Ball Bouncing off Walls - Pause＆Resume

Question

我正在學習這個JavaScript代碼，讓球從牆上彈開，並暫停&繼續點擊。我已經暫停了球，並希望對潛在選項提供反饋，以使用布爾值來啓用恢復。 setTimer（）& stopTimer（）是預定義的函數。

var ball; 
var dx = 4; 
var dy = 4; 
var isPaused = false; 


/* This program has a ball bounce around the screen. */ 
function start(){ 
    ball = new Circle(20); 
    ball.setPosition(100, 100); 
    add(ball); 

    setTimer(draw, 20); 
    if(isPaused == true){ 
     mouseClickMethod(resume); 
    } 
} 

function draw(){ 
    checkWalls(); 
    ball.move(dx, dy); 
    mouseClickMethod(pause); 
} 

function checkWalls(){ 
    // Bounce off right wall 
    if(ball.getX() + ball.getRadius() > getWidth()){ 
     dx = -dx; 
    } 

    // Bounce off left wall 
    if(ball.getX() - ball.getRadius() < 0){ 
     dx = -dx; 
    } 

    // Bounce off bottom wall 
    if(ball.getY() + ball.getRadius() > getHeight()){ 
     dy = -dy; 
    } 

    // Bounce off top wall 
    if(ball.getY() - ball.getRadius() < 0){ 
     dy = -dy; 
    } 
} 

function pause(e){ 
    var isPaused = true; 
    if(isPaused == true){ 
     stopTimer(draw); 
    } 
} 

function resume(e){ 
    var isPaused = false; 
    if(isPaused == false){ 
     setTimer(draw, 20); 
    } 
} 

Answer 1

只是想通了。這完成了工作。

var ball; 
var dx = 4; 
var dy = 4; 
var isPaused; 


/* This program has a ball bounce around the screen. */ 
function start(){ 
    ball = new Circle(20); 
    ball.setPosition(100, 100); 
    add(ball); 

    setTimer(draw, 20); 
} 

function draw(){ 
    checkWalls(); 
    ball.move(dx, dy); 
    mouseClickMethod(pause); 
} 

function checkWalls(){ 
    // Bounce off right wall 
    if(ball.getX() + ball.getRadius() > getWidth()){ 
     dx = -dx; 
    } 

    // Bounce off left wall 
    if(ball.getX() - ball.getRadius() < 0){ 
     dx = -dx; 
    } 

    // Bounce off bottom wall 
    if(ball.getY() + ball.getRadius() > getHeight()){ 
     dy = -dy; 
    } 

    // Bounce off top wall 
    if(ball.getY() - ball.getRadius() < 0){ 
     dy = -dy; 
    } 
} 

function pause(){ 
    isPaused = true; 
    if(isPaused == true){ 
     stopTimer(draw); 
    } 
    mouseClickMethod(resume); 
} 

function resume(){ 
    isPaused = false; 
    if(isPaused == false){ 
     setTimer(draw, 20); 
    } 
}