Android SQLIte 错误：无法从 CursorWindow 读取第 0 行、第 1 列

Question

I am using a prepopulated slqite database that I created using sqlitebrowser.

I have placed the database file (it doesnt seem to have an extension) into my assets folder.

I'm using the standard databasehelper class that everyone seems to be using.

 05-09 13:04:55.746      894-894/com.myapp.myappname E/CursorWindow﹕ Failed to read row 0, column 1 from a CursorWindow which has 19 rows, 1 columns.
05-09 13:04:55.766      894-894/com.myapp.myappname D/AndroidRuntime﹕ Shutting down VM
05-09 13:04:55.766      894-894/com.myapp.myappname W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x40a71930)
05-09 13:04:55.876      894-894/com.myapp.myappname E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myappname/com.myapp.myappname.MainActivity}: java.lang.IllegalStateException: Couldn't read row 0, col 1 from CursorWindow.  Make sure the Cursor is initialized correctly before accessing data from it.
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
            at android.app.ActivityThread.access$600(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5041)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.IllegalStateException: Couldn't read row 0, col 1 from CursorWindow.  Make sure the Cursor is initialized correctly before accessing data from it.
            at android.database.CursorWindow.nativeGetString(Native Method)
            at android.database.CursorWindow.getString(CursorWindow.java:434)
            at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:51)
            at com.myapp.myappname.DataBaseHelper.getAllOccasions(DataBaseHelper.java:193)
            at com.myapp.myappname.MainActivity.loadOccasionSpinnerData(MainActivity.java:155)
            at com.myapp.myappname.MainActivity.onCreate(MainActivity.java:72)
            at android.app.Activity.performCreate(Activity.java:5104)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
            at android.app.ActivityThread.access$600(ActivityThread.java:141)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
            at android.os.Handler.dispatchMessage(Handler.java:99)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:5041)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
            at dalvik.system.NativeStart.main(Native Method)

Here is my database helper class:

It fails on this line in the class:

  Cursor cursor = db.rawQuery(selectQuery, null);

Here is the Class:

import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

import java.io.FileOutputStream;
import java.io.IOException;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;


public class DataBaseHelper extends SQLiteOpenHelper {

    //The Android's default system path of your application database.
    private static String DB_PATH = "/data/data/com.myapp.myappname/databases/";

    private static String DB_NAME = "WTWDatabase";

    private SQLiteDatabase myDataBase;

    private final Context myContext;

    /**
     * Constructor
     * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
     * @param context
     */
    public DataBaseHelper(Context context) {

        super(context, DB_NAME, null, 1);
        if(android.os.Build.VERSION.SDK_INT >= 17){
            DB_PATH = context.getApplicationInfo().dataDir + "/databases/";
        }
        else
        {
            DB_PATH = "/data/data/" + context.getPackageName() + "/databases/";
        }

        this.myContext = context;
    }

    /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException {

        boolean dbExist = checkDataBase();

        if(dbExist){
            //do nothing - database already exist
        }else{

            //By calling this method and empty database will be created into the default system path
            //of your application so we are gonna be able to overwrite that database with our database.
            this.getReadableDatabase();

            try {

                copyDataBase();

            } catch (IOException e) {

                throw new Error("Error copying database");

            }
        }

    }

    /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase(){

        SQLiteDatabase checkDB = null;

        try{
            String myPath = DB_PATH + DB_NAME;
            checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        }catch(SQLiteException e){

            //database does't exist yet.

        }

        if(checkDB != null){

            checkDB.close();

        }

        return checkDB != null ? true : false;
    }

    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{

        //Open your local db as the input stream
        InputStream myInput = myContext.getAssets().open(DB_NAME);

        // Path to the just created empty db
        String outFileName = DB_PATH + DB_NAME;

        //Open the empty db as the output stream
        OutputStream myOutput = new FileOutputStream(outFileName);

        //transfer bytes from the inputfile to the outputfile
        byte[] buffer = new byte[1024];
        int length;
        while ((length = myInput.read(buffer))>0){
            myOutput.write(buffer, 0, length);
        }

        //Close the streams
        myOutput.flush();
        myOutput.close();
        myInput.close();

    }

    public void openDataBase() throws SQLException {

        //Open the database
        String myPath = DB_PATH + DB_NAME;
        myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); 

    }

    @Override
    public synchronized void close() {

        if(myDataBase != null)
            myDataBase.close();

        super.close();

    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }

    // Add your public helper methods to access and get content from the database.
    // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
    // to you to create adapters for your views.
    /**
     * Getting all labels
     * returns list of labels
     * */
    public List<String> getAllOccasions(){
        List<String> labels = new ArrayList<String>();

        // Select All Query
        String selectQuery = "SELECT  Occasion FROM Occasions";

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null); //FAILS HERE

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                labels.add(cursor.getString(1));
            } while (cursor.moveToNext());
        }

        // closing connection
        cursor.close();
        db.close();

        // returning lables
        return labels;
    }

    public List<String> getAllSubCategories(String Occasion){
        List<String> labels = new ArrayList<String>();

        // Select All Query
        String selectQuery = "Select subcategory from subcategory where Occasionkey = (select _id from Occasions where Occasion = '" + Occasion + "')";

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                labels.add(cursor.getString(1));
            } while (cursor.moveToNext());
        }

        // closing connection
        cursor.close();
        db.close();

        // returning lables
        return labels;
    }


    public List<String> getAllMessages(String Occasion, String SubCategory){
        List<String> labels = new ArrayList<String>();

        // Select All Query
        String selectQuery = "Select Message from Messages INNER JOIN\n" +
                "MessageSubCategory ON MessageSubCategory.MessageKey = Messages._id\n" +
                " where Messages.OccasionKey = (select _id from Occasions where Occasion = '\" + Occasion + \"')\n" +
                "AND MessageSubCategory.SubCategoryKey = (select SubCategory._id from SubCategory where SubCategory.Subcategory = '\" + SubCategory + \"')";

        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                labels.add(cursor.getString(1));
            } while (cursor.moveToNext());
        }

        // closing connection
        cursor.close();
        db.close();

        // returning lables
        return labels;
    }

}

Answer 1

列索引从 0 开始。您的光标只有 1 列，因此将getString(1)替换为getString(0)以访问唯一的列值。

Answer 2

Please, add following one line before where you write following code.

if(cursor!=null && cursor.getCount() > 0) 
{
 if (cursor.moveToFirst()) 
 {
   do {
       labels.add(cursor.getString(1));
      } while (cursor.moveToNext());
  }
}

because, when cursor is blank and you get value from cursor, its give error.

please try and give feedback.

Answer 3

增加数据库版本对我有用。

Answer 4

better try to use cursor.getColumnIndex() instead of integers to get particular value from Sqlite db like below

   if(cursor!=null && cursor.getCount() > 0) {
            if (cursor.moveToFirst()) {
                do {
                    labels.add(cursor.getColumnIndex(YOUR_DB_COLUMN_NAME));
                } while (cursor.moveToNext());
                cursor.close();
            }

        }