Question

当我使用findinbackground方法从解析下载数据时，我的项目出了问题。所以看看我的代码（loadAllData method（）和LoadDataAsyncTask）。我想在这个Activity中加载数据，我将在不同的活动中使用它但是当我在不同的活动中调用我的onjects时它是null。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_find);

    new LoadDataAsynceTask().execute();

    if (savedInstanceState == null) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.add(R.id.container, new HomeFragment(), FRAGMENT_HOME_TAG);
        transaction.commit();
    }

}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    ParseFacebookUtils.onActivityResult(requestCode, resultCode, data);
}

private class LoadDataAsynceTask extends AsyncTask<Void, Void, Void>{
    @Override
    protected Void doInBackground(Void...params) {
        loadAllData();
        return null;
    }
    @Override
    protected void onPostExecute(Void result) {
        Toast.makeText(FindActivity.this,
                "Stastions "+stations.size()+
                "\nTimes "+stationTimes.size()+ 
                "\nTaxis "+taxis.size() 
                ,LENGTH_LONG).show(); // "Station 0 stationTime 0 Taxis 0"


    }
    @Override
    protected void onProgressUpdate(Void...values) {

    }

    @Override
    protected void onPreExecute() {
    }
}

public void loadAllData() {
    ParseQuery<ThoiGianBusStation> query = new ParseQuery<>("ThoiGian");
    query.findInBackground(new FindCallback<ThoiGianBusStation>() {
        @Override
        public void done(List<ThoiGianBusStation> list, ParseException e) {
            for (ThoiGianBusStation i : list) {
                ThoiGianBusStation newTime = new ThoiGianBusStation();
                newTime.setPid(i.getPid());
                newTime.setPTime(i.getPTime());
                newTime.setPTimeId(i.getPTimeId());
                stationTimes.add(newTime);
            }
            Toast.makeText(FindActivity.this, "Times "+stationTimes.size() ,LENGTH_LONG).show(); 
// "statitonTimes 13"
        }
    });

    ParseQuery<ChuyenXe> query1 = new ParseQuery<>("BusStation");
    query1.findInBackground(new FindCallback<ChuyenXe>() {
        @Override
        public void done(List<ChuyenXe> list, ParseException e) {
            for (ChuyenXe chuyenXe : list) {
                ChuyenXe newXe = new ChuyenXe();
                newXe.setPHangxe(chuyenXe.getPHangxe());
                newXe.setPGotime(chuyenXe.getPGotime());
                newXe.setPTransforment(chuyenXe.getPTransforment());
                newXe.setPTram(chuyenXe.getPTram());
                newXe.setPGia(chuyenXe.getPGia());
                newXe.setPLoai(chuyenXe.getPLoai());
                newXe.setPNoidi(chuyenXe.getPNoidi());
                newXe.setPNoiden(chuyenXe.getPNoiden());
                newXe.setPSDT(chuyenXe.getPSDT());
                newXe.setPService(chuyenXe.getPService());
                newXe.setPXeID(chuyenXe.getPXeID());
                for (int i = 0; i < stationTimes.size(); i++) {
                    if (newXe.id == stationTimes.get(i).xe_id) {
                        newXe.addThoiGian(stationTimes.get(i).thoigian);
                    }
                }
                stations.add(newXe);
            }
            Toast.makeText(FindActivity.this, "Station " + stations.size(), LENGTH_LONG).show(); 
// "Station 4"
        }
    });

    ParseQuery<Taxi> query2 = new ParseQuery<>("Taxi");
    query2.findInBackground(new FindCallback<Taxi>() {
        @Override
        public void done(List<Taxi> list, ParseException e) {
            for (Taxi taxi : list){
                Taxi newTaxi = new Taxi();
                newTaxi.setPname(taxi.getPname());
                newTaxi.setPCost1(taxi.getPCost1());
                newTaxi.setPCost2(taxi.getPCost2());
                newTaxi.setPCost3(taxi.getPCost3());
                newTaxi.setPkv(taxi.getPkv());
                newTaxi.setPsdt(taxi.getPsdt());
                newTaxi.setPWay1(taxi.getPWay1());
                newTaxi.setPWay2(taxi.getPWay2());
                taxis.add(newTaxi);
            }
            Toast.makeText(FindActivity.this, "Taxis "+taxis.size() ,LENGTH_LONG).show(); 
// "Taxis 3"
        }
    });
}

}

ChuyenXe班：

public class ChuyenXe extends ParseObject {
public int getPXeID(){
    return getInt("xe_id");
}
public void setPXeID(int noidi) {
    put("xe_id", noidi);
}

public String getPTransforment(){
    return getString("transforment");
}
public void setPTransforment(String noidi) {
    put("transforment", noidi);
}

public String getPTram(){
    return getString("tram_dung_chan");
}
public void setPTram(String noidi) {
    put("tram_dung_chan", noidi);
}

public String getPService(){
    return getString("services");
}
public void setPService(String noidi) {
    put("services", noidi);
}

public String getPSDT(){
    return getString("sdt");
}
public void setPSDT(String noidi) {
    put("sdt", noidi);
}

public String getPLoai(){
    return getString("loaixe");
}
public void setPLoai(String noidi) {
    put("loaixe", noidi);
}

public String getPHangxe(){
    return getString("hangxe");
}
public void setPHangxe(String noidi) {
    put("hangxe", noidi);
}

public String getPGotime(){
    return getString("go_time");
}
public void setPGotime(String noidi) {
    put("go_time", noidi);
}

public String getPGia(){
    return getString("gia");
}
public void setPGia(String noidi) {
    put("gia", noidi);
}

public String getPNoiden(){
    return getString("bendi");
}
public void setPNoiden(String noidi) {
    put("benden", noidi);
}

public String getPNoidi(){
    return getString("bendi");
}
public void setPNoidi(String noidi) {
    put("bendi", noidi);
}

ThoiGianBusStation类：

public class ThoiGianBusStation extends ParseObject{
 public int getPTimeId(){
    return getInt("time_id");
}
public void setPTimeId(int timeId) {
    put("time_id", timeId);
}

public int getPid(){
    return getInt("xe_id");
}
public void setPid(int name) {
    put("xe_id", name);
}

public String getPTime(){
    return getString("time");
}
public void setPTime(String time) {
    put("time", time);
}

出租车类：

public class Taxi extends ParseObject{
public String getPname(){
    return getString("name");
}
public void setPname (String noidi) {
    put("name", noidi);
}

public String getPsdt(){
    return getString("sdt");
}
public void setPsdt (String noidi) {
    put("sdt", noidi);
}

public String getPkv(){
    return getString("khuvuc");
}
public void setPkv(String noidi) {
    put("khuvuc", noidi);
}

public int getPWay2(){
    return getInt("doan2");
}
public void setPWay2(int noidi) {
    put("doan2", noidi);
}

public int getPWay1(){
    return getInt("doan1");
}
public void setPWay1(int noidi) {
    put("doan1", noidi);
}

public int getPCost2(){
    return getInt("cost2");
}
public void setPCost2(int noidi) {
    put("cost2", noidi);
}
public int getPCost3(){
    return getInt("cost3");
}
public void setPCost3(int noidi) {
    put("cost3", noidi);
}
public int getPCost1(){
    return getInt("cost1");
}
public void setPCost1(int noidi) {
    put("cost1", noidi);
}

Answer 1

问题是findInBackground()，您应该使用find()进行更改，因为您已经执行了asnc任务，＆＃34; findInBackground（）＆＃34;创建新的后台线程，当你的asnc任务完成后，你可能无法获得结果。因为你的asnc任务不会等待Parse后台线程。您应该使用find()进行更改。 Parse在后台任务中建议findInBackground()。

来自parse.com的query.findInbackGround

1 个答案: