自定义导入类报错咨询：com.inducesmile.androidlocationtracking.database.DatabaseQuery

First, let's clarify what this class is:

Unlike Google's official libraries (like com.google.android.gms.maps.* which are public, widely available dependencies), com.inducesmile.androidlocationtracking.database.DatabaseQuery is not a standard or publicly distributed library class. It's a custom-written class from a specific Android location tracking tutorial/project hosted on the Inducesmile website. This class was created to wrap database CRUD (Create, Read, Update, Delete) operations for storing location data—something the tutorial's author built for their example project.

That's why your IDE is throwing a red error: your project doesn't contain this custom class file, so the import statement can't resolve it.

How to Fix the Error (Two Options) #

Option 1: Use the Original Tutorial's Code #

If you're following the Inducesmile location tracking tutorial:

• Locate the DatabaseQuery.java file (and any related helper classes like DatabaseHelper.java) from the tutorial's source code (usually available via a GitHub link or download button in the tutorial).
• Copy these files into your project, matching the package structure: create a com/inducesmile/androidlocationtracking/database directory in your src/main/java folder, then paste the files there.
• Alternatively, adjust the package name in the copied files to match your project's package structure, then update the import statement accordingly.

Option 2: Adapt It to Your Own Project (Recommended) #

Instead of relying on someone else's custom class, build your own database solution tailored to your project's needs. The modern, recommended way for Android is using Room (Google's official ORM for SQLite):

1. Add Room Dependencies
   Open your module-level build.gradle file and add these lines to the dependencies block:

   def room_version = "2.5.2"
   implementation "androidx.room:room-runtime:$room_version"
   annotationProcessor "androidx.room:room-compiler:$room_version"
   

2. Define a Location Entity
   Create a class to represent your location data stored in the database:

   @Entity(tableName = "user_locations")
   public class LocationRecord {
       @PrimaryKey(autoGenerate = true)
       private int id;
       private double latitude;
       private double longitude;
       private long timestamp;
   
       // Constructor, getters, and setters here
       public LocationRecord(double latitude, double longitude, long timestamp) {
           this.latitude = latitude;
           this.longitude = longitude;
           this.timestamp = timestamp;
       }
   
       // Add getters for all fields
       public int getId() { return id; }
       public double getLatitude() { return latitude; }
       public double getLongitude() { return longitude; }
       public long getTimestamp() { return timestamp; }
   
       // Setter for id (since it's auto-generated)
       public void setId(int id) { this.id = id; }
   }
   

3. Create a DAO (Data Access Object)
   This interface defines the database operations:

   @Dao
   public interface LocationDao {
       @Insert
       void insertLocation(LocationRecord record);
   
       @Query("SELECT * FROM user_locations ORDER BY timestamp DESC")
       List<LocationRecord> getAllLocations();
   
       @Delete
       void deleteLocation(LocationRecord record);
   }
   

4. Build the Room Database
   Create a singleton class to manage the database instance:

   @Database(entities = {LocationRecord.class}, version = 1)
   public abstract class AppDatabase extends RoomDatabase {
       public abstract LocationDao locationDao();
   
       private static volatile AppDatabase INSTANCE;
   
       public static AppDatabase getInstance(Context context) {
           if (INSTANCE == null) {
               synchronized (AppDatabase.class) {
                   if (INSTANCE == null) {
                       INSTANCE = Room.databaseBuilder(
                               context.getApplicationContext(),
                               AppDatabase.class,
                               "location_database"
                           ).build();
                   }
               }
           }
           return INSTANCE;
       }
   }
   

5. Replace the Original mQuery
   In your activity/fragment, replace the DatabaseQuery variable with your Room DAO:

   private LocationDao mLocationDao;
   
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
   
       // Initialize the DAO
       mLocationDao = AppDatabase.getInstance(this).locationDao();
   
       // Now you can use it to insert/query locations
       // Example: mLocationDao.insertLocation(new LocationRecord(37.7749, -122.4194, System.currentTimeMillis()));
   }
   

If you prefer using the older SQLiteOpenHelper approach instead of Room, you can create a custom helper class and a corresponding query wrapper (similar to DatabaseQuery) to handle database operations manually.

内容的提问来源于stack exchange，提问作者stuck