我正在尝试从列表视图中获取值。列表视图由hashmap类型的数组列表设置。所以，如果我想在字符串中获取值，我会收到错误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的
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)
我有什么方法可以检索值
答案 0 :(得分：8)
java.lang.ClassCastException：java.util.HashMap无法强制转换为 java.lang.String中
这一行是问题
String itemValue = (String) l.getItemAtPosition(position);
更改为
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
}