把java重置 java怎么重置界面

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mob64ca13fa2f9e 2024-04-23 16:08:06

文章标签 把java重置 Math java System 文章分类 Java 后端开发

重绘是指将图形的绘制所需要的关键元素保存下来，当对页面进行更改时，图形能够重新绘制，不会丢失。

无重绘操作时
创建的画图板主界面的代码：

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Graphics;

import javax.swing.JButton;
import javax.swing.JFrame;

public class NWDrawUI extends JFrame	{
	DListener lis1 = new DListener();
	public static void main(String[] args){
		NWDrawUI nw = new NWDrawUI();
		nw.showUI();
	}
	public void showUI(){
		this.setSize(1000,700);
		//创建窗体位置居中
		this.setLocationRelativeTo(null);
		//创建窗体关闭时的操作
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		//创建窗体的标题
		this.setTitle("画图板界面-3.0");
		//创建布局
		this.setLayout(new FlowLayout());
		String[] textArr = {"画线","直线","矩形边","椭圆边","矩形填充","椭圆填充","橡皮擦","颜色选择器"};
		for(int i=0;i<textArr.length;i++){
			//创建按钮
			JButton btn = new JButton(textArr[i]);
			btn.setSize(50,50);
			//添加按钮
			this.add(btn);
			//添加监听器
			btn.addActionListener(lis1);
		}
		this.setVisible(true);
		Graphics g = this.getGraphics();
		//给监听器的画布对象赋值
	      lis1.g = g;
	      this.addMouseListener(lis1);
	}
}

创建的画图板监听器的代码：：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import javax.swing.JColorChooser;
import javax.swing.JTextField;

public class DListener implements MouseListener, ActionListener, MouseMotionListener {
	// 记录坐标
	int x1,x2,y1,y2;
	Color color =Color.BLACK;
	// 画布
	public Graphics g;
	//保存图形信息
	String shapeText="画线";
	//存储图形的数组
	
	int count = 0;
	//获取按钮的信息
	public void actionPerformed(ActionEvent e) {	   
		shapeText = e.getActionCommand();
		System.out.println(shapeText);
	    if(shapeText.equals("颜色选择器")) {
        JColorChooser Jcolor = new JColorChooser();
        color = Jcolor.showDialog(Jcolor, null, color);
        g.setColor(color);
     }
	}
	//构造方法
	public void mousePressed(MouseEvent e) {
    // 获取按下的坐标
		 x1 = e.getX();
		 y1 = e.getY(); 		 
	}
	public void mouseDragged(MouseEvent e) {
	    	if (shapeText.equals("画笔")){
	    		System.out.println("已经点击了按钮画线");
	    		x2 = e.getX();
	    		y2 = e.getY();
	    		g.drawLine(x1, y1, x2, y2);
	    		System.out.println("x1: "+x1+"y1: "+y1);
	    		x1 = x2;
	    		y1 = y2;
	    	}
	 }
	public void mouseReleased(MouseEvent e) {
		// 获取松开的坐标
		 x2 = e.getX();
		 y2 = e.getY();
		
	     if(shapeText.equals("直线"))
		 {
	    	 System.out.println("直线");
	    	  g.drawLine(x1, y1, x2, y2);
		 }
		 else if(shapeText.equals("矩形边"))
		 {
	   		 g.drawRect(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("矩形填充"))
		 {
	   		 g.fillRect(Math.min(x1,x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("椭圆边"))
		 {
	   		 g.drawOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("椭圆填充"))
		 {
	   		 g.fillOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("橡皮擦")){
			 Color color = new Color(238,238,238);	
	   			g.setColor(color);
	   			g.fillOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1)); 
		 }
	}
	
	public void mouseMoved(MouseEvent e) {};
	public void mouseClicked(MouseEvent e) {}
	public void mouseEntered(MouseEvent e) {};
	public void mouseExited(MouseEvent e) {};

}

运行结果如下：

把java重置 java怎么重置界面_Math

当进行放大操作后：

把java重置 java怎么重置界面_System_02

原先的图形发生了丢失的情况

图形消失的原因：因为Java画板都是画出来的，当你进行放大操作时，对界面进行了重新绘制，但是原来所画的图形并没有重新显示出来，因此需要进行重新绘制

关于重绘的基本操作

1 . 重新创建一个类，目的是存储画板上图形的数据，并建立方法，利用这些数据，把图形在新的界面绘制出来。
这是新创建的Shap类用于重绘

import java.awt.Color;
import java.awt.Graphics;

public class Shap {
	String type;
	int x1,y1,x2,y2;
    public Shap(int x1, int y1, int x2, int y2, String type) {
    	this.x1 = x1;
    	this.x2 = x2;
    	this.y1 = y1;
    	this.y2 = y2;
    	this.type = type;
    }
	//绘制自己
    public void show(Graphics g){

	     if(type.equals("直线"))
		 {
	    	  g.drawLine(x1, y1, x2, y2);
		 }
		
		 else if(type.equals("矩形边"))
		 {
	   		 g.drawRect(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(type.equals("矩形填充"))
		 {
	   		 g.fillRect(Math.min(x1,x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(type.equals("椭圆边"))
		 {
	   		 g.drawOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(type.equals("椭圆填充"))
		 {
	   		 g.fillOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(type.equals("橡皮擦")){
			 Color color = new Color(238,238,238);
	   			g.setColor(color);
	   			g.fillOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1)); 
		 }
    }
   	}

2 . 对主方法也要进行一定的修改

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.Graphics;

import javax.swing.JButton;
import javax.swing.JFrame;

public class NWDrawUI extends JFrame	{ 
	Shap date[] = new Shap[100000];//所增添的内容
	DListener lis1 = new DListener(date);//所增添的内容
	public static void main(String[] args){
		NWDrawUI nw = new NWDrawUI();
		nw.showUI();
	}
	public void showUI(){
		this.setSize(1000,700);
		//创建窗体位置居中
		this.setLocationRelativeTo(null);
		//创建窗体关闭时的操作
		this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		//创建窗体的标题
		this.setTitle("画图板界面-3.0");
		//创建布局
		this.setLayout(new FlowLayout());
		String[] textArr = {"画线","直线","矩形边","椭圆边","矩形填充","椭圆填充","橡皮擦","颜色选择器"};
		for(int i=0;i<textArr.length;i++){
			//创建按钮
			JButton btn = new JButton(textArr[i]);
			btn.setSize(50,50);
			//添加按钮
			this.add(btn);
			//添加监听器
			btn.addActionListener(lis1);
		}
		this.setVisible(true);
		Graphics g = this.getGraphics();
		//给监听器的画布对象赋值
	      lis1.g = g;
	      this.addMouseListener(lis1);
	}
	//所增添的内容
	public void paint(Graphics g) {
		super.paint(g);	
		for (int i = 0; i < date.length; i++) {
			if (date[i] != null) {
					date[i].show(g);
			}
		}
		
	
	}
}

Shap date[] = new Shap[100000];//所增添的内容
DListener lis1 = new DListener(date);//所增添的内容
建立一个数组存储对象

public void paint(Graphics g) {
 super.paint(g); //继承父类的方法
 //根据数组所存储的数据进行重绘
 for (int i = 0; i < date.length; i++) {
 if (date[i] != null) {
 date[i].show(g);
 }
 }

监听器的代码如下：

import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;

import javax.swing.JColorChooser;
import javax.swing.JTextField;

public class DListener implements MouseListener, ActionListener, MouseMotionListener {
	// 记录坐标
	int x1,x2,y1,y2;
	Color color =Color.BLACK;
	// 画布
	public Graphics g;
	//保存图形信息
	String shapeText="画线";
	//存储图形的数组
	int count = 0;
	Shap[] h;
	public DListener(Shap[] s){
		this.h = s;
	}
	//获取按钮的信息
	public void actionPerformed(ActionEvent e) {	   
		shapeText = e.getActionCommand();
		System.out.println(shapeText);
	    if(shapeText.equals("颜色选择器")) {
        JColorChooser Jcolor = new JColorChooser();
        color = Jcolor.showDialog(Jcolor, null, color);
        g.setColor(color);
     }
	}
	//构造方法
	public void mousePressed(MouseEvent e) {
    // 获取按下的坐标
		 x1 = e.getX();
		 y1 = e.getY(); 		 
	}
	public void mouseDragged(MouseEvent e) {
	    	if (shapeText.equals("画笔")){
	    		System.out.println("已经点击了按钮画线");
	    		x2 = e.getX();
	    		y2 = e.getY();
	    		g.drawLine(x1, y1, x2, y2);
	    		System.out.println("x1: "+x1+"y1: "+y1);
	    		x1 = x2;
	    		y1 = y2;
	    	}
	 }
	public void mouseReleased(MouseEvent e) {
		// 获取松开的坐标
		 x2 = e.getX();
		 y2 = e.getY();
		
	     if(shapeText.equals("直线"))
		 {
	    	 System.out.println("直线");
	    	  g.drawLine(x1, y1, x2, y2);
		 }
		 else if(shapeText.equals("矩形边"))
		 {
	   		 g.drawRect(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("矩形填充"))
		 {
	   		 g.fillRect(Math.min(x1,x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("椭圆边"))
		 {
	   		 g.drawOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("椭圆填充"))
		 {
	   		 g.fillOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1));
		 }
		 else if(shapeText.equals("橡皮擦")){
			 Color color = new Color(238,238,238);	
	   			g.setColor(color);
	   			g.fillOval(Math.min(x1, x2),Math.min(y1,y2),Math.abs(x2-x1),Math.abs(y2-y1)); 
		 }
//	     创建一个图形对象
	     Shap a =new Shap(x1,y1,x2,y2,shapeText);
	     h[count] = a;
		 count++;
	}
	
	public void mouseMoved(MouseEvent e) {};
	public void mouseClicked(MouseEvent e) {}
	public void mouseEntered(MouseEvent e) {};
	public void mouseExited(MouseEvent e) {};

}

Shap[] h;
 public DListener(Shap[] s){
 this.h = s;
 }

对监听器进行处理，使数组间进行传值，保持监听器的一致性。

接下来进行运行，便可以实现重绘的操作。

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把java重置 java怎么重置界面

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