mardi 20 octobre 2015

Fetch SQLite single cell and display in single TextView

Firstly, I know there are a lot of these types of questions. I've looked at at least a dozen and can't seem to wrap my head around it, so I'm posting a question in hopes that someone can do me a favor and explain it to me in greater detail along with providing the method.

I want to create a method that fetches the KEY_NAME for the KEY_ROWID that I specify. (I think this can be done using the getRow() method that's already in DBAdapter). Then, turn that into a string in order to display it a TextView.

I need to know how to fill out the method at the bottom of DBAdapter named getName

A perfect answer would allow me to write the following code in a separate activity setting the title: mTitle1 = getName;

Thank you all so much for your time.

I have a really nice DBAdapter provided by a tutorial that I followed:

public class DBAdapter {

private static final String TAG = "DBAdapter"; //used for logging database version changes

// Field Names:
public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "name";
public static final String KEY_DATE = "date";

public static final String[] ALL_KEYS = new String[] {KEY_ROWID, KEY_NAME, KEY_DATE};

// Column Numbers for each Field Name:
public static final int COL_ROWID = 0;
public static final int COL_NAME = 1;
public static final int COL_DATE = 2;

// DataBase info:
public static final String DATABASE_NAME = "dbCharacters";
public static final String DATABASE_TABLE = "Character_Info";
// The version number must be incremented each time a change to DB structure occurs.
public static final int DATABASE_VERSION = 2;

//SQL statement to create database
private static final String DATABASE_CREATE_SQL = 
        "CREATE TABLE " + DATABASE_TABLE 
        + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
        + KEY_NAME + " TEXT NOT NULL, "
        + KEY_DATE + " TEXT"
        + ");";

private final Context context;
private DatabaseHelper myDBHelper;
private SQLiteDatabase db;


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

// Open the database connection.
public DBAdapter open() {
    db = myDBHelper.getWritableDatabase();
    return this;
}

// Close the database connection.
public void close() {
    myDBHelper.close();
}

// Add a new set of values to be inserted into the database.
public long insertRow(String name, String date) {
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_NAME, name);
    initialValues.put(KEY_DATE, date);

    // Insert the data into the database.
    return db.insert(DATABASE_TABLE, null, initialValues);
}

// Delete a row from the database, by rowId (primary key)
public boolean deleteRow(long rowId) {
    String where = KEY_ROWID + "=" + rowId;
    return db.delete(DATABASE_TABLE, where, null) != 0;
}

public void deleteAll() {
    Cursor c = getAllRows();
    long rowId = c.getColumnIndexOrThrow(KEY_ROWID);
    if (c.moveToFirst()) {
        do {
            deleteRow(c.getLong((int) rowId));              
        } while (c.moveToNext());
    }
    c.close();
}

// Return all data in the database.
public Cursor getAllRows() {
    String where = null;
    Cursor c =  db.query(true, DATABASE_TABLE, ALL_KEYS, where, null, null, null, null, null);
    if (c != null) {
        c.moveToFirst();
    }
    return c;
}

// Get a specific row (by rowId)
public Cursor getRow(long rowId) {
    String where = KEY_ROWID + "=" + rowId;
    Cursor c =  db.query(true, DATABASE_TABLE, ALL_KEYS, 
                    where, null, null, null, null, null);
    if (c != null) {
        c.moveToFirst();
    }
    return c;
}

// Change an existing row to be equal to new data.
public boolean updateRow(long rowId, String name, String date) {
    String where = KEY_ROWID + "=" + rowId;
    ContentValues newValues = new ContentValues();
    newValues.put(KEY_NAME, name);
    newValues.put(KEY_DATE, date);
    // Insert it into the database.
    return db.update(DATABASE_TABLE, newValues, where, null) != 0;
}


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_SQL);           
    }

    @Override
    public void onUpgrade(SQLiteDatabase _db, int oldVersion, int newVersion) {
        Log.w(TAG, "Upgrading application's database from version " + oldVersion
                + " to " + newVersion + ", which will destroy all old data!");

        // Destroy old database:
        _db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE);

        // Recreate new database:
        onCreate(_db);
    }
}

public void getName (long id) {

}

}

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