通过category_name从PHP获取到Android

Question

我一直在尝试通过类别名称获取表格中的所有数据，如果我通过tbl_menu中的category_id获取它，但我决定将其更改为通过category_name（在tbl_menu中命名的类别）进行提取。但它没有获取，而logcat没有多大帮助。

这是我的类别（tbl_category）的表格，它并不是真正相关的，因为它只是我添加产品时的表格，而这是获取类别的地方。

这是我的产品表（tbl_menu），它应该通过类别列获取产品。

现在，我认为我的api是正确的，但我可能错了，因为它应该在该类别中获取。

GET-菜单数据逐类别-id.php

<?php
    include_once('../includes/connect_database.php'); 
    include_once('../includes/variables.php');

    if(isset($_GET['accesskey']) && isset($_GET['category'])) {
        $access_key_received = $_GET['accesskey'];
        $category = $_GET['category'];

        if(isset($_GET['keyword'])){
            $keyword = $_GET['keyword'];
        }else{
            $keyword = "";
        }

        if($access_key_received == $access_key){
            if($keyword == ""){
                // find menu by category id in menu table
                $sql_query = "SELECT Menu_ID, Menu_name, Price, Menu_image 
                    FROM tbl_menu 
                    WHERE Category = ".$category." 
                    ORDER BY Menu_ID DESC";
            }else{
                // find menu by category id and keyword in menu table
                $sql_query = "SELECT Menu_ID, Menu_name, Price, Menu_image 
                    FROM tbl_menu 
                    WHERE Menu_name LIKE '%".$keyword."%' AND Category = ".$category." 
                    ORDER BY Menu_ID DESC";
            }

            $result = $connect->query($sql_query) or die("Error : ".mysql_error());

            $menus = array();
            while($menu = $result->fetch_assoc()) {
                $menus[] = array('Menu'=>$menu);
            }

            // create json output
            $output = json_encode(array('data' => $menus));
        }else{
            die('accesskey is incorrect.');
        }
    } else {
        die('accesskey and category are required.');
    }

    //Output the output.
    echo $output;

    include_once('../includes/close_database.php'); 
?>

单击某个类别时，它会为下一个活动（ActivityMenuList.java）提供putextra。 CTRL + F兴趣点＃3

ActivityCategoryList.java

package com.emman.motg;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.util.ArrayList;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ActionBar;
import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.drawable.ColorDrawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.ProgressBar;
import android.widget.TextView;

public class ActivityCategoryList extends Activity {

    GridView listCategory;
    ProgressBar prgLoading;
    TextView txtAlert;

    // declare adapter object to create custom category list
    AdapterCategoryList cla;

    // create arraylist variables to store data from server
    static ArrayList<Long> Category_ID = new ArrayList<Long>();
    static ArrayList<String> Category_name = new ArrayList<String>();
    static ArrayList<String> Category_image = new ArrayList<String>();

    String CategoryAPI;
    int IOConnect = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.category_list);

        ActionBar bar = getActionBar();
        bar.setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.header)));
        bar.setDisplayHomeAsUpEnabled(true);
        bar.setHomeButtonEnabled(true);
        bar.setTitle("Category");

        prgLoading = (ProgressBar) findViewById(R.id.prgLoading);
        listCategory = (GridView) findViewById(R.id.listCategory);
        txtAlert = (TextView) findViewById(R.id.txtAlert);

        cla = new AdapterCategoryList(ActivityCategoryList.this);

        // category API url
        CategoryAPI = Constant.CategoryAPI+"?accesskey="+Constant.AccessKey;

        // call asynctask class to request data from server
        new getDataTask().execute();

        // event listener to handle list when clicked
        listCategory.setOnItemClickListener(new OnItemClickListener() {

            public void onItemClick(AdapterView<?> arg0, View arg1, int position,
                    long arg3) {
                // TODO Auto-generated method stub
                // go to menu page
                Intent iMenuList = new Intent(ActivityCategoryList.this, ActivityMenuList.class);
                iMenuList.putExtra("category_id", Category_ID.get(position));
                iMenuList.putExtra("category", Category_name.get(position));//point of interest #3
                startActivity(iMenuList);
                overridePendingTransition(R.anim.open_next, R.anim.close_next);
            }
        });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_category, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        switch (item.getItemId()) {
        case R.id.cart:
            // refresh action
            Intent iMyOrder = new Intent(ActivityCategoryList.this, ActivityCart.class);
            startActivity(iMyOrder);
            overridePendingTransition (R.anim.open_next, R.anim.close_next);
            return true;

        case R.id.refresh:
            IOConnect = 0;
            listCategory.invalidateViews();
            clearData();
            new getDataTask().execute();
            return true;

        case android.R.id.home:
            // app icon in action bar clicked; go home
            this.finish();
            overridePendingTransition(R.anim.open_main, R.anim.close_next);
            return true;

        default:
            return super.onOptionsItemSelected(item);
        }
    }

    // clear arraylist variables before used
    void clearData(){
        Category_ID.clear();
        Category_name.clear();
        Category_image.clear();
    }

    // asynctask class to handle parsing json in background
    public class getDataTask extends AsyncTask<Void, Void, Void>{

        // show progressbar first
        getDataTask(){
            if(!prgLoading.isShown()){
                prgLoading.setVisibility(0);
                txtAlert.setVisibility(8);
            }
        }

        @Override
        protected Void doInBackground(Void... arg0) {
            // TODO Auto-generated method stub
            // parse json data from server in background
            parseJSONData();
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            // TODO Auto-generated method stub
            // when finish parsing, hide progressbar
            prgLoading.setVisibility(8);

            // if internet connection and data available show data on list
            // otherwise, show alert text
            if((Category_ID.size() > 0) && (IOConnect == 0)){
                listCategory.setVisibility(0);
                listCategory.setAdapter(cla);
            }else{
                txtAlert.setVisibility(0);
            }
        }
    }

    // method to parse json data from server
    public void parseJSONData(){

        clearData();

        try {
            // request data from Category API
            HttpClient client = new DefaultHttpClient();
            HttpConnectionParams.setConnectionTimeout(client.getParams(), 15000);
            HttpConnectionParams.setSoTimeout(client.getParams(), 15000);
            HttpUriRequest request = new HttpGet(CategoryAPI);
            HttpResponse response = client.execute(request);
            InputStream atomInputStream = response.getEntity().getContent();
            BufferedReader in = new BufferedReader(new InputStreamReader(atomInputStream));

            String line;
            String str = "";
            while ((line = in.readLine()) != null){
                str += line;
            }

            // parse json data and store into arraylist variables
            JSONObject json = new JSONObject(str);
            JSONArray data = json.getJSONArray("data");

            for (int i = 0; i < data.length(); i++) {
                JSONObject object = data.getJSONObject(i); 

                JSONObject category = object.getJSONObject("Category");

                Category_ID.add(Long.parseLong(category.getString("Category_ID")));
                Category_name.add(category.getString("Category_name"));
//              Category_image.add(category.getString("Category_image"));
                Log.d("Category name", Category_name.get(i));

            }


        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            IOConnect = 1;
            e.printStackTrace();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   
    }

    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        //cla.imageLoader.clearCache();
        listCategory.setAdapter(null);
        super.onDestroy();
    }


    @Override
    public void onConfigurationChanged(final Configuration newConfig)
    {
        // Ignore orientation change to keep activity from restarting
        super.onConfigurationChanged(newConfig);
    }

    @Override
    public void onBackPressed() {
        // TODO Auto-generated method stub
        super.onBackPressed();
        finish();
        overridePendingTransition(R.anim.open_main, R.anim.close_next);
    }

}

在此活动中，兴趣点＃1获取额外信息并将其置于变量

中

ActivityMenuList.java

package com.emman.motg;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URLEncoder;
import java.text.DecimalFormat;
import java.util.ArrayList;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ActionBar;
import android.app.Activity;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.drawable.ColorDrawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.TextView;

public class ActivityMenuList extends Activity {

    ListView listMenu;
    ProgressBar prgLoading;
    //TextView txtTitle;
    EditText edtKeyword;
    ImageButton btnSearch;
    TextView txtAlert;

    // declare static variable to store tax and currency symbol
    static double Tax;
    static String Currency;

    // declare adapter object to create custom menu list
    AdapterMenuList mla;

    // create arraylist variables to store data from server
    static ArrayList<Long> Menu_ID = new ArrayList<Long>();
    static ArrayList<String> Menu_name = new ArrayList<String>();
    static ArrayList<Double> Menu_price = new ArrayList<Double>();
    static ArrayList<String> Menu_image = new ArrayList<String>();

    String MenuAPI;
    String TaxCurrencyAPI;
    int IOConnect = 0;
    long Category_ID;
    String Category_name;
    String Keyword;

    // create price format
    DecimalFormat formatData = new DecimalFormat("#.##");


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.menu_list);

        ActionBar bar = getActionBar();
        bar.setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.header)));
        bar.setTitle("Product");
        bar.setDisplayHomeAsUpEnabled(true);
        bar.setHomeButtonEnabled(true);
        prgLoading = (ProgressBar) findViewById(R.id.prgLoading);
        listMenu = (ListView) findViewById(R.id.listMenu);
        edtKeyword = (EditText) findViewById(R.id.edtKeyword);
        btnSearch = (ImageButton) findViewById(R.id.btnSearch);
        txtAlert = (TextView) findViewById(R.id.txtAlert);

        // menu API url
        MenuAPI = Constant.MenuAPI+"?accesskey="+Constant.AccessKey+"&category=";
        // tax and currency API url
        TaxCurrencyAPI = Constant.TaxCurrencyAPI+"?accesskey="+Constant.AccessKey;

        // get category id and category name that sent from previous page
        Intent iGet = getIntent();
        Category_ID = iGet.getLongExtra("category_id",0);
        Category_name = iGet.getStringExtra("category");//point of interest #1
        MenuAPI += Category_name;

        // set category name to textview
//        txtTitle.setText(Category_name);

        mla = new AdapterMenuList(ActivityMenuList.this);

        // call asynctask class to request tax and currency data from server
        new getTaxCurrency().execute();

        // event listener to handle search button when clicked
        btnSearch.setOnClickListener(new OnClickListener() {

            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                // get keyword and send it to server
                try {
                    Keyword = URLEncoder.encode(edtKeyword.getText().toString(), "utf-8");
                } catch (UnsupportedEncodingException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                MenuAPI += "&keyword="+Keyword;
                IOConnect = 0;
                listMenu.invalidateViews();
                clearData();
                new getDataTask().execute();
            }
        });

        // event listener to handle list when clicked
        listMenu.setOnItemClickListener(new OnItemClickListener() {

            public void onItemClick(AdapterView<?> arg0, View arg1, int position,
                    long arg3) {
                // TODO Auto-generated method stub
                // go to menu detail page
                Intent iDetail = new Intent(ActivityMenuList.this, ActivityMenuDetail.class);
                iDetail.putExtra("menu_id", Menu_ID.get(position));
                startActivity(iDetail);
                overridePendingTransition(R.anim.open_next, R.anim.close_next);
            }
        });       

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_category, menu);

//      final SearchView searchView = (SearchView) menu.findItem(R.id.search).getActionView();
//        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
//          
//          @Override
//            public boolean onQueryTextChange(String newText) {                            
//                return true;
//            }  
//          
//          @Override
//            public boolean onQueryTextSubmit(String query) {
//              try {
//                  Keyword = URLEncoder.encode(query.toString(), "utf-8");
//              } catch (UnsupportedEncodingException e) {
//                  e.printStackTrace();    
//              }
//              
//              MenuAPI += "&keyword="+Keyword;
//              IOConnect = 0;
//              listMenu.invalidateViews();
//              clearData();
//              new getDataTask().execute();  
//                
//                return true;
//            }          
//        });
//        
//        searchView.addOnAttachStateChangeListener(new OnAttachStateChangeListener() {
//
//            @Override
//            public void onViewDetachedFromWindow(View arg0) {
//              IOConnect = 0;
//              listMenu.invalidateViews();
//              clearData();
//              new getDataTask().execute();
//            }
//
//            @Override
//            public void onViewAttachedToWindow(View arg0) {
//                // search was opened
//            }
//        });

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        switch (item.getItemId()) {
        case R.id.cart:
            // refresh action
            Intent iMyOrder = new Intent(ActivityMenuList.this, ActivityCart.class);
            startActivity(iMyOrder);
            overridePendingTransition (R.anim.open_next, R.anim.close_next);
            return true;

        case R.id.refresh:
            IOConnect = 0;
            listMenu.invalidateViews();
            clearData();
            new getDataTask().execute();
            return true;            

        case android.R.id.home:
            // app icon in action bar clicked; go home
            this.finish();
            overridePendingTransition(R.anim.open_main, R.anim.close_next);
            return true;

        default:
            return super.onOptionsItemSelected(item);
        }
    }

    // asynctask class to handle parsing json in background
    public class getTaxCurrency extends AsyncTask<Void, Void, Void>{

        // show progressbar first
        getTaxCurrency(){
            if(!prgLoading.isShown()){
                prgLoading.setVisibility(0);
                txtAlert.setVisibility(8);
            }
        }

        @Override
        protected Void doInBackground(Void... arg0) {
            // TODO Auto-generated method stub
            // parse json data from server in background
            parseJSONDataTax();
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            // TODO Auto-generated method stub
            // when finish parsing, hide progressbar
            prgLoading.setVisibility(8);
            // if internet connection and data available request menu data from server
            // otherwise, show alert text
            if((Currency != null) && IOConnect == 0){
                new getDataTask().execute();
            }else{
                txtAlert.setVisibility(0);
            }
        }
    }

    // method to parse json data from server
    public void parseJSONDataTax(){
        try {
            // request data from tax and currency API
            HttpClient client = new DefaultHttpClient();
            HttpConnectionParams.setConnectionTimeout(client.getParams(), 15000);
            HttpConnectionParams.setSoTimeout(client.getParams(), 15000);
            HttpUriRequest request = new HttpGet(TaxCurrencyAPI);
            HttpResponse response = client.execute(request);
            InputStream atomInputStream = response.getEntity().getContent();

            BufferedReader in = new BufferedReader(new InputStreamReader(atomInputStream));

            String line;
            String str = "";
            while ((line = in.readLine()) != null){
                str += line;
            }


            // parse json data and store into tax and currency variables
            JSONObject json = new JSONObject(str);
            JSONArray data = json.getJSONArray("data"); // this is the "items: [ ] part

            JSONObject object_tax = data.getJSONObject(0); 
            JSONObject tax = object_tax.getJSONObject("tax_n_currency");

            Tax = Double.parseDouble(tax.getString("Value"));

            JSONObject object_currency = data.getJSONObject(1); 
            JSONObject currency = object_currency.getJSONObject("tax_n_currency");

            Currency = currency.getString("Value");


        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            IOConnect = 1;
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   
    }

    // clear arraylist variables before used
    void clearData(){
        Menu_ID.clear();
        Menu_name.clear();
        Menu_price.clear();
        Menu_image.clear();
    }

    // asynctask class to handle parsing json in background
    public class getDataTask extends AsyncTask<Void, Void, Void>{

        // show progressbar first
        getDataTask(){
            if(!prgLoading.isShown()){
                prgLoading.setVisibility(0);
                txtAlert.setVisibility(8);
            }
        }

        @Override
        protected Void doInBackground(Void... arg0) {
            // TODO Auto-generated method stub
            // parse json data from server in background
            parseJSONData();
            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            // TODO Auto-generated method stub
            // when finish parsing, hide progressbar
            prgLoading.setVisibility(8);

            // if data available show data on list
            // otherwise, show alert text
            if(Menu_ID.size() > 0){
                listMenu.setVisibility(0);
                listMenu.setAdapter(mla);
            }else{
                txtAlert.setVisibility(0);
            }

        }
    }

    // method to parse json data from server
    public void parseJSONData(){

        clearData();

        try {
            // request data from menu API
            HttpClient client = new DefaultHttpClient();
            HttpConnectionParams.setConnectionTimeout(client.getParams(), 15000);
            HttpConnectionParams.setSoTimeout(client.getParams(), 15000);
            HttpUriRequest request = new HttpGet(MenuAPI);
            HttpResponse response = client.execute(request);
            InputStream atomInputStream = response.getEntity().getContent();

            BufferedReader in = new BufferedReader(new InputStreamReader(atomInputStream));

            String line;
            String str = "";
            while ((line = in.readLine()) != null){
                str += line;
            }

            // parse json data and store into arraylist variables
            JSONObject json = new JSONObject(str);//point of interest #2
            JSONArray data = json.getJSONArray("data"); // this is the "items: [ ] part

            for (int i = 0; i < data.length(); i++) {
                JSONObject object = data.getJSONObject(i); 

                JSONObject menu = object.getJSONObject("Menu");

                Menu_ID.add(Long.parseLong(menu.getString("Menu_ID")));
                Menu_name.add(menu.getString("Menu_name"));
                Menu_price.add(Double.valueOf(formatData.format(menu.getDouble("Price"))));
                Menu_image.add(menu.getString("Menu_image"));

            }


        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }   
    }


    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        //mla.imageLoader.clearCache();
        listMenu.setAdapter(null);
        super.onDestroy();
    }


    @Override
    public void onConfigurationChanged(final Configuration newConfig)
    {
        // Ignore orientation change to keep activity from restarting
        super.onConfigurationChanged(newConfig);
    }

    @Override
    public void onBackPressed() {
        // TODO Auto-generated method stub
        super.onBackPressed();
        finish();
        overridePendingTransition(R.anim.open_main, R.anim.close_next);
    }


}

最后，logcat显示的唯一信息是感兴趣的＃2中的JSONException: Value of type java.lang.String cannot be converted to JSONObject，我不知道为什么会这样做但是当我通过category_id获取它时肯定没有显示。对于长篇文章我感到非常抱歉，但我只是希望得到尽可能多的信息来试图获得帮助，因为我在这里结束了我的智慧。如果您需要更多信息，请与我们联系。谢谢。

Answer 1

$sql_query = "SELECT Menu_ID, Menu_name, Price, Menu_image 
                    FROM tbl_menu 
                    WHERE Category = ".$category." 
                    ORDER BY Menu_ID DESC";

请您尝试改为：

$sql_query = "SELECT Menu_ID, Menu_name, Price, Menu_image 
                    FROM tbl_menu 
                    WHERE Category = '".$category."' 
                    ORDER BY Menu_ID DESC";