This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Closed 5 years ago.
Can one controller class have two or more initialize () ?
Can multiple statements be in a single initialize() ?
#question 2...This is my controller class:
#Overide
public void initialize(URL url,ResourceBundle rb)
{
//adding itemList variable to itemBox
try{
itemBox.setValue("Gari");
itemBox.setItems(itemList);
}
catch(Exception e){
System.out.println(e);
}
//Animation for changing scene
String filename = url.getFile().substring(URL.getFile().lastIndexOf('/')+1, URL.getFile().length());
if(filename.equals("FXML.fxml")){
//calling fadeTransition method
fadeTrans(anchorPane);
}
else if(filename.equals("SignUp_In.fxml")){
fadeTrans (anchorPaneSignUp_In);
}
}
and it returns this error message:
java.lang.NullPointerException
Here, the multiple statements are adding itemList to itemBox and changing scene with animation
no
yes
Just some more characters to get over the minimum.
Related
This question already has answers here:
JavaFX periodic background task
(6 answers)
Closed 5 years ago.
I want to achieve something like this: user press the login button and then label shows:
"Connecting."
0.5 sec time interval
"Connecting.."
0.5 sec time interval
"Connecting..."
etc
Just a visual effect that indicates something is actually going on "under the hood".
All I managed to get wasn't quite what I was expecting. I click the button, wait 1.5 sec and then I got "Connecting...", missing 2 previous steps.
First, my Status class
public class Status {
private static StringProperty status = new SimpleStringProperty();
public static void setStatus(String newStatus) {
status.setValue(newStatus);
}
public static String getStatus() {
return status.getValue();
}
public static StringProperty get() {
return status;
}
}
and my LoginView class
public class LoginView extends Application {
private Button loginButton = new Button("Log in");
private Label statusLabel;
private void createLabels() {
statusLabel = new Label(Status.getStatus());
statusLabel.textProperty().bind(Status.get());
}
}
private void createButtons() {
loginButton.setOnAction(e -> {
try {
Status.setStatus("Connecting.");
Thread.sleep(500);
Status.setStatus("Connecting..");
Thread.sleep(500);
Status.setStatus("Connecting...");
Thread.sleep(500);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
});
}
Run a Task from a different thread. Task allows you to update it's message property on the JavaFX application thread that should be used to update the GUI and must not be blocked by long-running tasks, since it's responsible for rendering:
Task<Void> task = new Task<Void>() {
#Override
protected Void call() throws InterruptedException {
updateMessage("Connecting.");
Thread.sleep(500);
updateMessage("Connecting..");
Thread.sleep(500);
updateMessage("Connecting...");
Thread.sleep(500);
return null;
}
};
// bind status to task's message
Status.get().bind(task.messageProperty());
// run task on different thread
new Thread(task).start();
You should do animations with the Timeline API. Have a look here:
https://docs.oracle.com/javase/8/javafx/api/javafx/animation/Timeline.html
Basically you just define KeyFrames at 0.5 seconds distance and set the value of the text to add a another dot. You can also make it repeat indefinitely until the connection is established to get cyclic animation.
Another way is to make a SequentialTransition which will have two PauseTransitions of 0.5 seconds.
BTW in your code you pause the main UI thread and that is why you can’t see the animation.
This question already has an answer here:
How can I catch all crash exception in monotouch/ios?
(1 answer)
Closed 5 years ago.
I am trying to display an alert when an exception occurs and bubbles up to the iOS project.Main
Now let's suppose I have an "Object variable not set exception" somewhere in the program
it bubbles to the MyApp.IOS project but no UI alert pops up!!
public class Application
{
static void Main(string[] args)
{
try
{
UIApplication.Main(args, null, "AppDelegate");
}
catch (Exception ex)
{
Task.Run(() =>
{
Device.BeginInvokeOnMainThread(() => {
ShowAlert("MyTitle", ex.ToString(), UIApplication.SharedApplication.KeyWindow.RootViewController);
});
});
}
}
public static UIAlertController ShowAlert(string title, string description, UIViewController controller)
{
UIAlertController alert = UIAlertController.Create(title, description, UIAlertControllerStyle.Alert);
alert.AddAction(UIAlertAction.Create("OK", UIAlertActionStyle.Default, (action) => { }));
controller.PresentViewController(alert, true, null);
return alert;
}
}
any ideas what I am missing?
Is not possible catch the error and show the alert. Check the information about the native crash. And check the log files.
How can I catch all crash exception in monotouch/ios?
This question already has an answer here:
How to upload file using JSF 2.2 <h:inputFile>? Where is the saved File?
(1 answer)
Closed 5 years ago.
I am trying to get my JSF site to upload a picture to the server, but am having a time of it. I've found 4 methodologies to do, but I'd like to use h:InputFile as it seems the most direct.
It would seem I just need to supply the upload path correctly.
After adding #MultipartConfig I no longer get an exception, but I can't verify the file is uploaded or see any error.
public void AddPicture()
{
ConnInfo HitIt = new ConnInfo();
try
{
HitIt.save(fileCelebrityToAdd);
}
catch(Exception ex)
{
//?
}
}
#MultipartConfig(location="C:\\local\\pathway\\Netbeans\\project\\web\\Pictures\\items\\")
public class ConnInfo
{
private String uploadLocation;
public ConnInfo()
{
//uploadLocation = ".\\Pictures\\items\\";
uploadLocation = "C:\\local\\pathway\\Netbeans\\project\\web\\Pictures\\items\\";
}
public boolean TryOut(Part file) throws IOException
{
String monkey = uploadLocation+getFilename(file);
try
{
file.write(monkey);
}
catch(Exception ex)
{
return false;
}
return true;
}
}
Hopefully I've copied the necessary information correctly.
After going back and rereading all the articles I had bookmarked, it was actually the from the one Tam had suggested that I was able to strip out some information.
I didn't need the AJAX, or the #MultipartConfig, and my previous attempt was somehow incorrect, but the follow method allowed me to successfully upload a picture where I wanted it:
public boolean SaveHer(Part file)
{
String monkey = getFilename(file);
try (InputStream input = file.getInputStream())
{
Files.copy(input, new File(uploadLocation, monkey).toPath());
}
catch (IOException e)
{
// Show faces message?
return false;
}
return true;
}
This question already has answers here:
Display dynamic image from database or remote source with p:graphicImage and StreamedContent
(4 answers)
Closed 6 years ago.
I'm using primefaces to upload an image, crop it and then display the final image on a graphicImage.
The process works fine, but the problem is that when I retrieve the final image to display on the graphicImage, the stream is not closed and the file is being held up by java.exe, so I'm having problems on deleting the files/directory for example when the user logs out, because it's just a temp directory.
This is the getter of my StreamedContent:
public StreamedContent getGraphicCropped() {
try{
if (newImageName != null) {
File file2 = new File(pathCroppedImage);
InputStream input = new FileInputStream(file2);
graphicCropped = new DefaultStreamedContent(input);
showImageFinal = true;
}
} catch(Exception e){
e.printStackTrace();
}
return graphicCropped;
}
If I do input.close();then I'm able to delete the file, but it is not displayed, because I know that this getter is called more than once on the life cycle.
I've solved it by using the suggested getter of a StreamedContent:
public StreamedContent getGraphicCropped() throws FileNotFoundException {
FacesContext context = FacesContext.getCurrentInstance();
if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
// So, we're rendering the HTML. Return a stub StreamedContent so that it will generate right URL.
return new DefaultStreamedContent();
}
else {
// So, browser is requesting the image. Return a real StreamedContent with the image bytes.
File file2 = new File(pathCroppedImage);
InputStream input = new FileInputStream(file2);
showImageFinal = true;
return new DefaultStreamedContent(input);
}
}
I have a MainForm class (as you'd expect, it is a form) that has a text box on it. I also have another class called 'Application_Server' That does a load of other stuff (not just form-background related, quite a lot of network based stuff etc.).
The Application_Server class runs in it's own thread, but needs to be able to update the controls on the form, for this question, we will stick with just the textbox.
The problem is that even though I am executing the command to set the text of the textBox control via 'Invoke' I am still getting the following exception during runtime:
Additional information: Cross-thread operation not valid: Control
'DebugTextBox' accessed from a thread other than the thread it was
created on.
What could be causing this? I am definitely invoking a delegate within MainForm.
Here are the relevant code segments (cut down for readability):
MainForm.h:
public ref class MainForm : public System::Windows::Forms::Form {
delegate void del_updateDebugText(String^ msg);
del_updateDebugText^ updateDebugText = gcnew del_updateDebugText(this, &MainForm::postDebugMessage);
private: void postDebugMessage(String^ message);
};
MainForm.cpp:
void EagleEye_Server::MainForm::postDebugMessage(String^ message)
{
Monitor::Enter(DebugTextBox);
if (this->DebugTextBox->InvokeRequired)
{
this->Invoke(updateDebugText, gcnew array<Object^> { message });
}
else
{
this->DebugTextBox->AppendText(message);
}
Monitor::Exit(DebugTextBox);
}
And finally, the code calling it:
void ServerAppManager::postDebugMessage(System::String^ message)
{
mainFormHandle->updateDebugText(message);
}
void ServerAppManager::applicationStep()
{
postDebugMessage("Starting\n");
// This is Run in seperate thread in MainForm.cpp
while (s_appState == ApplicationState::RUN)
{
postDebugMessage("Testing\n");
}
}
Thanks!
From background worker called bwSearch we do the call as following from the DoWork event handler:
private: System::Void bwSearch_DoWork(System::Object^ sender, System::ComponentModel::DoWorkEventArgs^ e) {
//... logic
UpdateTxtOutput("Some message");
//... more logic
}
I have a RitchTextBox called txtOutput, also the windows form control containing this code is called frmMain, the UpdateTxtOutput is defined in three parts as follows:
delegate void UpdateTxtOutputDelegate(String^ text);
void UpdateTxtOutput(String^ text)
{
UpdateTxtOutputDelegate^ action = gcnew UpdateTxtOutputDelegate(this, &frmMain::Worker);
this->BeginInvoke(action, text);
}
void Worker(String^ text)
{
txtOutput->AppendText("\t" + text + "\n");
}
I managed to get it working by simplifying the method within the 'MainForm' class to:
void EagleEye_Server::MainForm::postDebugMessage(String^ message)
{
Monitor::Enter(DebugTextBox);
DebugTextBox->AppendText(message);
Monitor::Exit(DebugTextBox);
}
And then moving the 'Invoke' call to the method calling the delegate, not pretty but it works for now. I think the issue may have been caused by the form getting stuck inside an Invoke loop. I say this as I noticed that the form would lock up and stop responding after it hit the recursive Invoke statement.