java - android循环出现问题-无法将值放入hashmap

Question

这个问题困扰我很久了。我使用了一个叫bmob的云数据库，我发现我可以成功获取我想要的数据。不过，循环中可能会出现一些错误，只能获取最后选择的项目的信息。

附:我使用一个名为 Playlist 的数组列表来存储计算数据，我将使用该数据在下一个 Activity 中显示 ListView 。

这是我的代码:

public class DestinationActivity extends Activity implements OnClickListener, NumberPicker.OnValueChangeListener {

private TextView from_place, date, days, start_time, end_time, number, money_view;
private Button addButton, subButton;
private ImageView backButton, telephone;
private ListView listView;
private Button destinationOk_btn;
private ShapeLoadingDialog shapeLoadingDialog;

private Tip startTip;

private Calendar calendar;
private DatePickerDialog dialog;
private TimePickerDialog dialog2;

private List<Destination> destinationList = new ArrayList<Destination>();


private DestinationAdapter adapter;

private int number_value = 1; 

private String time_start;
private String time_end;
private int travel_days;
double travelTime;//total playing time
double travel_time;
private int money;
private int num = 1;


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();
                }


            }
        }

    });
}



//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，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());
                        }
                    }
                });

为“成功:共1条”。循环结束后，如果我选择了 3 项，则会显示“成功:共 1 项”。 3次，只捕获到最后一项的信息。AND 三个 HashMap 的大小:pMap、nameMap 和 objectMap 均为零。为什么？？？真是奇怪啊……

LogCAT 中没有错误，但是有序 ListView 无法在第二个 Activity 中显示。请帮助我，这困扰了我很长时间。谢谢!!!

Answer 1

不幸的是，我无法弄清楚太多，因为我对响应式(Reactive)编程还不太适应，因为该平台通常使用大量 rxjava，但这里有一些可以增强代码的东西

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>();

// this time only one list of three elements is added instead of three lists of one element each
query.addWhereContainedIn("id", Arrays.asList(selectedID));

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);

                        }
                        // continue execution here though you won't be able to return a list of plans here
                    } else {
                        Log.i("bmob", "error：" + e.getMessage() + "," + e.getErrorCode());
                    }
                }
});

希望这有帮助:)