java

[Solved] Why “non-static variable cannot be referenced from a static context” produced for one program but not another? [duplicate]

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Introduction When programming in Java, it is important to understand the concept of static and non-static variables. This is because the compiler will throw an error if a non-static variable is referenced from a static context. This error can be confusing, as it may appear in one program but not another. In this article, we … Read more

[Solved] Why can’t i call a method within a protected method of the same class [duplicate]

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Introduction When writing code in an object-oriented language, it is important to understand the concept of access modifiers. Access modifiers are used to control the visibility of class members, such as methods, variables, and constructors. One of the access modifiers is the protected modifier, which allows a class to access its own members, but not … Read more

[Solved] Why can’t i call a method within a protected method of the same class [duplicate]

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You are creating local variables of button1, button2 etc inside the onCreate method. This way, the generateQuestion method is unaware of these variables and uses the class variables with the same name (not included in your code, but I imagine you have somewhere declared them probably on top of your activity class) which are not … Read more

[Solved] Get integer value from edittext And Access value on Button

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Declare the ed_text and mViewPager in your onCreate like this final EditText ed_text =(EditText)findViewById(R.id.editText1); final ExtendedViewPager mViewPager = (ExtendedViewPager) findViewById(R.id.view_pager); and now you can access the ed_text value in the bt_Goto click listener like this bt_Goto.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(ed_text.getText().toString().length() > 0){ mViewPager.setCurrentItem(Integer.parseInt( ed_text.getText().toString())); } } }); 1 solved Get … Read more

[Solved] Is there a way to generate ints using i?

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I recommend just making a list of doubles. I don’t know if what you want to do is possible in Java. Like so: List<Double> dubs = new ArrayList<>(); while (in.hasNextLine) { dubs.add((double) in.next()); } 1 solved Is there a way to generate ints using i?

[Solved] Adding an element into a HashSet inside a HashMap Java [closed]

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As @AndyTurner said in a comment: fields[1] is a String, not a HashSet<String>. You can build the latter using new HashSet<>(Arrays.asList(fields[1])). But there are other issues with this snippet too. It would be better to rewrite like this, pay close attention to every little detail that I changed: private Map<String, Set<String>> userBusiness = new HashMap<>(); … Read more

[Solved] in java, why abstract class Number can be instantiated? [duplicate]

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You’re not instantiating a Number. You’re instantiating a Number[]. These are two completely different objects. You can generally expect to be able to instantiate an array of any type, even types that you can’t directly instantiate yourself. You can populate these arrays through type inheritance and the is-a relationship. For example, with the above, you … Read more

[Solved] Print string in maxlines 3 and width parametar, I’m not understand all, can someone help me

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package com.TnationChallange; import java.util.ArrayList; import java.util.List; public class Main { public static void main(String[] args) { for (String part : getParts(“limited screen space to display information”, 7, 3)) { System.out.println(part); } } private static List<String> getParts(String string, int partitionSize, int maxLine) { List<String> parts = new ArrayList<String>(); int len = string.length(); for (int i = … Read more