使用Sqlite db，我正在填充我的列表。该列表每分钟刷新一次（使用Timer）。我也在更新/插入Sqlite db（使用Service），检查新数据。
每分钟都会发生这种情况。这是有效的，但有时“数据库被锁定”。我该如何管理它而不是出错。感谢您的意见。
public class Services extends Service {
Context context;
int NOTIFICATION_ID = 1;
NotificationManager notificationManager, chatNotificationManager;
boolean connected = false;
boolean notconnected = false;
int numChat = 0;
int numTask = 0;
List<String> list = new ArrayList();
String android_id, syncDecision;
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
android_id = Secure.getString(this.getContentResolver(), Secure.ANDROID_ID);
context = getBaseContext();
/*
* THIS TIMER CONTAINS ANY SERVICE THAT ACCESSES THE SQLite database
*/
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
public void run() {
Log.d(TAG, "starting to do work in timer1");
synchronizeSQLiteDatabases();
}
}, 0, 60000);
private void synchronizeSQLiteDatabases() {
try {
if (Functions.isOnline(context) )
{
// ---------------------------------- COMMENT UPLOAD ----------------------------
if (!((GlobalMobileVianet) this.getApplication()).getUserid().equals("000000")) {
try
{
Log.i(TAG, "uploading comment data");
DataUploader_Comment commentupdater = new DataUploader_Comment(((GlobalMobileVianet) this.getApplication()).getUserid(),
((GlobalMobileVianet) this.getApplication()).getPassword(), context);
commentupdater.run();
}
catch(Exception e)
{
Log.i(TAG, " CATCH uploading comment data" + e.toString());
}
}
else
{
//Functions.logout(getApplicationContext());
Log.i(TAG, " NOT uploading comment data");
}
//--------------------------------------- TASK UPLOAD --------------------------------
if ( !((GlobalMobileVianet) this.getApplication()).getUserid().equals("000000")) {
try{
Log.i(TAG, "uploading task data");
DataUploader_Task taskuploader = new DataUploader_Task(((GlobalMobileVianet) this.getApplication()).getUserid(),
((GlobalMobileVianet) this.getApplication()).getPassword(), context);
taskuploader.run();
}
catch(Exception e)
{
Log.i(TAG, " CATCH uploading task data" + e);
}
}
else
{
//Functions.logout(getApplicationContext());
Log.i(TAG, " NOT uploading task data");
}
// ------------------------------------------AC DOWNLOAD ---------------------------------
if (!((GlobalMobileVianet) this.getApplication()).getUserid().equals("000000")) {
try{
Log.i(TAG, "running aircraft data download");
DataLoader_Aircraft acloader = new DataLoader_Aircraft(((GlobalMobileVianet) this.getApplication()).getUserid(),
((GlobalMobileVianet) this.getApplication()).getPassword(), context, "N");
acloader.run();
}
catch(Exception e)
{
Log.i(TAG, " CATCH running aircraft data download" + e.toString());
}
}
else
{
//Functions.logout(getApplicationContext());
Log.i(TAG, " NOT running aircraft data download");
}
// ------------------------------------ TASK DOWNLOAD ------------------------------------
if ( !((GlobalMobileVianet) this.getApplication()).getUserid().equals("000000")) {
try{
Log.i(TAG, "running task data download");
DataLoader_Task tasksloader = new DataLoader_Task(((GlobalMobileVianet) this.getApplication()).getUserid(),
((GlobalMobileVianet) this.getApplication()).getPassword(), context, "N");
tasksloader.run();
}
catch(Exception e)
{
Log.i(TAG, " CATCH running task data download" + e.toString());
}
}
else
{
//Functions.logout(getApplicationContext());
Log.i(TAG, " NOT running task data download");
}
// -------------------------------- EMPLOYEE DOWNLOAD -----------------------------------
if (!((GlobalMobileVianet) this.getApplication()).getUserid().equals("000000")) {
try
{
Log.i(TAG, "running employee data download");
DataLoader_Employee employeeloader = new DataLoader_Employee(((GlobalMobileVianet) this.getApplication()).getUserid(),
((GlobalMobileVianet) this.getApplication()).getPassword(), context, "N");
employeeloader.run();
}
catch(Exception e)
{
Log.i(TAG, " CATCH running employee data download " + e.toString());
}
}
else
{
//Functions.logout(getApplicationContext());
Log.i(TAG, " NOT running employee data download");
}
// ------------------------------------COMMENT DOWNLOAD -----------------------------------------
if (!((GlobalMobileVianet) this.getApplication()).getUserid().equals("000000")) {
try{
Log.i(TAG, "running comment data update");
DataLoader_Comment commentloader = new DataLoader_Comment(((GlobalMobileVianet) this.getApplication()).getUserid(),
((GlobalMobileVianet) this.getApplication()).getPassword(), context, "N");
commentloader.run();
}
catch(Exception e)
{
Log.i(TAG, " CATCH running comment data update" + e.toString());
}
}
else
{
//Functions.logout(getApplicationContext());
Log.i(TAG, " NOT running comment data download");
}
}
} catch (Exception e) {
Log.e(TAG,
"synchronizeSQLiteDatabases exception: " + e.toString());
}
}
这是刷新列表的活动
public class TestExList extends ExpandableListActivity{
String empid, ctext, fleet_name, rString;
private DbAdapter_Assignment assignment;
private DbAdapter_Task task;
private DbAdapter_Comment comment;
private DbAdapter_Aircraft aircraft;
private Cursor accursor, taskcursor;
private ExpandableListView expListView;
private Timer taskTimer;
private ListView lv;
private Camera cam;
private boolean onoff;
private boolean testValue;
private SimpleCursorTreeAdapter cursorTreeAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
empid = getIntent().getExtras().getString("EmpID");
Log.d("testValue","from onCreate, onoff is " + onoff);
setHeader();
if(empid.equals(Functions.getLoginEmpID(this))){
getData(empid);
}
taskTimer = new Timer();
taskTimer.schedule(new TimerTask() {
@Override
public void run() {
TimerMethod();
}
}, 0, 60000);
expListView.invalidateViews();
}
private void TimerMethod()
{
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable() {
public void run() {
if(Functions.getServiceStatus(getBaseContext()) != "No service")
{
if(empid.equals(Functions.getLoginEmpID(getBaseContext())))
{
getData(empid);
}
}
}
};
@Override
public void onDestroy()
{
super.onDestroy();
try
{
accursor.close();
taskcursor.close();
task.close();
comment.close();
aircraft.close();
assignment.close();
}
catch(Exception e)
{
Log.e("ViaNetError", "Unable to close cursors.");
}
if(cam != null)
{
cam.release();
cam = null;
}
}
public void getData(final String empid)
{
Log.e("Testing", "Getting data for emp: " + empid);
assignment = new DbAdapter_Assignment(getBaseContext());
assignment.open();
task = new DbAdapter_Task (getBaseContext());
task.open();
comment = new DbAdapter_Comment (getBaseContext());
comment.open();
}
}
答案 0 :(得分：2)
我用这个完全相同的问题打了很长时间，随机使用我的应用程序开放数据库会得到一个“数据库被锁定”，没有任何时间或原因。经过几个月的挣扎，这是我的解决方案。
1）在课堂上创建dbopenhelper，其所有方法都是正常的。
2）在APPLICATION类中创建该类的实例。
3）打开Application类的onCreate中的DB，永远不要关闭它。
4）通过Application类拥有的dbhelper副本运行所有查询。
我担心永远不会关闭数据库，但我的研究显示Android开发人员（IE Googles人员）的许多实例都表明了这一点。
希望它对你有用，对我来说也是如此。
答案 1 :(得分：0)
SQLite告诉你数据库已经在另一个线程中打开了。您必须以线程安全的方式使用SQLite。
您可以在打开数据库和计时器的问题中添加代码吗？