Question

一个简单的注册页面，其中包含用户名，密码和确认密码这三个文本字段。我将创建一个数据库，其中包含三个属性id，name和password的表，其中id是主键，我们从用户名textfield动态获取的名称和我们从密码textfield动态获得的密码。但问题是数据库已创建但动态给出的值不会在表格中存储/更新。我是android的新手，我已经使用互联网资源编写代码，但我仍然不知道在这个阶段。在此先感谢.. !!

MainActivity.java :
public class MainActivity extends Activity
{
EditText editTextUserName,editTextPassword,editTextConfirmPassword;
Button btnCreateAccount;
DbHelper myHelper;

@Override
protected void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    editTextUserName=(EditText)findViewById(R.id.editTextUserName);
    editTextPassword=(EditText)findViewById(R.id.editTextPassword);
    editTextConfirmPassword=(EditText)findViewById(R.id.editTextConfirmPassword);

    myHelper = new DbHelper(this, "", null, 1);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

    public void newName(View v) {
        // onClick function when account create button is clicked

        String userName=editTextUserName.getText().toString();
        String password=editTextPassword.getText().toString();
        Bus bus = new Bus(userName, password);
        myHelper.insertEntry(bus);
        String confirmPassword=editTextConfirmPassword.getText().toString();
               bus = new Bus(userName, password);
               myHelper.insertEntry(bus);
               editTextUserName.setText("");
               editTextPassword.setText("");
               editTextConfirmPassword.setText("");

               Toast.makeText(getApplicationContext(), "Account Successfully Created ", Toast.LENGTH_LONG).show();
        }
    }

        public void count (View view) {
//onClick function when no of tuples in the table button is clicked

            int a = myHelper.getNamesCount();
            String b = Integer.toString(a);
            editTextUserName.setText(b);

       }

@Override
protected void onDestroy() {
    // TODO Auto-generated method stub
    super.onDestroy();

    myHelper.close();
}
}

还有另一个名为DbHelper.java的数据库助手类，代码为：

DbHelper.java :
public class DbHelper extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 2;
private static final String DATABASE_NAME = "finalProjectDB.db";
private static final String TABLE_LOGIN = "Table1";

public static final String COLUMN_ID1 = "id";
public static final String COLUMN_NAME1 = "name";
public static final String COLUMN_PASSWORD1 = "password";

public DbHelper(Context context, String name, 
        CursorFactory factory, int version) {
    super(context, DATABASE_NAME, factory, DATABASE_VERSION);
}

public  SQLiteDatabase db;

@Override
public void onCreate(SQLiteDatabase db) {
      String CREATE_NAMES_TABLE = "CREATE TABLE "+TABLE_LOGIN+"("+COLUMN_ID1+" INTEGER PRIMARY KEY,"+COLUMN_NAME1+" TEXT,"+COLUMN_PASSWORD1+" TEXT)";
      db.execSQL(CREATE_NAMES_TABLE);

}

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



public void insertEntry(Bus bus)
{
   ContentValues newValues = new ContentValues();

    newValues.put("COLUMN_NAME1",bus.getName());
    newValues.put("COLUMN_PASSWORD1",bus.getPassword());
    SQLiteDatabase db = this.getWritableDatabase();

    db.insert("TABLE_LOGIN", null, newValues);
    ///Toast.makeText(context, "Reminder Is Successfully Saved", Toast.LENGTH_LONG).show();
    db.close();


}

public int getNamesCount(){

    String countQuery = "SELECT  * FROM "+TABLE_LOGIN;
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(countQuery, null);
    int count = cursor.getCount();
    return count;
}

}

最后，Bus.java文件：

Bus.java :
public class Bus {
private int _id;
    private String _name;
    private String _password;

    public Bus(){

    }

    public Bus(int id, String name, String password){
        this._id = id;
        this._name = name;
        this._password = password;
    }

    public Bus(String name, String password){
        this._name = name;
        this._password = password;
    }

    public void setID(int id){
        this._id = id;
    }

    public int getID(){
        return this._id;
    }

    public void setName(String name) {
        this._name = name;
    }

    public String getName() {
        return this._name;
    }

    public void setPassword(String password) {
        this._password = password;
    }

    public String getPassword() {
        return this._password;
    }

}

Answer 1

您的代码中似乎有错误：

db.insert("TABLE_LOGIN", null, newValues);

因此，您尝试在不存在的表中插入值。

使用常量而不是字符串。

数据库已创建！但是这个表没有价值

1 个答案: