我正在尝试使用for循环将多个csv文件导入Android sqlite。 但是，当应用程序尝试将csv内容导入数据库时，数据库将被锁定，并且数据库涉及的所有其他功能都将失败。
这是我的代码 导入功能：
Button button_import_csv = (Button) findViewById(R.id.button_import);
button_import_csv.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
DatabaseHelper helper = new DatabaseHelper(getApplicationContext());
SQLiteDatabase db = helper.getWritableDatabase();
int returnvalue;
long ret;
Log.d("ice","database opened");
returnvalue=db.delete(tableName[0], null, null );
Log.d("ice","Returnvalue of deleting table0:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[1], null, null );
Log.d("ice","Returnvalue of deleting table1:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[2], null, null );
Log.d("ice","Returnvalue of deleting table2:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[3], null, null );
Log.d("ice","Returnvalue of deleting table3:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[4], null, null );
Log.d("ice","Returnvalue of deleting table4:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[5], null, null );
Log.d("ice","Returnvalue of deleting table5:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[6], null, null );
Log.d("ice","Returnvalue of deleting table6:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[7], null, null );
Log.d("ice","Returnvalue of deleting table7:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[8], null, null );
Log.d("ice","Returnvalue of deleting table8:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[9], null, null );
Log.d("ice","Returnvalue of deleting table9:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[10], null, null );
Log.d("ice","Returnvalue of deleting table10:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[11], null, null );
Log.d("ice","Returnvalue of deleting table11:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[12], null, null );
Log.d("ice","Returnvalue of deleting table12:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[13], null, null );
Log.d("ice","Returnvalue of deleting table13:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[14], null, null );
Log.d("ice","Returnvalue of deleting table14:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[15], null, null );
Log.d("ice","Returnvalue of deleting table15:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[16], null, null );
Log.d("ice","Returnvalue of deleting table16:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[17], null, null );
Log.d("ice","Returnvalue of deleting table17:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[18], null, null );
Log.d("ice","Returnvalue of deleting table18:" + Integer.toString(returnvalue));
returnvalue=db.delete(tableName[19], null, null );
Log.d("ice","Returnvalue of deleting table19:" + Integer.toString(returnvalue));
Log.d("ice","old data existed in database was all cleared");
try{
File csvpath = new File("/sdcard/downloadedfolder/"+route_folder);
Log.d("ice","Path of csv folder get in modile");
File[] csvfile = csvpath.listFiles();
//get all csv files' name and store it as array
Log.d("ice","Name of csv was get and change into string");
//Put all name of csv into a string array
/*FileReader file = new FileReader("/sdcard/downloadedfolder/A1/adv_sales_order.csv");
BufferedReader buffer = new BufferedReader(file);*/
for(int j=0;j<20;j++){
FileReader file = new FileReader(csvfile[j]);
Log.d("ice","Current file reading");
Log.d("ice","csvfile"+Integer.toString(j)+": "+file.toString());
BufferedReader buffer = new BufferedReader(file);
ContentValues contentValues=new ContentValues();
String line = buffer.readLine(); //read first line to get the column
Log.d("ice","Column of "+file.toString()+": "+ line);
String[] cols = line.split("\t");
db.beginTransaction();
while ((line = buffer.readLine()) != null) {
Log.d("ice","Read next record");
Log.d("ice","Line"+ Integer.toString(j)+": "+ line);
//read every single line of record in csv
String[] str = line.split("\t");
for (int i = 0; i < cols.length; i++) {
contentValues.put(cols[i], str[i]);
Log.d("ice",cols[i] + "= " + str[i]);
}
ret = db.insert(tableName[j], null, contentValues);
Log.d("ice","Import result for " + tableName[j] +"= ");
Log.d("ice", Long.toString(ret));
}
buffer.close();
}
db.setTransactionSuccessful();
db.endTransaction();
}catch (IOException e){
}
helper.close();
}
});
每当调用数据库的任何函数时，这都是错误日志：
07-11 10：39：52.076：E / SQLiteDatabase（25198）：无法打开数据库'/data/data/com.iceapp/databases/icedb.db'。 07-11 10：39：52.076：E / SQLiteDatabase（25198）：android.database.sqlite.SQLiteDatabaseLockedException：数据库被锁定（代码5）:,编译时：PRAGMA journal_mode
我也在logcat中找到了相关的消息
/data/data/com.iceapp/databases/icedb.db的连接池已关闭，但仍有1个连接正在使用中。当他们被释放回游泳池时，他们将被关闭。
我没有关于数据库关闭和使用哪个连接的原因的线索。谁能给我一些帮助？谢谢。
答案 0 :(得分：0)
确保SQLiteOpenHelper是Singleton，这样可以防止数据库被锁定。
始终调用db.yieldIfContendedSafely（）。在做交易时。这样可以防止数据库死锁。
db.beginTransaction（）;
for（..）{
...//insert
db.yieldIfContendedSafely();
}
db.setTransactionSuccessful（）;
db.endTransaction（）;