我写了创建数据库代码;我得到 ERROR / AndroidRuntime(7193):at com.android.xont.db.DataBaseHelper.createDataBase(DataBaseHelper.java:43)
这是我的代码:
public class DataBaseHelper extends SQLiteOpenHelper {
private static String DB_PATH = "/data/data/com.android.xont.controller/databases/";
private static String DB_NAME = "DEMOUserVentura_HEMA.db";
private SQLiteDatabase DEMOUserVentura_HEMA;
private final Context myContext;
private DataBaseHelper myDbHelper;
public DataBaseHelper(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) {
} else {
this.getReadableDatabase().close();
//this.getReadableDatabase().getPath();
//System.out.println( " ===== " + this.getReadableDatabase().getPath());
try {
copyDataBase();
} catch (IOException e) {
throw new Error(e);
}
}
}
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;
}
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;
DEMOUserVentura_HEMA = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READONLY);
}
@Override
public synchronized void close() {
if (DEMOUserVentura_HEMA != null)
DEMOUserVentura_HEMA.close();
super.close();
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
当我调用此活动时,我得到一个例外。我的数据库大小是:4.55MB。
当我打印正确返回数据库路径的getReadableDatabase()。getPath()时。
请帮帮我。我已经把头发拉了一个星期。
当我浏览模拟器时,它会复制少量文件。不是全部。然后我做了手动方式复制。
现在的问题是HTC手机。如何解决该异常。请帮帮我。
提前致谢..
答案 0 :(得分:2)
AssetManager具有文件大小限制。在某些设备上,无法打开大于1MB的资产文件。您必须将文件拆分为较小的块,将它们放在资产文件夹中,并在应用程序运行时重新组合块。
请参阅this question有关如何重新组装块的信息。
要在OSX或Linux上创建块,您可以使用命令行工具“split”。
请参阅here或here或使用google与关键字'android databasehelper asset'来查找有关如何实施DatabaseHelper的教程,该数据库管理器在数据库开始时重新组装资产文件夹中的块时间。