布局元素无法识别

时间:2013-04-06 08:08:55

标签: android listview layout listadapter

我使用以下代码从数据库中显示列表视图;但是,似乎某些布局元素无法识别..任何人都可以告诉我为什么? 这是Logcat消息: 您的内容必须具有列表视图,其id属性为android.R.id。

P.S:非常感谢任何帮助!! //以下是xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <ListView
        android:id="@+id/list"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
    </ListView>

</LinearLayout>

//以下是代码

package com.example.androidhive;

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.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;

public class AllProductsActivity extends ListActivity {

    // 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://10.6.13.15/android_connect/get_all_products.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PID= "name";
    private static final String TAG_CATEGORY = "category";
    private static final String TAG_CALORY = "calory";
    /*private static final String TAG_UNIT = "unit";
    private static final String TAG_CALORY = "calory";
    private static final String TAG_CARBOHYDRATE = "carbohydrate";
    private static final String TAG_CATEGORY = "category";*/
    // the array was defined in PHP file
    private static final String TAG_PRODUCT = "product";
    // TO CONFIRM THE HASH INTO ARRAY
    private ArrayAdapter<mItems> listAdapter;
    private mItems[] itemss;
    private ListView mainListView;
    ArrayList<mItems> planetList = new ArrayList<mItems>();
    // products JSONArray
    JSONArray products = null;
    ArrayList<String> checked = new ArrayList<String>();
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.all_products);

        mainListView = (ListView)findViewById(R.id.list);
        // 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
        mainListView.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                    mItems planet = listAdapter.getItem(position);
                    planet.toggleChecked();
                    SelectViewHolder viewHolder = (SelectViewHolder) view
                            .getTag();
                    viewHolder.getCheckBox().setChecked(planet.isChecked());
                    Toast.makeText(getApplicationContext(), "msg msg", Toast.LENGTH_SHORT).show();


                //*********** OUR CODE****************
                // getting values from selected ListItem
                /*String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                        .toString();

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

                // starting new activity and expecting some response back
                startActivityForResult(in, 100);*/
                //*********** OUR CODE****************
            }
        });
        listAdapter = new SelectArralAdapter(this, planetList);
        mainListView.setAdapter(listAdapter);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // TODO Auto-generated method stub
        menu.add(0, 1, Menu.NONE, "Products");
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub

        switch (item.getItemId()) {
        case 1:

            for (int i = 0; i < checked.size(); i++) {
                Log.d("pos : ", "" + checked.get(i));
            }
            break;
        }
        return super.onOptionsItemSelected(item);
    }

    // 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);
            Log.d("NUN complete","tyt");
        }

    }

    /**
     * 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(AllProductsActivity.this);
            pDialog.setMessage("Loading items. 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) {
                    itemss = (mItems[]) getLastNonConfigurationInstance();
                    int ii=0;
                    while( ii < products.length()){
                        JSONObject c = products.getJSONObject(ii);
                        String category = c.getString(TAG_CATEGORY );
                        //Double dd =c.getDouble(TAG_CALORY);
                        String dd = c.getString(TAG_CALORY );
                        //itemss[ii]= dd;
                        planetList.add(new mItems(dd));

                        ii++;
                       // Log.d("d ", TextUtils.join(",", d));  

                    }

                    // products found
                    // Getting Array of Products
                    Log.d("All Products: ", json.toString());
                    products = json.getJSONArray(TAG_PRODUCT);

                    // 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); // also name
                        String category = c.getString(TAG_CATEGORY );
                        // NO NEED FOR THEM !!
                        /*
                        String unit = c.getString(TAG_UNIT );
                        String category = c.getString(TAG_CATEGORY );
                        String calory = c.getString(TAG_CALORY );
                        String carbohydrate = c.getString(TAG_CARBOHYDRATE ); */


                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        map.put(TAG_PID, id);
                        map.put(TAG_CATEGORY, category);
                        //map.put(TAG_NAME, name);

                        // adding HashList to ArrayList
                        productsList.add(map);
                        Log.d("All Products: ", json.toString());
                    }
                } else {
                    // no products found
                    // Launch Add New product Activity
                    Intent i = new Intent(getApplicationContext(),
                            NewProductActivity.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(
                            AllProductsActivity.this, productsList,
                            R.layout.list_item, new String[] { TAG_PID,
                                    TAG_CATEGORY},
                            new int[] { R.id.pid, R.id.category});
                    // updating listview
                    setListAdapter(adapter);
                }
            });

        } 
        */

    }
    private static class mItems {
        private String name = "";
        private boolean checked = false;
        private double calory = 0.0;
        public mItems() {
        }

        public mItems(String name) {
            this.name = name;
        }

        public mItems(String name, boolean checked) {
            this.name = name;
            this.checked = checked;
        }

        public String getName() {
            return name;
        }

        public double getCalroy() {
            return calory;
        }
        public void setName(String name) {
            this.name = name;
        }

        public boolean isChecked() {
            return checked;
        }

        public void setChecked(boolean checked) {
            this.checked = checked;
        }

        public String toString() {
            return name;
        }

        public void toggleChecked() {
            checked = !checked;
        }
    }
    // New class
    private static class SelectViewHolder {
        private CheckBox checkBox;
        private TextView textView;

        public SelectViewHolder() {
        }

        public SelectViewHolder(TextView textView, CheckBox checkBox) {
            this.checkBox = checkBox;
            this.textView = textView;
        }

        public CheckBox getCheckBox() {
            return checkBox;
        }

        public void setCheckBox(CheckBox checkBox) {
            this.checkBox = checkBox;
        }

        public TextView getTextView() {
            return textView;
        }

        public void setTextView(TextView textView) {
            this.textView = textView;
        }
    }
    // New class
    private static class SelectArralAdapter extends ArrayAdapter<mItems> {
        private LayoutInflater inflater;

        public SelectArralAdapter(Context context, List<mItems> planetList) {
            super(context, R.layout.list_item, R.id.rowTextView, planetList);
            // Cache the LayoutInflate to avoid asking for a new one each time.
            inflater = LayoutInflater.from(context);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            // Planet to display
            mItems planet = (mItems) this.getItem(position);

            // The child views in each row.
            CheckBox checkBox;
            TextView textView;
            TextView here;
            // Create a new row view
            if (convertView == null) {
                convertView = inflater.inflate(R.layout.list_item, null);

                // Find the child views.
                textView = (TextView) convertView
                        .findViewById(R.id.rowTextView);
                checkBox = (CheckBox) convertView.findViewById(R.id.CheckBox01);

                // Optimization: Tag the row with it's child views, so we don't
                // have to
                // call findViewById() later when we reuse the row.
                convertView.setTag(new SelectViewHolder(textView, checkBox));
                // If CheckBox is toggled, update the planet it is tagged with.
                checkBox.setOnClickListener(new View.OnClickListener() {
                    public void onClick(View v) {
                        CheckBox cb = (CheckBox) v;
                        mItems planet = (mItems) cb.getTag();
                        planet.setChecked(cb.isChecked());
                    }
                });
            }
            // Reuse existing row view
            else {
                // Because we use a ViewHolder, we avoid having to call
                // findViewById().
                SelectViewHolder viewHolder = (SelectViewHolder) convertView
                        .getTag();
                checkBox = viewHolder.getCheckBox();
                textView = viewHolder.getTextView();
            }

            // Tag the CheckBox with the Planet it is displaying, so that we can
            // access the planet in onClick() when the CheckBox is toggled.
            checkBox.setTag(planet);
            // Display planet data
            checkBox.setChecked(planet.isChecked());
            textView.setText(planet.getName());

            return convertView;
        }
    }
    public Object onRetainNonConfigurationInstance() {
        return itemss;
    }
}

2 个答案:

答案 0 :(得分:2)

您使用的是ListActivity而不是普通的Activity,您的视图应该有默认的android:id/list:
将xml中的列表视图更改为

<ListView
   android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
</ListView>

检查此ListActivity Tutorial以获取更多信息

答案 1 :(得分:0)

已成为

mainListView = (ListView)findViewById(R.id.list);

使用

 mainListView = getListView()