I am trying to understand the populating of a list view from data held in a SQLite table. I am using the following code. I have looked at a lot of similar questions on this site but have not been able to figure our where I have gone wrong as there seems to be a myriad of ways to tackle this. This is my bdhandler code:
public Product getAllRows(){
String query = "select * from "+TABLE_PRODUCTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);
Product product = new Product();
if (cursor.moveToFirst()){
cursor.moveToFirst();
cursor.close();
}else{
product = null;
}
db.close();
return product;
}
In the activity class, I do not understand what I should be using to populate the list view.
Where can I get more detailed info to try and understand where I am missing what I need to do?
Related
I'm currently trying to retrieve values from my SQLite Database. Screenshot
And output the value of the subname and units on checkboxes. I'm pretty sure I just have to get the IDs so I could output the subname and units values as checkboxes, so subname + unit = 1 checkbox. Could you please provide a sample code or link me a tutorial on how to do this? I'm rather clueless on how to do this and really new to Android.
I'm also looking for a way on how to save their IDs afterwards and add them into another table, so when I retrieve the IDs it will output the values. If you know how to do this too please do help. Thank you! Your time is much appreciated
Currently I have this in my DatabaseHandler.java. I just really don't know the code or syntax on how to retrieve it in my MainActivity and output it on checkboxes.
//get all subjects
public List < Subject > getAllSubjects() {
List < Subject > subjectList = new ArrayList < Subject > ();
//select all query
String selectQuery = " SELECT * FROM " + TABLE_SUBJECTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
//loop through all rows and add it to list
if (cursor.moveToFirst()) {
do {
Subject subject = new Subject();
subject.setID(Integer.parseInt(cursor.getString(0)));
subject.setSubName(cursor.getString(1));
subject.setUnits(cursor.getString(2));
//ADD CONTACT TO LIST
subjectList.add(subject);
} while (cursor.moveToNext());
}
return subjectList;
}
this is my query
SELECT *
FROM articles
WHERE id >1
ORDER BY id ASC
LIMIT 1
my requirement is very simple. I just want to select only one record and bind to textViews . This is what I had done so far.
public Article oneRecord()
{
SQLiteDatabase db = this.getWritableDatabase();
Cursor c = db.rawQuery("SELECT * FROM articles WHERE id=3;", null);
if(c.moveToFirst()){
Article a= new Article();
a.setId(c.getString(c.getColumnIndex("id")));
a.setImage_url(c.getString(c.getColumnIndex("image_url")));
a.setTitle(c.getString(c.getColumnIndex("title")));
a.setBody(c.getString(c.getColumnIndex("body")));
}
return a;
}
I am not sure I have understood you problem correctly or not. However there is not special thing to do. Just update TextView after getting article from database.
Article a = getOneRecordFromDB();
titleView.setText(a.getTitle());
bodyView.setText(a.getBody());
Now I want to access an entire column from database and then compare it with some text that I have stored...but I am getting no idea on how to do that..So can someone please help me with this...
Entire column? You mean all the values for a given column accross all records?
You should iterate the ResultSet obtained and start comparing the values (for example - if you iterate using "rs" object of ResultSet, you should compare:
String valueFromDB = rs.getString("myColumn");
String someTextStored = .... //the text being stored
if (valueFromDB != null) {
if (someTextStored.equals(valueFromDB) {
//Comparison succeeded - implement some logic here for handling success
}
}
And the above code should be inside a loop code that iterates over the ResultSet and
uses the "next" method to obtain the next record.
Hope this helps you
public ArrayList<String> getValues(){
Cursor cursor = null;
SQLiteDatabase db = getReadableDatabase();
Log.v("done","getting rows ");
cursor = db.rawQuery("SELECT YourColumnName FROM "+TABLE_NAME, null);
if(!cursor.moveToFirst()){
}
else{
do {
list_values.add(cursor.getString(0));
} while (cursor.moveToNext());
}
db.close();
cursor.close();
return list_values;
}
Now you are having all the values of a particular column you can compare it from this array list.
I am fetching the list of tables from the database. I am using this code to get the list of tables:
public void showAllTable()
{
db.execSQL("select name from sqlite_master where type = 'table'");
}
This query execute successful in to the shell window.
Now I want to display that list of tables in Android. How it is possible? I am calling this function from another activity.
Edited:
Thanks to Stack Overflow, I found the answer here.
The usual way to display a list of data is to use a ListView. To do this you will need to do the following:
1: change your db query to db.query instead of db.exec and store the values in a List:
ArrayList<String> tables = new ArrayList<String>();
Cursor mCursor = db.query("sqlite_master", new String[]{"name"}, "type = table",
null,null,null,null);
if (mCursor.getCount() > 0) {
for (mCursor.moveToFirst(), !mCursor.isAfterLast(), mCursor.moveToNext()) {
tables.add(mCursor.getString(0));
}
}
/** Important! always close cursors and DB's */
mCursor.close();
db.close();
return tables;
2: Use a ListView and an ArrayAdapter to display the information. See The Android Tutorial on how to do this.
My SQLite query returning only one record, However, the table has multiple rows
cursor=mydb.rawQuery("Select category from items;", null);
I have even tried GROUP BY but still wont work.
I am new to SQLite, would appreciate any help. Thanks.
First of all your string query must not be terminated so instead of passing it as:
"Select category from items;"
you should try passing it as:
"Select category from items"
as mentioned on this page.
Also, are you looping over the cursor? Here is an example of how to get data out of a cursor with a while loop:
ArrayList<String> results = new ArrayList<String>()
while (cursor.moveNext()) {
results.add(cursor.getString(0)); // 0 is the first column
}
First, search:
Cursor cs = myDataBase.rawQuery("Your query", null);
if (cs.moveToFirst()) {
String a = cs.getString(cs.getColumnIndex("your_column_name"));
cs.close();
return a;
}
cs.close();
return "";
Get the information from cursor:
if (cs.moveToFirst()) {
ArrayList<String> results = new ArrayList<String>()
do {
results.add(cs.getString(cs.getColumnIndex("your_column_name")));
} while (cs.moveNext());
}
Without if, I took error in my project. But this worked for me. By the way, your query doesn't look good. If you give some information about your database, we can help much more.
Use this to select all items from the table:
Cursor cursor = db.rawQuery("SELECT * FROM Tablename ,
null);
this can help you
public ArrayList<mydata> getallContents() {
ArrayList<mydata> lst = new ArrayList<mydata>();
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery("select * from " + GAMETABLE, null);
if (c.moveToFirst()) {
do {
lst.add(new mydata(c.getString(1),
c.getString(3),c.getString(4),c.getString(5),c.getString(6)));
} while (c.moveToNext());
}
db.close();
return lst;
}
you don't need raw query method. i think that the android way is better in this case:
db.query(items, category, null, null, null, null, null);
than use the cursor how already is written in the other comment.