Collision Detection between two images in Java

Question

I have two characters displayed in a game I am writing, the player and the enemy. defined as such:

public void player(Graphics g) {
    g.drawImage(plimg, x,         


        

Answer 1

is there a problem with:

Rectangle box1 = new Rectangle(100,100,100,100);
Rectangle box2 = new Rectangle(200,200,100,100);

// what this means is if any pixel in box2 enters (hits) box1
if (box1.contains(box2)) 
{
     // collision occurred
}

// your code for moving the boxes 

this can also be applied to circles:

Ellipse2D.Double ball1 = new Ellipse2D.Double(100,100,200,200);
Ellipse2D.Double ball2 = new Ellipse2D.Double(400,100,200,200);

// what this means is if any pixel on the circumference in ball2 touches (hits)
// ball1
    if (ball1.contains(ball2)) 
    {
         // collision occurred
    }

    // your code for moving the balls

to check whether youve hit the edge of a screen you could use the following:

Rectangle screenBounds = jpanel.getBounds();
Ellipse2D.Double ball = new Ellipse2D.Double(100,100,200,200);  // diameter 200
Rectangle ballBounds = ball.getBounds();

if (!screenBounds.contains(ballBounds))
{
// the ball touched the edge of the screen
}