android中操作SQLite常见错误

1. android.database.sqlite.SQLiteException: unable to close due to unfinalised statements

FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.evaluation/com.evaluation.VehicleActivity}: android.database.sqlite.SQLiteException: unable to close due to unfinalised statements
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2781)
 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2797)
 at android.app.ActivityThread.access$2300(ActivityThread.java:135)
 at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2132)
 at android.os.Handler.dispatchMessage(Handler.java:99)
 at android.os.Looper.loop(Looper.java:143)
 at android.app.ActivityThread.main(ActivityThread.java:4914)
 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:868)
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
 at dalvik.system.NativeStart.main(Native Method)
Caused by: android.database.sqlite.SQLiteException: unable to close due to unfinalised statements
 at android.database.sqlite.SQLiteDatabase.dbclose(Native Method)
 at android.database.sqlite.SQLiteDatabase.onAllReferencesReleased(SQLiteDatabase.java:363)
 at android.database.sqlite.SQLiteClosable.releaseReference(SQLiteClosable.java:45)
 at android.database.sqlite.SQLiteProgram.onAllReferencesReleased(SQLiteProgram.java:116)
 at android.database.sqlite.SQLiteClosable.releaseReference(SQLiteClosable.java:45)
 at android.database.sqlite.SQLiteProgram.close(SQLiteProgram.java:293)
 at android.database.sqlite.SQLiteQuery.close(SQLiteQuery.java:133)
 at android.database.sqlite.SQLiteCursor.close(SQLiteCursor.java:532)
 at com.DatabaseHelper.selectAssessInformation(DatabaseHelper.java:338)
 at com.JSKApplication.selectAssessInformation(JSKApplication.java:631)
 at com.VehicleActivity.onCreate(VehicleActivity.java:548)
 at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1065)
 at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2745)
 ... 11 more

这个错误翻译过来就是：不能关闭数据库由于未完成的语句。

我从网上查了一下，最可能的原因是：你在操作sqlite数据库时使用多线程了，但sqlite数据库是不支持多线程操作，所以你必须实现多线程同步的机制。

我的程序出错是因为：在后台启动了个service定时向服务器请求数据，并在线程中将数据插入数据库。在某个时间段，用户在向数据库插入数据后，关闭数据库，而此时线程正在向数据库中写入数据，就会造成上述异常。

2.android.database.sqlite.SQLiteConstraintException: error code 19: constraint failed

07-0416:18:56.677: W/System.err(29830): android.database.sqlite.SQLiteConstraintException: error code 19: constraint failed

约束失败，导致这类错误，原因一般有两个：

1)插入的数据有一个是主键，而且插入的主键相同；

2)插入的数据有一条数据为空，而数据库中定义不能为空，也会导致这样的错误；