这个问题困扰了我很长时间。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。但是，循环中可能会出现一些错误，我只能获取最后选择的项目的信息。
附注我使用一个名为 Playlist 的数组列表来存储计算数据，我将使用该数据在下一个活动中显示列表视图。
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());
}
}
});
是“成功：共 1 项”。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 三个哈希映射的大小：pMap、nameMap 和 objectMap 均为零。为什么？？？真是太奇怪了……
LogCAT 中没有错误，但是，有序列表视图无法在第二个活动中显示。请帮助我，这困扰了我很长时间。
谢谢你！！！
