我试图找出这个问题很长一段时间，也许它是由多线程引起的。我是初学者，所以我无法解决这个问题。请帮帮我〜
我使用名为＆＃34; bmob＆＃34;的云数据库，我发现我可以成功获取我想要的数据。但是，循环中可能存在一些错误，我只能获取最后一个选定项目的信息。
P.S。我使用一个名为Playlist的数组列表来存储我将用于在下一个活动中显示列表视图的计算数据。
这是我的代码：
public class DestinationActivity extends Activity implements OnClickListener, NumberPicker.OnValueChangeListener {
//textviews.....
private List<Destination> destinationList = new ArrayList<Destination>();
private DestinationAdapter adapter;
//I have successfully set up the list view
//some int and double values
//to store the id the user selects
private ArrayList<Integer> select_placeID = new ArrayList<Integer>();
public Map<Integer,Double> weightMap;
public List<Plan> planList = new ArrayList<Plan>();
int[] selectedID = new int[10];
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.destination_layout);
//initialize the cloud database
Bmob.initialize(this, BmobConfig.APP_ID);
listView = (ListView) findViewById(R.id.list_destination);
destinationOk_btn = (Button) findViewById(R.id.okButton);
initDestinations(); // initialize the data
adapter = new DestinationAdapter(destinationList, DestinationActivity.this);
//adapter = new DestinationAdapter(this, destinationList, DestinationAdapter.getIsSelected());
listView.setAdapter(adapter);
//....listeners and textviews.......
//submit button
destinationOk_btn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
select_placeID.clear();
for (int i = 0; i < destinationList.size(); i++) {
if (DestinationAdapter.getIsSelected().get(i)) {
select_placeID.add((i + 1));
}
}
//change to int array
selectedID = new int[select_placeID.size()];
for(int i = 0;i<select_placeID.size();i++){
selectedID[i] = select_placeID.get(i);
}
if (select_placeID.size() == 0) {
AlertDialog.Builder builder1 = new AlertDialog.Builder(DestinationActivity.this);
builder1.setMessage("no records");
builder1.show();
}
else {
AlertDialog.Builder builder = new AlertDialog.Builder(DestinationActivity.this);
builder.setMessage("waiting for magic...");
builder.show();
/**
* calculate the route
*/
if (validate()) {
new calRoute().execute();//switch to a new thread
}
}
}
});
}
//initialize the data
private void initDestinations() {
//........
}
@Override
public void onClick(View v) {
//.......
}
/**
* asynctask
*/
private class calRoute extends AsyncTask<Void, Void, List<Plan>>{
public calRoute(){
// TODO Auto-generated constructor stub
}
@Override
protected List<Plan> doInBackground(Void... params) {
List<Plan> result = calculate(time_start, time_end, travel_days);
return result;
}
@Override
protected void onPostExecute(List<Plan> result) {
super.onPostExecute(result);
if (result != null) {
Toast.makeText(DestinationActivity.this, "success", Toast.LENGTH_SHORT).show();
if(planList.size() > 0) {
Intent intent = new Intent();
intent.setClass(DestinationActivity.this, ActivityPlan.class);
intent.putParcelableArrayListExtra("planInfo", (ArrayList<? extends Parcelable>) planList);
startActivity(intent);
}
else{
Toast.makeText(DestinationActivity.this, "no plan", Toast.LENGTH_SHORT).show();
}
}
}
}
/**
*plan
**/
public List<Plan> calculate(String time_start, String time_end, int travel_days) {
SimpleDateFormat df = new SimpleDateFormat(("HH:mm"));
Date starttime = new Date();
Date endtime = new Date();
try {
starttime = df.parse(time_start);
} catch (ParseException e) {
e.printStackTrace();
}
try {
endtime = df.parse(time_end);
} catch (ParseException e) {
e.printStackTrace();
}
double l = endtime.getTime() - starttime.getTime();
double hour = (l / (60 * 60 * 1000));
double min = ((l / (60 * 1000)) - hour * 60);
if(min == 0){
min = 60;
}
else {
travel_time = ((1.0 * travel_days * hour) * (min / 60));
DecimalFormat decimalFormat = new DecimalFormat("#.0");
travelTime = Double.parseDouble(decimalFormat.format(travel_time));
}
weightMap = new LinkedHashMap<Integer, Double>(); //store weight
int totalPriority = 0;//total priority
final Destination start = new Destination(116.32133, 39.92269);
final HashMap<Integer, Integer> pMap = new HashMap<Integer, Integer>();
final HashMap<Integer, String> nameMap = new HashMap<Integer, String>();
final HashMap<Integer, Destination> objectMap = new LinkedHashMap<Integer, Destination>();
/**
* get the data from cloud database
*/
BmobQuery<Destination> query = new BmobQuery<Destination>();
for (int sid: selectedID) {
query.addWhereEqualTo("id", sid);
query.findObjects(new FindListener<Destination>() {
@Override
public void done(List<Destination> list, BmobException e) {
if (e == null) {
System.out.println("success：total" + list.size() + "items。");
for (Destination destination : list) {
int p = destination.getPriority();
int id = destination.getId();
String name = destination.getName();
double longitude = destination.getLongitude();
double latitude = destination.getLatitude();
objectMap.put(id, new Destination(longitude, latitude));
System.out.println(id);
double dis = DistanceUtil.distance(start.getLongitude(), start.getLatitude(),
longitude, latitude);
pMap.put(id, p);
weightMap.put(id, new Double(dis));
nameMap.put(id, name);
}
} else {
Log.i("bmob", "error：" + e.getMessage() + "," + e.getErrorCode());
}
}
});
}
for (Integer key : pMap.keySet()) {
int p = pMap.get(key).intValue();
totalPriority = totalPriority + p;
}
double weight = 0.0;
for (Map.Entry<Integer, Double> hm : weightMap.entrySet()) {
double hm2Value = pMap.get(hm.getKey());
weight = totalPriority / hm.getValue() * hm2Value;
weightMap.put(hm.getKey(), weight);
}
/**
* 按照weight值来排序
* 判断是否传递数据给plan_activity
*/
MapUtil.sortByValue(weightMap);
//排好序后计算距离
Iterator it = weightMap.entrySet().iterator();
int order = 0;
while (it.hasNext()) {
order++;
Map.Entry entry = (Map.Entry) it.next();
objectMap.put(new Integer(order), objectMap.get(entry.getKey()));
}
PlanTask planTask = new PlanTask();//封装了每个plan计算的方法
for (Map.Entry<Integer, Double> entry : weightMap.entrySet()) {
System.out.println("id= " + entry.getKey());
double play_time = planTask.calPlay_time(weightMap.size(),
weightMap.get(entry.getKey()), travelTime);
double driving_time = planTask.calDrive_time(DistanceUtil.distance(
objectMap.get(entry.getKey()).getLatitude(),
objectMap.get(entry.getKey()).getLongitude(),
objectMap.get(entry.getKey() + 1).getLatitude(),
objectMap.get(entry.getKey() + 1).getLongitude()
));
String arrive_time = "hello world";//未完待续
String place_name = nameMap.get(entry.getKey());
Plan plan = new Plan(place_name, arrive_time, driving_time, play_time);
//传递plan对象list
planList.add(entry.getKey(), plan);
}
return planList;
}
}
当我调试它时，我发现在calculate（）函数中，
的输出 BmobQuery<Destination> query = new BmobQuery<Destination>();
for (int sid: selectedID) {
query.addWhereEqualTo("id", sid);
query.findObjects(new FindListener<Destination>() {
@Override
public void done(List<Destination> list, BmobException e) {
if (e == null) {
System.out.println("success：total" + list.size() + "items。");
for (Destination destination : list) {
int p = destination.getPriority();
int id = destination.getId();
String name = destination.getName();
double longitude = destination.getLongitude();
double latitude = destination.getLatitude();
objectMap.put(id, new Destination(longitude, latitude));
System.out.println(id);
//calculate the distance
double dis = DistanceUtil.distance(start.getLongitude(), start.getLatitude(),longitude, latitude);
pMap.put(id, p);
weightMap.put(id, new Double(dis));
nameMap.put(id, name);
}
} else {
Log.i("bmob", "error：" + e.getMessage() + "," + e.getErrorCode());
}
}
});
成功：总共1项。＆＃34;在循环之后，如果我选择了3个项目，则成功：总共1个项目。＆＃34; 3次，只抓住最后一项的信息。 AND三个哈希映射的大小：pMap，nameMap和objectMap都是零。 为什么？？？这太奇怪了......请帮我找出错误的
P.S。方法findObject（）和done（）是由云数据库平台编写的，我想确保在执行这两个方法之后：我将把数据放入哈希映射中，这样哈希映射就不会了空。但我不知道如何同步代码。
LogCAT中没有错误，但是，有序列表视图无法显示在第二个活动中。请帮助我，它困扰了我很长一段时间。谢谢!!!