android - Android 的 SQLite DB 问题

Question

我是 Android 新手，一直在按照教程创建应用。我很难将数据插入数据库。我已经尝试了我能想到的一切，但无济于事。数据库类是:

package com.mckallip.BeerOnTheWall;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;

public class DatabaseUtil{

    private static final String TAG = "DatabaseUtil";

/**
 * Database Name
 */
private static final String DATABASE_NAME = "Beer_Database";

/**
 * Database Version
 */
private static final int DATABASE_VERSION = 1;

/**
 * Table Name
 */
private static final String DATABASE_TABLE = "Beer_List";

/**
 * Table columns
 */
public static final String KEY_BEER_NAME = "beer_name";
public static final String KEY_BEER_STYLE = "beer_style";
public static final String KEY_BREWERY = "beer_brewery";
public static final String KEY_ABV = "beer_abv";
public static final String KEY_BEER_SCORE = "beer_score";
public static final String KEY_BEER_IMAGE = "beer_image";
public static final String KEY_BEER_COMMENTS = "beer_comments";
public static final String KEY_ROWID = "_id";

/**
 * Database creation sql statement
 */
private static final String CREATE_BEER_TABLE =
    "CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_BEER_NAME + " TEXT, " + KEY_BEER_STYLE + " TEXT, " + KEY_BREWERY + " TEXT, " + KEY_ABV + " TEXT, " + KEY_BEER_SCORE + "TEXT, " + KEY_BEER_IMAGE + " TEXT, " + KEY_BEER_COMMENTS + "TEXT );";

/**
 * Context
 */
private final Context mCtx;

private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;


/**
 * Inner private class. Database Helper class for creating and updating database.
 */
private static class DatabaseHelper extends SQLiteOpenHelper {
    DatabaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
    /**
     * onCreate method is called for the 1st time when database doesn't exists.
     */
    @Override
    public void onCreate(SQLiteDatabase db) {
        Log.i(TAG, "Creating DataBase: " + CREATE_BEER_TABLE);
        db.execSQL(CREATE_BEER_TABLE);
    }
    /**
     * onUpgrade method is called when database version changes.
     */
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion);
    }
}
protected SQLiteDatabase getDataBase(){
    return mDb;
}
/**
 * Constructor - takes the context to allow the database to be
 * opened/created
 *
 * @param ctx the Context within which to work
 */
public DatabaseUtil(Context ctx) {
    this.mCtx = ctx;
}
/**
 * This method is used for creating/opening connection
 * @return instance of DatabaseUtil
 * @throws SQLException
 */
public DatabaseUtil open() throws SQLException {
    mDbHelper = new DatabaseHelper(mCtx);
    mDb = mDbHelper.getWritableDatabase();
    return this;
}
/**
 * This method is used for closing the connection.
 */
public void close() {
    mDbHelper.close();
}

/**
 * This method is used to create/insert new record Beer record.
 * @param sbeer_name
 * @param sbeer_style
 * @param sbeer_score
 * @param sbrewery
 * @param sabv
 * @param simageLoc
 * @param scomments
 * @return long
 */
public long createBeer(String beer_name, String beer_style, 
        String beer_score, String brewery, String abv, 
        String imageLoc, String comments) {
    ContentValues initialValues = new ContentValues();
    initialValues.put(KEY_BEER_NAME, beer_name);
    initialValues.put(KEY_BEER_STYLE, beer_style);
    initialValues.put(KEY_BREWERY, brewery);
    initialValues.put(KEY_ABV, abv);
    initialValues.put(KEY_BEER_SCORE, beer_score);
    initialValues.put(KEY_BEER_IMAGE, imageLoc);
    initialValues.put(KEY_BEER_COMMENTS, comments);
    return mDb.insert(DATABASE_TABLE, null, initialValues);
}
/**
 * This method will delete Beer record.
 * @param rowId
 * @return boolean
 */
public boolean deleteBeer(long rowId) {
    return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}

/**
 * This method will return Cursor holding all the Beer records.
 * @return Cursor
 */
public Cursor fetchAllBeers() {
    return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID, 
            KEY_BEER_NAME, KEY_BEER_STYLE, KEY_BREWERY, KEY_ABV, 
            KEY_BEER_SCORE, KEY_BEER_IMAGE, KEY_BEER_COMMENTS}, null, null, null, null, null);
}

/**
 * This method will return Cursor holding the specific Beer record.
 * @param id
 * @return Cursor
 * @throws SQLException
 */
public Cursor fetchBeer(long id) throws SQLException {
    Cursor mCursor =
        mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
                KEY_BEER_NAME, KEY_BEER_STYLE, KEY_BREWERY, KEY_ABV, 
                    KEY_BEER_SCORE, KEY_BEER_IMAGE, KEY_BEER_COMMENTS
                    }, KEY_ROWID + "=" + id, null,
                null, null, null, null);
    if (mCursor != null) {
        mCursor.moveToFirst();
    }
    return mCursor;
}

/**
 * This method will update Beer record.
 * @param id
 * @param name
 * @param standard
 * @return boolean
 */
public boolean updateBeer(int id, String beer_name, String beer_style, 
        String beer_score, String brewery, String abv, String imageLoc, 
        String comments) {
    ContentValues args = new ContentValues();
    args.put(KEY_BEER_NAME, beer_name);
    args.put(KEY_BEER_STYLE, beer_style);
    args.put(KEY_BREWERY, brewery);
    args.put(KEY_BEER_SCORE, beer_score);
    args.put(KEY_ABV, abv);
    args.put(KEY_BEER_IMAGE, imageLoc);
    args.put(KEY_BEER_COMMENTS, comments);
    return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + id, null) > 0;
}
}

添加数据的类是:

    package com.mckallip.BeerOnTheWall;

    import android.content.Context;
    import android.content.Intent;
    import android.database.sqlite.SQLiteDatabase;
    import android.os.Bundle;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.Spinner;
    import android.widget.TextView;
    import android.widget.Toast;

    public class AddBeerActivity extends BeerOnTheWallActivity {
        private EditText et1;
        private EditText et2;
        private EditText et3;
        private EditText et4;
        private Spinner score_spin;
        private EditText et5;
        
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.add_beer);
            mDatabase.open();
            Context e = getApplicationContext();
            String test = "read only";
            if (mDatabase.getDataBase().isReadOnly()){
                test = "Not ReadOnly" + mDatabase.getDataBase().getPath();
                
            }
            Toast t = Toast.makeText(e, test, 2);
            t.show();
            et1 = (EditText) findViewById(R.id.add_beer_name);
            et2 = (EditText)findViewById(R.id.add_beer_style);
            et3 = (EditText) findViewById(R.id.add_brewery);
            et4 = (EditText) findViewById(R.id.add_abv);
            score_spin = (Spinner) findViewById(R.id.score_spinner);
            et5 = (EditText) findViewById(R.id.add_comments);
            
            ((Button)findViewById(R.id.add_submit)).setOnClickListener(new OnClickListener() {
                public void onClick( View v ){
                    if (mDatabase.getDataBase().isReadOnly())mDatabase.open();
                    long beer_Id = mDatabase.createBeer( et1.toString(), et2.toString(), score_spin.toString(), et3.toString(), et4.toString(), "image", et5.toString() );
                    Context context = getApplicationContext();
                    CharSequence text = "Your beer was added at database position " + beer_Id;
                    if ( beer_Id == -1 ){
                        text = "There was an error and the beer could not be added.";
                    }
                    Toast toast = Toast.makeText(context, text, 2);
                    toast.show();
                    
                    // reset form
                    if ( beer_Id != -1 ){
                        et1.setText(null);
                        et2.setText(null);
                        et3.setText(null);
                        et4.setText(null);
                        et5.setText(null);
                    }
                }
            });
            
         // Handle Go to List button
            final Button gotoList = (Button) findViewById(R.id.beer_list);
            gotoList.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) {

                    // Go to other activity that displays beer list
                    Intent intent = new Intent(AddBeerActivity.this, BeerListActivity.class);
                    startActivity(intent);
                }
            });
        }
    }

我添加了 toasts 作为尝试和调试它的一种方式。第一个声称它是只读的，我不知道为什么或如何让它可写。

我还把 BeerOnTheWallActivity 中的 DatabaseUtil 实例化为静态变量，这样......

public class BeerOnTheWallActivity extends Activity {
    protected DatabaseUtil mDatabase = null; 
    //protected Cursor mCursor = null;
    //protected SQLiteDatabase mDB = null;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    
        mDatabase = new DatabaseUtil(this.getApplicationContext());
        mDatabase.open();
        
    }

当我按下按钮添加数据时，错误日志显示:

07-14 00:31:45.549: ERROR/Database(31512): Error inserting beer_abv=android.widget.EditText@47a27ea8 beer_style=android.widget.EditText@47a25d28 beer_score=android.widget.Spinner@47a2a768 beer_name=android.widget.EditText@47a245a8 beer_comments=android.widget.EditText@47a2b560 beer_image=image beer_brewery=android.widget.EditText@47a26de8

07-14 00:31:45.549: ERROR/Database(31512): android.database.sqlite.SQLiteException: table Beer_List has no column named beer_score: , while compiling: INSERT INTO Beer_List(beer_abv, beer_style, beer_score, beer_name, beer_comments, beer_image, beer_brewery) VALUES(?, ?, ?, ?, ?, ?, ?);

我想就是这样。任何帮助将不胜感激。

Answer 1

请检查下面

你的代码是

private static final String CREATE_BEER_TABLE =
    "CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_BEER_NAME + " TEXT, " + KEY_BEER_STYLE + " TEXT, " + KEY_BREWERY + " TEXT, " + KEY_ABV + " TEXT, " + KEY_BEER_SCORE + "TEXT, " + KEY_BEER_IMAGE + " TEXT, " + KEY_BEER_COMMENTS + "TEXT );";

改为使用这个

private static final String CREATE_BEER_TABLE =
    "CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_BEER_NAME + " TEXT, " + KEY_BEER_STYLE + " TEXT, " + KEY_BREWERY + " TEXT, " + KEY_ABV + " TEXT, " + KEY_BEER_SCORE + " TEXT, " + KEY_BEER_IMAGE + " TEXT, " + KEY_BEER_COMMENTS + " TEXT );";