I am using weka for my project. but get the error info"could not find class weka.core.FastVector" on the line below. I have already added weka.jar from the build path of the project by adding external jar file. How should I solve this problem? Thanks a lot for your time on reviewing my question.
import weka.core.Attribute;
import weka.core.FastVector;
import weka.core.Instance;
import weka.core.Instances;
FastVector atts;
private void setUpARFF(){
atts = new FastVector();}
I know that FastVector was marked as obsolete a while back, perhaps they've finally removed it. Are you using the dev version of weka (or what version are you using)? FastVector can be replaced with ArrayList (in dev version) so use that instead.
Related
I create a swift package in my work space.
I followed this guide just to test things out:
https://sarunw.com/posts/how-to-modularize-existing-ios-projects-using-swift-package/
All went well.
One of the things I added to the package is:
public extension Color {
static let customRed:Color = Color(uiColor: UIColor(named: "customRed", in: .module, compatibleWith: nil)!)
}
I deleted the customRed from the Assets.xcassets in my main app after I added the Assets to the actual package.
Everything works fine now and the package uses the customRed as defined in the package Assets.xcassets.
I have a lot files that use that Color.customRed in the app and I was thinking I had to go to each file and add the import statement for the package at the top. So:
import MyColorPackage
Question: I don't understand why the app works fine without doing that. Files can use the Color.customRed call without adding the import MyColorPackage at the top of the file that uses it. How can files use that customRed without having the import MyColorPackage in the file? App runs fine without importing the module in the files that use the customRed. Why?
The reason for this is due to a longstanding swift bug so you’re not doing anything wrong per se. It has various forms, some fixed over the years, some not but in your case what happens is that the first file in your main project that imports MyColorPackage will cause the whole rest of the project to “see” that Color extension. In my experience this happens only with public extensions nowadays and your package happens to do just that - declare a public extension to SwiftUI’s Color
If you add some public entity in that package, say …
import SwiftUI
public enum MyColorTheme {
public static let myThemeButtonsColor = Color.green
}
… then you won’t be able to use MyColorTheme in any file that doesn’t import MyColorPackage, as per what is intuitively normal.
I would suggest to still add the missing imports whenever you use symbols from that package as this issue might be fixed in a future version and your project will fail to build
Reference: https://github.com/apple/swift/issues/46493
I'm trying to add native swift code to my NativeScript app. According to these instructions in the documentation I can just add a swift source file to App_Resources/iOS/src/ and then use any publicly exposed classes directly in my TypeScript code.
Unfortunately this just doesn't work. I'll just get Cannot find name 'TestClass' and that's it.
Steps to reproduce:
Get a fresh NS project with ios tns create my-app-name --template tns-template-blank-ts
Update: I actually created the App with vue init nativescript-vue/vue-cli-template testapp. That seems to have caused the problems.
Add a TestClass.swift to App_Resources/iOS/src/
import Foundation
public class TestClass: NSObject {
#objc public func echo(param: String) -> String {
return param
}
}
Instantiate it in any TypeScript source file let instance = new TestClass()
Do tns debug ios
Compilation will fail with Cannot find name 'TestClass'
I have also tried generating TypeScript typings with TNS_TYPESCRIPT_DECLARATIONS_PATH="$(pwd)/typings" tns build ios or or just delcaring it as any with declare let KeyCommander: any; to eliminate the possibility that this is a TS related problem. The first approach doesn't generate any typings for my custom class so the TypeScript code will still not compile. The second approach let's the TS code compile but crashes on execution with JS ERROR ReferenceError: Can't find variable: TestClass.
I have also verified that the swift file is indeed getting compiled by inserting a syntax error which will crash the build process.
My NativeScript version is 6.4.0.
What am I missing?
Update: I just realized I actually created the App with vue init nativescript-vue/vue-cli-template testapp. I verified that as mentioned Tyler Blake's answer in an app created with the tns cli the described process actually works. In an app I just freshly created with vue init it doesn't, the objc!nsswiftsupport.d.ts is not being generated.
The question now is: What's causing the difference?
I followed your steps and I was able to get the typings to generate in objc!nsswiftsupport.d.ts. After you generate typings do you have that file with these contents?
declare class TestClass extends NSObject {
static alloc(): TestClass; // inherited from NSObject
static new(): TestClass; // inherited from NSObject
echoWithParam(param: string): string;
}
This shows that NS is able to pick up the Swift code.
All you need to do now is add tns-platform-declarations then in the references.d.ts file, add a line that points to the objc!nsswiftsupport.d.ts file. Then you'll get intellisense in your TS code.
Something like this:
/// <reference path="./typings/objc!nsswiftsupport.d.ts" />
Hope this helps!
I was able to solve the problem by inspecting the differences between the templates created with tns-cli and vue init. The difference is that the vue init template ships with an outdated version of the nativescript platform. You can just simply change
"tns-ios": {
"version": "6.0.1"
}
to version 6.4.0 (which the version the tns-cli template comes with) and then the process will work as described in the documentation.
** This question is edited and cleaned up some **
I have two projects and I want to use code from one in the other; I seem to be having trouble putting the code in the right directory structure to make the import statements work.
Both projects are created and managed exclusively from the Dart Editor on a Mac, if that makes any differences.
Project Directory Structures
Project 1: a command line app which contains the code I want to share in the following directory structure:
/dart/command_line_app
/lib
shared_library.dart
/bin
command_line_app.dart
Project 2: a web app which wants to import the code in shared_libary.dart
/dart/web_application
/packages
/web
web_application.dart
In the file shared_libary.dart, I declare it to be a library can create a simple class that provides output when instantiated:
library shared_library;
class ShareMe
{
ShareMe()
{
print("Hello, ShareMe");
}
}
This compiles, and works inside the command_line project: command_line_app.dart has the following:
import 'package:command_line_app/shared_library.dart';
void main() {
ShareMe shareMe = new ShareMe();
print("Hello, World!");
}
This imports the code runs, printing both "Hello Share Me," and Hello World.
THE PROBLEM
I want to instantiate the ShareMe class inside web_application.dart. I'd thought I could do that by putting in the same import statement I put in my command_line code:
import 'package:command_line_app/shared_library.dart';
But, when I put the same import into the web_appliation, it gets the error
Target of URI does not exist 'package:command_line_app/shared_library.dart'
Other Things I've Tried
I was certain I'd solved the problem when I cntrl-Clicked properties on Web_application and selected Project References.
It brings up a window allowing me to select command_line_app with a check box, but when I do, I get an error:
Could not set the project description for 'web_application' because the project description file (.project) is out of sync with the file system.
Whatever that means.
When I cntrl-click the underlined error and try Quick Fix it offers me "resolve dependencies" which sounds promising, but after a few seconds, it comes back and informs me that
Pub get failed, [1] Resolving dependencies... (15.3s)
Could not find package command_line_app at https://pub.dartlang.org.
Depended on by:
- web_application 0.0.0
I hope this is clear-er and gives a better insight into both what I'm trying to do and what I'm missing.
EDIT
you need to add
dependencies:
command_line_app:
path: ../command_line_app
to your dependencies in web_application/pubspec.yaml.
EDIT END
When you want to make code reusable in different packages, you should put that code into the lib directory of that package and import it using import 'package:mypackage/myfile.dart';.
Another problem you may face is, that browser applications can't import packages that have a dart:io dependency. If you want to reuse code between command line and browser applications you should move them into the lib directory of another package my_shared_code where you put only code that doesn't depend on dart:io (for example some entity classes) and import this code from both app packages (browser and command line).
I know you can use the library, import and even #import, but which is correct?
I have got two files, MainClass.dart and Library.Dart, and I want to add a reference to Library.dart in MainClass.dart. How can I do that?
Firstly let me just preface this by saying please do not use the hash symbol before import or library or anything else. This is an old syntax that is being deprecated. So we no longer want to use #import('...') The correct syntax is:
import 'some_file.dart';
That said, there are two different things we can do to access different dart source files within our current file. The first is to import the file. We use this such as in your case when you want to bring a different library into the current file (or more accurately current library).
Usually if your files are in the same directory, or a sub directory of the current one we would import them like this:
import 'lib/library.dart';
However If you are using the pub package layout you can also use some special short-cut references as well to import files (particularly from other packages you've imported). I highly suggest reading the documents on the pub site, as most applications and libraries are designed with this in mind. It also has suggestions on best naming conventions such as filenames in all lower case, and using underscore for spaces, and directory layouts.
The other important thing to know about bringing a dart file into another file, is that we can use the part and part of directives. This used to be called #source but was changed (with the removal of the hash sign) to reduce confusion. The part directive is used when we want to write a single library which spans multiple files. Say for instance you have an Awesome Library, which is starting to get a little large for a single file. We will create the main file of the library (not to be confused with the main method). This file will usually have the same name as the library itself.
// awesome_library.dart
library awesome_library;
import 'dart:math';
import '...';
// this injects all the content of secret_file.dart
// into this file right here almost as if it was
// here in the first place.
part 'src/secret_file.dart';
// The rest of our file here
// ...
The part directive basically takes everything from our src/secret_file.dart and inserts it into that part of the file. This allows us to split our huge Awesome Library into multiple smaller files that are easier to maintain. While not specifically required, it is helpful to use the part of directive in our secret_file.dart to help the editor know that it is "part of" the library.
// secret_file.dart
part of awesome_library;
// ... Rest of our secret_file code below.
Note that when using a part file like this, the part(s) (that is everything that is not the main file of the library) cannot import or use library declarations themselves. They import whatever is imported into the the main file, but they cannot add any additional imports.
For more information about library see this link.
Importing your own created libraries:
You will be importing the filename.dart and not the name of your library.
So if the name of your library is: myLib and it is saved in the file: someDartFile.dart you will have to
import 'someDartFile.dart';
If you have on Windows a library at: K:\SomeDir\someFile.dart you will need to write:
import '/K:/SomeDir/someFile.dart';
example:
import 'LibraryFile.dart'; //importing myLib
void main(){
//a class from myLib in the LibraryFile.dart file
var some = new SomeClassFromMyLibrary();
}
myLib in LibraryFile.dart:
library myLibrary;
import 'dart:math';
class SomeClassFromMyLibrary{
String _str = "this is some private String only to myLibrary";
String pubStr = "created instances of this class can access";
}
Here a full example.
//TestLib.dart
import 'LibFile.dart'; //SomeLibrary
void main() {
print("Hello, World!");
LibFile l = new LibFile();
print(l.publicString);//public
print(l.getPrivateString);//private
print(l.getMagicNumber); //42
}
//LibFile.dart
library SomeLibrary;
part 'LibFile2.dart';
class LibFile {
String _privateString = "private";
String publicString = "public";
String get getPrivateString => _privateString;
int get getMagicNumber => new LibFile2().number;
}
//LibFile2.dart
part of SomeLibrary;
class LibFile2 {
int number = 42;
}
Although i am answering very late, but the answer may help new developer.
Always use pubspec.yaml file in your dart package(application/library).
once you run pub get command it will add your local library in the dependencies list in .packages file.
Consider i have following project structure.
To refer to the content of greeting.dart in my main.dart file i should add the library as below
import 'package:my_project_name/greeting.dart'
Once imported we can use the content of greeting.dart file in our main.dart file.
Note: we have not used the actual path as you can see 'lib' directory is missing.
First make sure that's the name which you have mentioned in pubspec.yaml and the file you want to import are sharing the exact same name
example:
pubspec.yaml
name: flutter_wordpress_app
description: flutter wordpress app
...
....
// dirOne/dirTwo/greeting.dart
class FavArticleBloc {
// Your code goes here
}
import 'package:flutter_wordpress_app/dirOne/dirTwo/greeting.dart'
void main(){
var some = new FavArticleBloc();
}
But
in the main.dartyou don't need to specify
import 'package:flutter_wordpress_app
just do like below
import 'dirOne/dirTwo/greeting.dart
I'm having some trouble on a checked out project here at work.
I have a class called GridBuilder, which is located in a package called com.ent.proj.utils.grid
package com.ent.proj.utils.grid
import grails.orm.HibernateCriteriaBuilder
import org.hibernate.criterion.Criterion
import org.hibernate.Criteria
class GridBuilder {
}
The word grid in the package declaration is marked in red, and reads Cannot solve symbol grid
This is the directory structure:
grailsapp--
utils---
com---
ent---
proj---
utils---
grid---
GridBuilder.groovy
I'm using IntelliJ Idea 9 as an IDE. I see this file in the project view, but not in the Grails view.
Any thoughts?
Thanks in advance
update
Ran $grails run-app from command line, and the app. started OK. Maybe its an IntelliJIdea issue ?
did you declare grails-app/utils as a source folder in 'Project structure|Modules'?