In android studio I've created a map with hundreds of markers on it. I want to separate these into individual classes and put them in a separate package, so that there isn't one massive list of markers in my main code. Is there a way of doing this? I'm using Kotlin.
so what I think you are trying to say is.
There is an Activity let's say MainActivity and it has maps in it and has let's say some 200 markers on it.
and all are individually initialized and assigned and you want to club them all together so that you'll be able to use them just by searching for one.
if that's the case, what I would suggest is.
make a separate Data Class that stores Marker and other data related to it.
data class MarkerInfo(
//marker ID
val id:Int,
//marker Data
val markerData:Marker,
//other Data
var otherData:String
)
now coming to storing and accessing data.
class MainActivity(){
//at the top level, inside Activity
// This will create an empty list of Marker Info
var markerData = mutableListOf<MarkerInfo>()
//Now take any function, let's say x
private fun x(){
//Mark a Marker on Map and assign it to a variable.
val markerA : Marker = map.addMarker( MarkerOptions.position(somePosition))
//we assign a function with id and other relevant data
val x= markerData.size
//store data in list
markerData.add(MarkerInfo(x, markerA, "This is a very useful marker"))
}
}
//now to access that marker.
//let's say there is a function named y.
private fun y(){
//say we want to access the first marker
//there are two ways to do so.
//first method: you know some data which is already in there let's say we know id
for(i in markerData){
if(i.id == 1){
Log.d("TAG", i.toString())
}
}
//second method: directly
Log.d("TAG",markerData[0].toString())
}
Related
I am coding a data class that is wanting to read a csv file to grab some information that is stored on the file. How ever, every way that I have tried to read the file will not work.
Here is what I have tried so far:
data class Bird(val birdNumIn: Int){
private var birdNum = birdNumIn
/**
* A function that searches the bird-data.csv file which is a list of birds to find the bird that was
* inputted into the class constructor and then add the values of the bird to the private variables.
*/
fun updateValues(){
var birdNumber = birdNum
var birdInfo: MutableList<String> = mutableListOf()
val minput = InputStreamReader(assets().open("bird-data.csv"), "UTF-8")
val reader = BufferedReader(minput)
}
How ever the assets().open() does not work. It returns an error of trying to open a file that does not exist, but the is in the assets folder, and the filename is spelt right.
I have tried many other methods on trying to read files, like using Java.io.File and using the path of the file.
If you would like to look at our whole project, please feel free to go to our github
What's the assets() function you're calling? This is just a bare data class, it has no connection to the Android environment it's running in, so unless you've injected an AssetManager instance (or a Context to pull it from) into your class, you can't access it.
You probably need to do this:
fun updateValues(context: Context){
val inputStream = context.assets.open("bird-data.csv")
val minput = InputStreamReader(inputStream, "UTF-8")
...
}
which requires your caller to have access to a Context.
Honestly from a quick look at your class, you might want to rework this. Instead of having a bunch of empty fields in your data class (which aren't part of the "data" by the way, only stuff in the constructor parameters is), and then having those updated later by the data class doing some IO, you might want to keep them as just basic stores of data, and create them when you read from your assets file.
So something like:
// all fixed values, initialised during construction
// Also you won't need to override toString now (unless you want to)
data class Bird(
val birdNum: Int
val nameOfBird: String
val birdFilePic: String
val birdFileSong: String
val alternativeName: String
val birdInfoFile: String
) { ... }
Then somewhere else
fun getBirbs(context: Context) {
// open CSV
// read the lines
val allBirds = lines.map {
// parse data for each bird, use it to construct a Bird object
}
}
or whatever you need to do, e.g. loading certain birds by ID.
That way your Bird class is just data and some functions/properties that work with it, it doesn't need a Context because it's not doing any I/O. Something else (that does have access to a Context) is responsible for loading your data and turning it into objects - deserialising it basically. And as soon as it's created, it's ready and initialised and immutable - you don't have to call update on it to get it actually initialised.
And if you ever wanted to do that a different way (e.g. loading a file from the internet) the data class wouldn't need to change, just the thing that does the loading. You could even have different loading classes! One that loads local data, one that fetches from the internet. The point is the separation of concerns, so it's possible to do this kind of thing because that functionality isn't baked into a class that's really about something else.
Up to you but just a thought! Especially if passing the context in like I suggested is a problem - that's a sign your design might need tweaking
I'm quite new to progamming. So here's my function to select a random image in my drawable folder.
fun generateimage(index:Int)
{var images=arrayOf(R.drawable.img1,....)
main_imageView.setImageResource(images[index])
This works as an image is shown randomly every time I start the application. But I would like to be able to know which image was selected. Preferably from retrieving the image name to string.
Possible duplicate of
How to get drawable name from imageView
However, a better implementation would be to have the value in a list of int and put your R.drawable items inside it. That was you can access which element is being shown.
You can do something like this:
fun main() {
val arrayImages = arrayOf("image1", "image2", "image3", "image4", "image5")
// in your case actual images.
val randomIndex = (0..arrayImages.size).random()
val randomImage = arrayImages[randomIndex]
println(randomImage) // in your case: main_imageView.setImageResource(randomImage)
}
Note that you need to assign the variable of randomImage so you can access it later on. I don't know what type "R.drawable.img1" is, but the object you set inside this array has to store the name of the file, so you can retrieve it that way.
I want to get all the attributes from my "Actual Item Inventry" (From Stock Items Form) so i have:
PXResultset<CSAnswers> res = PXSelectJoin<CSAnswers,
InnerJoin<InventoryItem,
On<CSAnswers.refNoteID, Equal<Current<InventoryItem.noteID>>>
>
>.Select(new PXGraph());
But, this returns me 0 rows.
Where is my error?
UPDATED:
My loop is like this:
foreach (PXResult<CSAnswers> record in res)
{
CSAnswers answers = (CSAnswers)record;
string refnoteid = answers.RefNoteID.ToString();
string value = answers.Value;
}
... but i can not go inside foreach.
Sorry for the English.
You should use an initialized graph rather than just "new PXGraph()" for the select. This can be as simple as "this" or "Base" depending on where this code is located. There are times that it is ok to initialize a new graph instance, but also times that it is not ok. Not knowing the context of your code sample, let's assume that "this" and "Base" were insufficient, and you need to initialize a new graph. If you need to work within another graph instance, this is how your code would look.
InventoryItemMaint graph = PXGraph<InventoryItemMaint>.CreateInstance<InventoryItemMaint>();
PXResultset<CSAnswers> res = PXSelectJoin<CSAnswers,
InnerJoin<InventoryItem, On<CSAnswers.refNoteID, Equal<Current<InventoryItem.noteID>>>>>
.Select(graph);
foreach (PXResult<CSAnswers> record in res)
{
CSAnswers answers = (CSAnswers)record;
string refnoteid = answers.RefNoteID.ToString();
string value = answers.Value;
}
However, since you should be initializing graph within a graph or graph extension, you should be able to use:
.Select(this) // To use the current graph containing this logic
or
.Select(Base) // To use the base graph that is being extended if in a graph extension
Since you are referring to:
Current<InventoryItem.noteID>
...but are using "new PXGraph()" then there is no "InventoryItem" to be in the current data cache of the generic base object PXGraph. Hence the need to reference a fully defined graph.
Another syntax for specifying exactly what value you want to pass in is to use a parameter like this:
var myNoteIdVariable = ...
InventoryItemMaint graph = PXGraph<InventoryItemMaint>.CreateInstance<InventoryItemMaint>();
PXResultset<CSAnswers> res = PXSelectJoin<CSAnswers,
InnerJoin<InventoryItem, On<CSAnswers.refNoteID, Equal<Required<InventoryItem.noteID>>>>>
.Select(graph, myNoteIdVariable);
foreach (PXResult<CSAnswers> record in res)
{
CSAnswers answers = (CSAnswers)record;
string refnoteid = answers.RefNoteID.ToString();
string value = answers.Value;
}
Notice the "Required" and the extra value in the Select() section. A quick and easy way to check if you have a value for your parameter is to use PXTrace to write to the Trace that you can check after refreshing the screen and performing whatever action would execute your code:
PXTrace.WriteInformation(myNoteIdVariable.ToString());
...to see if there is a value in myNoteIdVariable to retrieve a result set. Place that outside of the foreach block or you will only get a value in the trace when you actually get records... which is not happening in your case.
If you want to get deep into what SQL statements are being generated and executed, look for Request Profiler in the menus and enable SQL logging while you run a test. Then come back to check the results. (Remember to disable the SQL logging when done or you can generate a lot of unnecessary data.)
I have a map1 which holds the information as
[40256942,6] [60246792,5]
Now that I want to prepare a map2 that holds information such as
itemNo, 40256942
qty, 6
itemNo, 60246792
qty, 5
to prepare final information as json
“partialArticlesInfo”: [{itemNo:”40256942”, availQty:”6”}, {itemNo:”60246792”, availQty:”5”}]
I am trying to iterate map1 to retrieve values and set that against the key. But I am getting only one entry which is last one. Is there any way , I get the new map with entries such as mentioned above
Map<String, String> partialArticlesInfo = new HashMap<String,String>();
Map<String, String> partialArticlesTempMap = null;
for (Map.Entry<String,String> entry : partialStockArticlesQtyMap.entrySet())
{
partialArticlesTempMap = new HashMap<String,String>();
partialArticlesTempMap.put("itemNo",entry.getKey());
partialArticlesTempMap.put("availQty",entry.getValue());
partialArticlesInfo.putAll(partialArticlesTempMap);
}
In Java (I'm assuming you're using Java, in the future it would be helpful to specify that) and every other language I know of, a map holds mappings between keys and values. Only one mapping is allowed per key. In your "map2", the keys are "itemNo" and "availQty". So what is happening is that your for loop sets the values for the first entry, and then is overwriting them with the data from the second entry, which is why that is the only one you see. Look at Java - Map and Map - Java 8 for more info.
I don't understand why you are trying to put the data into a map, you could just put it straight into JSON with something like this:
JSONArray partialArticlesInfo = new JSONArray();
for (Map.Entry<String,String> entry : partialStockArticlesQtyMap.entrySet()) {
JSONObject stockEntry = new JSONObject();
stockEntry.put("itemNo", entry.getKey());
stockEntry.put("availQty", entry.getValue());
partialArticlesInfo.put(stockEntry);
}
JSONObject root = new JSONObject();
root.put("partialArticlesInfo",partialArticlesInfo);
This will take "map1" (partialStockArticlesQtyMap in your code) and create a JSON object exactly like your example - no need to have map2 as an intermediate step. It loops over each entry in map1, creates a JSON object representing it and adds it to a JSON array, which is finally added to a root JSON object as "partialArticlesInfo".
The exact code may be slightly different depending on which JSON library you are using - check the docs for the specifics.
I agree with Brendan. Another solution would be otherwise to store in the Set or List objects like the following.
class Item {
Long itemNo;
int quantity;
public int hashCode() {
Long.hashCode(itemNo) + Integer.hashCode(quantity);
}
public int equals(Object other) {
other instanceOf Item && other.itemNo == this.itemNo && other.quantity = this.quantity;
}
}
}
then you can use the JsonArray method described by him to get the Json string in output
This means that adding new variables to the object won't require any more effort to generate the Json
I have data in a database, and my code is accessing it using LINQ to Entities.
I am writing some software where I need to be able to create a dynamic script. Clients may write the scripts, but it is more likely that they will just modify them. The script will specify stuff like this,
Dataset data = GetDataset("table_name", "field = '1'");
if (data.Read())
{
string field = data["field"];
while (cway.Read())
{
// do some other stuff
}
}
So that script above is going to read data from the database table called 'table_name' in the database into a list of some kind based on the filter I have specified 'field='1''. It is going to be reading particular fields and performing normal comparisons and calculations.
The most important thing is that this has to be dynamic. I can specify any table in our database, any filter and I then must be able to access any field.
I am using a script engine that means the script I am writing has to be written in C#. Datasets are outdated and I would rather keep away from them.
Just to re-iterate I am not really wanting to keep with the above format, and I can define any method I want to behind the scenes for my C# script to call. The above could end up like this for instance,
var data = GetData("table_name", "field = '1'");
while (data.ReadNext())
{
var value = data.DynamicField;
}
Can I use reflection for instance, but perhaps that would be too slow? Any ideas?
If you want to read dynamically a DataReader context, it's a pretty easy step:
ArrayList al = new ArrayList();
SqlDataReader dataReader = myCommand.ExecuteReader();
if (dataReader.HasRows)
{
while (dataReader.Read())
{
string[] fields = new string[datareader.FieldCount];
for (int i =0; i < datareader.FieldCount; ++i)
{
fields[i] = dataReader[i].ToString() ;
}
al.Add(fields);
}
}
This will return an array list composed by a dynamic object based on the number of field the reader has.