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android - 来自 AsyncTask 和 Activity 的数据库访问 - 锁定。解决方案？

转载 作者：行者123 更新时间：2023-11-29 02:12:33 25 4
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我有一个 android 应用程序，可以与服务器通信并同步一些数据到 SQLite 数据库。有一项服务每 5 分钟运行一次，跨越 AsyncTask 获取数据并将数据插入/更新数据库。

这是我的问题。当后台进程更新数据库时，可能需要相当长的时间。如果用户尝试同时使用应用程序并打开 ListView 并将光标绑定(bind)到同一个表 - 我会遇到死锁情况和 ANR 报告。

我该如何正确解决这个问题？

我觉得我需要从 UI 检查 asyncprocess 是否正在运行(如何运行？)，如果是，则向用户显示后台刷新正在进行并在进程访问数据在后台完成后立即加载列表。

解决这个问题的正确方法是什么？

编辑

这是报告

DALVIK THREADS:
"main" prio=5 tid=1 WAIT
  | group="main" sCount=1 dsCount=0 s=N obj=0x2aac88b8 self=0xcd58
  | sysTid=3967 nice=0 sched=0/0 cgrp=unknown handle=1876207664
  at java.lang.Object.wait(Native Method)
  - waiting on <0x2aac8948> (a java.lang.VMThread)
  at java.lang.Thread.parkFor(Thread.java:1535)
  at java.lang.LangAccessImpl.parkFor(LangAccessImpl.java:48)
  at sun.misc.Unsafe.park(Unsafe.java:317)
  at java.util.concurrent.locks.LockSupport.park(LockSupport.java:131)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:790)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:823)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1153)
  at java.util.concurrent.locks.ReentrantLock$FairSync.lock(ReentrantLock.java:200)
  at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:261)
  at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:375)
  at android.database.sqlite.SQLiteQuery.fillWindow(SQLiteQuery.java:61)
  at android.database.sqlite.SQLiteCursor.fillWindow(SQLiteCursor.java:283)
  at android.database.sqlite.SQLiteCursor.getCount(SQLiteCursor.java:264)
  at android.content.ContentResolver.query(ContentResolver.java:251)
  ****************at com.idatt.data.PreferenceData.getPreferenceString(PreferenceData.java:119)
  at com.idatt.data.PreferenceData.getPreferenceBoolean(PreferenceData.java:109)
  at com.idatt.common.Preferences.getIsShowRates(Preferences.java:136)
  at com.idatt.activities.TripListActivity$TripViewDataHolder.populateFrom(TripListActivity.java:211)
  at com.idatt.activities.TripListActivity$TripListCursorAdapter.getView(TripListActivity.java:147)
  at android.widget.AbsListView.obtainView(AbsListView.java:1294)
  at android.widget.ListView.measureHeightOfChildren(ListView.java:1198)
  at android.widget.ListView.onMeasure(ListView.java:1109)
  at android.view.View.measure(View.java:8187)
  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3146)
  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1012)
  at android.widget.LinearLayout.measureVertical(LinearLayout.java:381)
  at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
  at android.view.View.measure(View.java:8187)
  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3146)
  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1012)
  at android.widget.LinearLayout.measureVertical(LinearLayout.java:381)
  at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
  at android.view.View.measure(View.java:8187)
  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3146)
  at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  at android.view.View.measure(View.java:8187)
  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3146)
  at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
  at android.view.View.measure(View.java:8187)
  at android.view.ViewRoot.performTraversals(ViewRoot.java:801)
  at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
  at android.os.Handler.dispatchMessage(Handler.java:99)
  at android.os.Looper.loop(Looper.java:123)
  at android.app.ActivityThread.main(ActivityThread.java:4644)
  at java.lang.reflect.Method.invokeNative(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:521)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:878)
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
  at dalvik.system.NativeStart.main(Native Method)

"Binder Thread #3" prio=5 tid=14 NATIVE
  | group="main" sCount=1 dsCount=0 s=N obj=0x3033f218 self=0x2394d0
  | sysTid=4305 nice=0 sched=0/0 cgrp=unknown handle=2332488
  at dalvik.system.NativeStart.run(Native Method)

"AsyncTask #5" prio=5 tid=13 WAIT
  | group="main" sCount=1 dsCount=0 s=N obj=0x300dc038 self=0x25f0e0
  | sysTid=4073 nice=10 sched=0/0 cgrp=unknown handle=2965040
  at java.lang.Object.wait(Native Method)
  - waiting on <0x3013c610> (a java.lang.VMThread)
  at java.lang.Thread.parkFor(Thread.java:1535)
  at java.lang.LangAccessImpl.parkFor(LangAccessImpl.java:48)
  at sun.misc.Unsafe.park(Unsafe.java:317)
  at java.util.concurrent.locks.LockSupport.park(LockSupport.java:131)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:790)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:823)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1153)
  at java.util.concurrent.locks.ReentrantLock$FairSync.lock(ReentrantLock.java:200)
  at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:261)
  at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:375)
  at android.database.sqlite.SQLiteDatabase.insertWithOnConflict(SQLiteDatabase.java:1533)
  at android.database.sqlite.SQLiteDatabase.insert(SQLiteDatabase.java:1410)
  at com.idatt.data.Provider.insert(Provider.java:198)
  at android.content.ContentProvider$Transport.insert(ContentProvider.java:174)
  at android.content.ContentResolver.insert(ContentResolver.java:587)
  *************at com.idatt.data.TripData.InsertTrip(TripData.java:272)
  at com.idatt.common.AsyncProcessor.GetUserTrips(AsyncProcessor.java:252)
  at com.idatt.common.AsyncProcessor.doInBackground(AsyncProcessor.java:101)
  at com.idatt.common.AsyncProcessor.doInBackground(AsyncProcessor.java:27)
  at android.os.AsyncTask$2.call(AsyncTask.java:185)
  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
  at java.util.concurrent.FutureTask.run(FutureTask.java:137)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
  at java.lang.Thread.run(Thread.java:1096)

"AsyncTask #4" prio=5 tid=12 WAIT
  | group="main" sCount=1 dsCount=0 s=N obj=0x302ffd28 self=0x4e8f30
  | sysTid=4072 nice=10 sched=0/0 cgrp=unknown handle=5163584
  at java.lang.Object.wait(Native Method)
  - waiting on <0x302ffbd8> (a java.lang.VMThread)
  at java.lang.Thread.parkFor(Thread.java:1535)
  at java.lang.LangAccessImpl.parkFor(LangAccessImpl.java:48)
  at sun.misc.Unsafe.park(Unsafe.java:317)
  at java.util.concurrent.locks.LockSupport.park(LockSupport.java:131)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:790)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:823)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1153)
  at java.util.concurrent.locks.ReentrantLock$FairSync.lock(ReentrantLock.java:200)
  at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:261)
  at android.database.sqlite.SQLiteDatabase.lock(SQLiteDatabase.java:375)
  at android.database.sqlite.SQLiteProgram.close(SQLiteProgram.java:291)
  at android.database.sqlite.SQLiteQuery.close(SQLiteQuery.java:133)
  at android.database.sqlite.SQLiteCursor.close(SQLiteCursor.java:502)
  at android.database.CursorWrapper.close(CursorWrapper.java:45)
  at android.content.ContentResolver$CursorWrapperInner.close(ContentResolver.java:1355)
  ************at com.idatt.data.LogData.getLogItems(LogData.java:118)
  at com.idatt.data.LogData.getLogItems(LogData.java:125)
  at com.idatt.common.AsyncProcessor.PostDeviceLogs(AsyncProcessor.java:210)
  at com.idatt.common.AsyncProcessor.doInBackground(AsyncProcessor.java:96)
  at com.idatt.common.AsyncProcessor.doInBackground(AsyncProcessor.java:27)
  at android.os.AsyncTask$2.call(AsyncTask.java:185)
  at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
  at java.util.concurrent.FutureTask.run(FutureTask.java:137)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
  at java.lang.Thread.run(Thread.java:1096)

"AsyncTask #3" prio=5 tid=11 WAIT
  | group="main" sCount=1 dsCount=0 s=N obj=0x302ec858 self=0x4ff440
  | sysTid=4071 nice=10 sched=0/0 cgrp=unknown handle=2984848
  at java.lang.Object.wait(Native Method)
  - waiting on <0x302ec9b0> (a java.lang.VMThread)
  at java.lang.Thread.parkFor(Thread.java:1535)
  at java.lang.LangAccessImpl.parkFor(LangAccessImpl.java:48)
  at sun.misc.Unsafe.park(Unsafe.java:317)
  at java.util.concurrent.locks.LockSupport.park(LockSupport.java:131)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1996)
  at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:359)
  at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1001)
  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1061)
  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561)
  at java.lang.Thread.run(Thread.java:1096)

"AsyncTask #2" prio=5 tid=10 WAIT
  | group="main" sCount=1 dsCount=0 s=N obj=0x302c31a8 self=0x4dca78
  | sysTid=4062 nice=10 sched=0/0 cgrp=unknown handle=5111608
  at java.lang.Object.wait(Native Method)
  - waiting on <0x3027ab38> (a java.lang.VMThread)
  at java.lang.Thread.parkFor(Thread.java:1535)
  at java.lang.LangAccessImpl.parkFor(LangAccessImpl.java:48)
  at sun.misc.Unsafe.park(Unsafe.java:317)
  at java.util.concurrent.locks.LockSupport.park(LockSupport.java:131)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:790)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:823)
  at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1153)
  at java.util.concurrent.locks.ReentrantLock$FairSync.lock(ReentrantLock.java:200)
  at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:261)
  at android.database.sqlite.SQLiteDatabase....

见附件。检查我用 ** 标记的行我不擅长阅读它但这是我的结论.. 似乎在尝试执行时它被阻塞了

com.idatt.data.PreferenceData.getPreferenceString

此调用以只读模式打开数据库(它通过我的 COntentProvider)。这个调用发生在 UI 线程上。

有什么不好的 - 我注意到另外 2 个调用:InsertTrips 和 getLogData。 InsertTrips 进入数据库，但 getLogData 也应该是只读的。但是，它们都是同一个 AsyncTask 的一部分。因此，似乎 AsyncTask 的一个实例源自服务/警报(每 5 分钟一次)，第二个实例由用户发起(我给他们选择手动刷新)。

情况是这样的:

  • 应用按计划自行更新
  • 用户使用应用程序并手动调用刷新
  • 在用户启动手动刷新后 - 她尝试在访问相同数据的地方使用应用..

最佳答案

它是在您使用用于获取列表游标的表时锁定，还是在您访问数据库时锁定。如果锁是基于表的，你可以考虑有两个表，一个用于服务，一个用于 View ，或者两个表，你切换到一个用于显示，另一个用于填充数据...

如果锁是基于数据库而不是基于表的，我想到的另一个解决方案是，当您为表获取数据时，您可以从数据库中缓存数据，使用数组适配器而不是游标适配器。查询您的数据库，填充缓存并显示它，以便服务可以使用数据库填充新值。服务终止后，您可以发送一个 oberserupdate 以通知 UI 获取新数据并重新填充其缓存。

问候， 斯蒂芬

关于android - 来自 AsyncTask 和 Activity 的数据库访问 - 锁定。解决方案？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/6375573/

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