在Android中使用AsyncTask類中的sqlite時出錯？

Question

我得到這個錯誤..請幫我解決這個錯誤，或者知道原因！

03-18 15:59:39.094: ERROR/AndroidRuntime(480): FATAL EXCEPTION: AsyncTask #2 
03-18 15:59:39.094: ERROR/AndroidRuntime(480): java.lang.RuntimeException: An error occured while executing doInBackground() 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at android.os.AsyncTask$3.done(AsyncTask.java:200) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.util.concurrent.FutureTask.setException(FutureTask.java:125) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.util.concurrent.FutureTask.run(FutureTask.java:138) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.lang.Thread.run(Thread.java:1019) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480): Caused by: java.lang.IllegalStateException: database not open 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at android.database.sqlite.SQLiteDatabase.compileStatement(SQLiteDatabase.java:1146) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1549) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1422) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at aynoo.utility.DBAdapter.insertMessage(DBAdapter.java:67) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at aynoo.utility.Cach.AddMessages(Cach.java:23) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at aynoo.forms.FreindMessagesActivity$3$1RecentMessageLoader.doInBackground(FreindMessagesActivity.java:396) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at aynoo.forms.FreindMessagesActivity$3$1RecentMessageLoader.doInBackground(FreindMessagesActivity.java:1) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at android.os.AsyncTask$2.call(AsyncTask.java:185) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306) 
03-18 15:59:39.094: ERROR/AndroidRuntime(480):  ... 4 more 
03-18 15:59:39.484: ERROR/Database(480): close() was never explicitly called on database '/data/data/aynoo.forms/databases/aynoo' 
03-18 15:59:39.484: ERROR/Database(480): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here 
03-18 15:59:39.484: ERROR/Database(480):  at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1827) 
03-18 15:59:39.484: ERROR/Database(480):  at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:820) 
03-18 15:59:39.484: ERROR/Database(480):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:854) 
03-18 15:59:39.484: ERROR/Database(480):  at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:847) 
03-18 15:59:39.484: ERROR/Database(480):  at android.app.ContextImpl.openOrCreateDatabase(ContextImpl.java:541) 
03-18 15:59:39.484: ERROR/Database(480):  at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203) 
03-18 15:59:39.484: ERROR/Database(480):  at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:118) 
03-18 15:59:39.484: ERROR/Database(480):  at aynoo.utility.DBAdapter.open(DBAdapter.java:47) 
03-18 15:59:39.484: ERROR/Database(480):  at aynoo.utility.Cach.AddMessages(Cach.java:22) 
03-18 15:59:39.484: ERROR/Database(480):  at aynoo.forms.FreindMessagesActivity$3$1RecentMessageLoader.doInBackground(FreindMessagesActivity.java:396) 
03-18 15:59:39.484: ERROR/Database(480):  at aynoo.forms.FreindMessagesActivity$3$1RecentMessageLoader.doInBackground(FreindMessagesActivity.java:1) 
03-18 15:59:39.484: ERROR/Database(480):  at android.os.AsyncTask$2.call(AsyncTask.java:185) 
03-18 15:59:39.484: ERROR/Database(480):  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306) 
03-18 15:59:39.484: ERROR/Database(480):  at java.util.concurrent.FutureTask.run(FutureTask.java:138) 
03-18 15:59:39.484: ERROR/Database(480):  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 
03-18 15:59:39.484: ERROR/Database(480):  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 
03-18 15:59:39.484: ERROR/Database(480):  at java.lang.Thread.run(Thread.java:1019) 

，其中高速緩衝存儲器類是

public class Cach { 
    static DBAdapter db; 
    public Cach(Context c) 
    { 
    } 

    public static void AddMessages(Context c, 
            int id, 
            int fromId, 
            int toId, 
            String message, 
            String dir, 
            String MessageTime) 
    { 
     db = new DBAdapter(c); 
     db.open();   
     db.insertMessage(id, fromId, toId, message, dir,MessageTime); 
     db.close(); 
    } 
} 

Answer 1

這聽起來很像兩個線程（兩個並行運行的異步任務？）正試圖訪問該數據庫。所以第一個線程有一個鎖，然後你的Cach.AddMessages()出現並想要插入數據，所以它試圖獲得鎖，失敗，因此不打開數據庫，隨後的插入失敗。