獲取敲定尚未停用光標或封閉的錯誤

Question

大家

您好我是新來的Android和我使用的SQLiteDataBase，我獲取有關遊標不關閉它是不是致命的，但很煩人的錯誤。就這個。

01-14 15:53:42.503: E/Cursor(1090): Finalizing a Cursor that has not been deactivated or closed. database = /data/data/uk.ac.tees.L1087591/databases/Wettboff.db, table = webpages, query = SELECT _id, url, source, date FROM webpages WHERE _id=? 
01-14 15:53:42.503: E/Cursor(1090): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here 
01-14 15:53:42.503: E/Cursor(1090):  at android.database.sqlite.SQLiteCursor.<init>(SQLiteCursor.java:210) 
01-14 15:53:42.503: E/Cursor(1090):  at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:53) 
01-14 15:53:42.503: E/Cursor(1090):  at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345) 
01-14 15:53:42.503: E/Cursor(1090):  at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229) 
01-14 15:53:42.503: E/Cursor(1090):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184) 
01-14 15:53:42.503: E/Cursor(1090):  at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1301) 
01-14 15:53:42.503: E/Cursor(1090):  at uk.ac.tees.L1087591.DatabaseHandler.getWebPage(DatabaseHandler.java:237) 
01-14 15:53:42.503: E/Cursor(1090):  at uk.ac.tees.L1087591.Web.onCreate(Web.java:54) 
01-14 15:53:42.503: E/Cursor(1090):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
01-14 15:53:42.503: E/Cursor(1090):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
01-14 15:53:42.503: E/Cursor(1090):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
01-14 15:53:42.503: E/Cursor(1090):  at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
01-14 15:53:42.503: E/Cursor(1090):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
01-14 15:53:42.503: E/Cursor(1090):  at android.os.Handler.dispatchMessage(Handler.java:99) 
01-14 15:53:42.503: E/Cursor(1090):  at android.os.Looper.loop(Looper.java:123) 
01-14 15:53:42.503: E/Cursor(1090):  at android.app.ActivityThread.main(ActivityThread.java:4627) 
01-14 15:53:42.503: E/Cursor(1090):  at java.lang.reflect.Method.invokeNative(Native Method) 
01-14 15:53:42.503: E/Cursor(1090):  at java.lang.reflect.Method.invoke(Method.java:521) 
01-14 15:53:42.503: E/Cursor(1090):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
01-14 15:53:42.503: E/Cursor(1090):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
01-14 15:53:42.503: E/Cursor(1090):  at dalvik.system.NativeStart.main(Native Method) 

這裏是抱怨數據庫。

01-14 15:53:42.653: E/Database(1090): close() was never explicitly called on database '/data/data/uk.ac.tees.L1087591/databases/Wettboff.db' 
01-14 15:53:42.653: E/Database(1090): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here 
01-14 15:53:42.653: E/Database(1090): at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1810) 
01-14 15:53:42.653: E/Database(1090): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:817) 
01-14 15:53:42.653: E/Database(1090): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:851) 
01-14 15:53:42.653: E/Database(1090): at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:844) 
01-14 15:53:42.653: E/Database(1090): at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:540) 
01-14 15:53:42.653: E/Database(1090): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203) 
01-14 15:53:42.653: E/Database(1090): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98) 
01-14 15:53:42.653: E/Database(1090): at android.database.sqlite.SQLiteOpenHelper.getReadableDatabase(SQLiteOpenHelper.java:158) 
01-14 15:53:42.653: E/Database(1090): at uk.ac.tees.L1087591.DatabaseHandler.getWebPage(DatabaseHandler.java:236) 
01-14 15:53:42.653: E/Database(1090): at uk.ac.tees.L1087591.Web.onCreate(Web.java:54) 
01-14 15:53:42.653: E/Database(1090): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
01-14 15:53:42.653: E/Database(1090): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627) 
01-14 15:53:42.653: E/Database(1090): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 
01-14 15:53:42.653: E/Database(1090): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 
01-14 15:53:42.653: E/Database(1090): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 
01-14 15:53:42.653: E/Database(1090): at android.os.Handler.dispatchMessage(Handler.java:99) 
01-14 15:53:42.653: E/Database(1090): at android.os.Looper.loop(Looper.java:123) 
01-14 15:53:42.653: E/Database(1090): at android.app.ActivityThread.main(ActivityThread.java:4627) 
01-14 15:53:42.653: E/Database(1090): at java.lang.reflect.Method.invokeNative(Native Method) 
01-14 15:53:42.653: E/Database(1090): at java.lang.reflect.Method.invoke(Method.java:521) 
01-14 15:53:42.653: E/Database(1090): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 
01-14 15:53:42.653: E/Database(1090): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 
01-14 15:53:42.653: E/Database(1090): at dalvik.system.NativeStart.main(Native Method) 

這裏是我的數據庫處理器類

public class DatabaseHandler extends SQLiteOpenHelper { 

    /** 
    * The name of the database 
    */ 
    protected static final String DATABASE_NAME = "Wettboff.db"; 

    /** 
    * The name of the table. 
    */ 
    protected static final String TABLE_NAME = "webpages"; 

    /** 
    * The name of the first column (ID) 
    */ 
    protected static final String COL_ID = "_id"; 

    /** 
    * The name of the second column (URL) 
    */ 
    protected static final String COL_url = "url"; 

    /** 
    * The name of the third column (source) 
    */ 
    protected static final String COL_source = "source"; 

    /** 
     * The name of the fourth column (date) 
     */ 
    protected static final String COL_date = "date"; 

    /** 
    * A constructor which builds a DatabaseHandler object. Note that calling 
    * the constructor does not create a database. This does not happen until 
    * the first call to getReadableDatabase() or getWriteableDatabase() 
    * 
    * @param context , In this case, a reference to webpageActivity 
    */ 
    public DatabaseHandler(Context context) { 
     super(context, DATABASE_NAME, null, 1); 
    } 

    /** 
    * This method is called when the database is created for the first time. 
    * This is where the creation of tables and the initial population of the 
    * tables should happen. 
    */ 
    @Override 
    public void onCreate(SQLiteDatabase db) { 
     String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_NAME + "(" 
       + COL_ID + " INTEGER PRIMARY KEY," + COL_url + " TEXT," 
       + COL_source + " TEXT," + COL_date + " TEXT" + ");"; 
     Log.d("Table name in onCreate", TABLE_NAME); 
     db.execSQL(CREATE_CONTACTS_TABLE); 
     Log.d("WebOff", "Database populated"); 
    } 

    /** 
    * Called when the database needs to be upgraded. Only relevant when you 
    * have multiple versions of the database scheme in play. 
    * 
    */ 
    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldNum, int newNum) { 
     // Drop older table if exist and create fresh 
     Log.w("Updating database: ", " Upgrading database from version " + oldNum 
       + " to " 
       + newNum + ", which will destroy all old data"); 
     db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME); 
     onCreate(db); 
    } 

    /** 
    * Use this method to add a webpage to the database. 
    * 
    * @param webpage 
    *   the webpage you want to add 
    */ 
    public void addWebPage(List<WebPage> webpage) { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     ContentValues values = new ContentValues(); 
     for (WebPage lr : webpage) { 
      values.put(COL_ID, lr.getID()); 
      values.put(COL_url, lr.getUrl()); 
      values.put(COL_source, lr.getSource()); 
      values.put(COL_date, lr.getDate()); 
     } 
     db.insert(TABLE_NAME, null, values); 
     db.close(); 
    } 

    /** 
    * Use this method to add a webpage to the database. 
    * 
    * @param webpage 
    *   the webpage you want to add 
    */ 
    public void addWebPage(WebPage webpage) { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     ContentValues values = new ContentValues(); 
     values.put(COL_ID, webpage.getID()); 
     values.put(COL_url, webpage.getUrl()); 
     values.put(COL_source, webpage.getSource()); 
     values.put(COL_date, webpage.getDate()); 
     db.insert(TABLE_NAME, null, values); 
     db.close(); 
    } 

    /** 
    * Use this method to get all of the webpages in the database. 
    * 
    * @return a list of webpage objects, one per row 
    */ 
    public List<WebPage> getAll() { 
     List<WebPage> list = new ArrayList<WebPage>(); 
     String selectQuery = "SELECT * FROM " + TABLE_NAME; 
     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.rawQuery(selectQuery, null); 
     if (cursor.moveToFirst()) { 
      do { 
       WebPage webpage = new WebPage(cursor.getInt(0), 
         cursor.getString(1), cursor.getString(2), cursor.getLong(3)); 
       list.add(webpage); 
      } while (cursor.moveToNext()); 
     } 
     return list; 
    } 


    /** 
    * Use this method to get a Cursor object that points at all the webpages in 
    * the database 
    * 
    * @return a Cursor object pointing at all webpages in db 
    */ 
    public Cursor getAllAsCursor() { 
     String selectQuery = "SELECT * FROM " + TABLE_NAME; 
     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.rawQuery(selectQuery, null); 
     return cursor; 
    } 

    /** 
    * Use this method to remove all of the webpages from the database. This is 
    * useful when experimenting. After dropping all tables, the initial state 
    * of the database is re-created. 
    */ 
    public void removeAll() { 
     SQLiteDatabase db = this.getWritableDatabase(); 
     db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME); 
     onCreate(db); 
    } 

    /** 
    * This method removes one webpage from the database. 
    * 
    * @param webpage 
    *   the webpage to remove 
    */ 
    public void deletewebpage(int id) { 
     SQLiteDatabase db = this.getWritableDatabase(); 

     db.delete(TABLE_NAME, COL_ID + " = ?", 
       new String[] { String.valueOf(id)}); 
     db.close(); 
    } 

    /** 
    * This method updates the data stored in the database for one webpage. 
    * 
    * @param webpage 
    *   the webpage to update 
    * @return the number of rows affected 
    */ 
    public int updateWebPage(WebPage pages) { 

      SQLiteDatabase db = this.getWritableDatabase(); 
      ContentValues values = new ContentValues(); 
//   values.put(COL_ID, lr.getID()); 
      values.put(COL_url, pages.getUrl()); 
      values.put(COL_source, pages.getSource()); 
      values.put(COL_date, pages.getDate()); 
      return db.update(TABLE_NAME, values, COL_ID + " = ?", 
        new String[] { String.valueOf(((WebPage) pages).getID()) }); 
    } 


    /** 
    * This method gets a single webpage from the database, using the ID field 
    * as a key 
    * ; 
    * @param id 
    *   the ID of the webpage we want 
    * @return a webpage object 
    */ 
    public WebPage getWebPage(int id) { 
     SQLiteDatabase db = this.getReadableDatabase(); 
     Cursor cursor = db.query(TABLE_NAME, new String[] { COL_ID, COL_url, 
       COL_source, COL_date }, COL_ID + "=?", 
       new String[] { String.valueOf(id) }, null, null, null, null); 
     if (cursor != null) { 
      cursor.moveToFirst(); 
     } 
     WebPage webpage = new WebPage(Integer.parseInt(cursor.getString(0)), 
       cursor.getString(1), cursor.getString(2), cursor.getLong(3)); 
     return webpage; 
    } 
} 

，當我嘗試用下面的代碼

public class Read extends MenuActivity { 

    /** 
    * sca is an object of type SimpleCursorAdapter and we use it to set the 
    * adapter. 
    */ 
    private SimpleCursorAdapter sca; 

    /** 
    * dh is an object of type DatabaseHandler and we use it to connet to the 
    * data base. 
    */ 
    private DatabaseHandler dh; 

    /** 
    * mainListView is a List View. 
    */ 
    private ListView mainListView; 

    /** 
    * context is a Content that takes the current one(this) 
    */ 
    private final Context context = this; 

    /** 
    * myId stores the id of the selected url 
    */ 
    protected static int myId; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_read); 
     mainListView = (ListView) findViewById(R.id.mainListView); 
     dh = new DatabaseHandler(this); 

     /** 
     * Get a Cursor pointing at all web pages in the database 
     */ 
     final Cursor cursor = dh.getAllAsCursor(); 

     /** 
     * cols gets the value of the COL_url 
     */ 
     String[] cols = new String[] { DatabaseHandler.COL_url }; 

     /** 
     * to get the value of the url_entry. 
     */ 
     int[] to = new int[] { R.id.url_entry }; 
     sca = new SimpleCursorAdapter(this, R.layout.read, cursor, cols, to, 2); 
     mainListView.setAdapter(sca); 
     mainListView.showContextMenu(); 
     registerForContextMenu(mainListView); 


     // when the user does a longclick 
     mainListView.setOnItemLongClickListener(new OnItemLongClickListener() { 
      @Override 
      public boolean onItemLongClick(AdapterView<?> arg0, View arg1, 
        int id, long arg3) { 
       myId = id; 
       Log.d("WebOff ", 
         "Web page read: id number in OnItemLongCLick " + id); 
       cursor.close(); 
       return false; 
      } 
     }); 

    } 

    @Override 
    public void onCreateContextMenu(ContextMenu menu, View v, 
      ContextMenuInfo menuInfo) { 
     super.onCreateContextMenu(menu, v, menuInfo); 
     menu.setHeaderTitle("WebOff Menu"); 
     menu.add(0, v.getId(), 0, "Read using WebOff"); 
     menu.add(0, v.getId(), 0, "Read using web browser"); 
    } 

    @Override 
    public boolean onContextItemSelected(MenuItem item) { 
     if (item.getTitle() == "Read using WebOff") { 
      readUsingWebOff(item.getItemId()); 
     } else if (item.getTitle() == "Read using web browser") { 
      readUsingWebBrowser(item.getItemId()); 
     } else { 
      return false; 
     } 
     return true; 
    } 

    /** 
    * readUsingWebOff goes to the Web activity. 
    * 
    * @param id 
    *   of the web Page 
    */ 
    public void readUsingWebOff(int id) { 
     Toast.makeText(this, "WebOff called", Toast.LENGTH_SHORT).show(); 
     Intent k = new Intent(context, Web.class); 
     startActivity(k); 
    } 

    /** 
    * readUsingWebBrowser() reads the web pages through the web broweser. 
    * 
    * @param id 
    *   of the web page. 
    */ 
    public void readUsingWebBrowser(int id) { 
     Toast.makeText(this, "Web browser called", Toast.LENGTH_SHORT).show(); 
     WebPage page = dh.getWebPage(Read.myId); 
     String myUrl = page.getUrl(); 
     Uri uri = Uri.parse(myUrl); 

//  dh.close(); 

     Intent intent = new Intent(Intent.ACTION_VIEW, uri); 
     startActivity(intent); 
    } 

} 

讀超過一個網頁，我得到光標例外。

Answer 1

您需要正確地關閉遊標和數據庫。修改您的getWebPage（）方法如下：

public WebPage getWebPage(int id) { 
    SQLiteDatabase db = this.getReadableDatabase(); 
    Cursor cursor = db.query(TABLE_NAME, new String[] { COL_ID, COL_url, 
      COL_source, COL_date }, COL_ID + "=?", 
      new String[] { String.valueOf(id) }, null, null, null, null); 
    WebPage webpage = null; 
    if (cursor != null) { 
     if (cursor.moveToFirst()) { 
      webpage = new WebPage(Integer.parseInt(cursor.getString(0)), cursor.getString(1), cursor.getString(2), cursor.getLong(3)); 
     } 
     cursor.close(); 
    } 
    return webpage; // be aware, it might return null now! 
} 

Answer 2

電話：

cursor.close(); 

只要你有你有完一個打開的遊標（即在getAll()法）。

Answer 3

你應該關閉數據庫連接在最後的try-catch

String sqlQuery = "SELECT ...."; 

    Cursor c = null; 
    try { 
     c = this.rawQuery(sqlQuery, new String[] { params }); 
     if (c.moveToFirst()) { 
      do { 
       parseCusors(c); 
      } while (c.moveToNext()); 
     } 
    } catch (Exception e) { 
     e.printStackTrace(); 
    } finally { 
     if (c != null) { 
      try {c.close();} catch (Exception ignore) {;} 
     } 
    }