I dont understand why im getting an error, can somebody please help. I just started to code in dart, but i cannot find a logical reason why this shouldnt work.
void main() {
User userx = User('luigi', 21);
print(userx.age);
userx.login();
User usery = User('mario', 33);
print(usery.username);
usery.login();
}
class User {
String username;
int age;
User(String username, int age){
this.username = username;
this.age = age;
}
void login() {
print('user logged in');
}
}
The correct syntax is:
void main() {
User userx = User('luigi', 21);
print(userx.age);
userx.login();
User usery = User('mario', 33);
print(usery.username);
usery.login();
}
class User {
String username;
int age;
User(this.username, this.age);
void login() {
print('user logged in');
}
}
Your compiler should have underlined the problematic parts with a helpful error message. Best thing would be read the message and try to do what it suggests.
Maybe you should start at the beginning e.g. by looking at some documentation: https://dart.dev/guides/language/language-tour#using-constructors
Related
Is there a way in Vala to have multiple signal handlers perform the same code, while they have access to the local scope?
Defining a lambda using a delegate works, but requires a delegate definition and gives the warning "copying delegates is not supported":
delegate void ChangeHandler ();
void test () {
var answer = 42;
ChangeHandler handler = () => {
debug("size or position changed. answer: %i", answer);
};
size_changed.connect (handler);
position_changed.connect (handler);
}
As far as I know there is also no way to pass information to handlers? something like:
void test () {
var answer = 42;
size_changed.connect (handler, answer);
position_changed.connect (handler, answer);
}
void handler (answer) {
debug("size or position changed. answer: %i", answer);
}
I could do this, but this requires a lot of extra code, especially when there are many arguments.
void test () {
var answer = 42;
size_changed.connect (handler, answer);
position_changed.connect (() => handler(answer));
}
void handler (answer) {
debug("size or position changed. answer: %i", answer);
}
Is there a way to connect multiple signals to one anonymous function? Something like:
void test () {
var answer = 42;
multi_connect(size_changed, position_changed, () => {
debug("size or position changed. answer: %i", answer);
});
}
How about using this to pass data:
public class Test : GLib.Object {
public signal void sig_1 ();
public signal void sig_2 ();
private int answer = 42;
private void sig_handler (Test t) {
stdout.printf("sig_1 or sig_2 triggered. answer: %d\n", answer);
}
public static int main(string[] args) {
Test t1 = new Test();
t1.sig_1.connect(t1.sig_handler);
t1.sig_2.connect(t1.sig_handler);
t1.sig_1();
t1.sig_2();
return 0;
}
}
Maybe it is more readable with two classes:
public class SignalRaiser : GLib.Object {
public signal void sig_1 ();
public signal void sig_2 ();
}
public class SignalReceiver : GLib.Object {
private int answer = 42;
public void sig_handler (SignalRaiser sender) {
stdout.printf("sig_1 or sig_2 triggered. answer: %d\n", answer);
}
}
int main(string[] args) {
var raiser = new SignalRaiser();
var receiver = new SignalReceiver();
raiser.sig_1.connect(receiver.sig_handler);
raiser.sig_2.connect(receiver.sig_handler);
raiser.sig_1();
raiser.sig_2();
return 0;
}
Ok so I think I'm being a noob because it's a new semester but the method "palindromeTest" always return's false even though the string is equal and the number is a palindrome. (A palindrome example is: (565) 677-6565) (also don't give me the answer outright I want to solve it on my own)
public class IjazZ_PhoneStringPalindrome
{
public static void main(String[] args) throws IOException
{
String phoneNumber;
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.print("Enter a phone number in this format (###) ###-####: ");
phoneNumber = br.readLine();
phoneNumber = justNumbers(phoneNumber);
if (palindromeTest(phoneNumber))
{
System.out.println("This phone number is a palindrome!");
}
else
{
System.out.println("This phone number is not a palindrome!");
}
}
public static String justNumbers(String phoneNumber)
{
StringTokenizer st = new StringTokenizer(phoneNumber, " ()-");
StringBuffer number = new StringBuffer();
while(st.hasMoreTokens())
{
number.append(st.nextToken());
}
phoneNumber = number.toString();
return phoneNumber;
}
public static boolean palindromeTest(String pNumber)
{
StringBuffer reversedNumber = new StringBuffer(pNumber);
reversedNumber.reverse().toString();
if(pNumber.equals(reversedNumber))
{
return true;
}
else
{
return false;
}
}
}
You don't assign the value returned by reversedNumber.reverse().toString()to reversedNumber.
Do
String reversedNumberString = reversedNumber.reverse().toString();
And by the way, you can just return
return pNumber.equals(reversedNumber); - the if/else statement is unnecessary.
I am following following blog to click to call.
https://www.twilio.com/docs/tutorials/click-to-call-java-spring
I am able to place call and record too. But how can we store recording for each channel ?
Can someone please help.?
callCreator.setRecordingChannels("5"); or
callCreator.setRecordingChannels("dual");
does not help
Here is the complete class
public class TwilioLine {
private String twilioNumber;
private TwilioRestClient restClient;
public TwilioLine(TwilioRestClient restClient, String twilioNumber) {
this.restClient = restClient;
this.twilioNumber = twilioNumber;
}
public void call(final String phoneNumber, final String responseUrl) {
try {
CallCreator callCreator = new CallCreator(new PhoneNumber(phoneNumber), new PhoneNumber(twilioNumber), new URI(responseUrl));
callCreator.setRecord(true);
callCreator.setSendDigits("8245719056");
callCreator.setRecordingChannels("5");
callCreator.create(restClient);
} catch (URISyntaxException e) {
throw new CallException(e);
}
}
}
I am building an admin module for an intranet MVC application. This application implements Windows Authentication (users are automatically logged in).
Currently I base all the user experience based around their HttpContext.User.Identity data.
What I need to do is to be able to impersonate an user so I can replicate their experience if they are having problems.
With Forms Authentication this is very straight forward...
I tried replacing the IPrincipal.User object in the HttpContext but this only has a getter not a setter.
any pointers would be greatly appreciated.
Thanks.
using (new Impersonation()){
// now working in context of whatever user you want
}
and this is the class
[PermissionSet(SecurityAction.Demand, Name = "FullTrust")]
public class Impersonation : IDisposable
{
private readonly SafeTokenHandle _handle;
private readonly WindowsImpersonationContext _context;
//const int Logon32LogonNewCredentials = 9;
private const int Logon32LogonInteractive = 2;
public Impersonation()
{
var domain = "your domain;
var username = "the user";
var password = "their password";
var ok = LogonUser(username, domain, password, Logon32LogonInteractive, 0, out _handle);
if (!ok)
{
var errorCode = Marshal.GetLastWin32Error();
throw new ApplicationException(string.Format("Could not impersonate the elevated user. LogonUser returned error code {0}.", errorCode));
}
_context = WindowsIdentity.Impersonate(_handle.DangerousGetHandle());
}
public void Dispose()
{
_context.Dispose();
_handle.Dispose();
}
[DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
private static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, out SafeTokenHandle phToken);
public sealed class SafeTokenHandle : SafeHandleZeroOrMinusOneIsInvalid
{
private SafeTokenHandle()
: base(true) { }
[DllImport("kernel32.dll")]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[SuppressUnmanagedCodeSecurity]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool CloseHandle(IntPtr handle);
protected override bool ReleaseHandle()
{
return CloseHandle(handle);
}
}
}
i'm creating one application in which i get gift images with id's from web server through JSON. When i click on any gift image, it goes on next page where it shows all information of that image (get image information with its id from web server through JSON).
Problem is: When i click on any gift image on page to see its relevant information, it gets the last gift image id every time, i want when i click on any image, it gets the specific image id which i click. How it is possible??
Screenshot of the page is : http://ugo.offroadstudios.com/gifts.png
Here is sample code:
public class Gifts extends MainScreen {
String giftsid;
BitmapField giftimg;
public Gifts(){
setTitle("Gift Store");
creategifts();
}
public void creategifts()
{
//Link URL
String strURL = "http://ugo.offroadstudios.com/api/frndgift/?loginusername=adil;deviceside=true";
webConnection wb = new webConnection();
String res = wb.getJson(strURL);
try {
JSONObject object = new JSONObject(res);
if(object.getString("status") == "error")
{
Dialog.alert("Invalid "+object.getString("status"));
}
else
{
int totalgifts;
totalgifts = object.getInt("totalgifts");
Bitmap listThumb;
JSONArray imagearr;
JSONArray giftsidarr;
String imgname;
Bitmap bmpResized;
for(int i=0; i < totalgifts; i++){
imagearr = object.getJSONArray("gifts_image");
imgname = imagearr.getString(i);
giftsidarr = object.getJSONArray("gifts_id");
giftsid = giftsidarr.getString(i);
listThumb = getImage.getImageFromUrl("http://ugo.offroadstudios.com/wp-content/plugins/bp-gifts-rebirth/includes/images/"+imgname+";deviceside=true");
bmpResized = GPATools.ResizeTransparentBitmap(listThumb, 80, 80,
Bitmap.FILTER_LANCZOS, Bitmap.SCALE_TO_FIT);
giftimg =new BitmapField(bmpResized,FOCUSABLE)
{
protected boolean navigationClick(int status, int time)
{
Dialog.alert("giftsid "+giftsid);
UiApplication.getUiApplication().pushScreen(new SendGift(giftsid));
return true;
}
};
add(giftimg);
}
}
}
catch (JSONException e) {
System.out.println("EX is "+e);
e.printStackTrace();
}
}
}
You are always getting the gift id of the last gift in the list because you have created your buttons with this code:
giftimg =new BitmapField(bmpResized,FOCUSABLE)
{
protected boolean navigationClick(int status, int time)
{
Dialog.alert("giftsid "+giftsid);
UiApplication.getUiApplication().pushScreen(new SendGift(giftsid));
return true;
}
};
Your navigationClick() method used the giftsid variable, which is a persistent member variable of your class. You assign this variable in your for loop, so the final value it keeps is the last value assigned in the loop (giftsidarr.getString(totalgifts)).
Although you declare the navigationClick() method in a loop where the giftsid is many different values, the navigationClick() method uses the value of giftsid when it is run. The last value.
There's many ways to fix it. You can use a separate constant value in your loop:
final String nextGiftsId = giftsid;
giftimg =new BitmapField(bmpResized,FOCUSABLE)
{
protected boolean navigationClick(int status, int time)
{
Dialog.alert("nextGiftsId= "+nextGiftsId);
UiApplication.getUiApplication().pushScreen(new SendGift(nextGiftsId));
return true;
}
};
Or, as Signare suggested, attach a cookie to each button that identifies its corresponding gift:
giftimg =new BitmapField(bmpResized,FOCUSABLE)
{
protected boolean navigationClick(int status, int time)
{
String giftId = (String)getCookie(); // read gift id from the cookie
Dialog.alert("giftId= "+giftId);
UiApplication.getUiApplication().pushScreen(new SendGift(giftId));
return true;
}
};
giftimg.setCookie(giftsid); // set the cookie after creating the field
Inside your for loop, add the following code -
giftimg[i].setChangeListener(this);
Then -
public void fieldChanged(Field field, int context) {
for(int i=0;i<totalgifts;i++) {
if(field == giftimg[i]) {
// you can trigger your event
}
}
EDIT :-
giftimg[i].setChangeListener(listener);
listener = new FieldChangeListener() {
public void fieldChanged(Field field, int context) {
if ( field instanceof BitmapField ) {
for(int i=0;i<totalgifts;i++) {
if ( field == giftimg[i] ) {
// you can trigger your event
}
}
}
}
};