Question

我在使用自定义适配器在列表视图上选择多个项目时遇到问题。

这是我的ListActivity类，我使用JSON从MySQL数据库中获取数据：

public class ViewCitiesActivity extends ListActivity {

    // Progress Dialog
    private ProgressDialog pDialog;

    // Search EditText
    EditText inputSearch;

    // view elements
    Button execute_btn;

    ListView lv;

    // List adapter
    ListAdapter adapter;

    // Exercise type
    public Integer type;

    // string for selected items
    String my_sel_items;

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

    // Hashmap for received data
    ArrayList<HashMap<String, String>> cityList;

    // url to get all categories list
    private static String url_cities = "http://www.xxxxxxxxx.hr/sale/viewcities.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_cities = "cities";
    private static final String TAG_ID = "city_id";
    private static final String TAG_NAME = "city";

    // categories JSONArray
    JSONArray cities = null;

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

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

        Intent i = getIntent();
        type = i.getIntExtra("type", 0);

        // Loading products in Background Thread
        new LoadAll().execute(type.toString());

        // Get listview
        lv = getListView();
        execute_btn = (Button) findViewById(R.id.btn_newcity);

        lv.setLongClickable(true);
        lv.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
        lv.setOnItemLongClickListener(new OnItemLongClickListener() {
            public boolean onItemLongClick(AdapterView<?> parent, View v, int position, long id) {

                execute_btn.setText(R.string.btn_deletecity); 

                // setting new layout with checkedTextView for adapter 
                adapter = new SimpleAdapter(
                        ViewCitiesActivity.this, cityList,
                        R.layout.view_list_item2, new String[] { TAG_ID,
                                TAG_NAME},
                        new int[] { R.id.pid, R.id.name });
                // updating listview
                setListAdapter(adapter);



                return true;
            }
        });


        execute_btn.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {

                my_sel_items = new String("Test");
                SparseBooleanArray a = lv.getCheckedItemPositions();
                for (int i = 0; i < a.size(); i++) {
                    if (a.valueAt(i)) {
                        my_sel_items = my_sel_items + ","
                                + lv.getItemAtPosition(i).toString();
                    }
                }
                Log.d("values", my_sel_items);



            }
        });
    }


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

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(ViewCitiesActivity.this);
            pDialog.setMessage("Loading cities. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * getting All products from url
         * */
        protected String doInBackground(String... args) {

            // Building Parameters
            ArrayList<NameValuePair> params = new ArrayList<NameValuePair>();
            //params.add(new BasicNameValuePair("extype", args[0]));

            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_cities, "POST", params);

            // Check your log cat for JSON reponse
            Log.d("All cities: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // products found
                    // Getting Array of categories
                    cities = json.getJSONArray(TAG_cities);

                    // looping through All categories
                    for (int i = 0; i < cities.length(); i++) {
                        JSONObject c = cities.getJSONObject(i);

                        // Storing each json item in variable
                        String id = c.getString(TAG_ID);
                        String name = c.getString(TAG_NAME);

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

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

                        // adding HashList to ArrayList
                        cityList.add(map);
                    }
                } 
            } 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 categories
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    adapter = new SimpleAdapter(
                            ViewCitiesActivity.this, cityList,
                            R.layout.view_list_item, new String[] { TAG_ID,
                                    TAG_NAME},
                            new int[] { R.id.pid, R.id.name });
                    // updating listview
                    setListAdapter(adapter);

                }
            });

        }

    }

    // standard JSONParser class
    public class JSONParser {

}

以下是inital adapter build的view_list_item.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:columnCount="1"
android:orientation="vertical" >

    <TextView
        android:id="@+id/pid"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:visibility="gone" />

    <!-- Name Label --> 

    <TextView
        android:id="@+id/name"
        android:layout_width="260dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:paddingLeft="6dip"
        android:paddingTop="6dip"
        android:textColor="#000000"
        android:textSize="23sp"
        android:textStyle="bold" />

这是第二个view_list_item2.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:columnCount="1"
android:orientation="vertical" >

    <TextView
        android:id="@+id/pid"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:visibility="gone" />

    <!-- Name Label --> 

<GridLayout
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:columnCount="1"
    android:orientation="vertical"
    android:descendantFocusability="blocksDescendants" >

    <TextView
        android:id="@+id/name"
        android:layout_width="260dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="10dp"
        android:paddingLeft="6dip"
        android:paddingTop="6dip"
        android:textColor="#000000"
        android:textSize="23sp"
        android:textStyle="bold" />

    <CheckBox
        android:id="@+id/checkBox"
        android:layout_column="0"
        android:layout_gravity="right|top"
        android:layout_row="0"
        android:layout_marginRight="10dp"
        android:checkMark="?android:attr/listChoiceIndicatorMultiple" />

</GridLayout>

</LinearLayout>

现在，一切正常，但是当我点击按钮时，我无法从列表中获取已检查项目的列表。而我实际需要的是来自已检查项目的city_ID列表，以便我可以启动一个新线程从数据库中删除它们。

有谁知道怎么做？我已经搜索了StackOverflow问题和其他教程，但我似乎无法使其工作。

Answer 1

在您的帖子中，您需要列表中的已检查项目列表。如果这是你的问题，我可以提供帮助。首先，您应该使用 CustomArrayAdapter 。不是 SimpleAdapter 。现在，您必须创建布尔值的ArrayList 以保存列表项的检查状态。

ArrayList<boolean> checkstate = new ArrayList<boolean>();

当复选框发生变化时，在 CustomArrayAdatper 中，您可以使用 onCheckedChangeListener 将状态保存在布尔列表（检查状态）中。现在您有了已检查项目的列表。

如何使用自定义列表视图适配器捕获多个选定的项目数据？

1 个答案: