Java 我用数组创建JButton循环,但它';s不';行不通
我想按循环创建按钮Java 我用数组创建JButton循环,但它';s不';行不通,java,nullpointerexception,Java,Nullpointerexception,我想按循环创建按钮 1 2 3 4 5 6 7 8 9 但是当我写代码的时候,按钮有array2D private JButton cells[][]; // Constructor public SliderGameFrame() { JPanel panel = new JPanel(); this.add(panel); for (int i = 1; i <= cells.length; i++) { for (int j = 1; j
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private JButton cells[][];
// Constructor
public SliderGameFrame() {
JPanel panel = new JPanel();
this.add(panel);
for (int i = 1; i <= cells.length; i++) {
for (int j = 1; j <= cells.length; j++) {
cells[i][j] = new JButton(" " + i);
panel.add(cells[i][j]);
}
}
}
专用JButton单元[];
//建造师
公共SliderGameFrame(){
JPanel面板=新的JPanel();
本条添加(面板);
对于(int i=1;i变化:
for (int i = 1; i <= cells.length; i++) {
for (int j = 1; j <= cells.length; j++) {
for(int i=1;我知道你从来没有对数组进行过初始化。这是不一样的):哦,天哪,很抱歉我忘记了对数组进行初始化。即使你忘记初始化数组,你的循环也应该如我在答案中所示。否则它不会起作用。
for (int i = 0; i < cells.length; i++) {
for (int j = 0; j < cells.length; j++) {