Questions tagged as 'java'

Tagged questions
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Create an instance of another ArrayList

I have an ArrayList in a class and I want to reference it in another class, I've read that I can copy an ArrayList like this: ArrayList<Persona> profesor= new ArrayList<>(persona); However, every time I run it gives me a...
asked by 12.06.2016 / 16:15
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Is it possible to receive Firebase notifications on Android with the app closed?

The code I already have running but only receives the notification if the app is open or in the background, not if it is closed. I'm looking for a lot but I can not find the solution. I do not know if it will depend on something from the Mani...
asked by 09.06.2016 / 00:19
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Help, activity closes when launched

I'm new and I'm starting with Android in Android Studio .. I have a simple application that has two activities, the 1st asks for and sends a name and the second shows it, but when the second one is launched it does not show the name, the applica...
asked by 06.06.2016 / 04:48
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Compare hours in Java

I am learning Java and I try to make a program that controls the hours of a working day. The idea is: I ask the user for a start time (HH: mm) (of his work for example) and an end time (HH: mm). I keep that in order to be able to work with it la...
asked by 11.06.2016 / 20:13
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How to implement infinite scrolling in recyclerview

I have a recycler and inside that recycler cardviews are shown with info brought from a REST API and I would like to implement this feature in my application but I do not know how to do it, I have seen several examples online but I can not grasp...
asked by 22.03.2017 / 19:49
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Jasperreports chart: Error evaluating expression for source text: $ F {answers}

I'm using Jaspersoft Studio 6.2. to print graphics from a Class List and give me this error: Error evaluating expression for source text: $F{answers} This is the class that represents the data for a graph: public class GraphicP {// Gráfic...
asked by 25.03.2016 / 11:35
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keep the same position of a recyclerView when going back

I have a question as to how I can return to the same position as my recyclerView, since when I return from another activity it sends me to the beginning and I would like to keep the same position in which I left it. It should be noted that I am...
asked by 09.04.2016 / 16:23
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Handling date and time events in Java

I want to make a small application that launches a JFrame at a certain time of day but I do not know how to handle events that can perform those actions. I am currently using a thread to verify every so often if that is the time at which...
asked by 18.03.2016 / 00:43
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Read excel with Apache POI in java by column name

Good afternoon experts, I have a problem with a project that consists of reading an excel file and validating the data by columns, I have managed to read the file without problems and also validations (through regular expressions) through the li...
asked by 10.03.2016 / 00:39
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How to draw an Oval image in a JLabel using Graphics?

The detail of my problem is that I need to draw an oval image on a JLabel, I do not have much experience in Graphics until now this is what I have, I hope you can help me. class imagePanel extends JLabel { private BufferedImage buffImag...
asked by 14.08.2016 / 17:33