I'm writing an app that manipulates with database consists of 3 tables. I created this database from json file using models (Worker model, specialty model) with getters and setters. Now I want to get specific info from this database. I'v already made it but my code is pretty silly. What I need is to change the architecture of my app but I don't know how exactly it should looks like.
This is the examples of my methods, and they are pretty week
This is how I add info into database. I like it, I think it's correct:
public void addWorker(Worker worker){
List<Specialty> specialty;
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
//fixind names
String f_name = fixName(worker.getF_name());
String l_name = fixName(worker.getL_name());
String birthday = fixDate(worker.getBirthday());
values.put(KEY_F_NAME, f_name);
values.put(KEY_L_NAME, l_name);
values.put(KEY_BIRTHDAY, birthday);
values.put(KEY_AVATR_URL, worker.getAvart_url());
specialty = worker.getSpecialty();
long worker_id = db.insert(TABLE_WORKERS,null,values);
//add unique specialty
for (Specialty spec: specialty){
createRelations(worker_id, spec.getSpecialty_id());
if (getCount(spec.getSpecialty_id()) == 0){
addSpecialty(spec);
}
}
}
And this is how I take info from database:
public String[] getFullInfo(String worker_name){
String selectQuery = "HUGE QUERY HERE "where workers.f_name =?";
Log.e(LOG_TAG, selectQuery);
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, new String [] {worker_name});
String[] details = new String[5];
c.moveToFirst();
while (c.isAfterLast() == false){
details[0] = c.getString(c.getColumnIndex(KEY_F_NAME));
details[1] = c.getString(c.getColumnIndex(KEY_L_NAME));
details[2] = c.getString(c.getColumnIndex(KEY_BIRTHDAY));
details[3] = c.getString(c.getColumnIndex("age"));
details[4] = c.getString(c.getColumnIndex(KEY_SPEC_NAME));
c.moveToNext();
}
return details;
}
This is my another query and it has different return type:
public List<Map<String ,String>> getWorkerListBySpec(String spec_name){
String selectQuery = "HUGE QUERY HERE
"where specialty.spec_name=?";
Log.e(LOG_TAG, selectQuery);
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, new String [] {spec_name});
//making list of workers
List<Map<String ,String>> data = new ArrayList<Map<String,String>>();
c.moveToFirst();
while (c.isAfterLast() == false){
Map<String,String> datum = new HashMap<String,String>(2);
datum.put(KEY_F_NAME, c.getString(c.getColumnIndex(KEY_F_NAME)));
datum.put(KEY_L_NAME, c.getString(c.getColumnIndex(KEY_L_NAME)));
datum.put(KEY_BIRTHDAY, c.getString(c.getColumnIndex(KEY_BIRTHDAY)));
data.add(datum);
c.moveToNext();
}
return data;
}
and the third one, which also have different return type:
public List<String> getAllSpecs_Names(){
List<String> spec_names = new ArrayList<String>();
String selectQuery = "select * from " + TABLE_SPECIALTY;
Log.e(LOG_TAG, selectQuery);
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, null);
if (c.moveToFirst()){
do{
spec_names.add(c.getString(c.getColumnIndex(KEY_SPEC_NAME)));
}while (c.moveToNext());
}
return spec_names;
}
I know, that this is all wrong.
Please tell me how I should make all my queries.
It will be good if you give me the link to check how the app should look like
instead of returning a List or Map, you should better return a own CursorWrapper
so you could could look like this:
public WorkerCursor getWorkerListBySpec(String spec_name){
String selectQuery = "HUGE QUERY HERE
"where specialty.spec_name=?";
Log.e(LOG_TAG, selectQuery);
SQLiteDatabase db = this.getReadableDatabase();
Cursor c = db.rawQuery(selectQuery, new String [] {spec_name});
return new WorkerCursor(cursor);
}
public static class WorkerCursor extends CursorWrapper {
/**
* Creates a cursor wrapper.
*
* #param cursor The underlying cursor to wrap.
*/
public WorkerCursor(Cursor cursor) {
super(cursor);
}
public Worker getWorker() {
return getWorkerAtCursor();
}
public Worker getWorker(int position) {
if (moveToPosition(position)) {
return getWorkerCursor();
} else {
return null;
}
}
private Worker getWorkerAtCursor() {
if (isBeforeFirst() || isAfterLast()) {
return null;
}
worker worker = new Worker();
worker.name = c.getString(c.getColumnIndex(KEY_F_NAME));
....
return worker;
}
}
and the same for your List, just with a other CursorWrapper
and don't forget to close the CursorWrapper, when it's no more needed, like in onDestroy of Activity and so
Related
I have some data from the database that I want to show randomly and only 5 data appear, I've tried using ORDER BY RAND () but the app crashes when I open it
below is my syntax query
public List<Soal> getSoal(){
List<Soal> listSoal = new ArrayList<Soal>();
String query = "select * from tbl_soal ORDER BY RAND() LIMIT 5";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);
if(cursor.moveToFirst()){
do{
Soal s = new Soal();
s.setSoal(cursor.getString(1));
s.setPil_a(cursor.getString(2));
s.setPil_b(cursor.getString(3));
s.setPil_c(cursor.getString(4));
s.setPil_d(cursor.getString(5));
s.setJwban(cursor.getInt(6));
s.setGambar(cursor.getInt(7));
listSoal.add(s);
}while(cursor.moveToNext());
}
return listSoal;
}
so where is the error, or is there any solution for my problem ?
You can check this answer as well
https://stackoverflow.com/a/23628508/6672577
public List<Soal> getSoal() {
List<Soal> listSoal = new ArrayList<Soal>();
String query = "SELECT * FROM table ORDER BY RANDOM() LIMIT 5";
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(query, null);
if (cursor != null) { // To check that cursor is not null.
if (cursor.moveToFirst()) {
do {
Soal s = new Soal();
s.setSoal(cursor.getString(1));
s.setPil_a(cursor.getString(2));
s.setPil_b(cursor.getString(3));
s.setPil_c(cursor.getString(4));
s.setPil_d(cursor.getString(5));
s.setJwban(cursor.getInt(6));
s.setGambar(cursor.getInt(7));
listSoal.add(s);
} while (cursor.moveToNext());
}
}
return listSoal;
}
I am trying to populate my AutoCompleteTextView from a column of values in my database.
The query I am running in my database is:
// GET MEMOS
public ArrayList<String> autoCompleteMemo(String table)
{
SQLiteDatabase db = this.getReadableDatabase();
ArrayList<String> memoList = new ArrayList<String>();
String SQL_GET_MEMOS = "SELECT memo FROM " + table;
Cursor cursor = db.rawQuery(SQL_GET_MEMOS, null);
cursor.moveToFirst();
if (!cursor.isAfterLast()) {
do {
memoList.add(cursor.getString(0));
}
while (cursor.moveToNext());
}
cursor.close();
db.close();
return memoList;
}
And here is how I am attempting to set the values:
memoList = new String[db.autoCompleteMemo(table).size()];
ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_1, memoList);
etMemo.setAdapter(adapter);
For some reason, this does not appear to be working. Am i converting from ArrayList to String[] properly?
Thanks
Also,
If i do something similar to this
String[] memoList = getResources().getStringArray(R.array.memoList);
and populate that in Strings.xml it works fine.
I changed my DB method to the following and it now works
public String[] autoCompleteMemo(String table) {
SQLiteDatabase db = this.getReadableDatabase();
String SQL_GET_MEMOS = "SELECT memo FROM " + table;
Cursor cursor = db.rawQuery(SQL_GET_MEMOS, null);
if (cursor.getCount() > 0) {
String[] str = new String[cursor.getCount()];
int i = 0;
while (cursor.moveToNext()) {
str[i] = cursor.getString(cursor.getColumnIndex("memo"));
i++;
}
return str;
}
else {
return new String[] {};
}
}
I retrieve all the rows from my SQLite-DB Table
Cursor cursor = db.rawQuery("select * from table",null);
Then I want to add each row to an ArrayList
Please help!
IF you're using custom object array, then use like following :
public void fillDataToArray() {
ArrayList<BeanClass> arrayList = new ArrayList<BeanClass>();
DatabaseHandler db = new DatabaseHandler(getActivity());
db.open();
try
{
Cursor c = db.getImageNameForList();
if (c != null && c.getCount() > 0) {
c.moveToFirst();
for (int count = 0; count < c.getCount(); count++) {
Beanclass detail = new Beanclass ();
detail.setName(c.getString(c
.getColumnIndex(DatabaseHandler._ID)));
detail.setPath(c.getString(c
.getColumnIndexOrThrow(DatabaseHandler._PATH)));
arrayList.add(detail);
c.moveToNext();
}
}
}
catch(Exception e)
{
e.printStackTrace();
}
c.close();
db.close();
}
If you use this in activity, change getActivity() to local context or whichever way you use context in activities.
DATA RETRIEVAL METHOD IN DB ADAPTER CLASS :
> public Cursor getImageNameForList() {
return db.rawQuery("select " + IMAGE_PATH + " from "+ TABLE_PRODUCT_IMAGES , null);
}
Code to do that would look like this, depending on whats in your Table. You have to create a Class that is able to represent a Row in your table.
For example if there are people in your table, with name and age, you will need an object Human(String name, int age) to put into a list.
SQLiteDatabase db = helper.getReadableDatabase();
ArrayList<Human> results = new ArrayList<Human>();
try {
String rawQuery = "Select name, age from people";
Cursor c = db.rawQuery(rawQuery, null);
try {
if (!c.moveToFirst())
return null;
do {
results.add(new Human(c.getString(0),c.getInt(1)));
} while (c.moveToNext());
} finally {
c.close();
}
} finally {
db.close();
}
public class Human {
private String name;
private int age;
public Human (String name, int age) {
this.name = name;
this.age = age;
}
}
In your Db Adapter class, add this method
public ArrayList<String>getData()
{
ArrayList<String>names=new ArrayList<String>();
Cursor c = getReadableDatabase().rawQuery("Select * from tableName", null);
c.moveToFirst();
do
{
String s1=c.getString(c.getColumnIndex("<Column_Name>"));
names.add(s1);
}while(c.moveToNext());
return names;
}
after that in your activity class add this
ArrayList<String> cid;
DB_Adapter database = new DB_Adapter(getApplicationContext(), "<your schema name>", null, 1);
cid=database.getData();
After that add your arraylist to your array adapter which is set to ListView
I got really confused with the database usage in Android.
I have this database:
Table name: articles
Fields: id, article, chapterid
i currently have the below code and use it inside a fragment:
List<Comment> contents = ((MainActivity)getActivity()).connectRawQueryDB("database.sqlite", "SELECT * FROM articles WHERE chapterid = 1");
And in my MainActivity
public List<Comment> connectRawQueryDB(String DB_NAME, String RawQuery) {
List<Comment> comments = new ArrayList<Comment>();
Cursor cursor = database.rawQuery(RawQuery,null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
Comment comment = cursorToComment(cursor);
comments.add(comment);
cursor.moveToNext();
}
// make sure to close the cursor
cursor.close();
return comments;
}
private Comment cursorToComment(Cursor cursor) {
Comment comment = new Comment();
comment.setId(cursor.getLong(0));
comment.setComment(cursor.getString(1));
return comment;
}
What i need is to make a query to the database and then output values in the following format:
e.g. row[article] and get the value of article and from the same query get row[id] and get the value in id field.
Add this method in you dbhandler....
public ArrayList<Comment> getCommentdata()
{
//get db
SQLiteDatabase db = getWritableDatabase();
ArrayList<Comment> resultCommentList = new ArrayList<Comment>();
String resultQuery = "select id, article, chapterid from "+YOUR_TABLE;
Cursor cursor = db.rawQuery(resultQuery, null);
if(cursor.moveToFirst())
{
do
{
Comment commentObject = new Comment();
commentObject.setcommentUID(cursor.getInt(0));
commentObject.setarticle(cursor.getString(1));
commentObject.setChapterID(cursor.getInt(2));
resultCommentList.add(commentObject);
}
while(cursor.moveToNext());
}
//close db
if(db != null)
db.close();
return resultCommentList;
}
And when yout want to retrive data
allComent = localDBHelper.getCommentdata();
for(int i = 0; i < allComent .size(); i++)
{
int id=allComment.get(i).getcommentUID();
String =allComment.get(i).getarticle();
int cid=allComment.get(i).getChapteID();
}
i have an error in my application.
I'm new in making apps for android, so i don´t now what's wrong...
this is in the log:
java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteQuery: SELECT * FROM pets
i have a SQLite database in which is this method:
public List<Pet> getAllPets() {
List<Pet> petList = new ArrayList<Pet>();
String selectQuery = "SELECT * FROM " + TABLE_PETS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
Pet pet = new Pet();
pet.setID(Integer.parseInt(cursor.getString(0)));
pet.setName(cursor.getString(1));
pet.setAge(cursor.getString(2));
petList.add(pet);
} while (cursor.moveToNext());
}
return petList;
}
and then i'am using this method from database in other activity to fill the ListView by the names of every pet....
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
PetListView = (ListView)findViewById(R.id.list);
MyDatabaseHelper db = new MyDatabaseHelper(this);
String [] items = new String[db.getPetsCount()];
List<Pet> pets = db.getAllPets();
for (int i = 0; i < db.getPetsCount(); i++) {
items[i] = pets.get(i).getName();
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.activity_list_item, items);
PetListView.setAdapter(adapter);
}
when this activity starts the application crashes down..
Please, can you tell me what's worng? How can i fix it? Thanks a much for help.
EDIT:
getPetsCount() method:
public int getPetsCount() {
String countQuery = "SELECT * FROM " + TABLE_PETS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
return cursor.getCount();
}
i solved this by myself at the end by replace the getPetsCount method:
public int getPetsCount() {
String countQuery = "SELECT * FROM " + TABLE_PETS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
int count = cursor.getCount();
cursor.close();
db.close();
return count;
First, you should close your cursor once you have finished to use it (that may solve your issue)
public List<Pet> getAllPets() {
List<Pet> petList = new ArrayList<Pet>();
String selectQuery = "SELECT * FROM " + TABLE_PETS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
Pet pet = new Pet();
pet.setID(Integer.parseInt(cursor.getString(0)));
pet.setName(cursor.getString(1));
pet.setAge(cursor.getString(2));
petList.add(pet);
} while (cursor.moveToNext());
}
// Close cursor when finished using it
cursor.close();
return petList;
}