Android：错误从资产文件夹复制数据库(Sqliite)
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内容图文
我在SQLlite Browser中设计了数据库.现在我想把它复制到我的根路径.
面临的问题
错误复制数据库
链接： – 我正在从这个例子中获得帮助
Link to add external Sqllite Db to app
我的DBhelper类
package com.example.demo;
public class DBHelper extends SQLiteOpenHelper{
//The Android's default system path of your application database.
private static String DB_PATH = "/data/data/com.example.demo/databases/";
private static String DB_NAME = "assesmenttool";
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 DBHelper(Context context) {
super(context, DB_NAME, null, 1);
this.myContext = context;
}
/**
* 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.getReadableDatabase();
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(){
SQLiteDatabase checkDB = null;
try{
String myPath = DB_PATH + DB_NAME;
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}catch(SQLiteException e){
//database does't exist yet.
}
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;
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 + DB_NAME;
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
}
@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) {
}
// 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.
}
我的主要活动课程
package com.example.demo;
import java.io.IOException;
public class MainActivity extends Activity {
String Question_ID,Title,TitleDescription,QuestionText,QuestionTemplate,QuestionImage;
DBHelper dbhelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbhelper = new DBHelper(this);
try {
dbhelper.createDataBase();
} catch (IOException ioe) {
throw new Error("Unable to create database");
}
try {
dbhelper.openDataBase();
}catch(SQLException sqle){
throw sqle;
}
}
}
我的LogCat
07-15 05:24:09.171: E/SQLiteLog(19825): (14) cannot open file at line 30191 of [00bb9c9ce4]
07-15 05:24:09.171: E/SQLiteLog(19825): (14) os_unix.c:30191: (2) open(/data/data/com.example.demo/databases/assesmenttool) -
07-15 05:24:09.191: E/SQLiteDatabase(19825): Failed to open database '/data/data/com.example.demo/databases/assesmenttool'.
07-15 05:24:09.191: E/SQLiteDatabase(19825): android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:804)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:789)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at com.example.demo.DBHelper.checkDataBase(DBHelper.java:76)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at com.example.demo.DBHelper.createDataBase(DBHelper.java:43)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at com.example.demo.MainActivity.onCreate(MainActivity.java:27)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.app.Activity.performCreate(Activity.java:5231)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.app.ActivityThread.access$800(ActivityThread.java:135)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.os.Handler.dispatchMessage(Handler.java:102)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.os.Looper.loop(Looper.java:136)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at android.app.ActivityThread.main(ActivityThread.java:5017)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at java.lang.reflect.Method.invokeNative(Native Method)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at java.lang.reflect.Method.invoke(Method.java:515)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
07-15 05:24:09.191: E/SQLiteDatabase(19825): at dalvik.system.NativeStart.main(Native Method)
07-15 05:24:09.481: E/AndroidRuntime(19825): FATAL EXCEPTION: main
07-15 05:24:09.481: E/AndroidRuntime(19825): Process: com.example.demo, PID: 19825
07-15 05:24:09.481: E/AndroidRuntime(19825): java.lang.Error: Error copying database
07-15 05:24:09.481: E/AndroidRuntime(19825): at com.example.demo.DBHelper.createDataBase(DBHelper.java:59)
07-15 05:24:09.481: E/AndroidRuntime(19825): at com.example.demo.MainActivity.onCreate(MainActivity.java:27)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.app.Activity.performCreate(Activity.java:5231)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.app.ActivityThread.access$800(ActivityThread.java:135)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.os.Handler.dispatchMessage(Handler.java:102)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.os.Looper.loop(Looper.java:136)
07-15 05:24:09.481: E/AndroidRuntime(19825): at android.app.ActivityThread.main(ActivityThread.java:5017)
07-15 05:24:09.481: E/AndroidRuntime(19825): at java.lang.reflect.Method.invokeNative(Native Method)
07-15 05:24:09.481: E/AndroidRuntime(19825): at java.lang.reflect.Method.invoke(Method.java:515)
07-15 05:24:09.481: E/AndroidRuntime(19825): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
07-15 05:24:09.481: E/AndroidRuntime(19825): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
07-15 05:24:09.481: E/AndroidRuntime(19825): at dalvik.system.NativeStart.main(Native Method)
解决方法:
只是改变
这个
private static String DB_NAME = "assesmenttool";
至
private static String DB_NAME = "assesmenttool.db";
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