Question

我是初学者的Java经验，所以我希望你能帮助我。

我想从JTextfield中读取步数。但你怎么能让楼梯变化呢？

Graphics g = textP.getGraphics();

    int x = 5;
    int y = 20;
    int width = 10;
    int height = 10;

对于循环1 - whil给出drawRect为6件

    for (int i = 0; i < 6; i++) {
        g.drawRect(x, y * i, width, height);
    }

对于循环2 - whil给出5件的drawRect

    for (int i = 1; i < 6; i++) {
        g.drawRect(x + 15, y * i, width, height);
    }

对于循环3 - whil给出4件的drawRect

    for (int i = 2; i < 6; i++) {
        g.drawRect(x + 30, y * i, width, height);
    }

对于循环4 - whil给出3件的drawRect

    for (int i = 3; i < 6; i++) {
        g.drawRect(x + 45, y * i, width, height);
    }

对于循环5 - whil给出2件的drawRect

    for (int i = 4; i < 6; i++) {
        g.drawRect(x + 60, y * i, width, height);
    }

对于循环6 - whil给出1件的drawRect

    for (int i = 5; i < 6; i++) {
        g.drawRect(x + 75, y * i, width, height);
    }

输出（必须通过rect ipv *）：

*
**
***
****
*****
******

Answer 1

你可以这样做。

JTextField stairs = new JTextField("Enter no. of Stairs");
String noOfStairsStr = stairs.getText();
int noOfStairs = Integer.parseInt(noOfStairsStr);
...
for (int i = 0; i < noOfStairs; i++) { // Use that in the for loop.

Answer 2

你期待这样的事吗

for (int i = 0,k=15; i < 6; i++) {
            g.drawRect( ( x+(i*k) ), y * i, width, height);
}

Answer 3

图形环境很复杂。您不再具有固定字符宽度和高度的安全性，现在您需要开始处理更广泛的环境因素（例如您必须绘制的区域的宽度和高度......）

要开始，我建议你看看

涵盖基础知识。

为了绘制步骤，我们需要知道（至少）三件事。

要绘制的步骤数......
每个步骤的宽度
每一步的高度。

此示例计算步骤的宽度和高度，作为其绘制的容器的宽度和高度的因子。

enter image description here

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class SimpleSteps {

    public static void main(String[] args) {
        new SimpleSteps();
    }

    public SimpleSteps() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private JTextField steps;
        private StairPane stairPane;

        public TestPane() {
            setLayout(new BorderLayout());
            JPanel options = new JPanel();
            steps = new JTextField(10);
            JButton create = new JButton("Create");
            stairPane = new StairPane();

            options.add(new JLabel("Step count: "));
            options.add(steps);
            options.add(create);

            add(stairPane);
            add(options, BorderLayout.SOUTH);

            create.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    String value = steps.getText();
                    try {
                        int stepCount = Integer.parseInt(value);
                        stairPane.setStepCount(stepCount);
                    } catch (NumberFormatException exp) {
                        JOptionPane.showMessageDialog(TestPane.this, value + " is not a valid step count", "Error", JOptionPane.ERROR_MESSAGE);
                    }
                }
            });
        }

    }

    public class StairPane extends JPanel {

        private int stepCount = 0;

        public StairPane() {
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (stepCount > 0) {
                Graphics g2d = (Graphics2D) g.create();
                int stepHeight = getHeight() / stepCount;
                int stepWidth = getWidth() / stepCount;
                for (int step = stepCount; step != 0; step--) {
                    int width = stepWidth * step;
                    int y = (stepHeight * step) - stepHeight;
                    g2d.fillRect(0, y, width, stepHeight);                       
                }
                g2d.dispose();
            }
        }

        private void setStepCount(int stepCount) {
            this.stepCount = stepCount;
            repaint();
        }
    }
}

Java使用drawRect绘制楼梯，并使用inputField获取更多楼梯

3 个答案: