我正在从JSON中提取包含其名称和ID的菜单。我写过Fragment5，用于调用JSON的URL。在那个网址中我想调用菜单的id。 这是我的代码。如果我正在评论两行
，代码运行正常String scat = menu_nms.get(0);
int cat = Integer.parseInt(scat);
的 MainActivity.java
package com.latrodealz.wowwdealz;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.app.ProgressDialog;
import android.app.SearchManager;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.SearchView;
import android.widget.Toast;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;
import com.latrodealz.wowwdealz.adapter.SlidingMenuAdapter;
import com.latrodealz.wowwdealz.fragment.Fragment1;
import com.latrodealz.wowwdealz.fragment.Fragment2;
import com.latrodealz.wowwdealz.fragment.Fragment3;
import com.latrodealz.wowwdealz.fragment.Fragment4;
import com.latrodealz.wowwdealz.fragment.Fragment5;
import com.latrodealz.wowwdealz.model.ItemSlideMenu;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
/**
* Created by NgocTri on 10/18/2015.
*/
public class MainActivity extends AppCompatActivity {
private List<ItemSlideMenu> listSliding;
private SlidingMenuAdapter adapter;
private ListView listViewSliding;
private DrawerLayout drawerLayout;
private ActionBarDrawerToggle actionBarDrawerToggle;
//Web api url
public static final String MENU_URL = "http://69.89.31.191/~webtech6/android_wow/menu_dtls.php";
//Tag values to read from json
public static final String MENU_ID = "menu_id";
public static final String MENU_NM = "menu_nm";
//ArrayList for Storing menu ids and names
private ArrayList<String> menu_ids;
private ArrayList<String> menu_nms;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
menu_ids = new ArrayList<>();
menu_nms = new ArrayList<>();
//Calling the getMenuData method
getMenuData();
//Init component
listViewSliding = (ListView) findViewById(R.id.lv_sliding_menu);
drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
listSliding = new ArrayList<>();
//Add item for sliding list
listSliding.add(new ItemSlideMenu(R.drawable.ic_action_settings, "Home"));
adapter = new SlidingMenuAdapter(this, listSliding);
listViewSliding.setAdapter(adapter);
//Display icon to open/ close sliding list
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
//Set title
setTitle(listSliding.get(0).getTitle());
//item selected
listViewSliding.setItemChecked(0, true);
//Close menu
drawerLayout.closeDrawer(listViewSliding);
//Display fragment 1 when start
replaceFragment(0);
//Handle on item click
listViewSliding.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//Set title
setTitle(listSliding.get(position).getTitle());
//item selected
listViewSliding.setItemChecked(position, true);
//Replace fragment
replaceFragment(position);
//Close menu
drawerLayout.closeDrawer(listViewSliding);
}
});
actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, R.string.drawer_opened, R.string.drawer_closed) {
@Override
public void onDrawerOpened(View drawerView) {
super.onDrawerOpened(drawerView);
invalidateOptionsMenu();
}
@Override
public void onDrawerClosed(View drawerView) {
super.onDrawerClosed(drawerView);
invalidateOptionsMenu();
}
};
drawerLayout.addDrawerListener(actionBarDrawerToggle);
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
private void getMenuData() {
//Showing a progress dialog while our app fetches the data from url
final ProgressDialog loading = ProgressDialog.show(this, "Please wait...", "Fetching data...", false, false);
//Creating a json array request to get the json from our api
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(MENU_URL,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
//Dismissing the progressdialog on response
loading.dismiss();
//Displaying our grid
showMenu(response);
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
}
);
//Creating a request queue
RequestQueue requestQueue = Volley.newRequestQueue(this);
//Adding our request to the queue
requestQueue.add(jsonArrayRequest);
}
private void showMenu(JSONArray jsonArray) {
//Looping through all the elements of json array
for (int i = 0; i < jsonArray.length(); i++) {
//Creating a json object of the current index
JSONObject obj = null;
try {
//getting json object from current index
obj = jsonArray.getJSONObject(i);
//getting menuid and menuname from json object
menu_ids.add(obj.getString(MENU_ID));
menu_nms.add(obj.getString(MENU_NM));
} catch (JSONException e) {
e.printStackTrace();
}
}
//Add item for sliding list
for (int i = 0; i < menu_ids.size(); i++) {
listSliding.add(new ItemSlideMenu(R.drawable.ic_action_about, menu_nms.get(i)));
}
adapter = new SlidingMenuAdapter(this, listSliding);
listViewSliding.setAdapter(adapter);
//Add item for sliding list
listSliding.add(new ItemSlideMenu(R.drawable.ic_action_settings, "MY CART"));
listSliding.add(new ItemSlideMenu(R.drawable.ic_action_settings, "MY ACCOUNT"));
listSliding.add(new ItemSlideMenu(R.drawable.ic_action_settings, "MY ORDERS"));
adapter = new SlidingMenuAdapter(this, listSliding);
listViewSliding.setAdapter(adapter);
//Display Array List
// Toast.makeText(getBaseContext(), menu_ids + "", Toast.LENGTH_LONG).show();
// Toast.makeText(getBaseContext(), menu_nms + "", Toast.LENGTH_LONG).show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
if (actionBarDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
switch (item.getItemId()) {
case R.id.action_search:
// User chose the "Settings" item, show the app settings UI...
Intent intent = new Intent(MainActivity.this, SearchableActivity.class);
startActivityForResult(intent, 0);
//Toast.makeText(this, "You have selected Search Search Menu", Toast.LENGTH_SHORT).show();
return true;
case R.id.action_kart:
// User chose the "Favorite" action, mark the current item
// as a favorite...
Toast.makeText(this, "You have selected Search KART Menu", Toast.LENGTH_SHORT).show();
return true;
case R.id.action_notifications:
// User chose the "Favorite" action, mark the current item
// as a favorite...
Toast.makeText(this, "You have selected Search Notifications Menu", Toast.LENGTH_SHORT).show();
return true;
default:
// If we got here, the user's action was not recognized.
// Invoke the superclass to handle it.
return super.onOptionsItemSelected(item);
}
//return super.onOptionsItemSelected(item);
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
actionBarDrawerToggle.syncState();
}
/**
* Called when the user clicks the Search Menu
* public void callSearchActivity(View view) {
* Intent intent = new Intent(this, SearchActivity.class);
* startActivity(intent);
* }
*/
//Create method replace fragment
private void replaceFragment(int pos) {
Fragment fragment = null;
int menu_size = menu_ids.size();
String scat = menu_nms.get(0);
int cat = Integer.parseInt(scat);
if (pos == 0) {
fragment = new Fragment1();
} else if (pos > 0 && pos <= menu_size) {
SharedPreferences sharePref = getSharedPreferences("menu_dtls", Context.MODE_PRIVATE);
sharePref.edit().remove("menu_id").commit();
SharedPreferences.Editor editor = sharePref.edit();
editor.putInt("menu_id", pos);
editor.apply();
fragment = new Fragment5();
} else if (pos == (menu_size + 1)) {
fragment = new Fragment2();
} else if (pos == (menu_size + 2)) {
fragment = new Fragment3();
} else if (pos == (menu_size + 3)) {
fragment = new Fragment4();
} else {
fragment = new Fragment1();
}
if (null != fragment) {
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.main_content, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
}
@Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app deep link URI is correct.
Uri.parse("android-app://com.latrodealz.wowwdealz/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}
@Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app deep link URI is correct.
Uri.parse("android-app://com.latrodealz.wowwdealz/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
}
Fragment5.java
package com.latrodealz.wowwdealz.fragment;
import android.app.Fragment;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.ListView;
import com.latrodealz.wowwdealz.R;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
public class Fragment5 extends Fragment {
JSONObject jsonobject;
JSONArray jsonarray;
ListView listview;
ListViewAdapter adapter;
ProgressDialog mProgressDialog;
ArrayList<HashMap<String, String>> arraylist;
static String RANK = "rank";
static String COUNTRY = "country";
static String POPULATION = "population";
static String FLAG = "flag";
public Fragment5() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment5, container, false);
//TextView menu_id = (TextView)rootView.findViewById(R.id.textid);
//SharedPreferences sharePref = this.getActivity().getSharedPreferences("menu_dtls", Context.MODE_PRIVATE);
//int menuId = sharePref.getInt("menu_id", 0);
// menu_id.setText(String.valueOf(menuId));
ImageView purple=(ImageView)rootView.findViewById(R.id.gridicon);
purple.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
getFragmentManager()
.beginTransaction()
.replace(R.id.main_content, new Fragment4())
.commit();
}
});
new DownloadJSON().execute();
return rootView;
}
// DownloadJSON AsyncTask
private class DownloadJSON extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Create a progressdialog
mProgressDialog = new ProgressDialog(getActivity());
// Set progressdialog title
mProgressDialog.setTitle("Fetching data...");
// Set progressdialog message
mProgressDialog.setMessage("Loading...");
mProgressDialog.setIndeterminate(false);
// Show progressdialog
mProgressDialog.show();
}
@Override
protected Void doInBackground(Void... params) {
// Create an array
SharedPreferences sharePref = getActivity().getSharedPreferences("menu_dtls", Context.MODE_PRIVATE);
int menuId = sharePref.getInt("menu_id", 0);
arraylist = new ArrayList<HashMap<String, String>>();
// Retrieve JSON Objects from the given URL address
jsonobject = JSONfunctions
.getJSONfromURL("http://69.89.31.191/~webtech6/android_wow/load.php?catId="+menuId);
try {
// Locate the array name in JSON
jsonarray = jsonobject.getJSONArray("worldpopulation");
for (int i = 0; i < jsonarray.length(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
jsonobject = jsonarray.getJSONObject(i);
// Retrive JSON Objects
map.put("rank", jsonobject.getString("rank"));
map.put("country", jsonobject.getString("country"));
map.put("population", jsonobject.getString("population"));
map.put("flag", jsonobject.getString("flag"));
// Set the JSON Objects into the array
//Toast.makeText(getActivity().getBaseContext(), map + "", Toast.LENGTH_LONG).show();
arraylist.add(map);
}
} catch (JSONException e) {
Log.e("Error", e.getMessage());
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void args) {
// Locate the listview in listview_main.xml
listview = (ListView) getActivity().findViewById(R.id.listview);
// Pass the results into ListViewAdapter.java
adapter = new ListViewAdapter(getActivity(), arraylist);
// Set the adapter to the ListView
listview.setAdapter(adapter);
// Close the progressdialog
mProgressDialog.dismiss();
}
}
}
答案 0 :(得分：0)
也许你在JSON解析期间遇到异常。你可以包围Integer.parseInt（scat）;如果Json没有这样的字段，则使用try-catch捕获ParsingException。 但更简洁的解决方案是将GSON与Retrofit一起使用，这样您就可以自动解析对jsonschema2pojo.com创建的java对象的响应