Question

这是我想要创建数据库表的MainActivity的提取

public class GameDrive extends Activity {


DatabaseHelper databaseHelper;
SQLiteDatabase database;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_game_drive);
    getActionBar().setDisplayHomeAsUpEnabled(true);


    databaseHelper = new DatabaseHelper(this);
    database  = databaseHelper.getWritableDatabase();

。。

public class DatabaseHelper extends SQLiteOpenHelper {

private static final String DATABSE_NAME = "database";
private static final String TABLE_NAME = "tripdata";
private static final String COLUMN_ID = "_id";
private static final String COLUMN_TYP = "typ";
private static final String COLUMN_VALUE = "value";

private static final int DATABASE_VERSION = 1;




public DatabaseHelper(Context context){
    super(context, DATABSE_NAME, null, DATABASE_VERSION);
    Log.d("Database","Constructor called");

}


//database is created for first time. creation of table and initial data inside done here
@Override
public void onCreate(SQLiteDatabase db) {
    Log.d("Database","onCreate called");

    db.execSQL("CREATE TABLE "+TABLE_NAME+"("+COLUMN_ID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+COLUMN_TYP+" VARCHAR(255),"+COLUMN_VALUE+" VARCHAR(255));" );

    Log.d("Database","onCreate called succesfuly");

}

//drop tables, add tables etc.
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // TODO Auto-generated method stub
    try {
        db.execSQL("DROP TABLE IF EXISTS TABLE_NAME");
        onCreate(db);
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

}

为什么从未到达Log.d（“数据库”，“onCreate called”）？启动应用程序后，只需达到Log.d（“数据库”，“构造函数调用”）语句。

谢谢！

Answer 1

我猜这张桌子已经存在了。所以onDreate不会再被执行。尝试安装SQLite Viewer以更好地可视化您的数据库。我也无法在DatabaseHelper中看到方法getWritableDatabase（）。请检查一下。

您可以尝试的另一件事是将create table命令修改为create table（如果不存在）。

Android SQLite - 无法创建表

1 个答案: