我在sqllite android中收到数据库锁定错误。我的代码中有什么问题吗？我尝试了从这里发现的各种东西，甚至试图在我调用查询后把线程睡眠，但没有用。我仍然得到数据库锁定错误。任何人都可以告诉我为什么这样做？我该怎么做才能解决这个错误？
MainActivity类：
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.gson.Gson;
public class MapViewActivity extends Activity implements LocationListener,
SensorEventListener, OnClickListener {
GoogleMap googleMap;
private boolean started = false;
private ArrayList<AccelLocData> sensorData;
private SensorManager sensorManager;
private Button btnStart, btnStop;
private String provider;
// File root, dir, sensorFile;
FileOutputStream fOut;
private Sensor mAccelerometer;
private FileWriter writer;
private DatabaseHelper databaseHelper;
private BroadcastReceiver alarmReceiver;
private PendingIntent pendingIntentSender, pendingIntentReceiver;
private AlarmManager alarmManager;
private Intent alarmIntent,alarmIntent2;
// private Button btnUpload;
@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
databaseHelper = new DatabaseHelper(this);
databaseHelper.removeAll();
Log.v("datacount",
Integer.toString(databaseHelper.getLocDataCount()));
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mAccelerometer = sensorManager
.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
btnStart = (Button) findViewById(R.id.btnStart);
btnStop = (Button) findViewById(R.id.btnStop);
btnStart.setOnClickListener(this);
btnStop.setOnClickListener(this);
btnStart.setEnabled(true);
btnStop.setEnabled(false);
alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
int status = GooglePlayServicesUtil
.isGooglePlayServicesAvailable(getBaseContext());
if (status != ConnectionResult.SUCCESS) { // Google Play Services
// are
// not available
int requestCode = 10;
Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status,
this, requestCode);
dialog.show();
} else { // Google Play Services are available
// Getting reference to the SupportMapFragment of
// activity_main.xml
// SupportMapFragment supportMapFragment = (MapFragment)
// getFragmentManager().findFragmentById(R.id.map);
// Getting GoogleMap object from the fragment
googleMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
// can use for overlay on the map
List<Double> latList = new ArrayList<Double>();
latList.add(145.7309593);
latList.add(146.34);
latList.add(147.34);
List<Double> lonList = new ArrayList<Double>();
lonList.add(-122.6365384);
lonList.add(-123.6365384);
lonList.add(-124.6365384);
for (int i = 0; i < 3; i++) {
// LatLng latLng = new LatLng(45.7309593, -122.6365384);
LatLng latLng = new LatLng(latList.get(i).doubleValue(),
lonList.get(i).doubleValue());
googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
googleMap
.addMarker(new MarkerOptions()
.position(latLng)
.title("My Spot")
.snippet("This is my spot!")
.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
}
// Enabling MyLocation Layer of Google Map
googleMap.setMyLocationEnabled(true);
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Criteria criteria = new Criteria();
provider = locationManager.getBestProvider(criteria, true);
Location location = locationManager
.getLastKnownLocation(provider);
if (location != null) {
onLocationChanged(location);
}
locationManager
.requestLocationUpdates(provider, 20000, 0, this);
}
} catch (Exception e) {
e.printStackTrace();
}
}
public void onSensorChanged(SensorEvent event) {
if (started) {
double x = event.values[0];
double y = event.values[1];
double z = event.values[2];
long timestamp = System.currentTimeMillis();
LocationManager locManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setPowerRequirement(Criteria.POWER_MEDIUM);
criteria.setAccuracy(Criteria.ACCURACY_FINE);
provider = locManager.getBestProvider(criteria, true);
Location location = locManager.getLastKnownLocation(provider);
double latitude = 0;
double longitude = 0;
if (location != null) {
latitude = location.getLatitude();
longitude = location.getLongitude();
}
AccelLocData accelLocData = new AccelLocData(timestamp, x, y, z,
latitude, longitude);
// Log.d("X data","data x:" + data.getX());
try {
// writer.write(data.toString());
if (databaseHelper != null)
databaseHelper.insertLocData(accelLocData);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
@Override
public void onLocationChanged(Location location) {
TextView tvLocation = (TextView) findViewById(R.id.tv_location);
// Getting latitude of the current location
double latitude = location.getLatitude();
// Getting longitude of the current location
double longitude = location.getLongitude();
// Creating a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
// Showing the current location in Google Map
googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
// Zoom in the Google Map
googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.btnStart:
Context context = getApplicationContext();
alarmIntent = new Intent(context, AccelLocSender.class);
AlarmManager alarmManager = (AlarmManager) context
.getSystemService(Context.ALARM_SERVICE);
pendingIntentSender = PendingIntent.getBroadcast(context, 0,
alarmIntent, 0);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
System.currentTimeMillis(), 60000, pendingIntentSender);
alarmIntent2 = new Intent(context, AccelLocReceiver.class);
pendingIntentReceiver = PendingIntent.getBroadcast(context, 0,
alarmIntent2, 0);
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP,
System.currentTimeMillis(), 30000, pendingIntentReceiver);
btnStart.setEnabled(false);
btnStop.setEnabled(true);
Log.d("startbutton", "cam on click of start");
started = true;
// delete all files..
// start thread to send data
sensorManager.registerListener(this, mAccelerometer,
SensorManager.SENSOR_DELAY_UI);
break;
case R.id.btnStop:
try {
btnStart.setEnabled(true);
btnStop.setEnabled(false);
// btnUpload.setEnabled(true);
started = false;
sensorManager.unregisterListener(this);
Context context1 = getApplicationContext();
AlarmManager alarmManager1 = (AlarmManager) context1
.getSystemService(Context.ALARM_SERVICE);
alarmManager1.cancel(pendingIntentSender);
alarmManager1.cancel(pendingIntentReceiver);
// System.exit(0);
} catch (Exception e) {
e.printStackTrace();
}
break;
default:
break;
}
}
protected void onPause() {
super.onPause();
/*
* if (writer != null) { try { writer.close(); } catch (IOException e) {
* // TODO Auto-generated catch block e.printStackTrace(); } }
*/
}
protected void onResume() {
super.onResume();
/*
* try { Log.d("onresume","called onresume"); writer = new
* FileWriter(sensorFile, true); } catch (IOException e) { // TODO
* Auto-generated catch block e.printStackTrace(); }
*/
}
@Override
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public void onAccuracyChanged(Sensor arg0, int arg1) {
// TODO Auto-generated method stub
}
}
AccelLocSender.java
public class AccelLocSender extends BroadcastReceiver {
private DatabaseHelper databaseHelper;
private static int indexValue=1;
@Override
public void onReceive(Context context, Intent arg1) {
// TODO Auto-generated method stub
System.out.println("cmg in AccelLocsender");
Log.i("Alarm sender", "Came in alarm sender");
databaseHelper = new DatabaseHelper(context);
sendDataToServer();
}
private void sendDataToServer() {
try {
int locDataCount = databaseHelper.getLocDataCount();
List<AccelLocData> accelLocDataList = databaseHelper.getAllDataById(indexValue);
Thread.sleep(3000);
databaseHelper.deleteLocDataById(indexValue);
Thread.sleep(3000);
indexValue += 50;
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("*****");
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
Log.d("datacount", Integer.toString(locDataCount));
nameValuePairs.add(new BasicNameValuePair("datacount", Integer
.toString(locDataCount)));
for (int i = 0; i < accelLocDataList.size(); i++) {
nameValuePairs
.add(new BasicNameValuePair("latitude" + i,
Double.toString(accelLocDataList.get(i)
.getLatitude())));
nameValuePairs
.add(new BasicNameValuePair("longitude" + i, Double
.toString(accelLocDataList.get(i)
.getLongitude())));
nameValuePairs.add(new BasicNameValuePair("accelX" + i, Double
.toString(accelLocDataList.get(i).getX())));
nameValuePairs.add(new BasicNameValuePair("accelY" + i, Double
.toString(accelLocDataList.get(i).getY())));
nameValuePairs.add(new BasicNameValuePair("accelZ" + i, Double
.toString(accelLocDataList.get(i).getZ())));
nameValuePairs
.add(new BasicNameValuePair("timeStamp" + i, Double
.toString(accelLocDataList.get(i)
.getTimeStamp())));
}
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
httpClient.execute(httpPost);
} catch (Exception e) {
e.printStackTrace();
}
}
}
DatabaseHelper.java
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "myapp.db";
static String TABLE_NAME = "AccelLocation";
private static final String KEY_ID = "id";
private static final String LATITUDE_VAL = "latitude";
private static final String LONGITUDE_VAL = "longitude";
private static final String ACCEL_X = "accelX";
private static final String ACCEL_Y = "accelY";
private static final String ACCEL_Z = "accelZ";
private static final String CUR_TIME = "dataTime";
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, 3);
}
SQLiteDatabase db;
@Override
public void onCreate(SQLiteDatabase db) {
System.out.println("cmg in database helper");
String CREATE_TABLE_SQL = "create table if not exists " + TABLE_NAME
+ " (" + KEY_ID + " integer primary key autoincrement,"
+ LATITUDE_VAL + " TEXT," + LONGITUDE_VAL + " TEXT," + ACCEL_X
+ " TEXT," + ACCEL_Y + " TEXT," + ACCEL_Z + " TEXT," + CUR_TIME
+ " TEXT" + ")";
Log.d("createquery", CREATE_TABLE_SQL);
System.out.println("Create query :" + CREATE_TABLE_SQL);
// db.execSQL("DROP TABLE IF EXISTS"+TABLE_NAME);
db.execSQL(CREATE_TABLE_SQL);
// db.close();
}
public void insertLocData(AccelLocData accelLocData) {
if(db == null)
{
db = this.getWritableDatabase();
}
ContentValues values = new ContentValues();
values.put(LATITUDE_VAL, accelLocData.getLatitude());
values.put(LONGITUDE_VAL, accelLocData.getLongitude());
values.put(ACCEL_X, accelLocData.getX());
values.put(ACCEL_Y, accelLocData.getY());
values.put(ACCEL_Z, accelLocData.getZ());
values.put(CUR_TIME, accelLocData.getTimeStamp());
// Inserting Row
db.insert(TABLE_NAME, null, values);
// db.close(); // Closing database connection
}
public void dropTable(){
if( db == null){
db = this.getWritableDatabase();
}
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
}
public List<AccelLocData> getAllData() {
Cursor cursor = null;
List<AccelLocData> accelLocDataList = new ArrayList<AccelLocData>();
//SQLiteDatabase db = null;
// Select All Query
try {
String selectQuery = "SELECT * FROM " + TABLE_NAME;
if(db == null){
db = this.getWritableDatabase();
}
cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
AccelLocData accelLocData = new AccelLocData(
Integer.parseInt(cursor.getString(0)),
Long.parseLong(cursor.getString(6)),
Double.parseDouble(cursor.getString(3)),
Double.parseDouble(cursor.getString(4)),
Double.parseDouble(cursor.getString(5)),
Double.parseDouble(cursor.getString(1)),
Double.parseDouble(cursor.getString(2)));
accelLocDataList.add(accelLocData);
} while (cursor.moveToNext());
}
} catch (Exception e) {
Log.e("DatabasegetallData", e.toString());
} finally {
if(cursor!= null)
cursor.close();
// if(db!=null)
// db.close();
}
// return accelLocData list
return accelLocDataList;
}
public List<AccelLocData> getAllDataById(int indexValue) {
Cursor cursor = null;
List<AccelLocData> accelLocDataList = new ArrayList<AccelLocData>();
// SQLiteDatabase db = null;
// Select All Query
try {
String selectQuery = "SELECT * FROM " + TABLE_NAME + " where "+ KEY_ID + " < "+ indexValue;
if(db == null){
db = this.getWritableDatabase();
}
cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
AccelLocData accelLocData = new AccelLocData(
Integer.parseInt(cursor.getString(0)),
Long.parseLong(cursor.getString(6)),
Double.parseDouble(cursor.getString(3)),
Double.parseDouble(cursor.getString(4)),
Double.parseDouble(cursor.getString(5)),
Double.parseDouble(cursor.getString(1)),
Double.parseDouble(cursor.getString(2)));
accelLocDataList.add(accelLocData);
} while (cursor.moveToNext());
}
} catch (Exception e) {
Log.e("DatabasegetallData", e.toString());
} finally {
if(cursor!= null)
cursor.close();
// if(db!=null)
// db.close();
}
// return accelLocData list
return accelLocDataList;
}
// Deleting single accelLocData
public void deleteLocData(AccelLocData accelLocData) {
if( db == null){
db = this.getWritableDatabase();
}
db.delete(TABLE_NAME, KEY_ID + " = ?",
new String[] { String.valueOf(accelLocData.getId()) });
// db.close();
}
public void deleteLocDataById(int indexValue) {
if(db == null){
db = this.getWritableDatabase();
}
db.delete(TABLE_NAME, KEY_ID + " < ?",
new String[] { String.valueOf(indexValue) });
// if(db != null)
// db.close();
}
// Getting contacts Count
public int getLocDataCount() {
String countQuery = "SELECT * FROM " + TABLE_NAME;
if (db == null){
db = this.getReadableDatabase();
}
Cursor cursor = db.rawQuery(countQuery, null);
int noOfRows = cursor.getCount();
cursor.close();
// db.close();
return noOfRows;
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO Auto-generated method stub
}
public void removeAll() {
if(db == null)
db = this.getWritableDatabase(); // helper is object
// extends
// SQLiteOpenHelper
db.delete(DatabaseHelper.TABLE_NAME, null, null);
// db.close();
}
}
答案 0 :(得分：2)
尝试在数据库帮助程序中声明重入锁定，并在访问数据库的任何位置锁定和解锁。这应该允许线程等待数据库可用性并避免崩溃/错误。 例如在数据库助手中：
public static Lock l = new ReentrantLock(false);
您访问数据库的所有地方：
l.lock();
try
{
//do database editing
}
finally
{
l.unlock();
}
然而，如前所述，如果您尝试每秒写入数据库的次数超过数据库编辑实际可以完成的次数，那么最终会出现长时间的数据库写入积压。我的建议是每次发生数据库写入的触发器时都使用时间戳比较，并跳过写入数据库，除非自上次将该信息写入数据库以来已经过了半秒钟。
答案 1 :(得分：0)
假设您比在数据库中存储数据所花费的时间更频繁地收到新的onSensorData，您将需要以某种方式加速数据库写入或跳过事件。这是我头脑中的一些想法。
关于加速数据库写入，您可以假设位置提供程序不会在每个事件之间发生变化，如果您考虑可能发生更改的内容以及将某些内容存储为成员变量的频率，而不是每次都检索它们
跳过事件的一种方法是轮换列表。 onSensorData将一个新事件添加到结束列表中，如果它超过一定长度，则删除第一个（最旧的）元素。 db编写器（可能是一个线程）从列表的开头读取并写入当前最旧的元素。如果您为此使用线程，则需要稍微同步，为了减少同步，您可以批量读取事件而不是一次读取事件。
或者你可以将这两种方法结合起来。