解决 Android 7.0 SQLiteCantOpenDatabaseException: unknown error (code 14)

5.0好好的可以读数据库，换成7.0就总是未知错误：

Failed to open database '/storage/emulated/0/Xinguanjia/download.db'.                                                                           android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database                                                                               at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)                                                                               at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)                                                                               at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)                                                                               at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)                                                                               at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)                                                                               at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)                                                                               at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:808)                                                                               at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:793)                                                                               at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:696)                                                                               at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:711)                                                                               at android.database.sqlite.SQLiteDatabase.openOrCreateDatabase(SQLiteDatabase.java:704)                                                                               at com.xinguanjia.xinguanjia.utils.DatabaseHelper.openOrCreateDatabase(DatabaseHelper.java:38)                                                                               at com.xinguanjia.xinguanjia.utils.DatabaseHelper.getData(DatabaseHelper.java:109)                                                                               at com.xinguanjia.xinguanjia.ui.fragment.UserCenterFragment.init(UserCenterFragment.java:37)                                                                               at com.xinguanjia.xinguanjia.ui.fragment.UserCenterFragment.onCreateView(UserCenterFragment.java:31)                                                                               at android.support.v4.app.Fragment.performCreateView(Fragment.java:2080)                                                                               at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1108)                                                                               at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1290)                                                                               at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1272)                                                                               at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:2149)                                                                               at android.support.v4.app.FragmentController.dispatchActivityCreated(FragmentController.java:201)                                                                               at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:600)                                                                               at android.support.v7.app.AppCompatActivity.onStart(AppCompatActivity.java:178)                                                                               at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1249)                                                                               at android.app.Activity.performStart(Activity.java:6696)                                                                               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2612)                                                                               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2710)                                                                               at android.app.ActivityThread.-wrap12(ActivityThread.java)                                                                               at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1461)                                                                               at android.os.Handler.dispatchMessage(Handler.java:102)                                                                               at android.os.Looper.loop(Looper.java:154)                                                                               at android.app.ActivityThread.main(ActivityThread.java:6088)                                                                               at java.lang.reflect.Method.invoke(Native Method)                                                                               at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)                                                                               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

然后各种Google各种stackoverflow各种各种之后，没有一个行得通的。

然后翻源码也因道行不深没找到有价值的信息。

转念一想虽然声明了权限，但7.0毕竟是最最最最新的系统，会不会是权限不够的问题。

打开设置->应用->应用权限，

果然啥权限也没有

打开文件读写权限，好了……

看来是权限问题。

但是总不能让人家每次都自己打开权限吧……

于是乎继续……Google又上不去了，百度吧。

貌似6.0以后要动态申请权限了。

if (ContextCompat.checkSelfPermission(this,         Manifest.permission.WRITE_EXTERNAL_STORAGE)         != PackageManager.PERMISSION_GRANTED) {     ActivityCompat.requestPermissions(this,             new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},             MY_PERMISSIONS_REQUEST_WRITE_EXTERNAL_STORAGE); } else {     startApp(); }

强制获取权限就好了。

但是！

明明权限已经获取到了

第一次运行却还报错，只有重启后才能行。

怎么回事呢？

我想到了会不会是DatabaseHelper的静态变量的问题

然后没有查到☺