I'm using a web service which returns data in JSON format like this:
{"content":[{"id":"1","asset_id":"62","title":"sample page","alias":"","introtext":"","fulltext":"Some Contents"},{"id":"2","asset_id":"62","title":"sample page2","alias":"","introtext":"","fulltext":"Some Contents"},{"id":"3","asset_id":"62","title":"sample page3","alias":"","introtext":"","fulltext":"Some Contents"}]}
onCreate() of MainActivity.java is :
boolean myFlag = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.myView);
setFlag = PreferenceManager.getDefaultSharedPreferences(MainActivity.this);
dataSource = new ContentsDataSource(this);
dataSource.open();
parseAndIsertData();
}
the parseAndInsertData() is :
EDIT
private void parseAndIsertData() {
// Creating JSON Parser instance
MyJSONParser jParser = new MyJSONParser();
contentDataObject = new ContentDataObject();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(BASE_URL);
try {
// first time check if data is inserted
editor = setFlag.edit();
editor.putBoolean(MY_KEY, true);
// Getting Array of Contents
jsonArray = json.getJSONArray(MOBILE_CONTENT);
// looping through All Contents
if(!myFlag){
for(int i = 0; i < jsonArray.length(); i++){
contentDataObject.setId(jsonArray.getJSONObject(i).getInt(MOBILE_CONTENT_ID));
contentDataObject.setTitle(jsonArray.getJSONObject(i).getString(MOBILE_CONTENT_TITLE));
contentDataObject.setFulltext(jsonArray.getJSONObject(i).getString(MOBILE_CONTENT_FULLTEXT));
contentDataObject.setState(jsonArray.getJSONObject(i).getInt(MOBILE_CONTENT_STATE));
contentDataObject.setNewValue(jsonArray.getJSONObject(i).getInt(MOBILE_CONTENT_NEW));
contentDataObject.setHeader(jsonArray.getJSONObject(i).getString(MOBILE_CONTENT_HEADER));
contentDataObject.setColor(jsonArray.getJSONObject(i).getInt(MOBILE_CONTENT_COLOR));
contentDataObject.setNext(jsonArray.getJSONObject(i).getString(MOBILE_CONTENT_NEXT));
contentDataObject.setPrevious(jsonArray.getJSONObject(i).getString(MOBILE_CONTENT_PREVIOUS));
contentDataObject = dataSource.create(contentDataObject);
Log.i(MY_TAGT, "Data Inserted " + contentDataObject.getId() + " Times");
}
myFlag = setFlag.getBoolean(MY_KEY, false);
}
} catch (JSONException e) {
e.printStackTrace();
}
}}
Now My logcat for first time launch is :
and when I relaunch the app my logcat is :
Now I want ask that is this approach correct or not if YES! then will I be able to update that later on!!
Thanks!
You are correct that this code will insert the data multiple times. It will be up to you to implement a pattern that allows only one row.
You need to either query the data source first and not insert the data if it exists or you need to delete the data from the data source and then insert it every time. There are other patterns but these two will be the most common. Which one you choose will depend on what the data is and how you want it maintained or updated.
define a column in your table to be primary key or unique
use SQLiteDatabase.insertWithOnConflict(...) with the conflictAlgorithm parameter (the last one) set to ``SQLiteDatabase.CONFLICT_IGNORE`
See this
Related
I would like to ask if someone here knows how to convert a HashMap to JSON Array to be used on a Adapter. The logic is when you logged in, it will fetch data on a web server using Volley, store it on SQLite database and at the same time it will show the retrieve data on a custom listview. The thing is, if you will move to another fragment on the application and then go back, it will request again on the volley which it will take time. I wanted that if you will go back the data stored on the SQLite database will be retrieved and if the user wanted to update the data using SwipeRefresh, that's the time to update for new data.
Here is my code.
public void LoadMarkets()
{
Map<String,String>tmpRate = new HashMap<String,String>();
RateDb db = new RateDb(getActivity().getApplicationContext());
Cursor rs = db.getData();
if(rs!=null && rs.getCount()>0)
{
if(rs.moveToFirst())
{
while(rs.moveToNext())
{
tmpRate.put("rateID",rs.getString(rs.getColumnIndex(RateDb.rateID)));
tmpRate.put("Name",rs.getString(rs.getColumnIndex(RateDb.rateName)));
tmpRate.put("Rate",rs.getString(rs.getColumnIndex(RateDb.rateRate)));
tmpRate.put("Date",rs.getString(rs.getColumnIndex(RateDb.rateDate)));
tmpRate.put("Time",rs.getString(rs.getColumnIndex(RateDb.rateTime)));
tmpRate.put("Ask",rs.getString(rs.getColumnIndex(RateDb.rateAsk)));
tmpRate.put("Bid",rs.getString(rs.getColumnIndex(RateDb.rateBid)));
tmpRate.put("Balance",rs.getString(rs.getColumnIndex(RateDb.rateBalance)));
//Log.d("MyDebug",rs.getString(rs.getColumnIndex(RateDb.rateName)));
}
}
}
rs.close();
db.close();
JSONObject jsonObject = new JSONObject(tmpRate);
JSONArray jsonArray = new JSONArray();
jsonArray.put(jsonObject);
RowAAdapter rowAAdapter = new RowAAdapter(getActivity(),jsonArray);
lvMarkets.setAdapter(rowAAdapter);
swipeRefreshLayout.setRefreshing(false);
}
The problem is that when i load this function, it only shows the last data.
I hope you can help me with my problem.
Thank you very much.
You can put the values directly into the jsonObject instead of adding it to the hashmap like this :
public void LoadMarkets()
{
RateDb db = new RateDb(getActivity().getApplicationContext());
Cursor rs = db.getData();
if(rs!=null && rs.getCount()>0)
{
if(rs.moveToFirst())
{
while(rs.moveToNext())
{
JSONObject jsonObject = new JSONObject();
jsonObject.put("rateID",rs.getString(rs.getColumnIndex(RateDb.rateID)));
jsonObject.put("Name",rs.getString(rs.getColumnIndex(RateDb.rateName)));
jsonObject.put("Rate",rs.getString(rs.getColumnIndex(RateDb.rateRate)));
jsonObject.put("Date",rs.getString(rs.getColumnIndex(RateDb.rateDate)));
jsonObject.put("Time",rs.getString(rs.getColumnIndex(RateDb.rateTime)));
jsonObject.put("Ask",rs.getString(rs.getColumnIndex(RateDb.rateAsk)));
jsonObject.put("Bid",rs.getString(rs.getColumnIndex(RateDb.rateBid)));
jsonObject.put("Balance",rs.getString(rs.getColumnIndex(RateDb.rateBalance)));
jsonArray.put(jsonObject);
//Log.d("MyDebug",rs.getString(rs.getColumnIndex(RateDb.rateName)));
}
}
}
rs.close();
db.close();
RowAAdapter rowAAdapter = new RowAAdapter(getActivity(),jsonArray);
lvMarkets.setAdapter(rowAAdapter);
swipeRefreshLayout.setRefreshing(false);
}
The problem with your code is that :
You're putting the values with keys "rateID", "Name"... etc. in the while loop again and again, so the previous values are being replaced with the new values and finally you've just one set of data in your hashmap. That's why you're getting only the last set of data.
Try the above code. It should work as expected.
This will work as it creates a new JsonObject in the loop and adds it to the jsonArray when the data is successfully added to it.
I'm using parse backend to store and retrieve the datas for my android app, the storing gets done properly but i have problem in retrieving it. I just went through the parse documentation to retrieve the result but what i get is just 0 for all the retrieved values..im suret that the class exists in the parse cloud with valid values but still i get 0 for all the queries.. this is my code to save:
Toast.makeText(getApplicationContext(),"writing to parse",Toast.LENGTH_SHORT).show();
ParseObject dataObject = new ParseObject("Score");
dataObject.put("correct",correctAnswers);
dataObject.put("wrong",wrongAnswers);
dataObject.put("percent", percentage);
dataObject.saveInBackground();
this is how i get back the saved data
ParseQuery<Score> query = ParseQuery.getQuery("Score");
try {
List<Score> scoreList = query.find();
} catch (ParseException e) {
e.printStackTrace();
}
query = ParseQuery.getQuery("Score");
final Activity ctx = this;
query.findInBackground( new FindCallback<Score>() {
#Override public void done(List<Score> scoreList, ParseException e) {
if ( e == null ) {
ParseObject dataObject = ParseObject.create("Score");
int p = dataObject.getInt("correct");
int q = dataObject.getInt("wrong");
int r = dataObject.getInt("percent");
Toast.makeText(ExamRecordActivity.this,String.valueOf(p),Toast.LENGTH_SHORT).show();
Toast.makeText(ExamRecordActivity.this,String.valueOf(q),Toast.LENGTH_SHORT).show();
Toast.makeText(ExamRecordActivity.this,String.valueOf(r),Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(ctx,
"Error updating questions - please make sure you have internet connection",
Toast.LENGTH_LONG).show();
}
}
});
Inside the done method you are creating a new by calling ParseObject dataObject = ParseObject.create("Score"); and then trying to read values from it without putting any in.
I don't know what the structure of your class is but you need to be iterating through List<Score> scoreList in order to get the queried data.
I have a ArrayList<String> -named listObjectId below- of objectIds. I'm trying to get all the objects that have an objectId contained in the ArrayList.
The solution I have right now, I think, is very bad from a performance point of view:
for (int i = 0; i < listObjectId.size(); i++) {
ItemModel mItemModelRetrieved = null;
ParseQuery<ItemModel > query = ParseQuery.getQuery(ItemModel .class);
try {
mItemModelRetrieved = query.get(listObjectId.get(i));
subscriber.onNext(mItemModelRetrieved ); //-- I'm using RxJava
} catch (ParseException e) {
Log.e(TAG, "Error Local " + e.getMessage());
}
}
You're using the wrong method. You have the object ids, so create a ParseObject with them using ParseObject.createWithoutData and then fetch the object. Try the following:
List<ParseObject> parseObjects = new ArrayList<>();
for (String objectId : listObjectId) {
parseObjects.add(ParseObject.createWithoutData(ItemModel.class, objectId));
}
ParseObject.fetchAll(parseObjects);
// parseObjects will now contain all data retrieved from Parse.
The error you're getting tells you that the data type of the column you query must be of type Array, not the value you pass into the method.
As the title says really. I have two columns. I want to put them into textviews so I did it. However only the bottom two results, one from each column gets shown. Very odd. Here is my code: http://pastebin.com/qNgfHfT3
The parsing/onPostExecute is towards the bottom where the issue is.
One thing to note: The logs labeled "work" & "dontwork" show all my results, however the logs in the onPostExecute (Google & Google1) only show the last result so I presume the error is in the transfer from parsing to displaying.
Would really appreciate any help here. Thanks.
If you are receiving a JSON response I'd suggest you to parse it by using Gson. It's strongly recommendable as long as you can parse the whole thing in a pair of lines.
Note that creating a proper object it is as easy as doing the following:
YourObject object = gson.fromJson(responseReader, YourObject.class);
or even if you are retrieving a list of items:
Type listType = new TypeToken<List<YourObject>>() {}.getType();
List<YourObject> objects = gson.fromJson(responseReader, listType);
Here's an example that fits exactly your needs
After the process is done you'll have your object (or list of objects) available in an accesible variable.
EDIT:
First your Asynctask should have the following params:
public class HttpTask extends AsyncTask<Void, Void, ArrayList<Driver>> {
and your doInBackground method will need to pass that array to your onPostExecute:
#Override
protected ArrayList<Driver> doInBackground(Void... params) {
For the rest, I take it when the JSon parsing starts.
//PARSING JSON DATA
try {
JSONObject json_data;
Driver d;
jArray = new JSONArray(result);
int l = jArray.length();
if(l>0){
ArrayList<Driver> drivers = newArrayListList<Driver>();
for (int i = 0; i < l; i++) {
json_data = jArray.getJSONObject(i);
d = new Driver(json_data.optString("Driver_full_name"), json_data.optString("Drives_for"));
drivers.add(d);
Log.i("work", returnString);
Log.i("dontwork", somethingelse);
}
} catch (JSONException e1) {
Log.d("DB", "Error somewhere");
CurrentSeasonDrivers_DriverName.this.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(CurrentSeasonDrivers_DriversName, "Could not parse data so shut up", Toast.LENGTH_LONG).show();
}
});
}
return drivers;
}
protected void onPostExecute(ArrayList<Drivers>... drivers) {
Log.i("Google", returnString);
Log.i("Google1", somethingelse);
String firstDriverName = drivers.get(0).name;
String firstDriverDrivesFor = drivers.get(0).drivesfor;
String secondDriverName = drivers.get(1).name;
TextView drivername = (TextView) findViewById(R.id.DriverName);
drivername.setText(firstDriverName);
TextView drivesfor = (TextView) findViewById(R.id.DrivesFor);
drivesfor.setText(firstDriverDrivesFor);
}
With this and an object for your driver will complete the circle.
public class Driver{
public String name;
public String drivesfor;
public Driver(String _name, String _drivesfor){
name = _name;
drivesfor = _drivesfor;
}
}
I guess you can take over from here.
Let me know about your progress.
So I want to save an ordered set of double values, and I want to be able to insert, retrieve or delete any value from this easily. As of such, I'm using a an ArrayList, where I define a class called Doubles to store the double values.
How do I store this arraylist in a record in an SQLite database? I mean...what should the columns type be? Can it be done?
You cannot insert ArrayList directly into Sqlite. Instead, you could use JSONObject (org.json.JSONObject) to insert the ArrayList. Please check below snippet, you can try something like below....
To insert,
JSONObject json = new JSONObject();
json.put("uniqueArrays", new JSONArray(items));
String arrayList = json.toString();
Insert the string into db.
To Read,
Read the string from db as String,
JSONObject json = new JSONObject(stringreadfromsqlite);
ArrayList items = json.optJSONArray("uniqueArrays");
To Insert :
ArrayList<String> inputArray=new ArrayList<String>();
Add Values to inputArray
Gson gson = new Gson();
String inputString= gson.toJson(inputArray);
System.out.println("inputString= " + inputString);
Use "inputString" to save the value of ArrayList<String> in SQLite Database
To retreive:
Get the String from the SQLiteDatabse what you saved and changed into ArrayList type like below:
outputarray is a String which is get from SQLiteDatabase for this example.
Type type = new TypeToken<ArrayList<String>>() {}.getType();
ArrayList<String> finalOutputString = gson.fromJson(outputarray, type);
In my case it was ArrayList of POJO classes Note
private String mNoteTitle;
private int mFingerIndex;
private Point mNoteCoordinates;
public Note(String noteTitle, int fingerIndex, Point noteCoordinates) {
this.mNoteTitle = noteTitle;
this.mFingerIndex = fingerIndex;
this.mNoteCoordinates = noteCoordinates;
}
As manual says JSONObject supports only following types: Object: a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities. So, I should break my Note class into supported objects.
JSONObject json = new JSONObject();
JSONArray jsonArray = new JSONArray();
for(Note note: chordShape.getNotes()){
JSONObject singleNoteJsonObject = new JSONObject();
try {
singleNoteJsonObject.put(SHAPE_NOTE_TITLE, note.getNoteTitle());
singleNoteJsonObject.put(SHAPE_NOTE_FINGER_INDEX, note.getFingerIndex());
singleNoteJsonObject.put(SHAPE_NOTE_X, note.getNoteCoordinates().x);
singleNoteJsonObject.put(SHAPE_NOTE_Y, note.getNoteCoordinates().y);
} catch (JSONException e){
e.printStackTrace();
}
jsonArray.put(singleNoteJsonObject);
}
Pack created array into JSONObject.
try {
json.put(SHAPE_NOTES, jsonArray);
Log.i(TAG, json.toString());
} catch (JSONException e){
e.printStackTrace();
}
Create String.
String notesList = json.toString();
Put created String in ContentValues, cause in my case it's Android app
if(notesList.length() > 0){
contentValues.put(DatabaseHelper.SHAPE_NOTES_LIST, notesList);
}
And when i should read values from SQLite database.
ArrayList<Note> notes = new ArrayList<>();
while(cursor.moveToNext()){
JSONObject jsonNotes = null;
try {
jsonNotes = new JSONObject(cursor.getString(cursor.getColumnIndex(DatabaseHelper.SHAPE_NOTES_LIST)));
} catch (JSONException e){
e.printStackTrace();
}
if(jsonNotes != null){
Log.i(TAG, jsonNotes.toString());
JSONArray jsonArray = jsonNotes.optJSONArray(SHAPE_NOTES);
for(int i = 0; i < jsonArray.length(); i++){
Note note = null;
JSONObject arrayObject = null;
try {
arrayObject = jsonArray.getJSONObject(i);
} catch (JSONException e){
e.printStackTrace();
}
if(arrayObject != null){
try {
note = new Note(
arrayObject.getString(SHAPE_NOTE_TITLE),
arrayObject.getInt(SHAPE_NOTE_FINGER_INDEX),
new Point(
arrayObject.getInt(SHAPE_NOTE_X),
arrayObject.getInt(SHAPE_NOTE_Y)
)
);
} catch (JSONException e){
e.printStackTrace();
}
}
if(note != null){
notes.add(note);
}
}
}
}
cursor.close();
I suggest going through all 3 Notepad tutorials you want to store the values your storing to a database table. you don't store the actual array directly into the database just the data. but you shouldn't actually need to use an array at all instead of adding a new item to the array instead call your db insert method
I've needed to do something similar in my application, where I have a custom class (Foo, Bar, etc.) and I have an ArrayList of foo, bar, etc. that I persist to SQL. My knowledge of SQL isn't strong, but I'll explain my approach here in case it helps.
My understanding is that to store any kind of object, you need to define a particular table for that object type, where the table has separate columns representing the primitive types within that object. Furthermore, to persist and retrieve an ArrayList of those objects, you'll use one table row per ArrayList entry, and iterate over in a loop to store and retrieve.
There are ArrayLists of several custom classes in my application that I wanted to persist to DB. So, to make things tidy (well, to me at least -- I'm still a relatively new Java / Android programmer, so take this with a pinch of salt) I decided to implement a kind of "SQL Serializable Interface" that my DB-persistable objects must implement. Each object (Foo, Bar, etc.) that can be persisted to DB must implement:
A public static final TABLE_NAME string, the name of the SQL DB table used for this object type.
A public static final TABLE_CREATE_STRING, a complete SQL instruction to create the table for this object.
A constructor method to populate its member variables from a ContentValues object.
A 'get' method to populate a ContentValues from its member variables.
So, say I have ArrayLists of objects Foo and Bar. When the DB is first created, within my DB helper class I call Foo.TABLE_CREATE_STRING, Bar.TABLE_CREATE_STRING, etc. to create the tables for those objects.
To populate my ArrayList, I use something like:
cursor = dbh.retrieve(Foo.TABLE_NAME);
if(!cursor.moveToFirst()){
return false
}
do{
DatabaseUtils.cursorRowToContentValues(cursor, vales);
FooArrayList.add( new Foo(values) );
} while( cursor.moveToNext() );
Create a dbHelper class which has an inner class and pretty much whatever the notepad tutorial says. The class must be having an insertion method somthing like this :-
public long insertRows(ContentValues values, String tableName) {
long val = myDatabase.insert(tableName, null, values);
return val;
}
This method will then add values into the table row.
After that you can call this method from your main activity and since you are using cursor i believe you will call the method in a for loop
for(i=0;list.length();i++) // or may be its list.size :P
{
// Call the method here
}
and keep adding value in the database by calling the method in for loop