java - Use a variable returned in a getter method in another class

Question

I am still learning but seem to fall at what should be very simple hurdles; my strong points seem to be with the logic of equations but I possess little skill at remembering and implementing functions and correct simple syntax's.

The class that I am implementing the method in is MyClass, the method that I want to define the variable taken from the other class is establishIrEvent. The class that I want to collect the variable from is IREvent, the getter method that returns the variable in this class that I want to collect is getX.

Now for the code:

Getter method from IREvent class:

public int getX() {
    return x;
}

Method that I want to use that variable in to assign, (with my terribly poor attempt) in MyClass:

public void establishIrEvent(IREvent arg0) {

    int source = (IREvent)arg0.getX();

}

Any advice will be hugely appreciated and fingers crossed this question may aid someone else in a similar pickle! Please ask for any more info as I always seem to miss something or ask a question that annoys an experienced developer somewhat.

Answer 1

您的代码有几个问题。首先，您尝试将 an 分配int给 aString因为getX返回int并且source变量是 a String。如果您想这样做，请尝试：

String source = Integer.toString(arg0.getX());

其次，也不是什么大问题，没有必要强制arg0转换为，IREvent因为它已经在establishIrEvent方法中定义了。

Answer 2

getX()返回一个 int 以便您可以执行以下操作

public void establishIrEvent(IREvent arg0) {

   int x = arg0.getX(); // local variable x which is the x from the IREvent class
   String source = Integer.toString(x); // if that's what the source string should be given x

}

该代码应该可以编译并运行，但它仍然没用，因为调用不会改变任何内容establishIrEvent(IREvent arg0)，因为变量 x 和 source 在调用后都被丢弃了。因此，您可能希望将x和/或source变量作为方法所在类的成员变量establishIrEvent(IREvent arg0)。

Answer 3

下面的语句有问题：

String source = (IREvent)arg0.getX();

问题：IREvent 的 getX() 方法正在返回 int，而您正试图通过将返回类型转换为 IREvent 来将其分配给 String。最终让每个人都感到困惑，包括 JVM 和你自己。

如果是这种情况，我不确定您是否需要将值作为 String ，那么您需要这样做：

String source = String.valueOf(arg0.getX());

Answer 4

你已经完成了大部分工作。事情是arg0.getX()返回一个int. 这int不是您分配给它的字符串，因此您必须将其转换为int类型。您尝试将其转换（类型转换）IREvent为错误的类型。尝试这样的事情：

public void establishIrEvent(IREvent arg0) {
     String source = String.valueOf(arg0.getX());
} 

我建议您使用 Eclipse IDE，所有这些东西都会更容易处理。Eclipse IDE 将为您提供即时的编译器错误和警告消息并提出好的建议。