Question

我正在开发一个项目，我使用php mysql将android应用程序与数据库连接。我的要求是，布局中有一个微调器，我想在运行时初始化值（值来自db）。

我一直在试用这段代码

package com.example.festipedia_logo;

//import com.actionbarsherlock.app.SherlockFragment;


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.example.festipedia_logo.details1.LoadAllProducts;

import android.app.Activity;
import android.app.Fragment;
import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
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 mainpagetry extends Activity {
     Button button1;
     Button button4;
     ArrayAdapter<String> adapter;
        String[] city;
        String loc;
        Spinner spinner;
     //String loc;
        private static String url_all_products =new Global().getcon()+"loc.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";
            private static final String TAG_LOCATION = "location";
            private ProgressDialog pDialog;
            //String category,location;
            // Creating JSON Parser object
            JSONParser jParser = new JSONParser();
        EditText b;int flag=0;
            ArrayList<HashMap<String, String>> productsList;
            // products JSONArray
            JSONArray products = null;
        //ListView l;
        //Spinner spinner;
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);
        getActionBar().setDisplayShowTitleEnabled(false);
        getActionBar().setDisplayUseLogoEnabled(false);
        getActionBar().setDisplayShowCustomEnabled(true);
        getActionBar().setDisplayShowHomeEnabled(false);
        //getSupportActionBar().setIcon(R.drawable.fest);
        //getSupportActionBar().setLogo(R.drawable.fest);
        Drawable d=getResources().getDrawable(R.drawable.actionbar);
        getActionBar().setBackgroundDrawable(d);

        setContentView(R.layout.mainmenu);
        productsList = new ArrayList<HashMap<String, String>>();
        new LoadAllProducts().execute();
        spinner = (Spinner)this.findViewById(R.id.spinner1);
         /*city = new String[] { "Mumbai", "Chennai",
                    "Dubai"};

         /*adapter = new ArrayAdapter<String>(this,
                  android.R.layout.simple_spinner_dropdown_item,city
                  );
*/


    //      spinner.setAdapter(adapter);
//  View rootView = inflater.inflate(R.layout.mainmenu, container, false);
        //Intent in = getIntent();
        //loc = in.getStringExtra("loc");
        Button button1 = (Button) findViewById(R.id.button1);
        Button button4 = (Button) findViewById(R.id.button4);
        Button button2 = (Button) findViewById(R.id.button2);
        Button button5 = (Button) findViewById(R.id.button5);
        Button button3 = (Button) findViewById(R.id.button3);
        //TextView t1= (TextView) findViewById(R.id.getlocation);
        //t1.setText(loc);

button1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                // creating new product in background thread

                /*final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
                ft.replace(R.id.content_frame,new home1() , "Fest Content"); 
                ft.commit();*/
                String s=spinner.getSelectedItem().toString();
                Intent i = new Intent(getApplicationContext(),
                        MainActivity.class);
                i.putExtra("loc", 0);
                i.putExtra("category", "Technical");
                i.putExtra("location", s);
                // Closing all previous activities
                //i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);

                //new CreateNewProduct().execute();
            }
        });
button2.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View view) {
        // creating new product in background thread

        /*final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
        ft.replace(R.id.content_frame,new home1() , "Fest Content"); 
        ft.commit();*/
        String s=spinner.getSelectedItem().toString();
        Intent i = new Intent(getApplicationContext(),
                MainActivity.class);
        i.putExtra("loc", 0);
        i.putExtra("category", "Cultural");
        i.putExtra("location", s);
        // Closing all previous activities
        //i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(i);

        //new CreateNewProduct().execute();
    }
});
button3.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View view) {
        // creating new product in background thread

        /*final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
        ft.replace(R.id.content_frame,new home1() , "Fest Content"); 
        ft.commit();*/
        String s=spinner.getSelectedItem().toString();
        Intent i = new Intent(getApplicationContext(),
                MainActivity.class);
        i.putExtra("loc", 0);
        i.putExtra("category", "Sports");
        i.putExtra("location", s);
        // Closing all previous activities
        //i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(i);

        //new CreateNewProduct().execute();
    }
});
button4.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View view) {
        // creating new product in background thread
    /*  final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
        ft.replace(R.id.content_frame,new testing() , "Fest Content"); 
        ft.commit();*/
        Intent i = new Intent(getApplicationContext(),
                MainActivity.class);
        i.putExtra("loc", 1);
        // Closing all previous activities
        //i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(i);
        //new CreateNewProduct().execute();
    }
});
button5.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View view) {
        // creating new product in background thread
    /*  final FragmentTransaction ft = getFragmentManager().beginTransaction(); 
        ft.replace(R.id.content_frame,new testing() , "Fest Content"); 
        ft.commit();*/
        Intent i = new Intent(getApplicationContext(),
                MainActivity.class);
        i.putExtra("loc", 2);
        // Closing all previous activities
        //i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        startActivity(i);
        //new CreateNewProduct().execute();
    }
});


    }
    public void onBackPressed() {
                finish();

            }
    class LoadAllProducts extends AsyncTask<String, String, String> {

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

            pDialog = new ProgressDialog(mainpagetry.this);
            pDialog.setMessage("Loading festivals. 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>();
            //Log.d("test",category);
            //Log.d("test1",location);
            // 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);
                        String location = c.getString(TAG_LOCATION);
                        //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);
                        map.put(TAG_LOCATION, location);
                        // adding HashList to ArrayList
                        productsList.add(map);
                    }
                } else {
                //t1.setText("We currently do not have any events for this category at the chosen location");
                    //flag=1;
                }
            } 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
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */

                    adapter = new ArrayAdapter<String>(this,
                              android.R.layout.simple_spinner_dropdown_item,TAG_LOCATION
                              );
                        spinner.setAdapter(adapter);

                }
            });


        }
        }
    }

但我无法使用从db获得的值初始化微调器。错误说明：The constructor ArrayAdapter<String>(new Runnable(){}, int, String) is undefined

我也试过在void run方法中使用它：

public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */

                    ListAdapter adapter = new SimpleAdapter
                            (
                                    mainpagetry.this, productsList,
                                    R.layout.list_item, new String[] 
                                    {
                                        TAG_LOCATION
                                    },
                                        new int[] {  
                                        R.id.name 
                                        });         
                            spinner.setAdapter(adapter);
                    }

这里说明：The method setAdapter(SpinnerAdapter) in the type Spinner is not applicable for the arguments (ListAdapter) 请帮忙!!!

编辑：

错误的屏幕截图 error

数组适配器错误 - The constructor ArrayAdapter<String>(mainpagetry, int, String) is undefined

Answer 1

您应该像这样构建适配器：

adapter = new ArrayAdapter<String>
   (mainpagetry.this, 
   android.R.layout.simple_spinner_dropdown_item);

注意：原始代码中的this（Runnable）已更改为this外部类的实例（您的Activity）。

此外，删除最后一个参数以匹配其中一个ArrayAdapter构造函数，或者将其作为数组或字符串列表，如下所示：

adapter = new ArrayAdapter<String>
       (mainpagetry.this, 
       android.R.layout.simple_spinner_dropdown_item
       Arrays.asList("item1", "item2", "item3"));

Answer 2

没有ArrayAdapter构造函数将Runnable或通用T（在您的情况下，String）作为参数。请参阅JavadDoc。

而不是String，您可能希望使用String 数组或 List 。

另外，正如@kiruwka所述，第一个参数必须是Context，因此您必须使用mainpagetry.this或其他Context代替。

使用db中的数据初始化微调器

2 个答案: