class Measurement {
int time;
float value;
Measurement(int argTime, float argValue) {
time = argTime;
value = argValue;
}
}
ArrayList measurements;
void setup() {
measurements = new ArrayList();
measurements.append(new Measurement(1, 20));
}
Gives me this error:
The function append(sketch_140628b.Measurement) does not exist
What am I doing wrong?
The class ArrayList has no such method as 'append'. The function you want is 'add'.
Related
I'm building a weather app for practice and I'm getting following error:
Class 'Future<dynamic>' has no instance method '[]'.
Receiver: Instance of 'Future<dynamic>'
Tried calling: []("weather")
And this is where I think it comes from:
void updateUI(dynamic weatherData) {
var condition = weatherData['weather'][0]['id'];
String cityName = weatherData['name'];
double temp = weatherData['main']['temp'];
temperature = temp.toInt();
}
Had to create a class for my Data i got from my api call:
class WeatherData {
final int conditionID;
final String cityName;
final double temperature;
const WeatherData({
required this.conditionID,
required this.cityName,
required this.temperature,
});
factory WeatherData.fromJson(Map<String, dynamic> json) {
return WeatherData(
conditionID: json['weather'][0]['id'],
cityName: json['name'],
temperature: json['main']['temp'],
);
}
}
And then use it in updateUI() like this:
void updateUI(WeatherData weatherData) {
var condition = weatherData.conditionID;
String cityName = weatherData.cityName;
double temp = weatherData.temperature;
temperature = temp.toInt();
}
As always the documentation helped me a lot:
https://docs.flutter.dev/cookbook/networking/fetch-data
I have a List<List<String>> dataTableList and I would like to get a specific list from there and put it on my List<String> dataList so that I could loop through that specific lists' value and alter it.
However, whenever I try to do that,I always get an error of:
java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to java.util.List.
Here's a sample of how I am trying to assign a specific list from dataTableList to dataList:
//First I looped through the List of Lists and called each list fetched as dataList
for(List<String> dataList : getTryLang().getDataTableList()){
//then, I created an iterator to be used later when I return the List I fetched with altered value
int iter = 0;
//next, I created a for-loop to iterate through the values of the List the I feched
for(int x; x < dataList.size(); x++){
//here, I formatted each value to amount or currency format.
dataList.set(x, getDataConvert().convertAmount(dataList.get(x)));
//finally, after I formatted everything, I returned it or set it to the specific index it's been located before
getTryLang().getDataTableList().set(iter, dataList);
}
iter++;
}
EDIT:
Here's my code and I modified some of it and didn't include some so that I could focus on expressing where the problem occurs.
Here's my TryLang.java:
#ManagedBean
#SessionScoped
public class TryLang implements Serializable {
public TryLang() {}
//declare
private List<List<String>> dataTableList;
//getter setter
public List<List<String>> getDataTableList() {
return dataTableList == null ? dataTableList = new ArrayList<>() : dataTableList;
}
public void setDataTableList(List<List<String>> dataTableList) {
this.dataTableList = dataTableList;
}
}
Then here's my BookOfAccountsController.java:
#ManagedBean
#RequestScoped
public class BooksOfAccountsController implements Serializable {
public BooksOfAccountsController() {}
//declare
#ManagedProperty(value = "#{dataConvert}")
private DataConvert dataConvert;
#ManagedProperty(value = "#{tryLang}")
private TryLang tryLang;
//getter setter NOTE: I wouldn't include other getter setters to shorten the code here :)
public TryLang getTryLang() {
return tryLang == null ? tryLang = new TryLang() : tryLang;
}
public void setTryLang(TryLang tryLang) {
this.tryLang = tryLang;
}
//I would just go straight to the method instead
public void runBooksOfAccounts() throws SystemException, SQLException {
//So there are dbCons here to connect on my DB and all. And I'll just go straight on where the List<List<String>> is being set
//Here's where the List<List<String>> is being set
getTryLang().setDataTableList(getCemf().getFdemf().createEntityManager().createNativeQuery("SELECT crj.* FROM crj_rep crj").getResultList());
getTryLang().setDataTableColumns(getCemf().getFdemf().createEntityManager().createNativeQuery("SELECT col.column_name FROM information_schema.columns col WHERE table_schema = 'public' AND table_name = 'crj_rep'").getResultList());
for (int x = 0; x < getTryLang().getDataTableColumns().size(); x++) {
try {
Integer.parseInt(getTryLang().getDataTableColumns().get(x));
getTryLang().getDataTableColumns().set(x, getDataConvert().accountCodeConvert(getTryLang().getDataTableColumns().get(x)));
//then here is where the error points at
for (List<String> dataList : getTryLang().getDataTableList()) {
try{
int iter = 0;
dataList.set(x, getDataConvert().convertAmount(new BigDecimal(dataList.get(x))));
getTryLang().getDataTableList().set(iter, dataList);
iter++;
}catch(ClassCastException ne){
System.out.println("cannot convert " + ne);
}
}
} catch (NumberFormatException ne) {
//print the error
}
}
}
}
I have an example where I want to store an object into Redis.
class CyPoint
{
// Fields...
private bool _Done;
private string _Color;
private string _Position;
private long _Id;
public long Id
{
get { return _Id; }
set
{
_Id = value;
}
}
public string Position
{
get { return _Position; }
set
{
_Position = value;
}
}
public string Color
{
get { return _Color; }
set
{
_Color = value;
}
}
public bool Done
{
get { return _Done; }
set
{
_Done = value;
}
}
}
I am using this code to store the data
var redisCyPoint = redis.As<CyPoint>();
var cpt = new CyPoint
{
Id = redisCyPoint.GetNextSequence(),
Position = "new Vector3(200, 300, 0)",
Color = "new Vector3(.5f, .7f, .3f)",
};
redisCyPoint.Store(cpt);
This works as I am storing strings. But when I change position and color to Vector3 (which is: float, float, float) it only saves 0's. It seems that the Store will not work with complex types. Is this a limitation or is there a way to do this?
Struct's are serialized as a single scalar string value as returned by ToString(). You can implement custom support for Structs by implementing a constructor Vector3(string) that can populate itself from its ToString() value, or implement a static ParseJson(string) method.
Otherwise you can specify custom serializer to handle the serialization, e.g:
JsConfig<Vector3>.SerializeFn = v => "{0},{1},{2}".Fmt(v.X,v.Y,v.Z);
JsConfig<Vector3>.DeSerializeFn = s => {
var parts = s.Split(',');
return new Vector3(parts[0],parts[1],parts[2]);
};
Document structure is:
db.lookupdata.insert({ parent_key : "category" , key : "accessories" , value : ["belts","cases","gloves","hair","hats","scarves","sunglasses","ties","wallets","watches"]})
i want to store array filed values in java array list
i am finding the document like this:
FindIterable<Document> iterable1 = docCollectionLookup.find(Filters.eq("parent_key", "category"));
Iterator<Document> iter1=iterable1.iterator();
while(iter1.hasNext())
{
Document theObj = iter1.next();
categotyLookUpMap.put(theObj.getString("key"), list);
}
now here how can i retrieve array field values(key:"value") in ArrayList
You can retrieve array field values(key:"value") in ArrayList just like how you retrieve string field key. Please refer below:
FindIterable<Document> iterable1 = docCollectionLookup.find(Filters.eq("parent_key", "category"));
Iterator<Document> iter1=iterable1.iterator();
//Create a HashMap variable with type <String,ArrayList>,according to your needs
Map<String,ArrayList> categotyLookUpMap = new HashMap<String,ArrayList>();
while(iter1.hasNext())
{
Document theObj = iter1.next();
//Get method of Document class will return object,parse it to ArrayList
categotyLookUpMap.put(theObj.getString("key"), (ArrayList)theObj.get("value"));
}
Alternatively, you can use Morphia which is MongoDB object-document mapper in Java. You can setup dependency / download JAR from here
First, create LookupData class to map to lookupdata collection. Annotation #Id is required else will throw exception with message "No field is annotated with #Id; but it is required". So create an _id field for it.
#Entity("lookupdata")
public class LookupData {
#Id
String _id ;
#Property("parent_key")
String parentKey;
String key;
ArrayList<String> value;
public String get_id() {
return _id;
}
public void set_id(String _id) {
this._id = _id;
}
public String getParentKey() {
return parentKey;
}
public void setParentKey(String parentKey) {
this.parentKey = parentKey;
}
public String getKey() {
return key;
}
public void setKey(String key) {
this.key = key;
}
public void setValue(ArrayList<String> value) {
this.value = value;
}
public ArrayList<String> getValue() {
return value;
}
}
Retrieve array field values as below:
MongoClient mongoClient = new MongoClient(new MongoClientURI("mongodb://localhost"));
Morphia morphia = new Morphia();
morphia.map(LookupData.class);
//lookupdata collection is under my local db "tutorials" in this case
Datastore datastore = morphia.createDatastore(mongoClient, "tutorials");
Map<String,ArrayList> categotyLookUpMap = new HashMap<String,ArrayList>();
LookupData lookupData = datastore.find(LookupData.class).get();
categotyLookUpMap.put(lookupData.getKey(), lookupData.getValue());
This is a project I am working on and it is supposed to take input from the user then which is an area code then see if it is contained in a array list. My method that I have created will not work in another class and I am not sure why, it is returning a NullPointerException.
The NullPointerException is shown at this line of code: if (mountainTime.contains(input))
This is the class with methods
package finalPro;
import java.util.ArrayList;
public class Final
{
public Final()
{
input = 0;
timezone = 0;
}
public void checkIfTrue(int y)
{
input = y;
if (mountainTime.contains(input))
{
timezone = 1;
}
else
timezone = 0;
System.out.println(timezone);
}
public int getZone()
{
return timezone;
}
public ArrayList<Integer> mountainTime;
private int input;
private int timezone;
}
Here is test class
package finalPro;
import java.util.ArrayList;
import javax.swing.JOptionPane;
public class FinalLogic
{
public static void main(String[] args)
{
ArrayList<Integer> mountainTime = new ArrayList<Integer>();
mountainTime.add(480);
mountainTime.add(602);
mountainTime.add(623); //Arizona area codes
mountainTime.add(928);
mountainTime.add(520);
mountainTime.add(303);
mountainTime.add(719); //Colorado
mountainTime.add(720);
mountainTime.add(970);
mountainTime.add(406); //Montana
mountainTime.add(505); //New Mexico
mountainTime.add(575);
mountainTime.add(385);
mountainTime.add(435); //Utah
mountainTime.add(801);
mountainTime.add(307); //Wyoming
Final myMap = new Final();
{
String x = JOptionPane.showInputDialog("Please enter a number: ");
int input = Integer.parseInt(x);
myMap.checkIfTrue(input);
}
}
}
I hope it's not too late, I haven't done anything special to fix your code, just some movement of code,
Removed the initialization logic from class FinalLogic to Final class .(btw Final name is not really good, you might be aware final is reserved word in Java. Although your name is case sensitive but still)
package finalPro;
import javax.swing.JOptionPane;
public class FinalLogic {
public static void main(String[] args) {
Final myMap = new Final();
String x = JOptionPane.showInputDialog("Please enter a number: ");
int input = Integer.parseInt(x);
myMap.checkIfTrue(input);
}
}
And here is your class Final
package finalPro;
import java.util.ArrayList;
public class Final {
public Final() {
input = 0;
timezone = 0;
// moved all initialization logic to constructor
mountainTime = new ArrayList<>();
mountainTime.add(480);
mountainTime.add(602);
mountainTime.add(623); // Arizona area codes
mountainTime.add(928);
mountainTime.add(520);
mountainTime.add(303);
mountainTime.add(719); // Colorado
mountainTime.add(720);
mountainTime.add(970);
mountainTime.add(406); // Montana
mountainTime.add(505); // New Mexico
mountainTime.add(575);
mountainTime.add(385);
mountainTime.add(435); // Utah
mountainTime.add(801);
mountainTime.add(307); // Wyoming
}
public void checkIfTrue(int y) {
input = y;
if (mountainTime.contains(input)) {
timezone = 1;
} else
timezone = 0;
System.out.println(timezone);
}
public int getZone() {
return timezone;
}
public ArrayList<Integer> mountainTime;
private int input;
private int timezone;
}
I tried in my workspace, it gives no NPE, Hope it helps.