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我正在编写一个简单的数据库应用程序，您可以在其中输入您的姓名并使用 2 编辑文本进行标记，然后按下按钮保存数据库并移至显示数据库结果的第二个活动。数据库包含 4 列：id、名称、标记、操作，其中“操作”列从操作中获取结果，我已经将其输入放入程序中。

我在插入时尝试并捕获，它会显示一个对话框，通知我它是否成功。结果是成功的，但是当移动到查看活动时应用程序强制关闭。这是我的数据库类代码

 public class DateBase {

public static final String KEY_ID = "id";
public static final String KEY_NAME = "user_name";
public static final String KEY_MARK = "user_mark";
public static final String KEY_OPERATION = "operation";

private static final String DATABASE_NAME = "Statistic";
private static final String DATABASE_TABLE = "user_interface";
private static final int DATABASE_VERSION = 1;

private DBInterface MyInterface;
private final Context MyContext;
private SQLiteDatabase MyDB;


private static class DBInterface extends SQLiteOpenHelper
{

    public DBInterface(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        db.execSQL("CREATE TABLE " + DATABASE_TABLE + " ( " +
                KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                KEY_NAME + " TEXT NOT NULL, " +
                KEY_MARK + " TEXT NOT NULL, " +
                KEY_OPERATION + " TEXT NOT NULL );"
                );
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub
        db.execSQL("DROP TABLE IF EXISTS " + DATABASE_TABLE );
        onCreate(db);
    }

}

public DateBase(Context c)
{
    MyContext = c;
}

public DateBase open() throws SQLException
{
    MyInterface = new DBInterface(MyContext);
    MyDB = MyInterface.getWritableDatabase();
    return this;
}

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

public long InsertEntry(String name, String mark, String ops) {
    // TODO Auto-generated method stub
    ContentValues cv = new ContentValues();
    cv.put(KEY_NAME, name);
    cv.put(KEY_MARK, mark);
    cv.put(KEY_OPERATION, ops);
    return MyDB.insert(DATABASE_TABLE, null, cv);
    }

public String getData() {
    // TODO Auto-generated method stub
    String[] columns = new String[] { KEY_ID, KEY_NAME, KEY_MARK, KEY_OPERATION};
    Cursor c = MyDB.query(DATABASE_TABLE, columns, null, null, null, null, null);
    String result = "";

    int iRow = c.getColumnIndex(KEY_ID);
    int iName = c.getColumnIndex(KEY_NAME);
    int iMark = c.getColumnIndex(KEY_MARK);
    int iOperation = c.getColumnIndex(KEY_OPERATION);

    for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext())
    {
        result = result + c.getString(iRow) + " " + c.getString(iName) + " " + c.getString(iMark) + " " + c.getString(iOperation) + "\n";
    }


    return result;
}
  }

这是单击按钮时的插入代码：

 public void onClick(View v) {
    // TODO Auto-generated method stub

    boolean diditwork = true;
    try {String name = ed1.getText().toString();
    String mark = ed2.getText().toString();
    String ops = "";
    for (int i = 0; i < ops.length(); i++)
    {
        switch (op[i]) // int[] op = new int[]{1,3};
        {
        case 1:
            ops = ops + "+ ";
            break;
        case 2:
            ops = ops + "- ";
            break;
        case 3:
            ops = ops + "* ";
            break;
        case 4:
            ops = ops + "/ ";
            break;
        }
    }

    DateBase entry = new DateBase(MainActivity.this);
    entry.open();
    entry.InsertEntry(name, mark, ops);
    entry.close();

    } catch (Exception e)
    {
        diditwork = false;
        String error = e.toString();
        Dialog d = new Dialog (this);
        d.setTitle("NO WAY!!");
        TextView tv = new TextView(this);
        tv.setText(error);
        d.setContentView(tv);
        d.show();
    } finally {
        if (diditwork)
        {
            Dialog d = new Dialog (this);
            d.setTitle("Heck YA!");
            TextView tv = new TextView(this);
            tv.setText("Success");
            d.setContentView(tv);
            d.show();
        }
    }

    Intent i = new Intent();
    i.setClass(MainActivity.this, DatabaseView.class);
    startActivity(i);
     }

最后是我获取数据的代码： public class DatabaseView extends Activity {

TextView tv;
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.database_view);

    tv = (TextView) findViewById(R.id.textView1);

    DateBase info = new DateBase(this);
    info.open();
    String Data = info.getData();
    info.close();

    tv.setText(Data);
}

}

我在 LogCAT 上遇到的例外是：

  E/AndroidRuntime(490): FATAL EXCEPTION: main
  java.lang.RuntimeException: Unable to start activity   
  ComponentInfo{com.database/com.database.DatabaseView}:       
  android.database.sqlite.SQLiteException: no such column: user_mark: , while compiling: SELECT id, user_name, user_mark, operation FROM user_interface

我只是无法弄清楚问题出在哪里。请帮帮我，对不起我的英语不好

感谢您的时间和考虑。

4

2 回答 2

2

可能是您稍后添加了此字段 user_mark 以便系统仍在使用旧数据库尝试卸载该应用程序并再次安装它，否则我认为一切都已就绪

于 2013-05-29T04:57:47.797 回答
1

是的，代码没有错误，问题是 Aashish 告诉我们的。所以请从管理应用程序中清除数据并再次运行。

于 2013-05-29T05:03:26.727 回答