what is wrong with this code
when i run it the program don,t response
public Cursor checkauth(String username,String password)
{
Ecommerce=getReadableDatabase();
// Cursor curser =Ecommerce.rawQuery("select * from customer where username = ? and password =?", new String []{username,password});
//String [] details={"id","custname","gender"};
Cursor c = Ecommerce.rawQuery("select id from customer where username = ? AND password = ?" , new String[] {username,password });
//Cursor cursor = Ecommerce.query(true, "customer",details,"username = ? AND password = ?", new String[] { username, password },null, null, null, null, null);
while(c != null)
{
c.moveToFirst();
}
return c;
}
in activity
public void onClick(View arg0) {
// TODO Auto-generated method stub
user_name=username.getText().toString();
passwords=password.getText().toString();
Cursor c=data.checkauth(user_name, passwords);
while(!c.isAfterLast())
{
username.setText(String.valueOf(c.getInt(0)));
c.moveToNext();
}
}
![enter image description here][1]
You're blocking your UI thread.
This loop never completes:
while(c != null)
{
c.moveToFirst();
}
The while condition is always true. The loop doesn't seem to be doing anything useful, you can probably just leave a plain c.moveToFirst() there.
Try with this..
String selectQuery = "Write select query" ;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
boolean result = false;
if (cursor.moveToFirst())
{
do
{
result = true;
} while (cursor.moveToNext());
}
else
{
result = false;
}
Even though this question is answered already, I'd like to suggest a simple improvement. What you're doing is kind of useless. Your goal is to know whether or not a user exists and what his or her id is.
public int checkAuth(String username, String password) {
String sql = "select id from customer where username = ? AND password = ?";
Ecommerce = getReadableDatabase(); //field names never start with uppercase
Cursor c;
try {
c = Ecommerce.rawQuery(sql, new String[] { username, password });
if (c.moveToFirst()) //if the cursor has any records, this returns true, else false
return c.getInt(0); //so if a user exists with given params, we can return an id
else
return -1; //if not, we return -1, which means: user/pass-combination not found
}
finally { //but after the whole method, we need to do some things:
if (c != null && !c.isClosed())
c.close(); //close the cursor
closeDatabase(); //and close the database
}
}
This way you keep your UI code separated from your database code. A cursor shouldn't appear in UI-code. Which above modifications, the UI code looks a lot cleaner
int i = data.checkAuth(username, password);
if (i == -1) {
//alert of some kind
}
else
username.setText(String.valueOf(i));
Related
I am creating app in which i register user and store user's information in database,so i have created database and storing value in databse but i don't know how to fetch data from database and show in textview?Using below query to fetch data but it has error.What is correct way?
public void insertEntry(String fname, String lname, String gen,String weight)
{
SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("firstname", fname);
values.put("lastname", lname);
values.put("gender", gen);
values.put("weight",weight);
}
public Cursor fetchData()
{
SQLiteDatabase mDB = dbHelper.getWritableDatabase();
return mDB.rawQuery("SELECT * FROM Register WHERE firstname=? lastname =?" , null);
}
Using this to set fetched value on textview in different activity
Cursor name = sqliteDataBase.fetchData();
tv_name.setText((CharSequence) name);
Try this,
try {
SQLiteDatabase mDB = dbHelper.getReadableDatabase();
String selectQuery = "SELECT * FROM Register WHERE firstname= "+first+" lastname =" + last + ";";
cursor = db.rawQuery(selectQuery, null);
if (cursor != null && cursor.getCount() > 0) {
if (cursor.moveToFirst()) {
String firstName = cursor.getString(cursor.getColumnIndex("firstname")));
}
}
} catch(Exception e) {
e.printSTackTrace();
} finally {
if (cursor != null) {
cursor.close();
}
}
public String fecthResults()
{
String name = null;
SQLiteDatabase sqLiteDatabase = getReadableDatabase();
Cursor cursor = sqLiteDatabase.query(TABLE_NAME, null, null, null, null, null, null);
if (cursor.moveToFirst()) {
do {
name = cursor.getString(cursor.getColumnIndex("firstname")
} while (cursor.moveToNext());
cursor.close();
}
sqLiteDatabase.close();
return name;
Get the name and then set it directly to a texView
A Cursor is an interface that provides random read-write access to the result set returned by the query. It contains multiple rows of data and this data can be easily processed by help of For loop.
Lets take an example to understand the process. Suppose, you need to access data from a column name "col_1" and show the data in TextView. The For loop for the process will be as follows.
for (cursor.moveToNext()) {
textView.setText(cursor.getString(cursor.getColumnIndex("col_1")));
}
Now, if we need only one value (from only one record or tuple) then, we can opt out the For loop and change the code as shown below.
if (cursor.moveToFirst()) {
textView.setText(cursor.getString(cursor.getColumnIndex("col_1")));
}
Always remember to close the cursor after using it.
To close the cursor, use the following line of code.
cursor.close();
For more information, please visit the following links:
https://developer.android.com/reference/android/database/Cursor.html
https://developer.android.com/training/basics/data-storage/databases.html#ReadDbRow
I use this method for retrieving my data
public String getdata() {
String[] columns= new String[]{RowId,RowBusinessName};
Cursor c=OurDatabase.query(TableName,columns,null,null,null,null,null);
String Result="";
int iRowId=c.getColumnIndex(RowId);
int iRowBusinessName=c.getColumnIndex(RowBusinessName);
for(c.moveToFirst();!c.isAfterLast();c.moveToNext()){
Result=Result+c.getString(iRowBusinessName)+"\n";
}
return Result;
}
How can I make it return structured data (id & business_name)?
I want to display every business_name in a single textview.
Please help
If I understand what you are trying to do, here is the solution if you want to get only 1 RowBusinessName returned as a String. (Hoping that your RowBusinessName is type String).
public String getdata(int rowId) {
String[] columns= new String[]{RowId,RowBusinessName};
Cursor cursor = db.query(TABLENAME, columns, RowId + "=?", new String[]{rowId + ""}, null, null, null, null);
String Result="";
if (cursor != null && cursor.moveToFirst()) {
// not required though
int rowId = cursor.getInt(cursor.getColumnIndexOrThrow(RowId));
String rowBusinessName = cursor.getString(cursor.getColumnIndexOrThrow(RowBusinessName));
result = rowBusinessName;
}
return result;
}
Now if you want a list of RowBusinessName, then you have to build a List<String> rather than appending it to Result. That's not really a good way!
public List<String> getAll() {
List<String> businessNameList = new ArrayList<String>();
String[] columns= new String[]{RowId,RowBusinessName};
Cursor c=OurDatabase.query(TableName,columns,null,null,null,null,null);
if (c != null && c.moveToFirst()) {
// loop until the end of Cursor and add each entry to Ticks ArrayList.
do {
String businessName = cursor.getString(cursor.getColumnIndexOrThrow(RowBusinessName));
if (businessName != null) {
businessNameList.add(businessName);
}
} while (c.moveToNext());
}
return businessNameList;
}
These are work around.
The appropriate answer would be to create an Object that holds id and businessName. That way, you build an object from DB and just return the entire Object.
Hi i'm new to android programming and i have created a sample app which allows the user to get data from the database. however its not displaying the data, it doesn't have any error message its just not displaying it. database is confirmed that there is data. please check my code maybe i forgot something here. thanks
public void onClick(View arg){
name = txtNameS.getText().toString();
if(arg.getId()==R.id.btnfortune){
searchRecord(count);
lblmessageS1.setText(name); // this is just for me to check if it will be displayed and it is.
lblmessageS2.setText(message);
}
}
public void searchRecord(int count) throws SQLException {
Cursor rsCursor;
String [] rsFields = {"mesNum","Message"};
rsCursor = dbM.dbase.query("MessageFile", rsFields, "mesNum = " + count, null, null, null, null, null);
rsCursor.moveToFirst();
if (rsCursor.isAfterLast()==false){
message = rsCursor.getString(1);
}
rsCursor.close();
}
by the way count is initialized as 1. and there are 10 records in the database. and there are 2 columns in the database the mesNum and Message, what i want is to display only the message column.
// SQLiteDatabase sqldb
Cursor rsCursor= sqldb.rawQuery("your query", null);
if (rsCursor!= null) {
if (rsCursor.moveToFirst()) {
do {
// do here for get data message = rsCursor.getString(1);
}while (cursor.moveToNext());
}
cursor.close();
}
add only one column name in your array
String [] rsFields = {"Message"};
cursor = dbM.dbase.query(true,"MessageFile", rsFields, "yourcolumn= "+count, null, null, null, null, null);
while( cursor != null && cursor.moveToNext() )
{
cursor.getString(0);
}
cursor.close();
I have two buttons inside of my application, one for next and one for prev. I want the next button to get the next record inside of my database and display it inside of my view, and the prev button to get the previous record and display it inside of my view. How would I call the next or previous record? I have looked for tutorials and stuff but didn't find any. I anyone has a tutorial please share with me. Thanks for any help. I wish I had some code to provide but I really don't know where to start.
I use an int to pull the record from the dbase.
From my ContactView class
static long record = 1;
public void getData() {
DBase db = new DBase(this);
db.open();
lastRecord = db.lRec();
firstRecord = db.fRec();
rRec = db.getRec(record);
db.close();
}
then my query is from my Dbase class
public String[] getRec(long record) {
record = ContactView.record;
String[] columns = new String[] { KEY_ROWID, KEY_ONE, KEY_TWO,
KEY_THREE, KEY_FOUR, KEY_FIVE, KEY_SIX };
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, KEY_ROWID + "="
+ record, null, null, null, null);
if (c != null && c.moveToFirst()) {
String rRec = c.getString(0);
String rOne = c.getString(1);
String rTwo = c.getString(2);
String rThree = c.getString(3);
String rFour = c.getString(4);
String rFive = c.getString(5);
String rSix = c.getString(6);
String[] rData = { rRec, rOne, rTwo, rThree, rFour,
rFive, rSix };
return rData;
}
return null;
}
and the next few are from my ContactView class
my buttons
#Override
public void onClick(View arg0) {
switch (arg0.getId()) {
case R.id.bSQLvPrev:
recordMinus();
display();
break;
case R.id.bSQLvNext:
recordPlus();
display();
break;
}
}
and the methods they call
public void display() {
etSQLvRec.setText(rRec[0]);
etSQLvOne.setText(rRec[1]);
etSQLvTwo.setText(rRec[2]);
etSQLvThree.setText(rRec[3]);
etSQLvFour.setText(rRec[4]);
etSQLvFive.setText(rRec[5]);
etSQLvSix.setText(rRec[6]);
}
public void recordPlus() {
record++;
}
public void recordMinus() {
record--;
}
That will get the record from the database based on the "record" variable, and the buttons increment it, or decrement it, it also skips any "empty" records.
EDIT OK, I had changed some stuff around since I lasted used my db, so use the next recordPlus() and recordMinus() code instead
public void recordPlus() {
if (record < lastRecord) {
record++;
} else {
record = firstRecord;
}
getData();
do {
if (record < lastRecord) {
record++;
} else {
record = firstRecord;
}
getData();
} while (rRec == null);
}
public void recordMinus() {
if (record == 1) {
record = lastRecord;
} else {
record--;
}
getData();
do {
if (record == 1) {
record = lastRecord;
} else {
record--;
}
getData();
} while (rRec == null);
}
And you'll need my fRec() and lRec() which find the first and last records in the DB
public long fRec() {
Cursor c = ourDatabase.query(DATABASE_TABLE, new String[] { "min(" +
KEY_ROWID
+ ")" }, null, null, null, null, null);
c.moveToFirst();
long rowID = c.getInt(0);
return rowID;
}
}
public long lRec() {
long lastRec = 0;
String query = "SELECT ROWID from Table order by ROWID DESC limit 1";
Cursor c = ourDatabase.rawQuery(query, null);
if (c != null && c.moveToFirst()) {
lastRec = c.getLong(0);
}
return lastRec;
}
I've been playing with a sample application I found online. Just changing things to see how it works. Yesterday this was not an issue. Today is a different story. I seem to write the correct info to the db. I've checked through log outputs. When I return the information through a cursor I get "null". So, say I enter "Eggs","Bread", and "Candy". I get back "null","null", and "null".
It all starts with the listener for the add grocery button. Adds to the db and writes the list to an label.
Any help?
private void addEvent(String title) {
SQLiteDatabase db = eventsData.getWritableDatabase();
ContentValues values = new ContentValues();
Log.v(TAG, "Adding " + title);
values.put(EventsDataSQLHelper.TITLE, title);
db.insert(EventsDataSQLHelper.TABLE, null, values);
}
private Cursor getEvents() {
SQLiteDatabase db = eventsData.getReadableDatabase();
Cursor cursor = db.query(EventsDataSQLHelper.TABLE, null, null, null, null,
null, EventsDataSQLHelper.TITLE);
startManagingCursor(cursor);
return cursor;
}
private void showEvents(Cursor cursor) {
StringBuilder ret = new StringBuilder();
while (cursor.moveToNext()) {
String title = cursor.getString(1);
ret.append(title + "\n");
Log.v(TAG, "SHOWING RET VARIABLE" + ret);
}
t.setText(ret);
}
View.OnClickListener myhandler = new View.OnClickListener()
{
#Override
public void onClick(View GLview)
{
EditText eT = (EditText)findViewById(R.id.itemName1);
editTextStr = eT.getText().toString();
Log.v(TAG, editTextStr);
if(editTextStr != null)
{
addEvent(editTextStr.toString());
Cursor cursor = getEvents();
showEvents(cursor);
eT.setText(null);
}
}
};
Make sure cursor points to the first element of the result cursor.moveToFirst();
Then call cursor.moveToNext()