5

So this is my code:

public void onItemClick(AdapterView<?> listView, View view, int position, long id)
{
    Cursor cursor = (Cursor) listView.getItemAtPosition(position);

    int _id = cursor.getInt(0);
    String _recipe = cursor.getString(1);
    Intent intent = new Intent(Luzon1Activity.this,RecipeInstruction.class);
    intent.putExtra("id", _id);
    intent.putExtra("recipe", _recipe);
    startActivity(intent);
}

This is my code for the next activity:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.recipeinstruction);

    dbHelper = new Dbadapter(this);
    dbHelper.open();
    bg = (RelativeLayout) findViewById(R.id.relativeLayout1);

    Bundle extras = getIntent().getExtras();
    if (extras != null) {
        id = extras.getInt("id");   
        recipe = extras.getString("recipe");
    }
    Toast.makeText(this, id+"\n"+recipe, Toast.LENGTH_SHORT).show();
    bg.setBackgroundResource(getImageId(this, recipe));
}

My problem is on this part: String _recipe = cursor.getString(1). It always gives me the wrong data. I tried to change the number but still it gives me the wrong data.

This is my database:

package com.pinoycookbook;

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 Dbadapter
{
    public static final String ROWID = "_id";
    public static final String NAME = "foodname";
    public static final String ORIGIN = "origin";

    public static final String RECIPE = "recipe";

    public static final String CATEGORY = "category";

    private static final String TAG = "Dbadapter";
    private DatabaseHelper mDbHelper;
    private SQLiteDatabase mDb;

    private static final String DATABASE_NAME = "PinoyCookbook.sqlite";
    public static final String SQLITE_TABLE = "Food";
    private static final int DATABASE_VERSION = 1;

    private final Context mCtx;

    private static final String DATABASE_CREATE =
        "CREATE TABLE if not exists " + SQLITE_TABLE + " (" +
                ROWID + " integer PRIMARY KEY autoincrement," +
                NAME + " TEXT," +
                RECIPE + " TEXT," +
                ORIGIN + " TEXT," + 
                CATEGORY+ " TEXT,"+
                " UNIQUE (" + ROWID +"));";

    private static class DatabaseHelper extends SQLiteOpenHelper
    {

        DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            Log.w(TAG, DATABASE_CREATE);
            db.execSQL(DATABASE_CREATE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
                + newVersion + ", which will destroy all old data");
            db.execSQL("DROP TABLE IF EXISTS " + SQLITE_TABLE);
            onCreate(db);
        }
    }

    public Dbadapter(Context ctx) {
        this.mCtx = ctx;
    }

    public Dbadapter open() throws SQLException {
        mDbHelper = new DatabaseHelper(mCtx);
        mDb = mDbHelper.getWritableDatabase();
        return this;
    }

    public void close() {
        if (mDbHelper != null) {
            mDbHelper.close();
        }
    }

    public long createData(String foodname, String recipe, String origin,  int i) {
        ContentValues initialValues = new ContentValues();
        initialValues.put(NAME, foodname);
        initialValues.put(RECIPE, recipe);
        initialValues.put(ORIGIN, origin);

        initialValues.put(CATEGORY, i);

        return mDb.insert(SQLITE_TABLE, null, initialValues);
    }

    public boolean deleteAllData() {
        int doneDelete = 0;
        doneDelete = mDb.delete(SQLITE_TABLE, null , null);
        Log.w(TAG, Integer.toString(doneDelete));
        return doneDelete > 0;
    }

    public void insertData() {
        createData("Adobong Manok","adobongmanok","Manila",1);
        createData("Lechon","lechon","Cebu",2);
        createData("Crispy Pata","crispypata","Cebu",2);
        createData("Bulalo","bulalo","Batangas",1);
        createData("Taba ng Talangka Rice","talangkarice","Roxas",2);
        createData("Arroz Caldo","arrozcaldo","Roxas",2);
        createData("Sinigang","sinigang","Manila",1);
    }
}
4

2 回答 2

6

所以我建议你使用getColumnIndex()方法而不是硬编码它。

String _recipe = cursor.getString(cursor.getColumnIndex(Dbadapter.RECIPE));

它将确保您始终获得正确的字段。如果它仍然得到错误的数据问题是在查询而不是Cursor

注意：使用包含列名的静态字段始终是最佳实践。

更新：

我以前试过，它给了我这个错误：java.lang.IllegalArgumentException：列'recipe'不存在

您需要找出您的实际表结构。尝试执行此语句：

PRAGMA table_info(Dbadapter.SQLITE_TABLE);

文档（来源）怎么说：

此编译指示为命名表中的每一列返回一行。结果集中的列包括列名、数据类型、列是否可以为 NULL，以及列的默认值。对于不属于主键的列，结果集中的“pk”列为零，对于属于主键的列，它是主键中的列的索引。

例子：

在这里，我为您创建了通过以下方式获取 tableinfo 的方法PRAGMA：

public String getTableInfo() {
    StringBuilder b = new StringBuilder("");
    Cursor c = null;
    try {
        db = helper.getReadableDatabase();
        String query = "pragma table_info(" + Dbadapter.SQLITE_TABLE + ")";
        c = db.rawQuery(query, null);
        if (c.moveToFirst()) {
            do {
                b.append("Col:" + c.getString(c.getColumnIndex("name")) + " ");                     
                b.append(c.getString(c.getColumnIndex("type")));
                b.append("\n");
            } while (c.moveToNext());
        }
        return b.toString();
    }
    finally {
        if (c != null) {
            c.close();
        }
        if (db != null) {
            db.close();
        }
    }
}

输出将是这样的：

Column: type text
Column: date text

仅供想象，我会给你屏幕：

Pragram Android 示例截图

于 2013-03-28T11:46:32.600 回答
2

你可以这样试试：

cursor.getString(cursor.getColumnIndex("recipe"));

它会返回正确的索引并返回正确的值。

于 2013-03-28T11:45:35.497 回答