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您好,我想开发一个带有缩略图和产品名称的产品列表。我削减了产品名称,JSON但我想在左侧添加缩略图。是否可以AsyncTask与图像和Strings. 我该怎么做?如何将图像和文本一起返回。我想在如下所示的代码中调用图像:

package com.eticaret.hakan;

import java.io.BufferedInputStream;

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

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


import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;

import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;

import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;

public class ProductActivity extends ListActivity {
    int intid;
    // Progress Dialog
    private ProgressDialog pDialog;

    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();

    ArrayList<HashMap<String, String>> productsList;

    // url to get all products list
    private static String url_all_products = "http://10.0.2.2/projeler/e-ticaret/get_all_products.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCTS = "urunler";
    private static final String TAG_PID = "pid";
    private static final String TAG_PNAME = "pname";
    private static final String TAG_PPRICE = "pprice";
    private static final String TAG_PDESCRIPTION = "pdescription";
    private static final String TAG_CREATEDAT = "created_at";
    private static final String TAG_CATID = "cat_Id";

    // products JSONArray
    JSONArray products = null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.products);
        Bundle extras = getIntent().getExtras(); 
        String id = extras.getString("cat_Id");
        intid=Integer.parseInt(id);

        // Hashmap for ListView
        productsList = new ArrayList<HashMap<String, String>>();

        // Loading products in Background Thread
        new LoadAllProducts().execute();

        // Get listview
        ListView lv = getListView();

        // on seleting single product
        // launching Edit Product Screen
        lv.setOnItemClickListener(new OnItemClickListener() {

            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                        .toString();

                // Starting new intent
                Intent in = new Intent(getApplicationContext(),
                        Details.class);
                // sending pid to next activity
                in.putExtra(TAG_PID, pid);

                // starting new activity and expecting some response back
                startActivityForResult(in, 100);
            }
        });

    }

    // Response from Edit Product Activity
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // if result code 100
        if (resultCode == 100) {
            // if result code 100 is received 
            // means user edited/deleted product
            // reload this screen again
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        }

    }

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

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(ProductActivity.this);
            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);

            // Check your log cat for JSON reponse
            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 id = c.getString(TAG_PID);
                        String name = c.getString(TAG_PNAME);
                        String price = c.getString(TAG_PPRICE);
                        String description = c.getString(TAG_PDESCRIPTION);
                        String created_at = c.getString(TAG_CREATEDAT);
                        String catid = c.getString(TAG_CATID);
                        int intcatid=Integer.parseInt(catid);

                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();
                        if(intcatid==intid){
                            // adding each child node to HashMap key => value
                            map.put(TAG_PID, id);
                            map.put(TAG_PNAME, name);
                            map.put(TAG_PPRICE, price);
                            map.put(TAG_PDESCRIPTION, description);
                            map.put(TAG_CREATEDAT, created_at);

                            // adding HashList to ArrayList
                            productsList.add(map);

                        }

                    }
                } else {
                    // no products found
                    // Launch Add New product Activity
                    Intent i = new Intent(getApplicationContext(),
                            ProductActivity.class);
                    // Closing all previous activities
                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(i);
                }
            } 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
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            ProductActivity.this, productsList,
                            R.layout.plist_item, new String[] { TAG_PID,
                                    TAG_PNAME,TAG_PPRICE},
                                    new int[] { R.id.pid, R.id.pname,R.id.pprice});
                    // updating listview
                    setListAdapter(adapter);
                }
            });

        }

    }


}
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1 回答 1

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onPostExecute在 UI 线程上运行,因此无需在其中调用runOnUiThread()。您应该解析 doInBackground 中的数据,然后将数据传递给 onPostExecute,return result; 这是我通常做的:

我创建了一个空成员 ArrayList(比如说产品列表)并在 onCreate() 中用它初始化列表适配器。在 onPostExecute 中,我将项目添加到列表中(不要覆盖它)并在列表适配器上调用 notifyDataSetChanged(),瞧!

于 2012-09-17T19:03:08.427 回答