Question

嘿大家好我是Android编程的新手，所以请耐心等待。从db中检索记录时遇到一些问题。基本上，我想要做的就是存储GPS定位功能输出的纬度和经度，并在稍后使用不同标签上的ListActivity将它们显示在列表中。这就是我的DBAdapter助手类的代码如下所示：

public class DBAdapter 
{
    public static final String KEY_ROWID = "_id";
    public static final String KEY_LATITUDE = "latitude";
    public static final String KEY_LONGITUDE = "longitude";
    private static final String TAG = "DBAdapter";

    private static final String DATABASE_NAME = "coords";
    private static final String DATABASE_TABLE = "coordsStorage";
    private static final int DATABASE_VERSION = 1;

    private static final String DATABASE_CREATE =
        "create table coordsStorage (_id integer primary key autoincrement, "
        + "latitude integer not null, longitude integer not null);";

    private final Context context; 

    private DatabaseHelper DBHelper;
    private SQLiteDatabase db;

    public DBAdapter(Context ctx) 
    {
        this.context = ctx;
        DBHelper = new DatabaseHelper(context);
    }

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

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

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, 
        int newVersion) 
        {
            Log.w(TAG, "Upgrading database from version " + oldVersion 
                    + " to "
                    + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS titles");
            onCreate(db);
        }
    }    

    //---opens the database---
    public DBAdapter open() throws SQLException 
    {
        db = DBHelper.getWritableDatabase();
        return this;
    }

    //---closes the database---    
    public void close() 
    {
        DBHelper.close();
    }

    //---insert a title into the database---
    public long insertCoords(int latitude, int longitude) 
    {
        ContentValues initialValues = new ContentValues();
        initialValues.put(KEY_LATITUDE, latitude);
        initialValues.put(KEY_LONGITUDE, longitude);
        return db.insert(DATABASE_TABLE, null, initialValues);
    }

    //---deletes a particular title---
    public boolean deleteTitle(long rowId) 
    {
        return db.delete(DATABASE_TABLE, KEY_ROWID + 
                "=" + rowId, null) > 0;
    }

    //---retrieves all the titles---
    public Cursor getAllTitles() 
    {
        return db.query(DATABASE_TABLE, new String[] {
                KEY_ROWID, 
                KEY_LATITUDE,
                KEY_LONGITUDE}, 
                null, 
                null, 
                null, 
                null, 
                null);
    }

    //---retrieves a particular title---
    public Cursor getTitle(long rowId) throws SQLException 
    {
        Cursor mCursor =
                db.query(true, DATABASE_TABLE, new String[] {
                        KEY_ROWID,
                        KEY_LATITUDE, 
                        KEY_LONGITUDE}, 
                        KEY_ROWID + "=" + rowId, 
                        null,
                        null, 
                        null, 
                        null, 
                        null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;
    }

    //---updates a title---
    /*public boolean updateTitle(long rowId, int latitude, 
    int longitude) 
    {
        ContentValues args = new ContentValues();
        args.put(KEY_LATITUDE, latitude);
        args.put(KEY_LONGITUDE, longitude);
        return db.update(DATABASE_TABLE, args, 
                         KEY_ROWID + "=" + rowId, null) > 0;
    }*/
}

现在我的问题是 - 我在这里做错了吗？如果是，有人可以告诉我什么？我应该如何以有组织的列表方式检索记录？非常感谢帮助!!

这是它抛出的错误：

06-06 14:49:32.434: ERROR/Database(276): Error inserting latitude=0 longitude=0
06-06 14:49:32.434: ERROR/Database(276): android.database.sqlite.SQLiteException: no such table: coordsStorage: , while compiling: INSERT INTO coordsStorage(latitude, longitude) VALUES(?, ?);
06-06 14:49:32.434: ERROR/Database(276):     at android.database.sqlite.SQLiteProgram.native_compile(Native Method)
06-06 14:49:32.434: ERROR/Database(276):     at android.database.sqlite.SQLiteProgram.compile(SQLiteProgram.java:110)
06-06 14:49:32.434: ERROR/Database(276):     at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:59)
06-06 14:49:32.434: ERROR/Database(276):     at android.database.sqlite.SQLiteStatement.(SQLiteStatement.java:41)
06-06 14:49:32.434: ERROR/Database(276):     at android.database.sqlite.SQLiteDatabase.compileStatement(SQLiteDatabase.java:925)
06-06 14:49:32.434: ERROR/Database(276):     at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1300)
06-06 14:49:32.434: ERROR/Database(276):     at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1173)
06-06 14:49:32.434: ERROR/Database(276):     at tabs.app.DBAdapter.insertCoords(DBAdapter.java:81)
06-06 14:49:32.434: ERROR/Database(276):     at tabs.app.Tribocracy$1.onClick(Tribocracy.java:118)
06-06 14:49:32.434: ERROR/Database(276):     at android.view.View.performClick(View.java:2344)

然后当我试图检索它时，它抛出了这个：

06-06 14:49:52.734: INFO/Process(51): Sending signal. PID: 276 SIG: 3
06-06 14:49:52.734: INFO/dalvikvm(276): threadid=7: reacting to signal 3
06-06 14:49:52.734: ERROR/dalvikvm(276): Unable to open stack trace file /data/anr/traces.txt': 
Permission denied

Answer 1

看起来这个表因某种原因不存在。

您可能想尝试增加版本号，以强制升级;如果数据库本身存在则不会调用onCreate方法 - 增加版本将强制调用onUpgrade，并且您的实现将删除该表并重新创建它。这应该可以修复您的错误，或者为您提供新的错误！

Answer 2

将您的纬度和经度数据类型更改为加倍

double Latitude;
double Longitude;

尝试从中检索数据后，Android SQLite崩溃

2 个答案: