What exactly are your plans with this local variable from another method?

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hey guys, going to update on the position corrector, I set up a spreadsheet in excel based on a math spreadsheet, it involves cosine, arc of tangent and other mathematical things. Finally I got the result and converted the excel calculations into code

Guys, help please

How can i access a variable from a method inside another method?

Im working with Jpanels

A variable declared inside a method is knowing to be a local one. If your code needs its value, call that method and return the variables value.

And i want to refresh a label of onde panel by the button on another paner that comes before in script

Of one panel*

that seems to be something specific regarding JPanels. What exactly are your plans with this local variable from another method?
Can you fill us in about the exact situation you are facing and ideally also a copy of the relevant part of your code?

#Ask

I try to learn build the project from tutorial: https://itsourcecode.com/free-projects/java-projects/vehicle-management-system-project-in-java-with-source-code/

When I run, get error: import com.sun.glass.events.KeyEvent;

Try to solve with this solution (import java.awt.event.KeyEvent;) form:
https://stackoverflow.com/questions/43218019/com-sun-glass-does-not-exist

code: https://itsourcecode.com/wp-content/uploads/2021/07/Vehicle-Management-System-Project-In-Java-Source-Code.zip

Try to run: working. This is the best solution?

I hardly recommend to use

import java.awt.event.KeyEvent;

Exactly like it is recommended on stackoverflow: https://stackoverflow.com/a/43218233

If it not work. Then the code needs professional refactoring.

Who ever implemented it by using com.sun.glass.event.KeyEvent did a unprofessional mistake.

Hi, everyone.
I wonder if somebody could enlighten me on how can I prevent a parameter of a Class to accept negative values.

The idea I came up with was as follows in 2nd and 3rd attributes:

public Estoque(String nome, int qtdAtual, int qtdMinima) { //constructor
this.nome = nome;
this.qtdAtual = qtdAtual < 0 ? 0 : qtdAtual;
this.qtdMinima = qtdMinima < 0 ? 0 : qtdMinima;
}

I wonder if that’s the most efficient solution. In case not, I’d be really appreciated to know.

Hi Victor,
in this case it is better, to throw an exception. The user of the class will have no feedback, that his value was set to 0 and might assume, that it still is his negative value.
Therefore, you could use the guava library (https://guava.dev/releases/19.0/api/docs/com/google/common/base/Preconditions.html), which already has many cases covered, like Preconditions.checkNotNull(…)

I’d suggest the same thing, throwing an exception gives you more feedback and you can act directly on the undesired condition.

Here the most recent api doc of Preconditions: https://guava.dev/releases/31.1-jre/api/docs/com/google/common/base/Preconditions.html

in Jaschars link there is a good example code:

public static double sqrt(double value) {
checkArgument(value >= 0, “input is negative: %s”, value);
// calculate square root
}

I appreciate all the help and will work on it

‼️
I just downloaded the source code because I was suspicious about the quality after having a glance over the article. I am shocked how unprofessional the source code is…. Please don’t take it as an example of what good quality source code looks like.

There are multiple aspects which are designed badly. I would rather consider this source code as a good starting point, for practicing refactoring.

link to source code: https://itsourcecode.com/wp-content/uploads/2021/07/Vehicle-Management-System-Project-In-Java-Source-Code.zip

I’d rather not look at it.

thanks for your recommendation 👍