找不到自己的符号类？

Question

我有两个文件都使用特定的符号类“Car”。我在整个项目中选择了这个作为一种反复出现的模式。

我的错误：

DBhelper.java:

    package com.example.brad.myapplication;

/**
 * Created by Brad on 21/07/2014.
 */

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import  android.graphics.Bitmap;
import android.view.View;
import android.view.TextureView;

public class DBhelper {
    public static final String CAR_ID = "id";
    public static final String CAR_PHOTO = "photo";

    private DatabaseHelper mDbHelper;
    private SQLiteDatabase mDb;

    private static final String DATABASE_NAME = "CarDB.db";
    private static final int DATABASE_VERSION = 1;

    private static final String CARS_TABLE = "Cars";

    private static final String CREATE_CARS_TABLE = "create table "
            + CARS_TABLE + " (" + CAR_ID
            + " integer primary key autoincrement, " + CAR_PHOTO
            + " blob not null);";

    private final Context mCtx;

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

        public void onCreate(SQLiteDatabase db) {
            db.execSQL(CREATE_CARS_TABLE);
        }

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

    public void Reset() {
        mDbHelper.onUpgrade(this.mDb, 1, 1);
    }

    public DBhelper(Context ctx) {
        mCtx = ctx;
        mDbHelper = new DatabaseHelper(mCtx);
    }

    public DBhelper open() throws SQLException {
        mDb = mDbHelper.getWritableDatabase();
        return this;
    }

    public void close() {
        mDbHelper.close();
    }

    public void insertCarDetails(**Car** car) {
        ContentValues cv = new ContentValues();
        cv.put(CAR_PHOTO, Utility.getBytes(car.getBitmap()));
        mDb.insert(CARS_TABLE, null, cv);
    }

    public **Car** retriveCarDetails() throws SQLException {
        Cursor cur = mDb.query(true, CARS_TABLE, new String[] { CAR_PHOTO}, null, null, null, null, null, null);
        if (cur.moveToFirst()) {
            byte[] blob = cur.getBlob(cur.getColumnIndex(CAR_PHOTO));
            cur.close();
            return new Car(Utility.getPhoto(blob));
        }
        cur.close();
        return null;
    }
}

InsertandRetriveBlobData：

package com.example.brad.myapplication;

import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

/**
 * Created by Brad on 20/07/2014.
 */


public class InsertandRetriveBlobData extends MyActivity {
    private DBhelper DbHelper;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);
        DbHelper = new DBhelper(this);
        **Car** car_One = new Car(BitmapFactory.decodeResource(
                getResources(), R.drawable.photo), 1);
        DbHelper.open();
        DbHelper.insertCarDetails(car_One);
        DbHelper.close();
        car_One = null;
        DbHelper.open();
        car_One = DbHelper.retriveCarDetails();
        DbHelper.close();

        ImageView carphoto = (ImageView) findViewById(R.id.photo);
        carphoto.setImageBitmap(car_One.getBitmap());

    }
}

我觉得这是一个小错误，因为我在使用getBitmap()时也遇到错误“无法解析方法getBitmap（）”尽管导入了它的库。

Answer 1

检查您的Car类是否在myapplication目录中以及此处提到的其他两个类。

然后从myapplication目录编译。