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Java Swing - Repaint() 无法正常工作

转载 作者:行者123 更新时间:2023-12-02 04:53:34 25 4
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我从 this topic 获取程序。我尝试在实时模式下编辑点。我将 MouseMotionListener 添加到构造函数中,并编写一些基本函数来接近鼠标点并编辑该点。当我在构造函数中获得 (x,y) 点时,repaint() 的工作很奇怪。当我在 paintComponent 中获得 (x,y) 点时,repaint() 根本不起作用。因此,这是在构造函数和 PaintComponent 中获取 (x,y) 的图像。我的错误在哪里?

package simplegrapher2;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Stroke;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import static java.lang.Math.sqrt;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class SimpleGrapher2 extends JPanel {

private int width = 800;
private int heigth = 400;
private int padding = 25;
private int labelPadding = 25;
private Color lineColor = new Color(44, 102, 230, 180);
private Color pointColor = new Color(100, 100, 100, 180);
private Color gridColor = new Color(200, 200, 200, 200);
private static final Stroke GRAPH_STROKE = new BasicStroke(2f);
private int pointWidth = 4;
private int numberYDivisions = 10;
private List<Double> scores;
private static double serieX = 0;
public List<Point2D.Double> graphPoints;

public SimpleGrapher2(List<Double> scores) {
this.scores = scores;
addMouseMotionListener(new MouseMotionListener() {
@Override
public void mouseDragged(MouseEvent me) {
double x = me.getX();
double y = me.getY();
findNearPoint(x, y);
editSerie(x, y);
revalidate();
repaint();
}

@Override
public void mouseMoved(MouseEvent me) {}
});

double xScale = ((double) getWidth() - (2 * padding) - labelPadding) / (scores.size() - 1);
double yScale = ((double) getHeight() - 2 * padding - labelPadding) / (getMaxScore() - getMinScore());

graphPoints = new ArrayList<>();
for (int i = 0; i < scores.size(); i++) {
double x1 = (double) (i * xScale + padding + labelPadding);
double y1 = (double) ((getMaxScore() - scores.get(i)) * yScale + padding);
graphPoints.add(new Point2D.Double(x1, y1));
}
}

@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

/*double xScale = ((double) getWidth() - (2 * padding) - labelPadding) / (scores.size() - 1);
double yScale = ((double) getHeight() - 2 * padding - labelPadding) / (getMaxScore() - getMinScore());

graphPoints = new ArrayList<>();
for (int i = 0; i < scores.size(); i++) {
double x1 = (double) (i * xScale + padding + labelPadding);
double y1 = (double) ((getMaxScore() - scores.get(i)) * yScale + padding);
graphPoints.add(new Point2D.Double(x1, y1));
}*/

// draw white background
g2.setColor(Color.WHITE);
g2.fillRect(padding + labelPadding, padding, getWidth() - (2 * padding) - labelPadding, getHeight() - 2 * padding - labelPadding);
g2.setColor(Color.BLACK);

// create hatch marks and grid lines for y axis.
for (int i = 0; i < numberYDivisions + 1; i++) {
int x0 = padding + labelPadding;
int x1 = pointWidth + padding + labelPadding;
int y0 = getHeight() - ((i * (getHeight() - padding * 2 - labelPadding)) / numberYDivisions + padding + labelPadding);
int y1 = y0;
if (scores.size() > 0) {
g2.setColor(gridColor);
g2.drawLine(padding + labelPadding + 1 + pointWidth, y0, getWidth() - padding, y1);
g2.setColor(Color.BLACK);
String yLabel = ((int) ((getMinScore() + (getMaxScore() - getMinScore()) * ((i * 1.0) / numberYDivisions)) * 100)) / 100.0 + "";
FontMetrics metrics = g2.getFontMetrics();
int labelWidth = metrics.stringWidth(yLabel);
g2.drawString(yLabel, x0 - labelWidth - 5, y0 + (metrics.getHeight() / 2) - 3);
}
g2.drawLine(x0, y0, x1, y1);
}

// and for x axis
for (int i = 0; i < scores.size(); i++) {
if (scores.size() > 1) {
int x0 = i * (getWidth() - padding * 2 - labelPadding) / (scores.size() - 1) + padding + labelPadding;
int x1 = x0;
int y0 = getHeight() - padding - labelPadding;
int y1 = y0 - pointWidth;
if ((i % ((int) ((scores.size() / 20.0)) + 1)) == 0) {
g2.setColor(gridColor);
g2.drawLine(x0, getHeight() - padding - labelPadding - 1 - pointWidth, x1, padding);
g2.setColor(Color.BLACK);
String xLabel = i + "";
FontMetrics metrics = g2.getFontMetrics();
int labelWidth = metrics.stringWidth(xLabel);
g2.drawString(xLabel, x0 - labelWidth / 2, y0 + metrics.getHeight() + 3);
}
g2.drawLine(x0, y0, x1, y1);
}
}

// create x and y axes
g2.drawLine(padding + labelPadding, getHeight() - padding - labelPadding, padding + labelPadding, padding);
g2.drawLine(padding + labelPadding, getHeight() - padding - labelPadding, getWidth() - padding, getHeight() - padding - labelPadding);

Stroke oldStroke = g2.getStroke();
g2.setColor(lineColor);
g2.setStroke(GRAPH_STROKE);
for (int i = 0; i < graphPoints.size() - 1; i++) {
double x1 = graphPoints.get(i).x;
double y1 = graphPoints.get(i).y;
double x2 = graphPoints.get(i + 1).x;
double y2 = graphPoints.get(i + 1).y;
g2.draw(new Line2D.Double(x1, y1, x2, y2));
}

g2.setStroke(oldStroke);
g2.setColor(pointColor);
for (int i = 0; i < graphPoints.size(); i++) {
double x = graphPoints.get(i).x - pointWidth / 2;
double y = graphPoints.get(i).y - pointWidth / 2;
int ovalW = pointWidth;
int ovalH = pointWidth;
//g2.fillOval(x, y, ovalW, ovalH);
}
}

public void findNearPoint(double x, double y) {
double delta = 0;
for (int j = 0; j < graphPoints.size(); j++) {
double sx = graphPoints.get(j).x;
double sy = graphPoints.get(j).y;
double root = sqrt((x-sx)*(x-sx) + (y-sy)*(y-sy));
if (j == 0) {
delta = root;
serieX = sx;
}
else if (root < delta) {
serieX = sx;
delta = root;
}
}
}

public void editSerie(double x, double y) {
double tmpSerieX = serieX;
int ind = 0;
for (int i = 0; i < graphPoints.size(); i++) {
if (graphPoints.get(i).x == tmpSerieX) {
ind = i;
}
}
graphPoints.remove(ind);
graphPoints.add(ind, new Point2D.Double(x, y));
serieX = x;
}

private double getMinScore() {
double minScore = Double.MAX_VALUE;
for (Double score : scores) {
minScore = Math.min(minScore, score);
}
return minScore;
}

private double getMaxScore() {
double maxScore = Double.MIN_VALUE;
for (Double score : scores) {
maxScore = Math.max(maxScore, score);
}
return maxScore;
}

public void setScores(List<Double> scores) {
this.scores = scores;
invalidate();
this.repaint();
}

public List<Double> getScores() {
return scores;
}

private static void createAndShowGui() {
List<Double> scores = new ArrayList<>();
Random random = new Random();
int maxDataPoints = 40;
int maxScore = 10;
for (int i = 0; i < maxDataPoints; i++) {
scores.add((double) random.nextDouble() * maxScore);
}
SimpleGrapher2 mainPanel = new SimpleGrapher2(scores);
mainPanel.setPreferredSize(new Dimension(800, 600));
JFrame frame = new JFrame("DrawGraph");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}

public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

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最佳答案

当您计算x/yScale时,问题出在您的构造函数中...

public SimpleGrapher2(List<Double> scores) {
//...
double xScale = ((double) getWidth() - (2 * padding) - labelPadding) / (scores.size() - 1);
double yScale = ((double) getHeight() - 2 * padding - labelPadding) / (getMaxScore() - getMinScore());
//...
}

构建组件时,组件大小为0x0。您需要等到组件以某种有意义的方式调整大小后再计算点...

这也是有问题的,因为当组件首次在屏幕上实现时,可能会快速连续地多次调整大小。

我过去所做的是将 Swing Timer 设置为较小的延迟,以允许在较小的时间范围内多次调整组件的大小。一旦一切都稳定下来,计时器将触发,您可以执行所需的操作,例如...

public SimpleGrapher2(List<Double> scores) {
//...
addComponentListener(new ComponentAdapter() {

private Timer initTimer = new Timer(200, new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
initTimer.stop();
double xScale = ((double) getWidth() - (2 * padding) - labelPadding) / (scores.size() - 1);
double yScale = ((double) getHeight() - 2 * padding - labelPadding) / (getMaxScore() - getMinScore());

graphPoints = new ArrayList<>();
for (int i = 0; i < scores.size(); i++) {
double x1 = (double) (i * xScale + padding + labelPadding);
double y1 = (double) ((getMaxScore() - scores.get(i)) * yScale + padding);
graphPoints.add(new Point2D.Double(x1, y1));
}
repaint();
}
});

@Override
public void componentResized(ComponentEvent e) {
if (graphPoints == null) {
initTimer.restart();
}
}

});

}

这一切所做的只是等待 compoentResized 事件之间的计时器超过 200 毫秒(您可以使用此值使其更接近您想要的值,但我发现大约 250毫秒是合理的延迟)

您需要更正 paintComponent 以允许 graphPoints 也为 null

关于Java Swing - Repaint() 无法正常工作,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28999349/

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