Java - keyPressed 事件未被调用

Question

我正在用java为自己制作一个俄罗斯方 block 克隆，作为一个学习项目。然而，我现在陷入了获取左右移动棋子的输入部分。我不确定问题是否出在我的方法中，或者问题出在未调用的 keyPressed 方法中，我在调试中没有成功，因为它忽略了该方法。这是我的代码:

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.util.ArrayList;
import java.util.Arrays;

import javax.swing.*;

public class MainClass implements KeyListener{
    public static Painter painter = new Painter();
    public static LShape tetr = new LShape(150,0);

    public static void main(String[] args) throws InterruptedException {
        JFrame window = new JFrame("Tetris");
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setSize(300, 560);
        window.setBackground(Color.BLUE);

        window.getContentPane().add(painter);
        window.setVisible(true);

        ArrayList<Block> blocks = new ArrayList<Block>();
        ArrayList<Block> staticBlocks = new ArrayList<Block>();

        while(true){
            tetr = new LShape(150, 0);
            for (int i = 0; i < tetr.iterations; i++) {
                blocks = new ArrayList<Block>(Arrays.asList(tetr.getBlocks()));
                blocks.addAll(staticBlocks);
                painter.setBlocks(blocks);
                tetr.changeY(5);
                Thread.sleep(35);
                painter.repaint();
            }
            staticBlocks.addAll(blocks);
        }
    }

    public void keyTyped(KeyEvent e) {
        // TODO Auto-generated method stub

    }

    public void keyPressed(KeyEvent e) {  //I am not sure if this is even called
        switch(e.getKeyCode()){
        case KeyEvent.VK_RIGHT:
            tetr.changeX(20);
            break;
        case KeyEvent.VK_LEFT:
            tetr.changeX(-20);
        }
    }

    public void keyReleased(KeyEvent e) {
        // TODO Auto-generated method stub

    }
}

Answer 1

MainClass 未在任何地方使用。

创建一个实例并向窗口对象(JFrame 实例)添加一个键监听器，该监听器位于代码中的 MainClass 中。使用这个window.addKeyListener(new MainClass());

public class MainClass implements KeyListener {

public static Painter painter = new Painter();
public static LShape tetr = new LShape(150, 0);

public static void main(String[] args) throws InterruptedException {
    JFrame window = new JFrame("Tetris");
    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    window.setSize(300, 560);
    window.setBackground(Color.BLUE);
     window.addKeyListener(new MainClass()); 
    // window.getContentPane().add((PopupMenu) painter);
    window.setVisible(true);

    ArrayList<Block> blocks = new ArrayList<Block>();
    ArrayList<Block> staticBlocks = new ArrayList<Block>();

    while (true) {
        tetr = new LShape(150, 0);
        for (int i = 0; i < tetr.iterations; i++) {
            blocks = new ArrayList<Block>(Arrays.asList(tetr.getBlocks()));
            blocks.addAll(staticBlocks);
            painter.setBlocks(blocks);
            tetr.changeY(5);
            Thread.sleep(35);
            painter.repaint();
        }
        staticBlocks.addAll(blocks);
    }
}

public void keyTyped(KeyEvent e) {
    // TODO Auto-generated method stub

}

public void keyPressed(KeyEvent e) {  //I am not sure if this is even called
    System.out.println(e.getKeyCode());
    switch (e.getKeyCode()) {
        case KeyEvent.VK_RIGHT:
            // tetr.changeX(20);
            break;
        case KeyEvent.VK_LEFT:
        // tetr.changeX(-20);
    }
}

public void keyReleased(KeyEvent e) {
    // TODO Auto-generated method stub

}
}