Question

我正在创建一个简单的java计时器，但是当点击“开始”按钮时，负责显示时间的JPanel不会更新。我用摇摆计时器来更新JPanel，但无济于事。我在错误的组件上使用它吗？这是我的代码......

JFrame（主计时器组件）

if [[ ${USER} != "user1" && "user2" && "user3" && "user4" ]]; then

这是JPanel类（显示时间的内容）

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

public class theTimer extends JFrame{

    //Initialize fields
    private TimerPanel tp = new TimerPanel();
    private JButton start,stop,reset;
    private Dimension buttonSize = new Dimension(80,30);
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    //Main Method
    public static void main(String[] args){
        theTimer tT = new theTimer();
    }
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    //Constructor
    public theTimer(){
        setLayout(new FlowLayout());
        setSize(400,400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setResizable(false);
        add(tp);
        addButtonAction();
        setButtonSize();
        add(start); add(stop); add(reset);
        setTitle("Java Study Timer");
        setVisible(true);
    }
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    //Set the size of the timer buttons
    private void setButtonSize(){
        start.setPreferredSize(buttonSize);
        stop.setPreferredSize(buttonSize);
        reset.setPreferredSize(buttonSize);
    }
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    //Gives the buttons functionality
    private void addButtonAction(){
        start = new JButton("Start");
        stop = new JButton("Stop");
        reset = new JButton("Reset");
        start.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent event){
                tp.startTimer();

            }
        });
        stop.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent event){
                tp.stopTimer();

            }
        });
        reset.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent event){
                tp.resetTimer();
            }
        });
    }
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------
}

Answer 1

请在TimerPanel.java中插入以下声明：

theTime = min + ":" + sec;

在repaint();每次出现之前看到结果。

如果进行了上述更改，TimerPanel.java如下：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.*;

public class TimerPanel extends JPanel{
    private int min,sec;
    private String theTime = min + ":" + sec;
    private int width=350, height=300;
    private boolean timerStarted=false;
    private Timer swingTimer = new Timer(900, new ActionListener(){
        public void actionPerformed(ActionEvent event){
            if(sec<60){
                sec++;
                theTime = min + ":" + sec;
                repaint();
            }else{
                min++;
                sec=0;
                theTime = min + ":" + sec;
                repaint();
            }
        } 
    });
    //Constructor
    public TimerPanel(){

    setPreferredSize(new Dimension(350,300));
    }
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    //start the timer
    public void startTimer(){
        swingTimer.start();
    }

    //Stop the timer
    public void stopTimer(){
        swingTimer.stop();
    }

    //reset the timer
    public void resetTimer(){
        sec=0; min=0;
        theTime = min + ":" + sec;
        repaint();
    }
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------  
    //Paint Method
    public void paintComponent(Graphics g){
        super.paintComponent(g);
        g.setColor(Color.WHITE);
        g.setFont(new Font("Arial", Font.PLAIN, 40));
        g.drawString(theTime, width/2-45, height/2);
        setBackground(Color.BLACK);
    }
//------------------------------------------------------------------------------------------------------------------------------------------------------------------------  

}

此外，请从tp.updateTime();删除所有theTimer.java，因为不需要void PhysicsThread::run(){ qDebug() << "SUCCESSFULLY STARTED UP PHYSICS-SIMULATION"; forever{ mutex.lock(); qDebug() << "RUNNING PHYSICS-SIMULATION"; runSimulation(); if(stop){ mutex.unlock(); break; } if(bPause){ pauseManager.wait(&mutex); } mutex.unlock(); } } void PhysicsThread::runSimulation(){ auto startTime = std::chrono::high_resolution_clock::now(); // Collision Border for(int i = 0 ; i < pobjectsSphere.size() ; i++) { PhysicsSphere* op = pobjectsSphere.at(i); if(op->getIsMovable()){ if(op->getX()-(op->getSize()) < minx ){ if(op->getVelocityX() < 0){ op->setVelocityX(-op->getVelocityX()); }else{ op->setVelocityX(op->getVelocityX()); } }else if(op->getX()+(op->getSize()) > maxx) { if(op->getVelocityX() > 0){ op->setVelocityX(-op->getVelocityX()); }else{ op->setVelocityX(op->getVelocityX()); } } if(op->getY()-(op->getSize()) < miny){ if(op->getVelocityY() < 0){ op->setVelocityY(-op->getVelocityY() * op->getRemainingEnergy()); }else{ op->setVelocityY(op->getVelocityY()); } }else{ if(op->getY()+(op->getSize()) > maxy){ if(op->getVelocityY() > 0){ op->setVelocityY(-op->getVelocityY()); }else{ op->setVelocityY(op->getVelocityY()); } } // Gravity op->setVelocityY(op->getVelocityY() + g*deltaTimeMS*op->getMass()); } if(op->getZ()-(op->getSize()) < minz){ if(op->getVelocityZ() < 0){ op->setVelocityZ(-op->getVelocityZ()); }else{ op->setVelocityZ(op->getVelocityZ()); } }else if(op->getZ()+(op->getSize()) > maxz){ if(op->getVelocityZ() > 0){ op->setVelocityZ(-op->getVelocityZ()); }else{ op->setVelocityZ(op->getVelocityZ()); } } } } // Collision Sphere on Sphere for(int i = 0 ; i < pobjectsSphere.size() ; i++) { PhysicsSphere* op1 = pobjectsSphere.at(i); for(int j = i ; j < pobjectsSphere.size() ; j++) { PhysicsSphere* op2 = pobjectsSphere.at(j); // Sphere on Sphere if(i != j && Collision::SphereVersusSphere(op1->getX() ,op1->getY() ,op1->getZ() ,op1->getSize() ,op2->getX() ,op2->getY() ,op2->getZ() ,op2->getSize())){ double tempX (op1->getX() - op2->getX()); double tempY (op1->getY() - op2->getY()); double tempZ (op1->getZ() - op2->getZ()); double norm = sqrt(tempX*tempX + tempY*tempY + tempZ*tempZ); tempX = tempX / norm; tempY = tempY / norm; tempZ = tempZ / norm; double a1 = (op1->getVelocityX() * tempX) + (op1->getVelocityY() * tempY) + (op1->getVelocityZ() * tempZ); double a2 = (op2->getVelocityX() * tempX) + (op2->getVelocityY() * tempY) + (op2->getVelocityZ() * tempZ); double optimizedP = (2.0 * (a1 - a2)) / (op1->getMass() + op2->getMass()); // fix optimizedP = std::abs(optimizedP); // 0.9 Verlusst if(op1->getIsMovable()){ op1->setVelocityX( op1->getVelocityX() + (optimizedP * op2->getMass() * tempX) * (op1->getRemainingEnergy()*op2->getRemainingEnergy())); op1->setVelocityY( op1->getVelocityY() + (optimizedP * op2->getMass() * tempY) * (op1->getRemainingEnergy()*op2->getRemainingEnergy())); op1->setVelocityZ( op1->getVelocityZ() + (optimizedP * op2->getMass() * tempZ) * (op1->getRemainingEnergy()*op2->getRemainingEnergy())); } if(op2->getIsMovable()){ op2->setVelocityX( op2->getVelocityX() - (optimizedP * op1->getMass() * tempX) * (op1->getRemainingEnergy()*op2->getRemainingEnergy())); op2->setVelocityY( op2->getVelocityY() - (optimizedP * op1->getMass() * tempY) * (op1->getRemainingEnergy()*op2->getRemainingEnergy())); op2->setVelocityZ( op2->getVelocityZ() - (optimizedP * op1->getMass() * tempZ) * (op1->getRemainingEnergy()*op2->getRemainingEnergy())); } if(!op1->getIsMovable() && op2->getIsMovable()){ op2->setX(op2->getX() - op1->getVelocityX() * deltaTimeMS); op2->setY(op2->getY() - op1->getVelocityY() * deltaTimeMS); op2->setZ(op2->getZ() - op1->getVelocityZ() * deltaTimeMS); op1->setVelocityX(0.0); op1->setVelocityY(0.0); op1->setVelocityZ(0.0); }else if(op1->getIsMovable() && !op2->getIsMovable()){ op1->setX(op1->getX() - op2->getVelocityX() * deltaTimeMS); op1->setY(op1->getY() - op2->getVelocityY() * deltaTimeMS); op1->setZ(op1->getZ() - op2->getVelocityZ() * deltaTimeMS); op2->setVelocityX(0.0); op2->setVelocityY(0.0); op2->setVelocityZ(0.0); } op1->setX(op1->getX() + op1->getVelocityX() * deltaTimeMS); op1->setY(op1->getY() + op1->getVelocityY() * deltaTimeMS); op1->setZ(op1->getZ() + op1->getVelocityZ() * deltaTimeMS); op2->setX(op2->getX() + op2->getVelocityX() * deltaTimeMS); op2->setY(op2->getY() + op2->getVelocityY() * deltaTimeMS); op2->setZ(op2->getZ() + op2->getVelocityZ() * deltaTimeMS); } } } for(int i = 0 ; i < pobjectsSphere.size() ; i++) { PhysicsSphere* op1 = pobjectsSphere.at(i); for(int j = 0 ; j < pobjectsBox.size() ; j++) { PhysicsBox* op2 = pobjectsBox.at(j); if(Collision::SphereVersusBox( op1->getX() ,op1->getY() ,op1->getZ() ,op1->getSize() ,op2->getMinX()+op2->getX() ,op2->getMinY()+op2->getY() ,op2->getMinZ()+op2->getZ() ,op2->getMaxX()+op2->getX() ,op2->getMaxY()+op2->getY() ,op2->getMaxZ()+op2->getZ())){ if((op1->getX()+op1->getSize()) > op2->getMinX() && op1->getX() < op2->getMinX()+op2->getX()){ if(op1->getVelocityX() > 0){ op1->setVelocityX(-op1->getVelocityX()); } } if((op1->getX()-op1->getSize()) < op2->getMaxX() && op1->getX() > op2->getMaxX()+op2->getX()){ if(op1->getVelocityX() < 0){ op1->setVelocityX(-op1->getVelocityX()); } } if((op1->getY()+op1->getSize()) > op2->getMinY() && op1->getY() < op2->getMinY()+op2->getY()){ if(op1->getVelocityY() > 0){ op1->setVelocityY(-op1->getVelocityY()); } } if((op1->getY()-op1->getSize()) < op2->getMaxY() && op1->getY() > op2->getMaxY()+op2->getY()){ if(op1->getVelocityY() < 0){ op1->setVelocityY(-op1->getVelocityY()); } } if((op1->getZ()+op1->getSize()) > op2->getMinZ() && op1->getZ() < op2->getMinZ()+op2->getZ()){ if(op1->getVelocityZ() > 0){ op1->setVelocityZ(-op1->getVelocityZ()); } } if((op1->getZ()-op1->getSize()) < op2->getMaxZ() && op1->getZ() > op2->getMaxZ()+op2->getZ()){ if(op1->getVelocityZ() < 0){ op1->setVelocityZ(-op1->getVelocityZ()); } } } } } // Move for(int i = 0 ; i < pobjectsSphere.size() ; i++) { PhysicsSphere* op = pobjectsSphere.at(i); if(op->getIsMovable()){ op->setX(op->getX() + op->getVelocityX()*deltaTimeMS); op->setY(op->getY() + op->getVelocityY()*deltaTimeMS); op->setZ(op->getZ() + op->getVelocityZ()*deltaTimeMS); }else{ op->setVelocityX(0.0); op->setVelocityY(0.0); op->setVelocityZ(0.0); } } if(pauseTickTime > 0.0){ this->msleep(pauseTickTime); } auto endTime = std::chrono::high_resolution_clock::now(); std::chrono::duration<double> time = endTime - startTime; deltaTimeNS = std::chrono::duration_cast<std::chrono::nanoseconds>(time).count(); deltaTimeMS = deltaTimeNS / 1000000.0; //qDebug() << "DeltaT NS: " << deltaTimeNS << " DeltaT MS: " << deltaTimeMS; }。希望这可以帮助。

Java Timer Program不会更新显示的时间

1 个答案: