我正在制作一个像耐克运行应用程序这样的应用程序。 TrackerService 类是一种服务，它将锻炼记录保存在 stop(( 上，然后在resume()上从共享首选项重新加载数据。在我搜索了几个解决方案之后，我实现了将 ArrayList 解析为 Json 的方式。在第一次尝试停止((恢复((时，锻炼记录恢复成功，但是当第二次尝试停止((恢复((时，发生了RunTimeException。
如何解决这个问题？
package smu.ac.kr.johnber.run;
import android.annotation.SuppressLint;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.location.Location;
import android.os.Binder;
import android.os.IBinder;
import android.os.Looper;
import android.os.SystemClock;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationCallback;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationResult;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.model.LatLng;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.google.maps.android.SphericalUtil;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import smu.ac.kr.johnber.util.RecordUtil;
import static smu.ac.kr.johnber.util.LogUtils.LOGD;
import static smu.ac.kr.johnber.util.LogUtils.makeLogTag;
/**
* RunningFragment 와 통신
* - data의 전송은 callback listener을 사용
* 달리기 기록 측정을 위한 Service
* requestLocationUpdates()할 때 마다 거리, 칼로리를 계산한다.
*/
public class TrackerService extends Service {
private final String TAG = "TrackerService.class";
private static final int REQUEST_LOCATION_PERMISSION = 101;
private static final String PERMISSION = android.Manifest.permission.ACCESS_FINE_LOCATION;
// status flag
private static final int INIT = 20000;
private static final int START = 20001;
private static final int PAUSE = 20002;
private static final int RESUME = 20003;
private static final int STOP = 20003;
private final IBinder mIBinder = new TrackerBinder();
private TrackerCallback mtrackerCallback;
private Record mRecord;
private int mState;
private double distance;
private double elapsedTime;
private double calories;
// private ArrayList<LatLng> location;
private Location mCurrentLocation;
private Location mLastLocation;
private Location mActivityLastLocation; // 처음 start할때 location
private ArrayList<Location> locationArrayList = new ArrayList<Location>();
private Date date;
private double startTime;
private double currentTime;
private String title;
private FusedLocationProviderClient mFusedLocationClient;
private LocationRequest mLocationRequest;
// private Location mCurrentLocation;
private LocationCallback mLocationCallback;
//TODO : user 객체를 앱 로그인 성공후 사용자 만들어 놓고 weight만 getter로 받아와서 사용할 수 있도록 하기
private double weight = 70.0;
public TrackerService() {
}
/**
* 서비스에서 제공하는 public 함수들을 사용하기 위한 통신채널
*
*/
public class TrackerBinder extends Binder {
//외부에서 함수 호출시 RecService의 레퍼런스를 돌려줄 수 있도록함
public TrackerService getService(){
return TrackerService.this;
}
}
@Override
public void onCreate() {
super.onCreate();
LOGD(TAG,"onCreate");
// location 받아오기위한 준비
mFusedLocationClient = LocationServices.getFusedLocationProviderClient(this);
mLocationRequest = getLocationRequest();
createLocationCallback();
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
LOGD(TAG, "onStartCommand");
return START_STICKY;
}
@Override
public IBinder onBind(Intent intent) {
LOGD(TAG,"onBind");
// TODO: Return the communication channel to the service.
return mIBinder;
}
@Override
public void onDestroy() {
super.onDestroy();
LOGD(TAG, "onDestroy");
mFusedLocationClient.removeLocationUpdates(mLocationCallback);
}
/**
* 운동기록 변화에 따라 RunningActivity UI반영을 위한 콜백 메소드
*/
public interface TrackerCallback {
public void onDistanceChanged(double value);
public void onCaloriesChanged(double value);
public void onElapsedtimeChanged(double value);
public void onLocationChanged(LatLng from, LatLng value);
//TODO:
public void onPausedLisenter(Record record);
}
// @SuppressLint("MissingPermission")
// private void startLocationTracking() {
// LOGD(TAG, "enableLocationTracking : check permission");
// //TODO : request current location
// LOGD(TAG, "Start location tracking");
// mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
// }
/**
* LocationRequest 설정
- interval
- fastest interval
- priority
*/
private LocationRequest getLocationRequest() {
@SuppressLint("RestrictedApi")
LocationRequest locationRequest = new LocationRequest();
locationRequest.setInterval(10000);
//5 seconds
locationRequest.setFastestInterval(5000);
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
return locationRequest;
}
/**
mFusedLocationClient로 부터 위치를 받았을 때 실행할 콜백 메소드
매 위치가 바뀔때마다 기록 측정
*/
private void createLocationCallback() {
mLocationCallback = new LocationCallback() {
@Override
public void onLocationResult(LocationResult locationResult) {
super.onLocationResult(locationResult);
// INIT -> START하는경우 LastLocation 설정
if (mState == INIT) {
//RUN버튼 누른 시점의 위치
mActivityLastLocation = locationResult.getLastLocation();
//ArrayList에 시작 location 저장
mLastLocation = mActivityLastLocation;
locationArrayList.add(mLastLocation);
}
startImpl(locationResult);
}
};
}
// 변수들 초기화
public void init(){
mState = INIT;
distance = 0;
elapsedTime = 0;
calories = 0;
// location = null;
mCurrentLocation = null;
mLastLocation = null;
mActivityLastLocation = null;
if (locationArrayList != null) {
if (!locationArrayList.isEmpty()) {
locationArrayList.clear();
LOGD(TAG,"locationList cleared"+locationArrayList.size());
}
}
currentTime = 0;
startTime = SystemClock.elapsedRealtime();
date = new Date(System.currentTimeMillis());
}
/**
* state 확인 ( resume인경우 이전값에 이어서 측정)
* locationrequestUpdates (onLocationResult콜백이 호출되고, 여기서 운동기록 측정 함수 호출)
* Timer.start
*/
@SuppressLint("MissingPermission")
public void start(int Action) {
LOGD(TAG, "start tracking");
// set state
switch (Action) {
case INIT:
mState = INIT;
break;
case RESUME:
mState = RESUME;
break;
}
if(mState != RESUME){
//init variables
init();
} else if (mState == RESUME) {
//reload variables from sharedPreferences
resume();
}
mFusedLocationClient.requestLocationUpdates(mLocationRequest, mLocationCallback, Looper.myLooper());
//기록 계산은 requsetLocationUpdates()에 따른 콜백 메소드인 onLocationResult에서 이루어짐 -> startImpl()
//변수 초기화
}
// TODO : 운동기록 측정 함수 , mCallback의 각 함수 호출
public void startImpl(LocationResult locationResult){
mState = START;
//거리 측정
mCurrentLocation = locationResult.getLastLocation();
//ArrayList에 location 저장
locationArrayList.add(mCurrentLocation);
LOGD(TAG,"size of location list"+locationArrayList.size());
LatLng from = new LatLng(mLastLocation.getLatitude(), mLastLocation.getLongitude());
LatLng to = new LatLng(mCurrentLocation.getLatitude(), mCurrentLocation.getLongitude());
if(!from.equals(to))
//mLastLocation~mCurrentLocation간 거리 구하기
distance += SphericalUtil.computeDistanceBetween(from,to);
LOGD(TAG, "기록 측정"+"Current: "+from.toString()+" Last: "+to.toString()+" distance: "+Integer.toString((int)distance));
//runningfragment에서 오버라이딩한 onDistanceChanged를 호출하여 UI업데이트
mtrackerCallback.onDistanceChanged(distance);
mtrackerCallback.onLocationChanged(from,to);
//운동시간
elapsedTime = SystemClock.elapsedRealtime() - startTime;
//평균속도
double averageSpeed = distance / elapsedTime;
LOGD(TAG, "sppeed: " + averageSpeed+" dist and elapsed "+distance+" "+elapsedTime);
//칼로리 계산
calories = RecordUtil.getAverageCalories(weight, elapsedTime);
LOGD(TAG,"calories:"+calories);
mtrackerCallback.onCaloriesChanged(calories);
//LastLocation 업데이트
mLastLocation = mCurrentLocation;
}
/**
* sharedPreference로 부터 데이터 복원
* - distance
* - calories
* - elapsedTime
* - startTime
* - locationArrayList
* - lastLocation
* locationArrayList.get(마지막)값으로 복원
*/
public void resume() {
SharedPreferences preferences;
preferences = getApplicationContext().getSharedPreferences("savedRecord", Context.MODE_PRIVATE);
Gson gson = new Gson();
String response = preferences.getString("LOCATIONLIST", "");
locationArrayList = gson.fromJson(response, new TypeToken<ArrayList<Location>>() {}.getType());
LOGD(TAG, "size of saved array list " + locationArrayList.size());
mLastLocation = locationArrayList.get(locationArrayList.size() - 1);
LOGD(TAG, "lat of last location" + mLastLocation.getLatitude());
// 나머지 복원
distance = Double.parseDouble(preferences.getString("DISTANCE", ""));
elapsedTime = Double.parseDouble(preferences.getString("ELAPSEDTIME", ""));
calories = Double.parseDouble(preferences.getString("CALORIES", ""));
startTime = Double.parseDouble(preferences.getString("STARTTIME", ""));
LOGD(TAG, "distance: " + distance + " elapsedTime: " + elapsedTime + " statTime: " + startTime);
mState = RESUME;
}
/**
* save 기록
* 자원 해제
* stopSelf()
*/
public void stop() {
double endTime = SystemClock.elapsedRealtime();
// mRecord = new Record(distance,elapsedTime,calories, locationArrayList,date, startTime, endTime, date.toString());
/**
* sharedPreference에 Record값 저장
*/
//TODO:
//locaitonArrayList저장
SharedPreferences preferences;
SharedPreferences.Editor editor;
preferences = getApplicationContext().getSharedPreferences("savedRecord", Context.MODE_PRIVATE);
Gson gson = new Gson();
String json = gson.toJson(locationArrayList);
editor = preferences.edit();
editor.putString("LOCATIONLIST", json);
editor.apply();
// 나머지 저장
//TODO : String으로 변환해 저장 한 후 데이터 복원시 double로 다시 복원
editor.putString("DISTANCE", Double.toString(distance));
editor.putString("ELAPSEDTIME", Double.toString(elapsedTime));
editor.putString("CALORIES", Double.toString(calories));
//TODO : Date와 Title은 firebase에 Record 객체를 저장하기 전에 설정할것
editor.putString("STARTTIME", Double.toString(startTime));
editor.putString("ENDTIME", Double.toString(endTime));
editor.commit();
//서비스 종료
this.stopSelf();
LOGD(TAG, "stopTrackerService");
}
/**
* RunningFragment에 데이터 전달을 위한 callback listener를 등록/해제
*/
public void registerCallback(TrackerCallback callback){
mtrackerCallback = callback;
}
public void unregisterCallback(TrackerCallback callback){
mtrackerCallback = null;
}
}
05-14 01：43：03.974 1276-1276/smu.ac.kr.johnber E/Android运行时：致命 异常：主要
Process: smu.ac.kr.johnber, PID: 1276
java.lang.RuntimeException: Failed to invoke protected java.lang.ClassLoader() with no args
at com.google.gson.internal.ConstructorConstructor$3.construct(ConstructorConstructor.java:111)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:210)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:129)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:220)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:129)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:220)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:41)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:82)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61)
at com.google.gson.Gson.fromJson(Gson.java:887)
at com.google.gson.Gson.fromJson(Gson.java:852)
at com.google.gson.Gson.fromJson(Gson.java:801)
at smu.ac.kr.johnber.run.TrackerService.resume(TrackerService.java:284)
at smu.ac.kr.johnber.run.TrackerService.start(TrackerService.java:227)
at smu.ac.kr.johnber.run.RunningFragment$1.onServiceConnected(RunningFragment.java:226)
at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1453)
at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1481)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
Caused by: java.lang.InstantiationException: Can't instantiate abstract class java.lang.ClassLoader
at java.lang.reflect.Constructor.newInstance0(Native Method)
at java.lang.reflect.Constructor.newInstance(Constructor.java:430)
at com.google.gson.internal.ConstructorConstructor$3.construct(ConstructorConstructor.java:108)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:210)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:129)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:220)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:129)
at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:220)
at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:41)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:82)
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61)
at com.google.gson.Gson.fromJson(Gson.java:887)
at com.google.gson.Gson.fromJson(Gson.java:852)
at com.google.gson.Gson.fromJson(Gson.java:801)
at smu.ac.kr.johnber.run.TrackerService.resume(TrackerService.java:284)
at smu.ac.kr.johnber.run.TrackerService.start(TrackerService.java:227)
at smu.ac.kr.johnber.run.RunningFragment$1.onServiceConnected(RunningFragment.java:226)
at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1453)
at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1481)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
相反，使用其构造函数创建Gson对象，我制作了GsonBuilder并附加serializeNulls(( 它成功工作
GsonBuilder builder = new GsonBuilder();
builder.serializeNulls();