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在这里，我想使用我预先填充的SQLite数据库到我的Android应用程序。 因此，首次运行时，它会自动从assets文件夹中复制数据库，并在我的Android应用程序中将其用作数据库。
到目前为止，我已经做了这些事：
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String MyVillageSoftware ="MyVillageSoftware";
public static final String table_Question ="table_question";
private static final String DATABASE_PATH="/Users/ever_ncn/Documents/Project/PsikologiKarakter/app/src/main/assets/";
private static final String DATABASE_NAME="question.db";
//TOL for transaction Coloumn
SQLiteDatabase db;
Context context;
private static final String TAG = DatabaseHelper.class.getSimpleName();
public DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, 1);
this.context=context;
}
@Override
public void onCreate(SQLiteDatabase db) {
}
public void createDatabase(){
createDB();
}
public void createDB(){
boolean dbExist = DBExist();
if(!dbExist){
this.getReadableDatabase();
copyDBFromResource();
}
}
private boolean DBExist(){
SQLiteDatabase db = null;
try{
String databasePath = DATABASE_PATH+DATABASE_NAME;
db=SQLiteDatabase.openDatabase(databasePath, null,
SQLiteDatabase.OPEN_READWRITE);
db.setLocale(Locale.getDefault());
db.setLockingEnabled(true);
db.setVersion(1);
}catch(SQLiteException e){
Log.e("SqlHelper","Database nda ada babi");
}
if(db != null){
db.close();
}return db != null ? true : false;
}
private void copyDBFromResource(){
InputStream inStream=null;
OutputStream outStream = null;
String dbFilePath=DATABASE_PATH+DATABASE_NAME;
try{
inStream=context.getAssets().open(DATABASE_NAME);
outStream=new FileOutputStream(dbFilePath);
byte[] buffer = new byte[1024];
int length;
while((length=inStream.read(buffer))>0){
outStream.write(buffer, 0 , length);
}
outStream.flush();
outStream.close();
inStream.close();
}catch (IOException e){
throw new Error("Problem cuk");
}
}
public List getAllCategory() {
List AllCategoryList = new ArrayList();
List AllCategIdList = new ArrayList();
String selectQuery ="SELECT * FROM" + table_Question;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
String Id = cursor.getString(0);
String A = cursor.getString(1);
String B = cursor.getString(2);
String C = cursor.getString(3);
String D = cursor.getString(4);
String aExplain = cursor.getString(5);
String bExplain = cursor.getString(6);
String cExplain = cursor.getString(7);
String dExplain = cursor.getString(8);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return AllCategoryList;
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS" + table_Question);
onCreate(db);
}
}
但我得到一个这样的错误信息：
10-28 07:18:38.988 2425-2425/gook.psikologikarakter E/SQLiteLog﹕ (14) cannot open file at line 30046 of [9491ba7d73]
10-28 07:18:38.988 2425-2425/gook.psikologikarakter E/SQLiteLog﹕ (14) os_unix.c:30046: (2) open(/Users/ever_ncn/Documents/Project/PsikologiKarakter/app/src/main/assets/question.db) -
10-28 07:18:38.989 2425-2425/gook.psikologikarakter E/SQLiteDatabase﹕ Failed to open database '/Users/ever_ncn/Documents/Project/PsikologiKarakter/app/src/main/assets/question.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:806)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:791)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:694)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:669)
at gook.psikologikarakter.DatabaseHelper.DBExist(DatabaseHelper.java:65)
at gook.psikologikarakter.DatabaseHelper.createDB(DatabaseHelper.java:52)
at gook.psikologikarakter.DatabaseHelper.createDatabase(DatabaseHelper.java:48)
at gook.psikologikarakter.MainActivity.onCreate(MainActivity.java:59)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
我不知道到底发生了什么，但我想我无法打开数据库文件。 但我不知道该怎么办。 请高手帮帮我。
谢谢你。
您不能使用assets文件夹中的数据库。您希望在首次运行时将数据库复制到/ data / data / YOUR_PACKAGE / databases /。这将有所帮助：stackoverflow.com/questions/513084/…
是的先生，我的意思是，所以我的问题是如何在第一次启动应用程序时将数据库从assets文件夹复制到data / data / your_package / databases /？
我的朋友就像复制你使用java的任何其他文件一样简单。以下是专门针对您的案例：stackoverflow.com/a/20592481/1371041
但是我在这个先生上得到了错误：private String DATABASE_PATH = context.getApplicationInfo()。dataDir +"/ databases /";我收到错误"非法转发参考"
@ChallengeAccepted谢谢先生，它运作良好
很高兴解决了你的问题。至于"非法前向引用"你确定它是在构造函数中吗？你做了什么来解决你的错误？
我使用另一个模式代码来做那个先生。我使用此代码先生，private void copyDatabase(File dbFile)抛出IOException {InputStream is = context.getAssets()。open(DATABASE_NAME); OutputStream os = new FileOutputStream(dbFile); byte [] buffer = new byte [1024]; while(is.read(buffer)> 0){os.write(buffer); os.flush(); os.close(); is.close(); }
private static final String DATABASE_PATH="/Users/ever_ncn/Documents/Project/PsikologiKarakter/app/src/main/assets/";
这是本地文件系统上的路径，而不是运行时设备上文件的路径。 使用getResources().getAssets().openFile(...)获取文件的InputStream。
代码就像这先生一样？。context.getResources()getAssets()中openFile(DATABASE_NAME)。 但我在openFile()上遇到错误;
