485)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.widget.AbsListView$3.run(AbsListView.java:4843)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.os.Handler.handleCallback(Handler.java:733)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.os.Handler.dispatchMessage(Handler.java:95)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.os.Looper.loop(Looper.java:157)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at android.app.ActivityThread.main(ActivityThread.java:5356)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at java.lang.reflect.Method.invokeNative(Native Method)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at java.lang.reflect.Method.invoke(Method.java:515)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
03-30 20:03:49.416: E/AndroidRuntime(8395):     at dalvik.system.NativeStart.main(Native Method)

Is there any way by which I will be able to retrieve values

解决方案

java.lang.ClassCastException: java.util.HashMap cannot be cast to java.lang.String

This line is the problem

String  itemValue = (String) l.getItemAtPosition(position); 

Change to

l.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,int position, long id) {

HashMap<String,String> map =(HashMap<String,String>)l.getItemAtPosition(position);
String value = map.get(TAG_SUCCESS);
Sting products = map.get(TAG_PRODUCTS);
String name= map.get(TAG_NAME);
... // rest of the code
}

 
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