【发布时间】：2016-11-18 01:44:25
【问题描述】：
我一直在网上发疯，寻找答案。
目前，我正在构建一个使用 SQLite DB 的 android 应用程序。 一切都设置好了，注册工作，登录工作，我连接了相机并可以拍照，这些照片会保存到我当地的画廊。但是，以下内容不起作用：
- 模拟器不工作。在我的手机上进行测试。
- DDMS 未显示我的数据库。
- CPU 不支持所需的功能 VT-x 或 SVM。
但是，重点是，我一直在到处寻找 SQLiteDB。 android studio 在哪里存储 SQLiteDB 的数据库？
另外，我尝试将数据写入手机的本地存储中，但也没有用：
public class DBUtil {
//Because of the fact that laptop refuses to let me use an emulator, data gets saved to my phone directory, folder DataAndroid
final static String FOLDER_EXTERNAL_DIRECTORY = Environment.getExternalStorageDirectory()+ "/DataAndroid";
//saving the data in my local data folder
public static void copyDatabaseToExtStg(Context context){
//external storage file
File externalDirectory = new File(FOLDER_EXTERNAL_DIRECTORY);
if(!externalDirectory.exists())
externalDirectory.mkdirs();
File toFile = new File(externalDirectory, DBHelper.DATABASE_NAME);
//internal storage file
File fromFile = context.getDatabasePath(DBHelper.DATABASE_NAME);
if (fromFile.exists())
copy(fromFile, toFile);
}
//copy from making the file to 'writing' the file
static void copy(File fromFile, File toFile) {
try {
FileInputStream is = new FileInputStream(fromFile);
FileChannel src = is.getChannel();
FileOutputStream os = new FileOutputStream(toFile);
FileChannel dst = os.getChannel();
dst.transferFrom(src, 0, src.size());
src.close(); is.close();
dst.close(); os.close();
} catch (Exception e) {
}
} }
我的 DBHelper 类如下所示：
public class DBHelper extends SQLiteOpenHelper {
//db attr.
SQLiteDatabase DataBase;
//confirm password doesn't need to be stored, it is just a small check up
private static final int DATABASE_VERSION = 1;
public static final String DATABASE_NAME = "contacts.db";
private static final String TABLE_NAME = "contacts";
private static final String COLUMN_ID = "id";
private static final String COLUMN_NAME = "name";
private static final String COLUMN_SURNAME = "surname";
private static final String COLUMN_EMAIL = "email";
private static final String COLUMN_USERNAME = "username";
private static final String COLUMN_PASSWORD = "password";
//constructor
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
//create table +TABLE_NAME
private static final String TABLE_CREATE = "create table contacts(id integer primary key not null , " +
"name text not null, surname text not null, email text not null, username text not null, password text not null);";
@Override
public void onCreate(SQLiteDatabase DataBase) {
DataBase.execSQL(TABLE_CREATE);
this.DataBase = DataBase;
}
public void insertContact(Contact contact){
//To be able to insert anything in DB, it should be writeable.
//Because of the fact that password.equals(confirmpassword), COLUMN_CONFPASS. is missing in list below
DataBase = this.getWritableDatabase();
ContentValues values = new ContentValues();
String query = "SELECT * FROM contacts";
Cursor cursor = DataBase.rawQuery(query, null);
int count = cursor.getCount();
//To make sure that the count increments, istead of assigning same number to different numbers.
values.put(COLUMN_ID, count);
values.put(COLUMN_NAME, contact.getName());
values.put(COLUMN_SURNAME, contact.getSurname());
values.put(COLUMN_EMAIL, contact.getEmail());
values.put(COLUMN_USERNAME, contact.getUsername());
values.put(COLUMN_PASSWORD, contact.getPassword());
//Insert contact object into DB
DataBase.insert(TABLE_NAME, null, values);
DataBase.close();
}
//Keeping DB up to date
@Override
public void onUpgrade(SQLiteDatabase DataBase, int CurrentVersionOld, int NewVersion) {
String query = "DROP TABLE IF EXISTS "+TABLE_NAME;
DataBase.execSQL(query);
this.onConfigure(DataBase);
}
//Read the DB
public String searchPassword(String username) {
DataBase = this.getReadableDatabase();
String query = "SELECT username, password FROM " + TABLE_NAME;
Cursor cursor = DataBase.rawQuery(query, null);
String uname, pw;
//If the password is not found, then print:
pw = "not found";
if (cursor.moveToFirst()) {
do {
//assign index to username(0) and password (1)
uname = cursor.getString(0);
pw = cursor.getString(1);
if (uname.equals(username)) {
pw = cursor.getString(1);
break;
}
} while (cursor.moveToNext());
} return pw;
}
}
有人可以帮帮我吗？ 我的编码不是很好。请多多包涵 :) （新手）
【问题讨论】：
标签： java android sqlite emulation