我知道之前已经问过这个问题。但是，问题是，相同的代码（对于数据库处理程序）适用于另一个应用程序，但不适用于我目前正在处理的应用程序。我甚至通过检查设置中的权限来确保权限。这是logcat：
05-13 15：35：45.693 29696-29696 / com.example.hack.corrector E / SQLiteLog：（14）无法打开[5a3022e081]第31282行的文件 （14）os_unix.c：31282：（21）open（/data/user/0/com.example.hack.corrector/databases/） - 05-13 15：35：45.694 29696-29696 / com.example.hack.corrector E / SQLiteDatabase：无法打开数据库＆＃39; /data/user/0/com.example.hack.corrector/databases /＆＃ 39 ;. android.database.sqlite.SQLiteCantOpenDatabaseException：未知错误（代码14）：无法打开数据库 在android.database.sqlite.SQLiteConnection.nativeOpen（本机方法） 在android.database.sqlite.SQLiteConnection.open（SQLiteConnection.java:207） 在android.database.sqlite.SQLiteConnection.open（SQLiteConnection.java:191） 在android.database.sqlite.SQLiteConnectionPool.openConnectionLocked（SQLiteConnectionPool.java:463） 在android.database.sqlite.SQLiteConnectionPool.open（SQLiteConnectionPool.java:185） 在android.database.sqlite.SQLiteConnectionPool.open（SQLiteConnectionPool.java:177） 在android.database.sqlite.SQLiteDatabase.openInner（SQLiteDatabase.java:806） 在android.database.sqlite.SQLiteDatabase.open（SQLiteDatabase.java:791） 在android.database.sqlite.SQLiteDatabase.openDatabase（SQLiteDatabase.java:694） 在android.database.sqlite.SQLiteDatabase.openDatabase（SQLiteDatabase.java:669） 在com.example.hakc.corrector.VocabDatabase.openDataBase（VocabDatabase.java:127） 在com.example.hakc.corrector.scrapeservice.createDB（scrapeservice.java:31） 在com.example.hakc.corrector.scrapeservice.onStartCommand（scrapeservice.java:23） 在android.app.ActivityThread.handleServiceArgs（ActivityThread.java:3049） 在android.app.ActivityThread.access $ 2300（ActivityThread.java:154） 在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1479） 在android.os.Handler.dispatchMessage（Handler.java:102） 在android.os.Looper.loop（Looper.java:157） 在android.app.ActivityThread.main（ActivityThread.java:5571） at java.lang.reflect.Method.invoke（Native Method） 在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:745） 在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:635）
以及数据库处理程序代码：
package com.example.hack.corrector;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
public class VocabDatabase extends SQLiteOpenHelper {
//The Android's default system path of your application database.
private static String DB_PATH = "";
private static String DB_NAME = "ztr.db";
private SQLiteDatabase myDataBase;
private final Context myContext;
/**
* Constructor
* Takes and keeps a reference of the passed context in order to access to the application assets and resources.
*
* @param context
*/
public VocabDatabase(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
this.DB_PATH = context.getApplicationInfo().dataDir + "/databases/";
}
/**
* Creates a empty database on the system and rewrites it with your own database.
*/
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
//do nothing - database already exist
} else {
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getWritableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
*
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase() {
this.getReadableDatabase();
SQLiteDatabase checkDB = null;
try {
String myPath = DB_PATH;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
} catch (SQLiteException e) {
e.printStackTrace();
}
if (checkDB != null) {
checkDB.close();
}
return (checkDB != null) ? true : false;
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
*/
private void copyDataBase() throws IOException {
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME);
// Path to the just created empty db
String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length = 0;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
//Open the database
String myPath = DB_PATH;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if (myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion > oldVersion) {
try {
copyDataBase();
} catch (Exception e) {
e.printStackTrace();
}
}
}
// Add your public helper methods to access and get content from the database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
// to you to create adapters for your views.
//add your public methods for insert, get, delete and update data in database.
public Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy) {
SQLiteDatabase db = this.getWritableDatabase();
return db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy);
}
public long insert(String table, String nullColumnHack, ContentValues contentValues) {
SQLiteDatabase db = this.getWritableDatabase();
return db.insert(table, nullColumnHack, contentValues);
}
public Cursor rawQuery(String string, String[] selectionArguments) {
SQLiteDatabase db = this.getWritableDatabase();
return db.rawQuery(string, selectionArguments);
}
}
我已检查过文件资源管理器，数据库已被复制并到位。但是，错误仍在发生。我从未遇到过实现相同数据库处理程序代码（Vocabdatabase）的其他应用程序的问题。我花了一天半的时间试图解决这个问题，但没有任何工作......
答案 0 :(得分：1)
您的问题是您尝试使用不包含数据库名称的路径打开。
即。
无法打开14 /data/user/0/com.example.hack.corrector/databases/
虽然公开应该试图打开
的 /data/user/0/com.example.hack.corrector/databases/ztr.db
不使用完整路径会导致两个可能导致混淆的问题。
在这两种情况下，正确使用应该是DB_PATH + DB_NAME，而不仅仅是DB_PATH。
以下是您的数据库处理程序被重写以包含上述内容，但也更改了对数据库的检查以检查文件，因此不显示非错误的打开错误14（复制数据库时）来自资产文件）。
//<<<< ????表示更改。： -
public class VocabDatabase extends SQLiteOpenHelper {
//The Android's default system path of your application database.
//private static String DB_PATH = ""; //<<<< RMVD
private static String DB_PATH_ALT; //<<<< ADDED
private static String DB_NAME = "ztr.db";
private SQLiteDatabase myDataBase;
private final Context myContext;
/**
* Constructor
* Takes and keeps a reference of the passed context in order to access to the application assets and resources.
*
* @param context
*/
public VocabDatabase(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
//this.DB_PATH = context.getApplicationInfo().dataDir + "/databases/"; //<<<< RMVD
this.DB_PATH_ALT = context.getDatabasePath(DB_NAME).getPath(); //<<<< ADDED
}
/**
* Creates a empty database on the system and rewrites it with your own database.
*/
public void createDataBase() throws IOException {
//boolean dbExist = checkDataBase(); //<<<< RMVD
boolean dbExist = checkDataBaseAlt(); //<<<< CHANGED
if (dbExist) {
//do nothing - database already exist
} else {
//By calling this method and empty database will be created into the default system path
//of your application so we are gonna be able to overwrite that database with our database.
this.getWritableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
//<<<< ADDED Alternative method checks the file rather than database
//<<<< as such no open error 14 messages
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
*
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBaseAlt() {
//File chkdb = new File(myContext.getDatabasePath(DB_NAME).getPath()); //<<<< RMVD
File chkdb = new File(DB_PATH_ALT); //<<<< ADDED
return chkdb.exists();
}
/**
* Check if the database already exist to avoid re-copying the file each time you open the application.
*
* @return true if it exists, false if it doesn't
*/
private boolean checkDataBase() {
this.getReadableDatabase();
SQLiteDatabase checkDB = null;
try {
//String myPath = DB_PATH; //<<<< RMVD so no open error 14 uses alt method
checkDB = SQLiteDatabase.openDatabase(
DB_PATH_ALT, //<<<< CHANGED
null,
SQLiteDatabase.OPEN_READWRITE
);
} catch (SQLiteException e) {
e.printStackTrace();
}
if (checkDB != null) {
checkDB.close();
}
return checkDB != null; //<<<< simplified
}
/**
* Copies your database from your local assets-folder to the just created empty database in the
* system folder, from where it can be accessed and handled.
* This is done by transfering bytestream.
*/
private void copyDataBase() throws IOException {
//Open your local db as the input stream
InputStream myInput = myContext.getAssets().open(DB_NAME); //<<<< CHANGED
// Path to the just created empty db
//String outFileName = DB_PATH + DB_NAME;
//Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(DB_PATH_ALT); //<<<< CHANGED
//transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length = 0;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
//Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public void openDataBase() throws SQLException {
//Open the database
//String myPath = DB_PATH; //<<<< RMVD
myDataBase = SQLiteDatabase.openDatabase(
DB_PATH_ALT, //<<<< CHANGED
null,
SQLiteDatabase.OPEN_READWRITE
);
}
@Override
public synchronized void close() {
if (myDataBase != null)
myDataBase.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
if (newVersion > oldVersion) {
try {
copyDataBase();
} catch (Exception e) {
e.printStackTrace();
}
}
}
// Add your public helper methods to access and get content from the database.
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
// to you to create adapters for your views.
//add your public methods for insert, get, delete and update data in database.
public Cursor query(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy) {
SQLiteDatabase db = this.getWritableDatabase();
return db.query(table, columns, selection, selectionArgs, groupBy, having, orderBy);
}
public long insert(String table, String nullColumnHack, ContentValues contentValues) {
SQLiteDatabase db = this.getWritableDatabase();
return db.insert(table, nullColumnHack, contentValues);
}
public Cursor rawQuery(String string, String[] selectionArguments) {
SQLiteDatabase db = this.getWritableDatabase();
return db.rawQuery(string, selectionArguments);
}
}