如何从列表视图中删除已检查的数据

Question

我有自定义列表视图，它从外部数据库MySQL加载数据。现在我在删除数据时遇到问题，当我检查任何特定的复选框并尝试删除数据时，它删除了数据库中的所有数据而不是所选数据，但我只想删除已检查的记录。

我知道为什么会出现这个问题，但我不知道如何解决这个问题，问题是虽然删除它没有获得检查值位置，因为我没有做任何关于检查特定位置和删除的编码。因为我不知道如何获得检查值。

所以有人请告诉我如何只删除选中的值...以下是我的完整代码。我使用http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/作为参考的信息。

public class Classes_Ext_DB extends Activity implements OnClickListener {

ImageView imageViewNewClass, imageViewDelete;
ListView mListView;

/** Sliding Menu */
boolean alreadyShowing = false;
private int windowWidth;
private Animation animationClasses;
private RelativeLayout classesSlider;
LayoutInflater layoutInflaterClasses;
ArrayAdapter<CharSequence> adapterSpinner;

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_classDetail = "http://my-server/get_all_classdetail.php";

// url to delete product
private static final String url_delete_class = "http://my-server/delete_class.php";

// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCTS = "products";
private static final String TAG_ID = "ID";
private static final String TAG_CLASSNAME = "class_name";

// products JSONArray
JSONArray products = null;

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

    imageViewNewClass = (ImageView) findViewById(R.id.newclass);
    imageViewDelete = (ImageView) findViewById(R.id.deletemenu);
    mListView = (ListView) findViewById(R.id.displaydata);

    productsList = new ArrayList<HashMap<String, String>>();

    imageViewNewClass.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
            Intent intent = new Intent(Classes_Ext_DB.this,
                    Class_Create_Ext_DB.class);
            startActivity(intent);
        }
    });

    imageViewDelete.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View arg0) {
            AlertDialog.Builder alertDialog = new AlertDialog.Builder(
                    Classes_Ext_DB.this);

            final Spinner spinnerDelete = new Spinner(Classes_Ext_DB.this);
            alertDialog.setView(spinnerDelete);

            adapterSpinner = ArrayAdapter.createFromResource(
                    Classes_Ext_DB.this, R.array.delete_menu,
                    android.R.layout.simple_spinner_item);
            adapterSpinner
                    .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            spinnerDelete.setAdapter(adapterSpinner);

            alertDialog.setPositiveButton("Ok",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog,
                                int which) {
                            if (spinnerDelete.getSelectedItemPosition() == 0) {
                                new DeleteProduct().execute();
                            }
                        }
                    });
            alertDialog.setNegativeButton("Cancel",
                    new DialogInterface.OnClickListener() {
                        public void onClick(DialogInterface dialog,
                                int which) {
                            dialog.cancel();
                        }
                    });
            alertDialog.show();

        }
    });

    new LoadAllClassDetail().execute();
}

class LoadAllClassDetail extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(Classes_Ext_DB.this);
        pDialog.setMessage("Loading Classes. 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_classDetail,
                "GET", params);

        // Check your log cat for JSON reponse
        Log.d("All Classes: ", 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 cid = c.getString(TAG_ID);
                    String cn = c.getString(TAG_CLASSNAME);

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

                    // adding each child node to HashMap key => value
                    map.put(TAG_ID, cid);
                    map.put(TAG_CLASSNAME, cn);

                    // adding HashList to ArrayList
                    productsList.add(map);
                }
            } else {
                // no products found
                // Launch Add New product Activity
                Intent i = new Intent(getApplicationContext(),
                        Class_Create_Ext_DB.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(
                        Classes_Ext_DB.this, productsList,
                        R.layout.custom_class, new String[] {
                                TAG_CLASSNAME, TAG_ID },
                        new int[] { R.id.classname});

                // updating listview
                mListView.setAdapter(adapter);
                mListView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
                mListView.setCacheColorHint(Color.TRANSPARENT);
                mListView.setDivider(new ColorDrawable(0x99000000));
                mListView.setDividerHeight(1);
            }
        });
    }
}

/*****************************************************************
 * Background Async Task to Delete Class
 * */
class DeleteProduct extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(Classes_Ext_DB.this);
        pDialog.setMessage("Deleting Class... Please wait...");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    /**
     * Deleting product
     * */
    protected String doInBackground(String... args) {

        // Check for success tag
        int success;
        try {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("ID", TAG_ID));

            // getting product details by making HTTP request
            JSONObject json = jParser.makeHttpRequest(url_delete_class,
                    "POST", params);
            // check your log for json response
            Log.d("Delete Product", json.toString());
            // json success tag
            success = json.getInt(TAG_SUCCESS);
            if (success == 1) {
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    protected void onPostExecute(String file_url) {
        pDialog.dismiss();
    }
}
}

custom_class.xml

<?xml version="1.0" encoding="utf-8"?>

<CheckBox
    android:id="@+id/checkBox1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/classname"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="10dip"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:textColor="#000000"
    android:textStyle="bold" />

</LinearLayout>

现在的问题是，我已经将我的自定义类调整为

                       ListAdapter adapter = new SimpleAdapter(
                        Classes_Ext_DB.this, productsList,
                        R.layout.custom_class, new String[] {
                                TAG_CLASSNAME, TAG_ID },
                        new int[] { R.id.classname});

所以我不知道如何声明我的Check-box并获取删除或编辑的特定check-box值。

请帮我解决这个问题。先感谢您。任何帮助将不胜感激。

**编辑**

delete_class.php

<?php

/*
 * Following code will delete a product from table
 * A product is identified by product id (pid)
 */

// array for JSON response
$response = array();

// check for required fields
if (isset($_POST['ID'])) {
    $ID= $_POST['ID'];

    // include db connect class
    require_once ('db_connect.php');

    // connecting to db
    $db = new DB_CONNECT();

    // mysql update row with matched pid
    $result = mysql_query("DELETE FROM class_create WHERE ID = $ID");

    // check if row deleted or not
    if (mysql_affected_rows() > 0) {
        // successfully updated
        $response["success"] = 1;
        $response["message"] = "Product successfully deleted";

        // echoing JSON response
        echo json_encode($response);
    } else {
        // no product found
        $response["success"] = 0;
        $response["message"] = "No product found";

        // echo no users JSON
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";

    // echoing JSON response
    echo json_encode($response);
}
?>

get_all_classdetail.php

<?php

/*
 * Following code will list all the products
 */

// array for JSON response
$response = array();


// include db connect class
require_once ('db_connect.php');

// connecting to db
$db = new DB_CONNECT();

// get all products from products table
$result = mysql_query("SELECT * FROM class_create") or die(mysql_error());

// check for empty result
if (mysql_num_rows($result) > 0) {
    // looping through all results
    // products node
    $response["products"] = array();

    while ($row = mysql_fetch_array($result)) {
        // temp user array
        $product = array();
        $product["ID"] = $row["ID"];
        $product["class_name"] = $row["class_name"];
        $product["class_days"] = $row["class_days"];
        $product["class_time"] = $row["class_time"];


        // push single product into final response array
        array_push($response["products"], $product);
    }
    // success
    $response["success"] = 1;

    // echoing JSON response
    echo json_encode($response);
} else {
    // no products found
    $response["success"] = 0;
    $response["message"] = "No products found";

    // echo no users JSON
    echo json_encode($response);
}
?>

Answer 1

    package com.example.test;

    import java.util.ArrayList;

    import android.os.Bundle;
    import android.app.Activity;
    import android.content.Context;
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.Menu;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.Button;
    import android.widget.CheckBox;
    import android.widget.CompoundButton;
    import android.widget.CompoundButton.OnCheckedChangeListener;
    import android.widget.ListView;
    import android.widget.RadioGroup;
    import android.widget.TextView;

    public class MainActivity extends Activity {
        ArrayList<String> delteID;

        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            ListView listView=(ListView) findViewById(R.id.listView1);
             String[] values = new String[] { "Android", "iPhone", "WindowsMobile",
                        "Blackberry", "WebOS", "Ubuntu", "Windows7", "Max OS X",
                        "Linux", "OS/2", "Ubuntu", "Windows7", "Max OS X", "Linux",
                        "OS/2", "Ubuntu", "Windows7", "Max OS X", "Linux", "OS/2",
                        "Android", "iPhone", "WindowsMobile" };
            MySimpleArrayAdapter adapter=new MySimpleArrayAdapter(getApplicationContext(), values);
            listView.setAdapter(adapter);

            delteID=new ArrayList<String>();


            Button deleteButton=(Button) findViewById(R.id.deleteBt);
            deleteButton.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View arg0) {
                    // TODO Auto-generated method stub
                    for (String string : delteID) {
                        Log.i("TAG", string);

                        //U can send the Delete Request from HERE
                    }
                }
            });
        }

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


    public class MySimpleArrayAdapter extends ArrayAdapter<String> {
          private final Context context;
          private final String[] values;

          public MySimpleArrayAdapter(Context context, String[] values) {
            super(context, R.layout.custom_list, values);
            this.context = context;
            this.values = values;
          }

          @Override
          public View getView(int position, View convertView, ViewGroup parent) {
            LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View rowView = inflater.inflate(R.layout.custom_list, parent, false);
            TextView textView = (TextView) rowView.findViewById(R.id.text1);
            CheckBox checkBox = (CheckBox) rowView.findViewById(R.id.check1);
            textView.setText(values[position]);
            checkBox.setOnCheckedChangeListener(new CheckUpdateListener(position));
            // Change the icon for Windows and iPhone
            String s = values[position];

            return rowView;
          }

          private final class CheckUpdateListener implements OnCheckedChangeListener
            {
                private final int index;
                /**
                 * @param child
                 */
                private CheckUpdateListener(int index)
                {
                    this.index = index;
                }
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked)
                {

                    if(isChecked)
                    {
                        delteID.add("ID"+index);
                        //U may get the id from the actual data u received form the server itself with  **index** variable
                    }
                    else
                    {
                        delteID.remove("ID"+index);
//remove the unchecked id from list
                    }
                }
            }

        } 

    }

<强> activity_main.xml中

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/deleteBt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:text="Delete" />

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button1"
        android:layout_below="@+id/button1"
        android:layout_marginTop="15dp" >
    </ListView>

</RelativeLayout>

<强> custom_list.xml

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

    <TextView
        android:id="@+id/text1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_weight="1.0" />

    <CheckBox
        android:id="@+id/check1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="0.1" />

</LinearLayout>

这是代码将具有如何处理listView中的复选框的基本模型。

Answer 2

使用BaseAdapter而不是CustomAdapter，在基本适配器中，您可以使用按钮和复选框。

CheckBox = cbx;
for (int x = 0; x<lst.getChildCount();x++){
            cbx = (CheckBox)lst.getChildAt(x).findViewById(R.id.checkBox);
            if(cb.isChecked()){
            doSomething();
            }

然后在doSomething中你可以调用一个php文件删除表中的项目。