java - 快速查询时 SQLite 上出现 CursorIndexOutOfBoundsException 错误

Question

我正在使用字段 ID 和 8 个字段字符串(有些可为空)从 SQLite 进行查询。我有一个 getSearchedItemsFromSQLite 方法，每当 EditText 对象(自动搜索)上发生更改状态时就会触发该方法，并且这些错误消息会随机出现，但应用程序根本不会崩溃。

    07-27 18:24:52.619: ERROR/AndroidRuntime(1173): ERROR: thread attach failed
    07-27 18:24:55.188: ERROR/AndroidRuntime(1184): ERROR: thread attach failed
    07-27 18:25:18.649: ERROR/GuitarTabs(1191): getSearchedItemsFromSQLite: Handler for DB + cursor: Index 6 requested, with a size of 6


    07-27 18:25:18.659: WARN/System.err(1191): android.database.CursorIndexOutOfBoundsException: Index 6 requested, with a size of 6
    07-27 18:25:18.889: WARN/System.err(1191):     at android.database.AbstractCursor.checkPosition(AbstractCursor.java:580)
    07-27 18:25:18.889: WARN/System.err(1191):     at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:214)
    07-27 18:25:18.889: WARN/System.err(1191):     at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:41)
    07-27 18:25:18.889: WARN/System.err(1191):     at com.package.project.activity.ItemBrowserActivity.getSearchedItemsFromSQLite(ItemBrowserActivity.java:351)
    07-27 18:25:18.889: WARN/System.err(1191):     at com.package.project.activity.ItemBrowserActivity$AppInitialization.doInBackground(ItemBrowserActivity.java:199)
    07-27 18:25:18.889: WARN/System.err(1191):     at com.package.project.activity.ItemBrowserActivity$AppInitialization.doInBackground(ItemBrowserActivity.java:1)
    07-27 18:25:18.889: WARN/System.err(1191):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
    07-27 18:25:18.899: WARN/System.err(1191):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
    07-27 18:25:18.909: WARN/System.err(1191):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
    07-27 18:25:18.909: WARN/System.err(1191):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
    07-27 18:25:18.909: WARN/System.err(1191):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
    07-27 18:25:18.909: WARN/System.err(1191):     at java.lang.Thread.run(Thread.java:1096)

我该如何解决这个问题？

这是该方法的代码 fragment :

        dbHelper.open();
        cursor = dbHelper.fetchAllTabs(fetchMethod);
        startManagingCursor(cursor);
        if(cursor != null && cursor.getCount() > 0) {
            if(cursor.moveToFirst()) {
                while (cursor.isAfterLast() == false) {
                    if(cursor.getColumnCount() > 0) {
                        Log.i(logAppName, "/ - Column count is:  " + cursor.getColumnCount());
                        if(!cursor.isNull(0) && !cursor.isNull(1)) {
                            if(!cursor.isNull(0)) {
                                ListedItem tab = new ListedItem();
                                tab.setSongID(cursor.getInt(0));
                                if(!cursor.isNull(1)) tab.setTitle(cursor.getString(1));
                                if(!cursor.isNull(2)) tab.setArtist(cursor.getString(2));
                                if(!cursor.isNull(3)) tab.setDifficulty(cursor.getString(3));
                                if(!cursor.isNull(4)) tab.setGenre(cursor.getString(4));
                                if(!cursor.isNull(5)) tab.setFilename(cursor.getString(5));
                                if(!cursor.isNull(6)) tab.setFileformat(cursor.getString(6));
                                if(!cursor.isNull(7)) tab.setSource(cursor.getString(7));
                                if(!cursor.isNull(8)) tab.setDeleted(cursor.getString(8));
                                if(Integer.parseInt(tab.getDeleted()) == 0)
                                    ret.add(tab);
                                else 
                                    Log.i(logAppName, "Not adding tab: " + tab.getSongTitle() + " (" + tab.getSongFilename() + ") " + "since it's already deleted.");
                                cursor.moveToNext();
                            } else {
                                Log.i(logAppName, "x - ID is null.");
                            }
                        } else {
                            Log.i(logAppName, "x - Either id or title is null.");
                        }
                    } else {
                        Log.i(logAppName, "x - Column count is:  " + cursor.getColumnCount());
                    }
                }
            }      
            if(cursor != null)
                cursor.close();

Answer 1

我添加了这些条件:

if ( cursor != null && cursor.getCount() > 0 ) { 
    totalRows = cursor.getCount();
if(cursor.moveToFirst()) {
    while (cursor.isAfterLast() == false) {
        if(cursor.getColumnCount() > 0) {
               ...

之后，我添加了一个 sleep 线程，以允许前一个进程先完成，然后再进行另一个进程:

private boolean processing = false;
...

int ctr = 0;
// added fix to avoid error on cursor
while(processing) {
    try {
    Log.i(logAppName, "Still processing. Count: " + ctr + ". Is processing? " + processing);
        ctr++;
        Thread.sleep(500);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    if(ctr > 5) {
        break;
    }
}