Question

我正在开发我的自定义ContentProvier来存储来自手机的GPS坐标，然后使用Android中的SyncAdapter框架将它们发送到服务器。

到目前为止，我所做的是创建ContentProvider，但我有一个问题，让我解释一下：每次用户改变位置时，我都会得到坐标并存储它们。但问题是，当我尝试检查SQLite数据库记录时，我只找到最后一个位置！这就像我无法存储我发送的所有信息。

这是我的ContentProvider和SQLite数据库的代码：

package com.sifast.gps.tracking;

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import android.net.wifi.ScanResult;
import android.support.annotation.Nullable;
import android.support.annotation.StringDef;
import android.text.TextUtils;

import java.util.HashMap;

/**
 * Created by ghassen.ati on 18/03/2016.
 */
public class GeoLocProvider extends ContentProvider {

    static final String PROVIDER_NAME = "com.sifast.gps.tracking.GeoLocProvider";
    static final String URL = "content://"+PROVIDER_NAME+"/geoloc";
    static final Uri CONTENT_URI = Uri.parse(URL);

    static final String _ID = "_id";
    static final String DATEANDTIME = "dateandtime";
    static final String DEVICE_ID = "deviceid";
    static final String LONGITUDE = "longitude";
    static final String LATITUDE = "latitude";

    private static HashMap<String,String> GEOLOC_PROJECTION_MAP;

    static final int GEOLOC = 1;
    static final int GEOLOC_ID = 2;

    static final UriMatcher uriMatcher;
    static {
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        uriMatcher.addURI(PROVIDER_NAME, "geoloc", GEOLOC);
        uriMatcher.addURI(PROVIDER_NAME, "geoloc/#", GEOLOC_ID);
    }

    //Base de données
    private SQLiteDatabase db;
    static final String DATABASE_NAME = "GeoLoc";
    static final String TABLE_NAME = "geolocstore";
    static final int DATABASE_VERSION = 1;
    static final String CREATE_DB_TABLE =
            " CREATE TABLE " + TABLE_NAME +
                    " (_id INTEGER PRIMARY KEY AUTOINCREMENT, " +
                    " dateandtime TEXT NOT NULL, " +
                    " deviceid INTEGER NOT NULL, " +
                    " longitude INTEGER NOT NULL, " +
                    " latitude INTEGER NOT NULL);";

    //Classe Helper
    private static class DatabaseHelper extends SQLiteOpenHelper {
        DatabaseHelper(Context context) {
            super(context,DATABASE_NAME,null,DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db){
            db.execSQL(CREATE_DB_TABLE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion){
            db.execSQL("DROP TABLE IF EXISTS"+TABLE_NAME);
            onCreate(db);
        }
    }

    @Override
    public boolean onCreate() {
        Context context = getContext();
        DatabaseHelper dbHelper = new DatabaseHelper(context);
        db = dbHelper.getWritableDatabase();
        return (db==null)? false:true;
    }

    @Nullable
    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
        SQLiteQueryBuilder queryBuilder = new SQLiteQueryBuilder();
        queryBuilder.setTables(TABLE_NAME);
        switch (uriMatcher.match(uri)) {
            case GEOLOC:
                queryBuilder.setProjectionMap(GEOLOC_PROJECTION_MAP);
                break;
            case GEOLOC_ID:
                queryBuilder.appendWhere(_ID+"="+uri.getPathSegments().get(1));
                break;
            default:
                throw new IllegalArgumentException("URI Inconnue" + uri);
        }
        if (sortOrder == null || sortOrder == ""){
            sortOrder = DEVICE_ID;
        }
        Cursor cursor = queryBuilder.query(db,projection,selection,selectionArgs,null,null,sortOrder);
        cursor.setNotificationUri(getContext().getContentResolver(), uri);
        return cursor;
    }

    @Nullable
    @Override
    public String getType(Uri uri) {
        switch (uriMatcher.match(uri)){
            case GEOLOC:
                return "vnd.android.cursor.dir/vnd.gps.tracking.geoloc";
            case GEOLOC_ID:
                return "vnd.android.cursor.item/vnd.gps.tracking.geoloc";
            default:
                throw new IllegalArgumentException("URI Inconnue" + uri);
        }
    }

    @Nullable
    @Override
    public Uri insert(Uri uri, ContentValues values) {

        //Ajout d'un enregistrement
        long rowID = db.insert(TABLE_NAME,"",values);

        //Si l'ajout est effectué avec succès
        if (rowID > 0) {
            Uri _uri = ContentUris.withAppendedId(CONTENT_URI,rowID);
            getContext().getContentResolver().notifyChange(_uri,null);
            return _uri;
        }
        throw new SQLException("Echec lors de l'ajout d'un enregistrement"+uri);
    }

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        int count = 0;
        switch (uriMatcher.match(uri)){
            case GEOLOC:
                count = db.delete(TABLE_NAME,selection,selectionArgs);
                break;
            case GEOLOC_ID:
                String id = uri.getPathSegments().get(1);
                count  = db.delete(TABLE_NAME, _ID+" = "+id+(!TextUtils.isEmpty(selection)?" AND ("+selection+')':""),selectionArgs);
                break;
            default:
                throw new IllegalArgumentException("URI Inconnue "+ uri);
        }
        getContext().getContentResolver().notifyChange(uri,null);
        return count;

    }

    @Override
    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        int count = 0;
        switch (uriMatcher.match(uri)) {
            case GEOLOC:
                count = db.update(TABLE_NAME,values,selection,selectionArgs);
                break;
            case GEOLOC_ID:
                count = db.update(TABLE_NAME,values, _ID + " = " + uri.getPathSegments().get(1) +
                        (!TextUtils.isEmpty(selection) ? " AND (" +selection + ')' : ""), selectionArgs);
                break;
            default:
                throw new IllegalArgumentException("URI Inconnue"+ uri);
        }
        getContext().getContentResolver().notifyChange(uri, null);
        return count;
    }

}

这是我每次用户移动时调用的方法：

public void addGeoLocRecord (int uniqueId, Location location) {

        ContentValues values = new ContentValues();

        values.put(GeoLocProvider.DATEANDTIME,getDateTime());
        values.put(GeoLocProvider.DEVICE_ID,uniqueId);
        values.put(GeoLocProvider.LONGITUDE,location.getLongitude());
        values.put(GeoLocProvider.LATITUDE,location.getLatitude());
        Uri uri = getContentResolver().insert(GeoLocProvider.CONTENT_URI,values);

    }

我使用此方法显示数据库中的记录：

public void onClickshowGeoLocRecords (View view){
    int count=0;
    String URL = "content://com.sifast.gps.tracking.GeoLocProvider/geoloc";
    Uri geoloc = Uri.parse(URL);
    Cursor cursor = managedQuery(geoloc,null,null,null,"longitude");

    if (cursor.moveToFirst()){
        count++;
        Log.i(TAG,cursor.getString(cursor.getColumnIndex(GeoLocProvider.DATEANDTIME))+
                ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.DEVICE_ID))+
                ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.LATITUDE))+
                ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.LONGITUDE)) );

    }while(cursor.moveToNext());
}

Answer 1

我认为这是因为你的代码只对第一行做了一些有用的事情。

稍微更改格式会显示它实际执行的操作：

// log the first row if it exists
if (cursor.moveToFirst()){
        count++;
        Log.i(TAG,cursor.getString(cursor.getColumnIndex(GeoLocProvider.DATEANDTIME))+
            ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.DEVICE_ID))+
            ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.LATITUDE))+
            ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.LONGITUDE)) );

}

// loop over all remaining rows, doing nothing
while(cursor.moveToNext());

你可能只是错过了do。请尝试通过以下方式替换上面的块：

if (cursor.moveToFirst()) {
    do {
        count++;
        Log.i(TAG,cursor.getString(cursor.getColumnIndex(GeoLocProvider.DATEANDTIME))+
            ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.DEVICE_ID))+
            ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.LATITUDE))+
            ", "+ cursor.getString(cursor.getColumnIndex(GeoLocProvider.LONGITUDE)) );

    } while(cursor.moveToNext());
}

SQLite数据库仅存储通过ContentProvider发送的最后一条记录

1 个答案: