我有一个利用SQLite数据库的应用程序。
我在应用程序启动时创建了数据库，调用了RSSDatabase的构造函数，效果很好。单击按钮后，我从RSS提要中获取数据并将数据插入到AsyncTask中，但是当我调用db.insert("posts", "", values)时会导致错误，这是logcat的错误消息:
02-04 21:43:22.050 19154-19357/com.example.aolreader E/SQLiteLog﹕ (1802) os_unix.c:30026: (2) stat(/data/data/com.example.aolreader/databases/rss_db) -
02-04 21:43:22.050 19154-19357/com.example.aolreader E/SQLiteLog﹕ (1802) statement aborts at 13: [INSERT INTO posts(author,title,date,description,link) VALUES (?,?,?,?,?)]
02-04 21:43:22.050 19154-19357/com.example.aolreader E/SQLiteDatabase﹕ Error inserting author=AP title=UK admits ‘limited’ role in Operation Blue Star date=Tue, 4 Feb 2014 19:03:27 +0530 description=
The British government had recently ordered an urgent investigation into possible U.K. involvement in the raid.
link=http://www.thehindu.com/news/international/world/uk-admits-limited-role-in-operation-blue-star/article5653316.ece
android.database.sqlite.SQLiteDiskIOException: disk I/O error (code 1802)
at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:782)
at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1469)
at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1339)
at com.example.aolreader.RSSDatabase.insertPost(RSSDatabase.java:44)
at com.example.aolreader.XMLRSSActivity.parseNews(XMLRSSActivity.java:386)
at com.example.aolreader.XMLRSSActivity.access$000(XMLRSSActivity.java:33)
at com.example.aolreader.XMLRSSActivity$ParseTask.doInBackground(XMLRSSActivity.java:171)
at com.example.aolreader.XMLRSSActivity$ParseTask.doInBackground(XMLRSSActivity.java:134)
at android.os.AsyncTask$2.call(AsyncTask.java:288)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:841)
我搜索了此错误，发现它可能是由不同的线程同时访问数据库引起的，但是我查看了我的代码，发现没有多个线程具有竞争条件的情况。
这是我的数据库助手类:
class RSSDatabaseHelper extends SQLiteOpenHelper {
private static final String createPostTableSql = "create table posts (" +
"_id integer primary key autoincrement," +
"title varchar," +
"author varchar," +
"link varchar," +
"description varchar," +
"date varchar)";
private Context context;
public RSSDatabaseHelper(Context c, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(c, name, factory, version);
context = c;
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(createPostTableSql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop table if exists posts");
onCreate(db);
}
}
而我的数据库类:
public class RSSDatabase {
private static RSSDatabase instance;
private SQLiteDatabase db;
private RSSDatabaseHelper dbHelper;
private RSSDatabase(Context c) {
dbHelper = new RSSDatabaseHelper(c, "rss_db", null, 1);
db = dbHelper.getWritableDatabase();
}
public static synchronized RSSDatabase getDatabaseInstance(Context c) {
if (instance == null) {
instance = new RSSDatabase(c);
}
return instance;
}
public void insertPost(Post post) {
ContentValues values = new ContentValues();
values.put("title", post.title);
values.put("author", post.author);
values.put("link", post.link);
values.put("description", post.description);
values.put("date", post.date);
db.insert("posts", "", values);
}
}
谁能在这个问题上阐明一些想法？
提前致谢!
最佳答案
当应用程序启动时，调用RSSDatabase的构造函数，UI线程正在锁定您的数据库
db = dbHelper.getWritableDatabase(); // In the constructor
现在，从异步任务(不同的线程)开始，您正在尝试将数据插入由UI线程锁定的数据库中。这将引发异常，因为第一次写入在数据库上具有锁。
关于Android SQLite数据库: SQLiteDiskIOException: disk I/O error (code 1802)，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/21554277/