在安装应用程序后的第一次启动过程中，我收到以下错误，然后稍后正常启动应用程序而没有问题。
> > 06-29 14:56:20.811 19467-19467/com.domain.sample E/SQLiteLog: (14) cannot open file at line 36667 of [0c55d17973]
> (14) os_unix.c:36667: (2) open(/data/user/0/com.domain.sample/databases/quotes.sqlite3) - 06-29
> 14:56:20.812 19467-19467/com.domain.sample E/SQLiteDatabase: Failed to
> open database
> '/data/user/0/com.domain.sample/databases/quotes.sqlite3'.
> android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14 SQLITE_CANTOPEN): Could not open database
> at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
> at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:211)
> at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:195)
> at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:503)
> at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:204)
> at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:196)
> at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:880)
> at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:865)
> at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:766)
> at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:714)
> at com.domain.sample.database.ExternalDbOpenHelper.checkDataBase(ExternalDbOpenHelper.java:93)
> at com.domain.sample.database.ExternalDbOpenHelper.createDataBase(ExternalDbOpenHelper.java:70)
> at com.domain.sample.database.ExternalDbOpenHelper.openDataBase(ExternalDbOpenHelper.java:133)
> at com.domain.sample.database.ExternalDbOpenHelper.<init>(ExternalDbOpenHelper.java:48)
> at com.domain.sample.database.ExternalDbOpenHelper.getInstance(ExternalDbOpenHelper.java:32)
> at com.domain.sample.loader.AbstractQueryLoader.<init>(AbstractQueryLoader.java:14)
> at com.domain.sample.loader.QuoteGroupLoader.<init>(QuoteGroupLoader.java:17)
> at com.domain.sample.QuoteGroupActivity.onCreateLoader(QuoteGroupActivity.java:154)
> at android.support.v4.app.LoaderManagerImpl.createAndInstallLoader(LoaderManagerImpl.java:370)
> at android.support.v4.app.LoaderManagerImpl.initLoader(LoaderManagerImpl.java:404)
> at com.domain.sample.QuoteGroupActivity.onCreate(QuoteGroupActivity.java:107)
> at android.app.Activity.performCreate(Activity.java:7131)
> at android.app.Activity.performCreate(Activity.java:7122)
> at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
> at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2882)
> at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3037)
> at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
> at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
> at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
> at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1797)
> at android.os.Handler.dispatchMessage(Handler.java:106)
> at android.os.Looper.loop(Looper.java:193)
> at android.app.ActivityThread.main(ActivityThread.java:6642)
> at java.lang.reflect.Method.invoke(Native Method)
> at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
> at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 06-29
> 14:56:20.812 19467-19467/com.domain.sample
> E/class com.domain.sample.database.ExternalDbOpenHelper: Error while
> checking db 06-29 14:56:20.812 19467-19467/com.domain.sample
> W/SQLiteAssetHelper: copying database from assets... 06-29
> 14:56:20.813 19467-19467/com.domain.sample W/SQLiteAssetHelper:
> extracting file: 'quotes.sqlite3'... 06-29 14:56:20.847
> 19467-19467/com.domain.sample W/SQLiteAssetHelper: database copy
> complete 06-29 14:56:20.869 19467-19467/com.domain.sample
> I/SQLiteAssetHelper: successfully opened database quotes.sqlite3 06-29
> 14:56:20.870 19467-19467/com.domain.sample I/Jalal: copyDataBase()
> 06-29 14:56:20.870 19467-19467/com.domain.sample D/AndroidRuntime:
> Shutting down VM
>
> > --------- beginning of crash 06-29 14:56:20.870 19467-19467/com.domain.sample E/AndroidRuntime: FATAL EXCEPTION: main
> Process: com.domain.sample, PID: 19467
> java.lang.Error: Error copying com.domain.sample.database!
> at com.domain.sample.database.ExternalDbOpenHelper.createDataBase(ExternalDbOpenHelper.java:78)
> at com.domain.sample.database.ExternalDbOpenHelper.openDataBase(ExternalDbOpenHelper.java:133)
> at com.domain.sample.database.ExternalDbOpenHelper.<init>(ExternalDbOpenHelper.java:48)
> at com.domain.sample.database.ExternalDbOpenHelper.getInstance(ExternalDbOpenHelper.java:32)
> at com.domain.sample.loader.AbstractQueryLoader.<init>(AbstractQueryLoader.java:14)
> at com.domain.sample.loader.QuoteGroupLoader.<init>(QuoteGroupLoader.java:17)
> at com.domain.sample.QuoteGroupActivity.onCreateLoader(QuoteGroupActivity.java:154)
> at android.support.v4.app.LoaderManagerImpl.createAndInstallLoader(LoaderManagerImpl.java:370)
> at android.support.v4.app.LoaderManagerImpl.initLoader(LoaderManagerImpl.java:404)
> at com.domain.sample.QuoteGroupActivity.onCreate(QuoteGroupActivity.java:107)
> at android.app.Activity.performCreate(Activity.java:7131)
> at android.app.Activity.performCreate(Activity.java:7122)
> at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
> at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2882)
> at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3037)
> at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
> at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
> at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
> at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1797)
> at android.os.Handler.dispatchMessage(Handler.java:106)
> at android.os.Looper.loop(Looper.java:193)
> at android.app.ActivityThread.main(ActivityThread.java:6642)
> at java.lang.reflect.Method.invoke(Native Method)
> at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
> at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 06-29
> 14:56:20.882 19467-19467/com.domain.sample I/Process: Sending signal.
> PID: 19467 SIG: 9
这是课程：
public class ExternalDbOpenHelper extends SQLiteAssetHelper {
//Path to the device folder with databases
public static String DB_PATH;
//Database file name
public static final String DB_NAME = quotesDatabaseInfo.DB_NAME;
public static final int DB_VERSION = quotesDatabaseInfo.DB_VERSION;
private static ExternalDbOpenHelper sInstance;
public SQLiteDatabase database;
public Context context;
public static ExternalDbOpenHelper getInstance(Context context) {
if (sInstance == null) {
sInstance = new ExternalDbOpenHelper(
context.getApplicationContext(), DB_NAME);
}
Log.i("Jalal", "ExternalDbOpenHelper getInstance(Context context)");
return sInstance;
}
private ExternalDbOpenHelper(Context context, String databaseName) {
super(context, databaseName, null, DB_VERSION);
this.context = context;
Log.i("Jalal", "ExternalDbOpenHelper(Context context, String databaseName)");
//Write a full path to the databases of your application
String packageName = context.getPackageName();
//DB_PATH = String.format("//data//data//%s//databases//", packageName);
DB_PATH = context.getApplicationInfo().dataDir +"/databases/";
openDataBase();
}
public ExternalDbOpenHelper(Context context){
super(context, DB_NAME, null, DB_VERSION);
Log.i("Jalal", "ExternalDbOpenHelper(Context context)");
}
public SQLiteDatabase getDb() {
Log.i("Jalal", "SQLiteDatabase getDb()");
return database;
}
//This piece of code will create a com.domain.sample.database if it’s not yet created
public void createDataBase() {
Log.i("Jalal", "createDataBase()");
boolean dbExist = checkDataBase();
if (!dbExist) {
this.getReadableDatabase();
//this.getWritableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying com.domain.sample.database!");
}
} else {
Log.i(this.getClass().toString(), "Database already exists");
}
}
//Performing a com.domain.sample.database existence check
private boolean checkDataBase() {
Log.i("Jalal", "checkDataBase()");
SQLiteDatabase checkDb = null;
try {
String path = DB_PATH + DB_NAME;
checkDb = SQLiteDatabase.openDatabase(path, null,
SQLiteDatabase.OPEN_READONLY);
} catch (SQLException e) {
Log.e(this.getClass().toString(), "Error while checking db");
}
//Android doesn’t like resource leaks, everything should
// be closed
if (checkDb != null) {
checkDb.close();
}
return checkDb != null;
}
//Method for copying the com.domain.sample.database
private void copyDataBase() throws IOException {
Log.i("Jalal", "copyDataBase()");
//Open a stream for reading from our ready-made com.domain.sample.database
//The stream source is located in the assets
InputStream externalDbStream = context.getAssets().open(DB_NAME);
//Path to the created empty com.domain.sample.database on your Android device
String outFileName = DB_PATH + DB_NAME;
//Now create a stream for writing the com.domain.sample.database byte by byte
OutputStream localDbStream = new FileOutputStream(outFileName);
//Copying the com.domain.sample.database
byte[] buffer = new byte[1024];
int bytesRead;
while ((bytesRead = externalDbStream.read(buffer)) > 0) {
localDbStream.write(buffer, 0, bytesRead);
}
//Don’t forget to close the streams
localDbStream.flush();
localDbStream.close();
externalDbStream.close();
}
public SQLiteDatabase openDataBase() throws SQLException {
Log.i("Jalal", "openDataBase()");
final String path = DB_PATH + DB_NAME;
if (database == null) {
createDataBase();
database = SQLiteDatabase.openDatabase(path, null,
SQLiteDatabase.OPEN_READWRITE);
}
return database;
}
@Override
public synchronized void close() {
Log.i("Jalal", "close");
if (database != null) {
database.close();
}
super.close();
}
// @Override
// public void onCreate(SQLiteDatabase db) {}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {}
}
答案 0 :(得分：0)
您似乎过分复杂了。也就是说，如果您使用SQLiteAssetHelper的子类，则只需要让该子类来完成即可。即它将根据需要从资产/数据库文件夹中复制数据库。
作为一个现有数据库.../assets/databases/Data.db的示例，并假设使用单例，则：-
SQLiteAssetHelper （在此示例中为DatabaseOpenHelper）的子类可以是：-
public class DatabaseOpenHelper extends SQLiteAssetHelper {
private static final String DATABASE_NAME = "Data.db";
private static final int DATABASE_VERSION = 1;
public DatabaseOpenHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
}
Singleton 的类可以是：-
public class DatabaseAccess {
private SQLiteAssetHelper openHelper;
private static SQLiteDatabase database;
private static DatabaseAccess instance;
private DatabaseAccess(Context context) {
this.openHelper = new DatabaseOpenHelper(context);
}
/**
* Return a singleton instance of DatabaseAccess.
*
* @param context the Context
* @return the instance of DabaseAccess
*/
public static DatabaseAccess getInstance(Context context) {
if (instance == null) {
instance = new DatabaseAccess(context);
database = instance.openHelper.getWritableDatabase();
}
return instance;
}
/**
* Get the SQLiteDatabase
* @return the SQLiteDatabase
*/
public SQLiteDatabase getDatabase() {
return this.database;
}
}
然后，调用代码（在这种情况下，来自MainActivity）可能类似于：-
public class MainActivity extends AppCompatActivity {
SQLiteDatabase mDB;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DatabaseAccess dba = DatabaseAccess.getInstance(this); // get DBAccess Instance
mDB = dba.getDatabase(); //Get the database
// use the database (list tables and indexes)
Cursor csr = mDB.query("sqlite_master",
null,
null,
null ,
null,
null,
"name"
);
StringBuilder tables = new StringBuilder();
StringBuilder indexes = new StringBuilder();
while (csr.moveToNext()) {
String current_name = csr.getString(csr.getColumnIndex("name"));
String current_type = csr.getString(csr.getColumnIndex("type"));
switch (current_type) {
case "table":
tables.append("\n\t").append(current_name);
break;
case "index":
indexes.append("\n\t").append(current_name);
break;
}
}
csr.close();
Log.d("DB TABLES","Tables in the Database are :-" + tables.toString());
Log.d("DB INDEXES","Indexes in the Database are:-" + indexes);
}
@Override
protected void onDestroy() {
if (mDB.isOpen()) {
mDB.close();
}
super.onDestroy();
}
}
假设当前不存在，则输出将与：-
相似07-01 00:55:18.567 1436-1436/? W/SQLiteAssetHelper: copying database from assets...
database copy complete
07-01 00:55:18.571 1436-1439/? D/dalvikvm: GC_CONCURRENT freed 227K, 10% free 6168K/6791K, paused 1ms+0ms, total 8ms
07-01 00:55:18.615 1436-1436/? I/SQLiteAssetHelper: successfully opened database Data.db
07-01 00:55:18.615 1436-1436/? D/DB TABLES: Tables in the Database are :-
android_metadata
data
07-01 00:55:18.619 1436-1436/? D/DB INDEXES: Indexes in the Database are:-
如果数据库确实存在，则输出将与：-
相似07-01 00:56:52.502 1483-1483/? I/SQLiteAssetHelper: successfully opened database Data.db
07-01 00:56:52.502 1483-1483/? D/DB TABLES: Tables in the Database are :-
android_metadata
data
07-01 00:56:52.502 1483-1483/? D/DB INDEXES: Indexes in the Database are:-
W/SQLiteAssetHelper: copying database from assets...
database copy complete 如果资产文件不存在或存在其他问题，则输出将与以下内容相似：-
07-01 00:58:57.004 1552-1552/? W/SQLiteAssetHelper: copying database from assets...
07-01 00:58:57.004 1552-1552/? D/AndroidRuntime: Shutting down VM
07-01 00:58:57.004 1552-1552/? W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0xa6223288)
07-01 00:58:57.004 1552-1552/? E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{examples.mjt.sqliteassethelperexample/examples.mjt.sqliteassethelperexample.MainActivity}: com.readystatesoftware.sqliteasset.SQLiteAssetHelper$SQLiteAssetException: Missing databases/Dataaaaa.db file (or .zip, .gz archive) in assets, or target folder not writable
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: com.readystatesoftware.sqliteasset.SQLiteAssetHelper$SQLiteAssetException: Missing databases/Dataaaaa.db file (or .zip, .gz archive) in assets, or target folder not writable
at android.content.res.AssetManager.openAsset(Native Method)
at android.content.res.AssetManager.open(AssetManager.java:315)
at android.content.res.AssetManager.open(AssetManager.java:289)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.copyDatabaseFromAssets(SQLiteAssetHelper.java:436)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.createOrOpenDatabase(SQLiteAssetHelper.java:400)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getWritableDatabase(SQLiteAssetHelper.java:176)
at examples.mjt.sqliteassethelperexample.DatabaseAccess.open(DatabaseAccess.java:45)
at examples.mjt.sqliteassethelperexample.MainActivity.onCreate(MainActivity.java:33)
at android.app.Activity.performCreate(Activity.java:5008)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
如您所见，不需要编写自己的代码来检查和复制数据库。
此外，当检查已存在的数据库未按照以下说明找到数据库时，您不会得到令人困惑的转储：-
06-29 14:56:20.811 19467-19467/com.domain.sample E/SQLiteLog: (14) cannot open file at line 36667 of [0c55d17973]
(14) os_unix.c:36667: (2) open(/data/user/0/com.domain.sample/databases/quotes.sqlite3) - 06-29 14:56:20.812 19467-19467/com.domain.sample E/SQLiteDatabase: Failed to open database '/data/user/0/com.domain.sample/databases/quotes.sqlite3'.
android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14 SQLITE_CANTOPEN): Could not open database
at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:211)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:195)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:503)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:204)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:196)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:880)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:865)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:766)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:714)
at com.domain.sample.database.ExternalDbOpenHelper.checkDataBase(ExternalDbOpenHelper.java:93)
at com.domain.sample.database.ExternalDbOpenHelper.createDataBase(ExternalDbOpenHelper.java:70)
at com.domain.sample.database.ExternalDbOpenHelper.openDataBase(ExternalDbOpenHelper.java:133)
at com.domain.sample.database.ExternalDbOpenHelper.<init>(ExternalDbOpenHelper.java:48)
at com.domain.sample.database.ExternalDbOpenHelper.getInstance(ExternalDbOpenHelper.java:32)
at com.domain.sample.loader.AbstractQueryLoader.<init>(AbstractQueryLoader.java:14)
at com.domain.sample.loader.QuoteGroupLoader.<init>(QuoteGroupLoader.java:17)
at com.domain.sample.QuoteGroupActivity.onCreateLoader(QuoteGroupActivity.java:154)
at android.support.v4.app.LoaderManagerImpl.createAndInstallLoader(LoaderManagerImpl.java:370)
at android.support.v4.app.LoaderManagerImpl.initLoader(LoaderManagerImpl.java:404)
at com.domain.sample.QuoteGroupActivity.onCreate(QuoteGroupActivity.java:107)
at android.app.Activity.performCreate(Activity.java:7131)
at android.app.Activity.performCreate(Activity.java:7122)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2882)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3037)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1797)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6642)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858) 06-29 14:56:20.812 19467-19467/com.domain.sample