我的程序在Android上的sqlite数据库中找不到表
我有SQLite数据库文件（我没有在这个程序中创建，它有它的表和数据），我在我的android程序中打开它，但是当我写SELECT语句程序找不到表时我得到错误：
错误：没有这样的表：人
这是代码：
public class SQLiteAdapter {
private DbDatabaseHelper databaseHelper;
private static String dbfile = "/data/data/com.example.searchpersons/databases/";
private static String DB_NAME = "Person.db";
static String myPath = dbfile + DB_NAME;
private static SQLiteDatabase database;
private static final int DATABASE_VERSION = 3;
private static String table = "Person";
private static Context myContext;
public SQLiteAdapter(Context ctx) {
SQLiteAdapter.myContext = ctx;
databaseHelper = new DbDatabaseHelper(SQLiteAdapter.myContext);
}
public static class DbDatabaseHelper extends SQLiteOpenHelper {
public DbDatabaseHelper(Context context) {
super(context, DB_NAME, null, DATABASE_VERSION);
dbfile = "/data/data/" + context.getPackageName() + "/databases/";
myPath = dbfile + DB_NAME;
//this.myContext = context;
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
public SQLiteDatabase open() {
try {
database = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
Log.v("db log", "database exist open");
} catch (SQLiteException e) {
Log.v("db log", "database does't exist");
}
if (database != null && database.isOpen())
return database;
else {
database = databaseHelper.getReadableDatabase();
Log.v("db log", "database exist helper");
}
return database;
}
public Cursor onSelect(String firstname, String lastname) {
Log.v("db log", "database exist select");
Cursor c = database.rawQuery("SELECT * FROM " + table + " where Firstname='" + firstname + "' And Lastname='" + lastname + "'", null);
c.moveToFirst();
return c;
}
public void close() {
if (database != null && database.isOpen()) {
database.close();
}
}
}
这是按钮点击功能：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
final View rootView = inflater.inflate(R.layout.fragment_main, container, false);
Button btn1 = (Button) rootView.findViewById(R.id.button1);
btn1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
EditText t = (EditText) rootView.findViewById(R.id.editText1);
String name = t.getText().toString();
EditText tt = (EditText) rootView.findViewById(R.id.editText2);
String lastname = tt.getText().toString();
if (name.length() == 0 || lastname.length() == 0) {
Toast.makeText(rootView.getContext(), "Please fill both box", Toast.LENGTH_LONG).show();
} else {
GridView gridview = (GridView) rootView.findViewById(R.id.gridView1);
List < String > li = new ArrayList < String > ();
ArrayAdapter < String > adapter = new ArrayAdapter < String > (rootView.getContext(), android.R.layout.simple_gallery_item, li);
try {
SQLiteAdapter s = new SQLiteAdapter(rootView.getContext());
s.open();
Cursor c = s.onSelect(name, lastname);
if (c != null) {
if (c.moveToFirst()) {
do {
String id = c.getString(c.getColumnIndex("ID"));
String name1 = c.getString(c.getColumnIndex("Firstname"));
String lastname1 = c.getString(c.getColumnIndex("Lastname"));
String personal = c.getString(c.getColumnIndex("PersonalID"));
li.add(id);
li.add(name1);
li.add(lastname1);
li.add(personal);
gridview.setAdapter(adapter);
} while (c.moveToNext());
}
} else {
Toast.makeText(rootView.getContext(), "There is no data", Toast.LENGTH_LONG).show();
}
c.close();
s.close();
} catch (Exception e) {
Toast.makeText(rootView.getContext(), "Error : " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}
});
return rootView;
}
我在SQLite数据库浏览器中检查数据库，一切正常（有表和数据），但程序仍然无法找到它们。
我在eclipse中添加了sqlitemanager，它也看不到表：
只有一个表android_metadata，没有我的表。
任何人都可以帮助我吗？
3 个答案:
答案 0 :(得分：0)
我想了大约一个星期，答案很简单。我解决了这个问题：
来自 sqlitemanager 
我从该按钮添加了数据库。 现在一切正常;）
答案 1 :(得分：-1)
In oncreate you have to create your db. I am sending you my db class.
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.SQLiteOpenHelper;
public class DbAdapter extends SQLiteOpenHelper {
private static DbAdapter mDbHelper;
public static final String DATABASE_NAME = "demoDb";
public static final String TABLE_Coin= "coin_table";
public static final String TABLE_Inbox= "inbox";
public static final String TABLE_Feature= "feature";
public static final String TABLE_Time= "time";
public static final String TABLE_Deduct_money= "deduct_time";
public static final String TABLE_Unread_message= "unread_message";
public static final String COLUMN_Email= "email";
public static final String COLUMN_Appearence= "appearence";
public static final String COLUMN_Drivability= "drivability";
public static final String COLUMN_Fuel= "fuel";
public static final String COLUMN_Insurance= "insurance";
public static final String COLUMN_Wow= "wow";
public static final String COLUMN_CurrentValue= "current_value";
public static final String COLUMN_coin = "name";
public static final String COLUMN_seenTime = "seen";
public static final String COLUMN_number_of_times = "number_of_times";
public static final String COLUMN_name = "name";
public static final String COLUMN_type = "type";
public static final String COLUMN_text = "text";
public static final String COLUMN_image = "image";
public static final String COLUMN_created_time = "created_time";
public static final String COLUMN_unread = "unread";
// ****************************************
private static final int DATABASE_VERSION = 1;
private final String DATABASE_CREATE_BOOKMARK = "CREATE TABLE "
+ TABLE_Coin + "(" + COLUMN_coin
+ " Varchar,"+COLUMN_Email +" Varchar, UNIQUE("
+ COLUMN_Email + ") ON CONFLICT REPLACE)";
private final String DATABASE_CREATE_BOOKMARK1 = "CREATE TABLE "
+ TABLE_Feature + "(" + COLUMN_Appearence
+ " Integer,"+COLUMN_Email +" Varchar ,"+COLUMN_name +" Varchar ,"+COLUMN_Drivability +" Integer ,"+COLUMN_Wow +" Integer,"+COLUMN_CurrentValue +" Integer,"+COLUMN_Fuel +" Integer,"+COLUMN_Insurance +" Integer, UNIQUE("
+ COLUMN_Email + ") ON CONFLICT REPLACE)";
private final String DATABASE_CREATE_BOOKMARK2 = "CREATE TABLE "
+ TABLE_Time + "(" + COLUMN_Email +" Varchar ,"+COLUMN_seenTime +" Integer,"+COLUMN_number_of_times +" Integer, UNIQUE("
+ COLUMN_Email + ") ON CONFLICT REPLACE)";
private final String DATABASE_CREATE_BOOKMARK3 = "CREATE TABLE "
+ TABLE_Deduct_money + "(" + COLUMN_seenTime
+ " Varchar,"+ COLUMN_number_of_times
+ " Integer,"+COLUMN_Email +" Varchar, UNIQUE("
+ COLUMN_Email + ") ON CONFLICT REPLACE)";
private final String DATABASE_CREATE_BOOKMARK4 = "CREATE TABLE "
+ TABLE_Inbox + "(" + COLUMN_created_time
+ " DATETIME,"+ COLUMN_image
+ " Varchar,"
+ COLUMN_type
+ " Varchar,"+ COLUMN_name
+ " Varchar,"+ COLUMN_text
+ " Varchar,"+COLUMN_Email +" Varchar)";
private final String DATABASE_CREATE_BOOKMARK5 = "CREATE TABLE "
+ TABLE_Unread_message + "(" + COLUMN_unread
+ " Varchar,"+COLUMN_Email +" Varchar, UNIQUE("
+ COLUMN_Email + ") ON CONFLICT REPLACE)";
private DbAdapter(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
public static synchronized DbAdapter getInstance(Context context) {
if (mDbHelper == null) {
mDbHelper = new DbAdapter(context);
}
return mDbHelper;
}
/**
* Tries to insert data into table
*
* @param contentValues
* @param tablename
* @throws SQLException
* on insert error
*/
public void insertQuery(ContentValues contentValues, String tablename)
throws SQLException {
try {
final SQLiteDatabase writableDatabase = getWritableDatabase();
writableDatabase.insert(tablename, null, contentValues);
// writableDatabase.insertWithOnConflict(tablename, null,
// contentValues,SQLiteDatabase.CONFLICT_REPLACE);
} catch (Exception e) {
e.printStackTrace();
}
}
// public void insertReplaceQuery(ContentValues contentValues, String tablename)
// throws SQLException {
//
// try {
// final SQLiteDatabase writableDatabase = getWritableDatabase();
// writableDatabase.insertOrThrow(tablename, null, contentValues);
//
// } catch (Exception e) {
// e.printStackTrace();
// }
// }
//
// /**
// * Update record by ID with contentValues
// *
// * @param id
// * @param contentValues
// * @param tableName
// * @param whereclause
// * @param whereargs
// */
public void updateQuery(ContentValues contentValues, String tableName,
String whereclause, String[] whereargs) {
try {
final SQLiteDatabase writableDatabase = getWritableDatabase();
writableDatabase.update(tableName, contentValues, whereclause,
whereargs);
} catch (Exception e) {
e.printStackTrace();
}
}
public Cursor fetchQuery(String query) {
final SQLiteDatabase readableDatabase = getReadableDatabase();
final Cursor cursor = readableDatabase.rawQuery(query, null);
if (cursor != null) {
cursor.moveToFirst();
}
return cursor;
}
public Cursor fetchQuery(String query, String[] selectionArgs) {
final SQLiteDatabase readableDatabase = getReadableDatabase();
final Cursor cursor = readableDatabase.rawQuery(query, selectionArgs);
if (cursor != null) {
cursor.moveToFirst();
}
return cursor;
}
public void delete(String table) {
final SQLiteDatabase writableDatabase = getWritableDatabase();
writableDatabase.delete(table, null, null);
}
public void delete(String table, String whereClause, String[] selectionArgs) {
final SQLiteDatabase writableDatabase = getWritableDatabase();
writableDatabase.delete(table, whereClause, selectionArgs);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DATABASE_CREATE_BOOKMARK);
db.execSQL(DATABASE_CREATE_BOOKMARK1);
db.execSQL(DATABASE_CREATE_BOOKMARK2);
db.execSQL(DATABASE_CREATE_BOOKMARK3);
db.execSQL(DATABASE_CREATE_BOOKMARK4);
db.execSQL(DATABASE_CREATE_BOOKMARK5);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_Coin);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_Feature);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_Time);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_Deduct_money);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_Inbox);
db.execSQL("DROP TABLE IF EXISTS " + TABLE_Unread_message);
onCreate(db);
}
}
答案 2 :(得分：-2)
你正在弄乱路径。
请清除对dbfile和myPath的每个定义或引用。您正在定义中使用某些值（可能是复制粘贴）初始化它们，然后在{{{{{{{ 1}}构造函数。并且帮助程序不会使用这些路径，它只会在默认目录中创建数据库。
然后，在DbDatabaseHelper方法中，您使用预期路径调用open。请使用帮助程序中的getReadableDatabase和getWritableDatabase。
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