I tried to do it with multiple Shared Preferences keys, but it goes quiet complicated.
I saw some said that it is possible with JSON, but have no idea how to do it.
My app has many items in ListView, and I want to save several values in each item.
You can imagine a contact management app.
When the Item(person name) is clicked, you can check the values like phone number, address, and picture. And of course, they can be edited, added and deleted.
Is it possible to save values in single KEY with JSON?
So that I can load the values for each item when it is clicked.
To be able to save multiple values inside a jsonObject you can do this
try {
JSONObject Contacts = new JSONObject();
Contacts.put("Name", "Saul Goodman");
Contacts.put("Address", "Ocean Drive");
Contacts.put("Phone", "13456");
Contacts.put("Contacts", Contacts);
} catch (JSONException e) {
e.printStackTrace();
}
So that will create a structure like this
"Contacts":{
"Name":"Saul Goodman",
"Address":"Ocean Drive",
"Phone":"123456"
}
};
To retrieve this values you should do this
JSONArray array = object.getJSONArray("Contacts");
for(int i = 0; i < array.length; i++) {
JSONObject object = (JSONObject) array.get(i);
String name = object.get("Name");
String address = object.get("Address");
String phone = object.get("Phone");
//you also can use object.getString(""); to get the strings
}
hope it helps
Happy coding !
Related
I have the following string, which was created using javascript JSON. (It's passed from a Webview to the native code using JavascriptInterface.)
{"var1":1,"var2":8}
How do I convert that into an object and then iterate over the key/value pairs? The names of the keys are NOT known in advance.
I have seen this JSON Array iteration in Android/Java and this Converting json string to java object? and this how to convert JSON string to object in JAVA android.
None of those seem to fit with my example, which is a dictionary with unknown key names. At least, it's certainly not clear to me which of the 15+ answers is relevant for my case.
The org.json library comes "for free" with Android, so I'd go with that. Usage when you don't know the keys ahead of time could be something like this:
try {
JSONObject jsonObject = new JSONObject(/* your json String here */);
Iterator<String> keys = jsonObject.keys();
while (keys.hasNext()) {
String key = keys.next();
String value = jsonObject.getString(key);
// do whatever you want with key/value
}
}
catch (JSONException e) {
// thrown when:
// - the json string is malformed (can't be parsed)
// - there's no value for a requested key
// - the value for the requested key can't be coerced to String
}
You can use it by converting the getting the json length like this:-
JSONObject obj = new JSONObject(response);
for (int i = 0; i < obj.length(); i++) {
//getting the json object of the particular index inside the array
JSONObject heroObject = obj.getJSONObject(i);
String aka=heroObject.getString("your key here");
}
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.
anyone know hot to display random data from database in mysql and display in listview?
i can display all data without random, but i want to displayed it random, anyone can help?
my code :
for (int i = 0; i < response.length() ; i++) {
try {
JSONObject obj = response.getJSONObject(i);
Exercise exercise = new Exercise();
if (obj.getString("KindOf").equals(textKind.getText().toString()) && obj.getString("Type").equals("Strength")) {
exercise.setTipe(obj.getString("Type"));
exercise.setJenis(obj.getString("KindOf"));
exercise.setNama(obj.getString("Name"));
exerciseList.add(exercise);
} catch (JSONException e) {
e.printStackTrace();
}
}
If you want to shuffle an ArrayList, you can just use the Collections shuffle method.
Collections.shuffle(exerciseList);
Or
SELECT *
FROM excercises
ORDER BY RAND();
If you want it at DB level.
Create a random number with
Random rand = new Random();
int n = rand.nextInt(exerciseList.size());
Then use the random number as an index to get an item from your exerciseList and add it to a new array if it doesnt exist there yet.
To random ArrayList, you can just use the Collections shuffle method.
Collections.shuffle(exerciseList);
Or you can use random function in web service method when you access data from database.
I was wondering if it could be possible to save in the shared preferences an array of Strings, in a way that, every time we save a certain String, we store it in that array.
For example I have a list of locations with a certain ID that I want to mark as favorite.
The ideal situation would be, having an array and saving a certain location ID (let's call it Location1) in that array, so next time I want to mark a new location as favorite (let's call it Location2), I retrieve that array (which so far contains Location1) and add the ID of this new location I want to add (Location2).
Android has methods to store primitive objects, but not for arrays.
Any idea in order to do this, please?
This is doable: I was just blogging about it:
SAVE YOUR ARRAY
//String array[]
//SharedPreferences prefs
Editor edit = prefs.edit();
edit.putInt("array_size", array.length);
for(int i=0;i<array.length; i++)
edit.putString("array_" + i, array[i]);
edit.commit();
RETRIEVE YOUR ARRAY
int size = prefs.getInt("array_size", 0);
array = new String[size];
for(int i=0; i<size; i++)
prefs.getString("array_" + i, null);
Just wrote that so there might be typos.
You could make the array a JSON array and then store it like this:
SharedPreferences settings = getSharedPreferences("SETTINGS KEY", 0);
SharedPreferences.Editor editor = settings.edit();
JSONArray jArray = new JSONArray();
try {
jArray.put(id);
} catch (JSONException e) {
e.printStackTrace();
}
editor.putString("jArray", jArray.toString());
editor.commit();
You can then get the array like this:
SharedPreferences settings = getSharedPreferences("SETTINGS KEY", 0);
try {
JSONArray jArray = new JSONArray(settings.getString("jArray", ""));
} catch (JSONException e) {
e.printStackTrace();
}
Just an alternative solution that I have used in the past
Write methods to read and write a serialized array. This shouldn't be too difficult. Just flatten the array of strings into a single string that you store in the preferences. Another option would be to convert the array into an XML structure that you then store in the preferences, but that is probably overkill.
I have an application that gets an api key and account name from a webservice, I am storing this apikey and account name for further use(multiple accounts and apikeys).
because you can only store primitive types in the sharedPreferences I parse the JSONArray toString.
In another part of the application the user must be able to remove an account from his app.
So I retrieve the string and Parse it back to an JSONArray.
how do I remove an JSONObject from the array and save it so I can parse it back to an string and save it again?
You should convert it in arraylist and remove object and create jsonarray,,,
ArrayList<String> list = new ArrayList<String>();
//First Position remove
list.remove(0);
JSONArray jsArray = new JSONArray(list);
i use:
public static JSONArray RemoveJSONArray( JSONArray jarray,int pos) {
JSONArray Njarray=new JSONArray();
try{
for(int i=0;i<jarray.length();i++){
if(i!=pos)
Njarray.put(jarray.get(i));
}
}catch (Exception e){e.printStackTrace();}
return Njarray;
}