Java 以另一种方法访问数组
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/29551268/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Accessing an array in another method
提问by Michael Miller
I am trying to access an array in a separate method that it is initialized in.
我试图在一个单独的方法中访问一个数组，它是在其中初始化的。
public void initializeArray()
{
String sentences[] = new String[5];
for(int i=0; i<5; i++)
{
sentences[i] = i+1;
}
}
public void printArray()
{
for(int i=0; i<5; i++)
{
System.out.println(sentences[i]);
}
}
I know that I could do this in one for loop, but can someone explain how I could print the array this way? I need to access the sentences array in a separate method that it is initialized in. I tried to make an instance of the array at the top of the program but it gives me an error saying "Local variable hides a field".
我知道我可以在一个 for 循环中执行此操作，但是有人可以解释我如何以这种方式打印数组吗？我需要在一个单独的方法中访问句子数组，它被初始化。我试图在程序的顶部创建一个数组的实例，但它给了我一个错误，说“局部变量隐藏了一个字段”。
回答by MadConan
Change the signature of your printArraymethod to be
将您的printArray方法的签名更改为
public void printArray(String[] sentences){...}
So you have
所以你有了
public void initializeArray(){
int arraySize = 5;
String[] sentences = new String[arraySize];
for(int i=0; i<arraySize; i++){
sentences[i] = new String(i+1);
}
printArray(sentences);
}
回答by Gentatsu
Make sentences a global variable or parameters to both functions.
使句子成为两个函数的全局变量或参数。
回答by Gentatsu
I tried to make an instance of the array at the top of the program but it gives me an error saying "Local variable hides a field".
我试图在程序顶部创建一个数组实例，但它给了我一个错误，说“局部变量隐藏了一个字段”。
You already have a instance variable, so remove the local variable within method:
您已经有一个实例变量，因此删除方法中的局部变量：
public void initializeArray()
{
//String Sentences[] = new String[5];
...
}
Also don't use magic numbers like you did in for-loop:
也不要像在 for 循环中那样使用幻数：
for(int i=0; i<5; i++)//use `sentences.length` instead of `5`
回答by dasblinkenlight
There are two ways to access the same array from two methods:
有两种方法可以从两种方法访问同一个数组：
- Access the array through an instance variable of array type, or
- Pass the array to methods as a parameter.
- 通过数组类型的实例变量访问数组，或
- 将数组作为参数传递给方法。
The first approach looks like this:
第一种方法如下所示：
class TestInstanceVar {
private String[] sentences = new String[5];
public static void main(String[] args) {
TestInstanceVar obj = new TestInstanceVar();
obj.initializeArray();
obj.printArray();
}
public void initializeArray() {
...
}
public void printArray() {
...
}
}
Here, the methods access sentencesas an instance variable, which is shared across all methods running on the same instance.
在这里，方法sentences作为实例变量访问，该变量在同一实例上运行的所有方法之间共享。
The second approach looks like this:
第二种方法如下所示：
class TestPassArray {
public static void main(String[] args) {
private String[] sentences = new String[5];
initializeArray(sentences);
printArray(sentences);
}
public static void initializeArray(String[] sentences) {
...
}
public static void printArray(String[] sentences) {
...
}
}
Here the array is created in the mainmethod, and is passed explicitly as a parameter to the initialization and printing methods. Note that the methods are marked static, and accessed without creating an object.
这里数组是在main方法中创建的，并作为参数显式传递给初始化和打印方法。请注意，这些方法被标记为static，并且无需创建对象即可访问。
回答by Scary Wombat
Have your initializeArrayreturn an Array as in
让你initializeArray返回一个数组
public String[] initializeArray () {
...
return sentences;
}
Change yourprintArrayto
改变你printArray的
public void printArray (String [] arr) {
...
System.out.println(arr[i]);
}
Imagine a main method like
想象一个主要的方法，比如
String myArr [] = initializeArray ();
printArray (myArr);
回答by DWright
The following should work:
以下应该工作：
class MyClass
{
private String sentences[] = new String[5];
public void initializeArray()
{
for(int i=0; i<5; i++)
{
sentences[i] = i+1;
}
}
public void printArray()
{
for(int i=0; i<5; i++)
{
System.out.println(sentences[i]);
}
}
}
回答by gran_profaci
The printArraymethod knows nothing of sentences right?
该printArray方法对句子一无所知，对吗？
Java is pass by value and requires you to literally give the value of a piece of data to a method in order for the method to crunch on it. Global values are basically values that are known to every object.
Java 是按值传递的，它要求您按字面意思将一段数据的值赋予一个方法，以便该方法对其进行处理。全局值基本上是每个对象都知道的值。
Thus, you need something that will tell both initializeArrayand printArraythat there is this piece of data sentences that should be worked on.
因此，您需要一些可以告诉两者的东西，initializeArray并且printArray应该处理这段数据语句。
// A Calling Function
public void initializeAndPrintStringArray
{
// Get the initialized Sentences Array
String[] sentences = initializeArray();
// Print this Initialized Array
printArray(sentences)
}
// For doing this, you need to change the definitions of your methods
public String[] initializeArray()
{
String[] sentences = new String[5]; // You have a spelling mistake here
for(int i=0; i<5; i++)
{
sentences[i] = i+1;
}
return sentences
}
public void printArray(String[] sentences)
{
// Don't assume the length will always be 5 or something you know beforehand.
for(int i=0; i<sentences.length; i++)
{
System.out.println(sentences[i]);
}
}
回答by Local Maximum
You are declaring the variable sentences[]inside the method initializeArray(). Because of this, it doesn't exist outside of this method. As soon as the method finishes, it disapears. Other methods can't use the variable.
您在initializeArray()方法中声明了变量句子 []。因此，它在此方法之外不存在。该方法一完成，它就会消失。其他方法不能使用该变量。
You should declare the variable outside the method, like this:
您应该在方法之外声明变量，如下所示：
public class Example {
static String sentences[] = new String[5];;
public static void main(String[] args) {
initializeArray();
printArray();
}
public static void initializeArray() {
for (int i = 0; i < 5; i++) {
sentences[i] = "" + (i + 1);
}
}
public static void printArray() {
for (int i = 0; i < 5; i++) {
System.out.println(sentences[i]);
}
}
}
That way, you can use it anywhere in this class. If you want to use it somewhere else, too, add the keyword public before it.
这样，你就可以在这个类的任何地方使用它。如果您也想在其他地方使用它，请在它之前添加关键字 public。
