java - 删除数组列表中 ListView 中的项目

Question

这是我的 Activity ，我在其中显示来自在线数据库的数据。我想做的是 - 当单击 ListView 内的项目时，它可以删除项目。但它不起作用，你能帮我吗？

这是我的代码:

订单列表.java

package com.system.receivingoforder;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ListActivity;
import android.graphics.Typeface;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.Request.Method;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.system.receivingoforder.app.AppConfig;
import com.system.receivingoforder.app.AppController;

public class ListOfOrders extends ListActivity{

private static final String TAG = RegisterActivity.class.getSimpleName();
ArrayList<HashMap<String,String>> list = new ArrayList<HashMap<String,String>>();

Typeface customFont;
TextView list_of_orders_txt;
ListView listView1;
SimpleAdapter adapter;

String[] table = new String[9999];
String desc[] = new String[9999];
String price[] = new String[9999];
String quantity[] = new String[9999];

String num, info;
int x;

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.listoforders);

    customFont = Typeface.createFromAsset(getAssets(), "fonts/EraserRegular.ttf");

    list_of_orders_txt = (TextView)findViewById(R.id.list_of_orders_tv);
    list_of_orders_txt.setTypeface(customFont);

    adapter = new SimpleAdapter( this, list, R.layout.listoforders_items,
            new String[] {"title","subtitle"}, 
            new int[] {R.id.loo_tablenumber,R.id.loo_itemquantity} );

    getOrderDetails();

}

@Override
public void finish() {
    // TODO Auto-generated method stub
    super.finish();
}

@Override
public void onBackPressed() {
    // TODO Auto-generated method stub
    super.onBackPressed();
    finish();
}

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    // TODO Auto-generated method stub
    super.onListItemClick(l, v, position, id);
    deleteOrder(table[position], desc[position], price[position], quantity[position]);
}

public void getOrderDetails() {
    // Tag used to cancel the request
    String tag_string_req = "req_register";

    StringRequest strReq = new StringRequest(Method.POST,
            AppConfig.URL_REGISTER, new Response.Listener<String>() {

                @Override
                public void onResponse(String response) {
                    Log.d(TAG, "Register Response: " + response.toString());

                    try {
                        JSONObject jObj = new JSONObject(response);
                        boolean error = jObj.getBoolean("error");

                        if (!error) {
                            JSONObject user = jObj.getJSONObject("user");

                            JSONArray tablenumarray = jObj.getJSONArray("tablearray");
                            JSONArray descarray = jObj.getJSONArray("descarray");
                            JSONArray pricearray = jObj.getJSONArray("pricearray");
                            JSONArray quantityarray = jObj.getJSONArray("quantityarray");

                            num = user.getString("prows");
                            x = Integer.parseInt(num);

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

                            for(int i=0; i<x; i++) {
                                table[i] = tablenumarray.getString(i);
                                //treatment[i] = treatmentarray.getString(i);
                                desc[i] = descarray.getString(i);
                                price[i] = pricearray.getString(i);
                                quantity[i] = quantityarray.getString(i);

                            }

                            for(int i=0; i<x; i++) {

                                info = "Description:  " + desc[i].toString() + "   \n" + "Price:  " + price[i].toString() + "   \n" + "Quantity:  " + quantity[i].toString();

                                map = new HashMap<String,String>(); 
                                map.put("title", "Table Number:  " + table[i].toString()); 
                                map.put("subtitle", info); 
                                list.add(map);
                            }
                            setListAdapter(adapter);

                        } else {

                            // Error occurred in registration. Get the error
                            // message
                            String errorMsg = jObj.getString("error_msg");
                            Toast.makeText(getApplicationContext(),
                                    errorMsg, Toast.LENGTH_LONG).show();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }

                }
            }, new Response.ErrorListener() {

                @Override
                public void onErrorResponse(VolleyError error) {
                    Log.e(TAG, "Registration Error: " + error.getMessage());
                    Toast.makeText(getApplicationContext(),
                            error.getMessage(), Toast.LENGTH_LONG).show();

                }
            }) {

        @Override
        protected Map<String, String> getParams() {
            // Posting params to register url
            Map<String, String> params = new HashMap<String, String>();
            params.put("tag", "orderinfo");

            return params;
        }
    };

    // Adding request to request queue
    AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}

//delete Order
private void deleteOrder(final String tablenum, final String desc, final String price, final String quantity) {
    // Tag used to cancel the request
    String tag_string_req = "req_registerpatient";

    StringRequest strReq = new StringRequest(Method.POST,
            AppConfig.URL_REGISTER, new Response.Listener<String>() {

                @Override
                public void onResponse(String response) {
                    Log.d(TAG, "Register Response: " + response.toString());


                    try {
                        JSONObject jObj = new JSONObject(response);
                        boolean error = jObj.getBoolean("error");
                        if (!error) {

                            Toast.makeText(getApplicationContext(), "Order Deleted", Toast.LENGTH_LONG).show(); 
                        } else {
                            // Error occurred in registration. Get the error
                            // message
                            String errorMsg = jObj.getString("error_msg");
                            Toast.makeText(getApplicationContext(),
                                    errorMsg, Toast.LENGTH_LONG).show();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }

                }
            }, new Response.ErrorListener() {

                @Override
                public void onErrorResponse(VolleyError error) {
                    Log.e(TAG, "Registration Error: " + error.getMessage());
                    Toast.makeText(getApplicationContext(),
                            error.getMessage(), Toast.LENGTH_LONG).show();
                }
            }) {

        @Override
        protected Map<String, String> getParams() {
            // Posting params to register url
            Map<String, String> params = new HashMap<String, String>();
            params.put("tag", "deleteorder");
            params.put("tablenum", tablenum);
            params.put("desc", desc);
            params.put("price", price);
            params.put("quantity", quantity);

            //params.remove("tablenum");
            //params.remove("desc");
            //params.remove("price");
            //params.remove("quantity");

            return params;
        }
    };

    // Adding request to request queue
    AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}
}

RegisterActivity.java

package com.system.receivingoforder;

import com.system.receivingoforder.app.AppConfig;
import com.system.receivingoforder.app.AppController;
import com.system.receivingoforder.helper.SQLiteHandler;
import com.system.receivingoforder.helper.SessionManager;


import java.util.HashMap;
import java.util.Map;

import org.json.JSONException;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import com.android.volley.Request.Method;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;

public class RegisterActivity extends Activity {
private static final String TAG = RegisterActivity.class.getSimpleName();
private Button btnRegister;
private EditText inputFullName;
private EditText inputEmail;
private EditText inputPassword;
private ProgressDialog pDialog;
private SessionManager session;
private SQLiteHandler db;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    // Progress dialog
    pDialog = new ProgressDialog(this);
    pDialog.setCancelable(false);

    // Session manager
    session = new SessionManager(getApplicationContext());

    // SQLite database handler
    db = new SQLiteHandler(getApplicationContext());

    // Check if user is already logged in or not
    if (session.isLoggedIn()) {
        // User is already logged in. Take him to main activity


    }

    // Register Button Click event
    btnRegister.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            String name = inputFullName.getText().toString();
            String email = inputEmail.getText().toString();
            String password = inputPassword.getText().toString();

            if (!name.isEmpty() && !email.isEmpty() && !password.isEmpty()) {
                registerUser(name, email, password);
            } else {
                Toast.makeText(getApplicationContext(),
                        "Please enter your details!", Toast.LENGTH_LONG)
                        .show();
            }
        }
    });

    // Link to Login Screen

}

/**
 * Function to store user in MySQL database will post params(tag, name,
 * email, password) to register url
 * */
private void registerUser(final String name, final String email,
        final String password) {
    // Tag used to cancel the request
    String tag_string_req = "req_register";

    pDialog.setMessage("Registering ...");
    showDialog();

    StringRequest strReq = new StringRequest(Method.POST,
            AppConfig.URL_REGISTER, new Response.Listener<String>() {

                @Override
                public void onResponse(String response) {
                    Log.d(TAG, "Register Response: " + response.toString());
                    hideDialog();

                    try {
                        JSONObject jObj = new JSONObject(response);
                        boolean error = jObj.getBoolean("error");
                        if (!error) {
                            // User successfully stored in MySQL
                            // Now store the user in sqlite
                            String uid = jObj.getString("uid");

                            JSONObject user = jObj.getJSONObject("user");
                            String name = user.getString("name");
                            String email = user.getString("email");
                            String created_at = user
                                    .getString("created_at");

                            // Inserting row in users table
                            db.addUser(name, email, uid, created_at);

                            // Launch login activity

                        } else {

                            // Error occurred in registration. Get the error
                            // message
                            String errorMsg = jObj.getString("error_msg");
                            Toast.makeText(getApplicationContext(),
                                    errorMsg, Toast.LENGTH_LONG).show();
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }

                }
            }, new Response.ErrorListener() {

                @Override
                public void onErrorResponse(VolleyError error) {
                    Log.e(TAG, "Registration Error: " + error.getMessage());
                    Toast.makeText(getApplicationContext(),
                            error.getMessage(), Toast.LENGTH_LONG).show();
                    hideDialog();
                }
            }) {

        @Override
        protected Map<String, String> getParams() {
            // Posting params to register url
            Map<String, String> params = new HashMap<String, String>();
            params.put("tag", "register");
            params.put("name", name);
            params.put("email", email);
            params.put("password", password);

            return params;
        }

    };

    // Adding request to request queue
    AppController.getInstance().addToRequestQueue(strReq, tag_string_req);
}

private void showDialog() {
    if (!pDialog.isShowing())
        pDialog.show();
}

private void hideDialog() {
    if (pDialog.isShowing())
        pDialog.dismiss();
}

}

listoforders.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/greenboard_background" >

<TextView
    android:id="@+id/list_of_orders_tv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="45dp"
    android:text="@string/list_of_orders"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textSize="35sp" />

<ListView
    android:id="@+id/android:list"
    android:layout_width="543dp"
    android:layout_height="800dp"
    android:layout_below="@+id/list_of_orders_tv"
    android:layout_centerHorizontal="true" >
</ListView>

</RelativeLayout>

listoforders_items.xml

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

<TextView
    android:id="@+id/loo_tablenumber"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:text="@string/table_no"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textSize="30sp" />

<TextView
    android:id="@+id/loo_itemquantity"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/loo_tablenumber"
    android:text="@string/item_quantity"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:textSize="30sp" />

</RelativeLayout>

Answer 1

您使用arraylist，因此您可以使用arrayList.remove(position)，之后您只需添加adapter.notifyDataSetChanged();