我已经完成了ListView并使用了CHOICE_MODE_MULTIPLE和simple_list_item_multiple_choice来允许用户从列表中删除任何项目（通过取消选中该项旁边的复选框）。然后，此操作应仅将选中的项目保留在列表中 我的问题是ListView的出现顺序与它在数据库中存储的顺序不同（也就是创建记录的日期）， 因此，当取消选中某个项目时，它不会从数据库中删除。而是删除了一些其他记录，因为ListView中的项目的顺序与数据库中的顺序不同。每次刷新页面时，ListView中的项目顺序都会重新排列。 如何始终以与数据库中相同的顺序将项目显示在ListView中？ 我想指出我用过：
queryProducts.orderByAscending（ “createdAt”）;
但是，由于某种原因，它没有正确排序。
这是我的代码：
package com.androidbegin.parselogintutorial;
import java.util.ArrayList;
import java.util.List;
import com.parse.FindCallback;
import com.parse.ParseException;
import com.parse.ParseObject;
import com.parse.ParseQuery;
import com.parse.ParseUser;
import com.parse.SaveCallback;
import android.app.ActionBar.Tab;
import android.app.Activity;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.util.SparseBooleanArray;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.ProgressBar;
import android.widget.Toast;
public class OrderListActivity extends Activity{
@Override
public void onBackPressed() {
Log.d("CDA", "onBackPressed Called");
Intent setIntent = new Intent(getApplicationContext(),TabsActivity.class);
startActivity(setIntent);
}
@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;
}
@Override
public boolean onOptionsItemSelected(MenuItem item){
switch(item.getItemId()){
case R.id.action_contactus:
String [] to = new String[]{"Shatha-sa@hotmail.com", "",};
String [] subject = new String[]{"Test Email - Smart Shopping System",};
Intent emailActivity = new Intent(Intent.ACTION_SEND);
//set up the recipient address
emailActivity.putExtra(Intent.EXTRA_EMAIL, to );
//set up the email subject
emailActivity.putExtra(Intent.EXTRA_SUBJECT, subject);
//you can specify cc addresses as well
emailActivity.putExtra(Intent.EXTRA_CC, new String[] {"nabuhossain@stu.kau.edu.sa"});
emailActivity.setType("message/rfc822");
startActivity(Intent.createChooser(emailActivity, "Select your Email Provider :"));
return true;
case R.id.action_logout:
ParseUser.logOut();
Intent intent = new Intent(this, FirstScreenActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
finish();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
ListView OrderItem;
Button button_confirmOrder;
private ProgressBar pb =null;
ParseObject u = new ParseObject("OrderItem");
int counter = 0;
int i;
int m = 0;
public void onStart() {
super.onStart();
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.orderslist);
OrderItem = (ListView) findViewById(R.id.listV_displayorders);
button_confirmOrder = (Button) findViewById(R.id.button_confirmorder);
pb = (ProgressBar) findViewById(R.id.progressBar1);
pb.setVisibility(View.VISIBLE);
ParseQuery<ParseObject> queryId = new ParseQuery<ParseObject>("orders");
queryId.whereEqualTo("Customer", ParseUser.getCurrentUser());
queryId.findInBackground(new FindCallback<ParseObject>() {
public void done(final List<ParseObject> ParseObject,final ParseException e) {
for (final ParseObject parseObject : ParseObject) {
final ParseQuery<ParseObject> queryProducts = new ParseQuery("OrderItem");
queryProducts.whereEqualTo("OrderID", parseObject.getObjectId());
queryProducts.orderByAscending("createdAt");
queryProducts.findInBackground(new FindCallback<ParseObject>() {
public void done(final List<ParseObject> ParseObject1, final ParseException e) {
if(ParseObject1.size() != 0){
if (e == null) {
final ArrayAdapter<String> listAdapter = new ArrayAdapter<String>(OrderListActivity.this,
android.R.layout.simple_list_item_multiple_choice);
for (i = 0; i < ParseObject1.size(); i++) {
u = ParseObject1.get(i);
final int Quantity = u.getInt("Quantity");
ParseQuery<ParseObject> query = new ParseQuery<ParseObject>("products");
query.whereEqualTo("productID", u.get("Barcode"));
query.findInBackground(new FindCallback<ParseObject>() {
public void done(List<ParseObject> ParseObject, ParseException e) {
if (e == null) {
for (final ParseObject parseObject : ParseObject) {
final String ProductName = parseObject.get("productName").toString();
final int Price = parseObject.getInt("price");
int TotalPrice = Quantity * Price;
listAdapter.add(ProductName + " " + TotalPrice + " $ " + "Q. " + Quantity);
counter++;
OrderItem.setAdapter(listAdapter);
OrderItem.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
for (m = 0; m <= ParseObject1.size(); m++) {
OrderItem.setItemChecked(m , true);
}
pb.setVisibility(View.INVISIBLE);
}}}});
button_confirmOrder.setOnClickListener(new OnClickListener() {
//SparseBooleanArray checkedPositions = OrderItem.getCheckedItemPositions();
public void onClick(View v) {
int count=0;
for(int j=0; j < ParseObject1.size() ; j++){
if (OrderItem.isItemChecked(j) == false)
count++;
}
if(count == ParseObject1.size()){
Toast.makeText(getApplicationContext(),"Please select a product",Toast.LENGTH_LONG).show();
return;}
else{
SparseBooleanArray checkedPositions = OrderItem.getCheckedItemPositions();
for(int j=0; j < counter ; j++) {
if(checkedPositions.get(j) == false) {
// UNCHECKED
final int n = j;
ParseQuery<ParseObject> queryId = new ParseQuery<ParseObject>("orders");
queryId.whereEqualTo("Customer", ParseUser.getCurrentUser());
queryId.findInBackground(new FindCallback<ParseObject>() {
public void done( List<ParseObject> ParseObject, ParseException e) {
final ParseQuery<ParseObject> queryProducts = new ParseQuery("OrderItem");
queryProducts.whereEqualTo("OrderID", parseObject.getObjectId());
queryProducts.findInBackground(new FindCallback<ParseObject>() {
public void done( List<ParseObject> ParseObject, ParseException e) {
int r = n;
ParseObject.get(n).deleteInBackground();
listAdapter.notifyDataSetChanged();
}});
}});
}}
Intent i = new Intent(getApplicationContext(),locationsActivity.class);
startActivity(i);
return;
}}});
}}
}else{
final ArrayAdapter<String> listAdapter1 = new ArrayAdapter<String>(OrderListActivity.this,
android.R.layout.simple_list_item_1);
listAdapter1.add("There are no results.");
OrderItem.setAdapter(listAdapter1);
pb.setVisibility(View.INVISIBLE);
}}});
}}});
}}
答案 0 :(得分：0)
我认为问题不在于物品的顺序。
要从多选ListView中获取所选项，您需要正确处理SparseBoolean数组。 SparseBoolean数组基本上是一个键值对数组，
所以而不是
if（checkedPositions.get（j）== false）{
你应该做
if（checkedPositions.get（checkedPositions.keyAt（j））== false）{