java - 数组和方法的问题

Question

当我在方法中为数组赋值时，当我尝试在其他方法中使用它们时，它们变为 0。

我对 Java 编程也不是很熟悉。

这是我的代码:

    public int[] pVectorCoinOne = new int[2];
    public int[] pVectorCoinTwo = new int[2];
    public int[] pVectorCoinThree = new int[2];
    public int[] pVectorCoinFour = new int[2];
    public int[] pVectorCoinFive = new int[2];
    public int[] pVectorCoinSix = new int[2];


public void setPositionVectors(){

    int[] pVectorCoinOne = {lblCoinImage1.getX(), lblCoinImage1.getY()};
    int[] pVectorCoinTwo = {lblCoinImage2.getX(), lblCoinImage2.getY()};
    int[] pVectorCoinThree = {lblCoinImage3.getX(), lblCoinImage3.getY()};
    int[] pVectorCoinFour = {lblCoinImage4.getX(), lblCoinImage4.getY()};
    int[] pVectorCoinFive = {lblCoinImage5.getX(), lblCoinImage5.getY()};
    int[] pVectorCoinSix = {lblCoinImage6.getX(), lblCoinImage6.getY()};

 }

 public void printAllToOutput(){

    setPositionVectors();

    System.out.println(Arrays.toString(pVectorCoinOne));
    System.out.println(Arrays.toString(pVectorCoinTwo));
    System.out.println(Arrays.toString(pVectorCoinThree));
    System.out.println(Arrays.toString(pVectorCoinFour));
    System.out.println(Arrays.toString(pVectorCoinFive));
    System.out.println(Arrays.toString(pVectorCoinSix));

 }

Answer 1

像这样修复:

public void setPositionVectors(){

    pVectorCoinOne[0] = lblCoinImage1.getX(); //example

 }

一切都与范围有关——本地与全局。而且你不能像这样直接设置数组。在java中，只能在初始化时将常量设置为数组。

喜欢:

public int[] array = {1, 2};

当你写作时

public void setPositionVectors(){

    int[] pVectorCoinOne = {lblCoinImage1.getX(), lblCoinImage1.getY()};
    int[] pVectorCoinTwo = {lblCoinImage2.getX(), lblCoinImage2.getY()};
    int[] pVectorCoinThree = {lblCoinImage3.getX(), lblCoinImage3.getY()};
    int[] pVectorCoinFour = {lblCoinImage4.getX(), lblCoinImage4.getY()};
    int[] pVectorCoinFive = {lblCoinImage5.getX(), lblCoinImage5.getY()};
    int[] pVectorCoinSix = {lblCoinImage6.getX(), lblCoinImage6.getY()};

 }

该方法在其自身内部初始化具有相同名称的新局部变量，而不是调用您在上面声明的变量。所以方法结束时变量会消失，什么都不会改变。