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我正在计算来自数据库（元素）的数据。但我在这一行遇到异常这是我的日志。

这是我的主要 java 文件，这里有两个保存 ok 日志，打印然后异常显示在计数行

package com.example.database_example;

    import java.util.List;

    import android.os.Bundle;
    import android.app.Activity;
    import android.util.Log;
    import android.view.Menu;

    public class MainActivity extends Activity {

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

            Information inf=new Information("naveen");
            Information inf2=new Information("Rvi");
            DataBaseExample dbx=new DataBaseExample(MainActivity.this);

            if(dbx.insertname(inf)){
                Log.v("checkdbx.insertname(inf);", "save ok.");
            }else{
                Log.v("checkdbx.insertname(inf);", "save failed.");
            }

            if(dbx.insertname(inf2)){
                Log.v("checkdbx.insertname(inf);", "save ok.");
            }else{
                Log.v("checkdbx.insertname(inf);", "save failed.");
            }
            Log.v("count", "mane ok."+dbx.getContactsCount());


            List<Information> itemsList= dbx.getAllItems();
            for (int i = 0; i < itemsList.size(); i++) {


            Information inft= itemsList.get(i);
            Log.v("name", "mane ok."+inft.getName()+inft.getKey());


            }


        }           

    }

和下面的错误..

09-24 09:38:51.288: V/checkdbx.insertname(inf);(674): save ok.
09-24 09:38:51.318: V/checkdbx.insertname(inf);(674): save ok.
09-24 09:38:51.328: D/AndroidRuntime(674): Shutting down VM
09-24 09:38:51.328: W/dalvikvm(674): threadid=1: thread exiting with uncaught exception (group=0x40015560)
09-24 09:38:51.348: E/AndroidRuntime(674): FATAL EXCEPTION: main
09-24 09:38:51.348: E/AndroidRuntime(674): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.database_example/com.example.database_example.MainActivity}: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT  * FROM Name) 
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.os.Handler.dispatchMessage(Handler.java:99)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.os.Looper.loop(Looper.java:123)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.app.ActivityThread.main(ActivityThread.java:3683)
09-24 09:38:51.348: E/AndroidRuntime(674):  at java.lang.reflect.Method.invokeNative(Native Method)
09-24 09:38:51.348: E/AndroidRuntime(674):  at java.lang.reflect.Method.invoke(Method.java:507)
09-24 09:38:51.348: E/AndroidRuntime(674):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
09-24 09:38:51.348: E/AndroidRuntime(674):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
09-24 09:38:51.348: E/AndroidRuntime(674):  at dalvik.system.NativeStart.main(Native Method)
09-24 09:38:51.348: E/AndroidRuntime(674): Caused by: java.lang.IllegalStateException: attempt to re-open an already-closed object: android.database.sqlite.SQLiteQuery (mSql = SELECT  * FROM Name) 
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteClosable.acquireReference(SQLiteClosable.java:34)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:67)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:287)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:268)
09-24 09:38:51.348: E/AndroidRuntime(674):  at com.example.database_example.DataBaseExample.getContactsCount(DataBaseExample.java:98)
09-24 09:38:51.348: E/AndroidRuntime(674):  at com.example.database_example.MainActivity.onCreate(MainActivity.java:32)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-24 09:38:51.348: E/AndroidRuntime(674):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
09-24 09:38:51.348: E/AndroidRuntime(674):  ... 11 more


package com.example.database_example;

import java.util.ArrayList;
import java.util.List;

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

public class DataBaseExample extends SQLiteOpenHelper{

    private static final int DATABASE_VERSION = 1;

    // Database Name
    private static final String DATABASE_NAME = "information";

    // Contacts table name
    private static final String TABLE_Name= "Name";

    // Contacts Table Columns names
    private static final String KEY_ID = "id";
    private static final String KEY_NAME = "name";

    public DataBaseExample(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
        String createTable= "CREATE TABLE " + TABLE_Name+"("
                + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_NAME + " TEXT"
                + ")";
        db.execSQL(createTable);
    }

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

            // Create tables again
            onCreate(db);
    }

    public boolean insertname(Information information) {

        boolean createSuccessful = false;

        ContentValues values = new ContentValues();

      //  values.put(KEY_ID, information.getId());
        values.put(KEY_NAME, information.getName());

        SQLiteDatabase db = this.getWritableDatabase();

        createSuccessful = db.insert(TABLE_Name, null, values) > 0;
        db.close();

        return createSuccessful;
    }

    public List<Information> getAllItems(){
    List<Information> itemsList = new ArrayList<Information>();
    Cursor cursor = null;
    try {
        //get all rows
        SQLiteDatabase mDatabase = this.getReadableDatabase();
        cursor = mDatabase.query(TABLE_Name, null, null, null, null,
                null, null);
        if (cursor.moveToFirst()) {
            do {
                Information c = new Information();
                c.setName(cursor.getString(cursor.getColumnIndex((KEY_NAME))));
                c.setKey(cursor.getString(cursor.getColumnIndex((KEY_ID))));
                itemsList.add(c);
            } while (cursor.moveToNext());
        }
    } catch (SQLiteException e) {
        e.printStackTrace();
    } finally {
        cursor.close();
    }
    return itemsList;
}

    public int getContactsCount() {
        String countQuery = "SELECT  * FROM " + TABLE_Name;
        SQLiteDatabase db = this.getReadableDatabase();
        Cursor cursor = db.rawQuery(countQuery, null);
        cursor.close();

        // return count
        return cursor.getCount();
    }

}

package com.example.database_example;

import android.R.string;

public class Information {

    String name;

    String key;
    public String getKey() {
        return key;
    }
    public void setKey(String key) {
        this.key = key;
    }
    public Information(String name) {
        // TODO Auto-generated constructor stub
        this.name=name;
    }
    public Information() {
        // TODO Auto-generated constructor stub

    }

    public String getName() {
        return name;
    }

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

}
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1 回答 1

1

在您的 getContactsCount() 中，您关闭光标，然后尝试访问它。将计数存储在局部变量中，然后关闭游标。

于 2013-09-24T04:39:45.480 回答