Intersect method not working, keeps returning true

Question

My intersect method keeps returning true and setting my "score text" to intersect detected when my images do not collide, instead it changes the text as soon as the emulator starts. Please notify me if more code is needed and check back within 10 minutes. Thanks! -this is all my code and collision code starts at line 163, something is wrong with my collision code because collision isn't being detected, what should I do to fix my collision code.

here is my code:

public class MainActivity extends AppCompatActivity {



//Layout
private RelativeLayout myLayout = null;

//Screen Size
private int screenWidth;
private int screenHeight;

//Position
private float ballDownY;
private float ballDownX;

//Initialize Class
private Handler handler = new Handler();
private Timer timer = new Timer();

//Images
private ImageView net = null;
private ImageView ball = null;

//for net movement along x-axis
float x;
float y;

//points
private int points = 0;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    setContentView(R.layout.activity_main);
    myLayout = (RelativeLayout) findViewById(R.id.myLayout);

    //score
    TextView score = (TextView) findViewById(R.id.score);


    //imageviews
    net = (ImageView) findViewById(R.id.net);
    ball = (ImageView) findViewById(R.id.ball);




    //retrieving screen size
    WindowManager wm = getWindowManager();
    Display disp = wm.getDefaultDisplay();
    Point size = new Point();
    disp.getSize(size);
    screenWidth = size.x;
    screenHeight = size.y;

    //move to out of screen
    ball.setX(-80.0f);
    ball.setY(screenHeight + 80.0f);





    //start timer
    timer.schedule(new TimerTask() {
        @Override
        public void run() {
            handler.post(new Runnable() {
                @Override
                public void run() {
                    changePos();
                }
            });
        }
    }, 0, 20);
}

public void changePos() {
    //down

    ballDownY += 10;
    if (ball.getY() > screenHeight) {
        ballDownX = (float) Math.floor((Math.random() * (screenWidth - 
ball.getWidth())));
        ballDownY = -100.0f;

    }
    ball.setY(ballDownY);
    ball.setX(ballDownX);




    /*INTERSECT METHOD
    Rect rc1 = new Rect();
    net.getDrawingRect(rc1);
    Rect rc2 = new Rect();
    ball.getDrawingRect(rc2);
    if (Rect.intersects(rc1, rc2)) {

    TextView score = (TextView) findViewById(R.id.score);
    score.setText("INTERSECT DETECTED");

    }*/




    //make net follow finger
    myLayout.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent event) {
            MainActivity.this.x = event.getX();
            y = event.getY();

            if (event.getAction() == MotionEvent.ACTION_MOVE) {
                net.setX(MainActivity.this.x);
                net.setY(y);



            }
            return true;
        }


    });

}


public boolean Collision(ImageView net, ImageView ball)
{
    Rect AR = new Rect();
    net.getHitRect(AR);
    Rect BR = new Rect();
    ball.getHitRect(BR);
    Render();
    return AR.intersect(BR) || AR.contains(BR) || BR.contains(AR);
}

public void Render()
{
    if(Collision(net, ball))
    {
        points++;
        TextView score = (TextView)findViewById(R.id.score);
        score.setText("Score:" + points);
    }
}



}

There are a lot of ways to do this, the simplest would be to get the bounding Rect for each Bitmap and on each time step to check for a collision using Rect.intersect() method. — Héctor M., Mar 16 '18 at 01:08
Why do you call the Boolean Collision inside the Boolean Coliision? — Héctor M., Mar 16 '18 at 03:38
i moved boolean collision outside the method but it says "invalid method declaration; return type required" — NBA MIXTAPE3, Mar 16 '18 at 03:45
Did you remove the keyword return>> return Rect.intersects(AR, BR);? — Héctor M., Mar 16 '18 at 04:30
@Héctor Manuel Martinez Durán -changed my code to the edited version still not working, any suggestions — NBA MIXTAPE3, Mar 16 '18 at 20:32
@NBAMIXTAPE3 I added some more things to my post, check the code and the link at the end — Héctor M., Mar 16 '18 at 21:01
@Héctor Manuel Martinez Durán - still no luck, i checked the other post and tried to implement that return method into my program but no luck — NBA MIXTAPE3, Mar 17 '18 at 00:43
@NBAMIXTAPE3 You know? I think there is something with your program, because none of the techniques has been used, and the truth is strange — Héctor M., Mar 17 '18 at 00:47
@Héctor Manuel Martinez Durán-? I am going to paste my whole main.java code and maybe try and run the program for yourself, i'm very grateful for your time, help and advice — NBA MIXTAPE3, Mar 17 '18 at 01:09
@Héctor Manuel Martinez Durán - check my recent edit thats all the code, yet intersects is still not working, im sorry that i made you think the truth is strange, thanks again — NBA MIXTAPE3, Mar 17 '18 at 01:15
@Héctor Manuel Martinez Durán - please elaborate, im new to programming, it shows no error in android studio — NBA MIXTAPE3, Mar 17 '18 at 01:18
@NBAMIXTAPE3 I have reformed your code, try now, chek my new post — Héctor M., Mar 17 '18 at 01:45
@NBAMIXTAPE3 Am, hello NBA MIXTAPE, I am writing to ask you if you could do me the favor of upvote to this question https://stackoverflow.com/questions/49397760/fill-octagon-in-c-sharp I have asked 5 questions, of which only 4 have received votes, it is at zero, but if it receives a positive vote, I will get a bronze medal more, could you do it? — Héctor M., Mar 29 '18 at 03:18

Héctor M. · Answer 1 · 2018-03-16T20:59:31.300

1

Something like this:

boolean collision = net.getRect().intersect(ball.getRect());

Collision is a boolean

if(boolean) //Action

Then

if(collision) score.setText("INTERSECT DETECTED");

OR

public boolean Collision(ImageView a, ImageView b)
{  
  Rect AR = new Rect();
  a.getHitRect(myViewRect);
  Rect BR = new Rect();
  b.getHitRect(otherViewRect1);
  return Rect.intersects(AR, BR);
}

--

if(Collision(net, ball))
{
   //Do action
}

--

ImageView ball = (ImageView) findViewById(R.id.Ball);
ImageView net = (ImageView) findViewById(R.id.Net);

if(Collision(net, ball))
{ 
   //Collision detected
}

--

import android.graphics.Rect;

public boolean Collision(ImageView ball, ImageView net)
{
Rect ballRect = new Rect();
ball.getDrawingRect(ballRect);
Rect netRect = new Rect();
net.getDrawingRect(netRect);
return Rect.intersects(ballRect, netRect);
}

Check this post how to detect when a ImageView is in collision with another ImageView?

edited Mar 16 '18 at 20:59

answered Mar 16 '18 at 01:05

Héctor M.

2,302
4
17
35

1

@NBAMIXTAPE3 Mmmmm, What kind of control are net and ball? – Héctor M. Mar 16 '18 at 01:18
1

@NBAMIXTAPE3 ImageViews? – Héctor M. Mar 16 '18 at 01:21
I see, then I will create another method, because if they are images, then they are in an imageview – Héctor M. Mar 16 '18 at 01:23
@NBAMIXTAPE3 Look, I hope it serves you – Héctor M. Mar 16 '18 at 01:32
@NBAMIXTAPE3 No problem, people should help us – Héctor M. Mar 16 '18 at 01:34
@NBAMIXTAPE3 No problem, tell me you do not understand – Héctor M. Mar 16 '18 at 01:39
@NBAMIXTAPE3 Well, Try Now – Héctor M. Mar 16 '18 at 01:56
@NBAMIXTAPE3 I really do not understand why, in that case, we will use the generic method, look at my post – Héctor M. Mar 16 '18 at 02:27
@NBAMIXTAPE3 Do not worry, if this one does not work either, let me know, I will do everything possible to help you – Héctor M. Mar 16 '18 at 02:28
Rect AR = new Rect(); net.getHitRect(myViewRect); //what do i type here, image views =net, ball Rect BR = new Rect(); ball.getHitRect(otherViewRect1);//^^ same thing up here what should i type return Rect.intersects(AR, BR); – NBA MIXTAPE3 Mar 16 '18 at 03:00
1

thanks man you are getting me really close to solving this problem – NBA MIXTAPE3 Mar 16 '18 at 03:01
@NBAMIXTAPE3 Sorry, I was wrong in that part but I fixed it – Héctor M. Mar 16 '18 at 03:06
1

check my recent edit hector, THANKS SO MUCH FOR ALL YOUR HARD WORK – NBA MIXTAPE3 Mar 16 '18 at 03:15

score 1 · Accepted Answer · edited Jun 20 '20 at 09:12

1

I have reformed your code, try now

public class MainActivity extends AppCompatActivity 
{
   //Layout
   private RelativeLayout myLayout = null;

   //Screen Size
   private int screenWidth;
   private int screenHeight;

   //Position
   private float ballDownY;
   private float ballDownX;

   //Initialize Class
   private Handler handler = new Handler();
   private Timer timer = new Timer();

   //Images
   private ImageView net = null;
   private ImageView ball = null;
   
   //score
   private TextView score = null;

   //for net movement along x-axis
   public float x = 0;
   public float y = 0;

   //points
   private int points = 0;


   @Override
    protected void onCreate(Bundle savedInstanceState) 
    {
         super.onCreate(savedInstanceState);

         this.setContentView(R.layout.activity_main);
         this.myLayout = (RelativeLayout) findViewById(R.id.myLayout);

         this.score = (TextView) findViewById(R.id.score);

         this.net = (ImageView) findViewById(R.id.net);
         this.ball = (ImageView) findViewById(R.id.ball);

         //retrieving screen size
         WindowManager wm = getWindowManager();
         Display disp = wm.getDefaultDisplay();
         Point size = new Point();
         disp.getSize(size);
         screenWidth = size.x;
         screenHeight = size.y;

         //move to out of screen
         this.ball.setX(-80.0f);
         this.ball.setY(screenHeight + 80.0f);
         
          //Error here
         /*//Run constantly
         new Handler().postDelayed(new Runnable()
         {
           @Override
           public void run()
           {
              Render();
           }
         }, 100); //100 is miliseconds interval than sleep this process, 1000 miliseconds is 1 second*/

     Thread t = new Thread() {
     @Override
     public void run() {
     try {
        while (!isInterrupted()) {
             Thread.sleep(100);
             runOnUiThread(new Runnable() {
             @Override
             public void run(){Render();}});}
             }catch (InterruptedException e) {}}};

     t.start();
         
    }

    public void Render()
    {
        changePos();
        if(Collision(net, ball))
        {
          points++; //You dont need findView Textview score for that exists in OnCreate Method
          this.score.setText("Score:" + points);
        }
    }

    public void changePos() 
    {
    
        //down
        ballDownY += 10;
        if (ball.getY() > screenHeight) {
        ballDownX = (float) Math.floor((Math.random() * (screenWidth - ball.getWidth())));
        ballDownY = -100.0f;

    }
    ball.setY(ballDownY);
    ball.setX(ballDownX);

      //make net follow finger
      myLayout.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View view, MotionEvent event) {
            x = event.getX();
            y = event.getY();

            if (event.getAction() == MotionEvent.ACTION_MOVE) {
                net.setX(x);
                net.setY(y);
            }
            return true;
        }

    });

    public boolean Collision(ImageView net, ImageView ball)
    {
       Rect BallRect = new Rect();
       ball.getHitRect(BallRect);
       Rect NetRect = new Rect();
       net.getHitRect(NetRect);
       return BallRect.intersect(NetRect);
    }
}

edited Jun 20 '20 at 09:12

Community

1
1

answered Mar 17 '18 at 01:44

Héctor M.

2,302
4
17
35

wow spectacular how talented you are, everything looks good except on line 126 ---- this.x-----> cannot resolve symbol and this.y has the same error – NBA MIXTAPE3 Mar 17 '18 at 02:18
Héctor Manuel Martinez Durán – NBA MIXTAPE3 Mar 17 '18 at 02:29
@NBAMIXTAPE3, Ok cheking – Héctor M. Mar 17 '18 at 02:30
@NBAMIXTAPE3 Try now – Héctor M. Mar 17 '18 at 02:31
Héctor Manuel Martinez Durán still doesn't work but i added the public floats on top of @override boolean Ontouch and that seemed to get rid of the problem, but now the imageview ball wont fall down from the top of the screen, imageview ball is not even on the emulator anymore – NBA MIXTAPE3 Mar 17 '18 at 03:17
@NBAMIXTAPE3 The ball does not fall because you repeated the floating x and y, I have edited this post again, copy it and paste it and let me know if it works – Héctor M. Mar 17 '18 at 03:37
Héctor Manuel Martinez Durán- copy and pasted your code, no error in android studio but the ball is still not falling from the top of the screen. – NBA MIXTAPE3 Mar 17 '18 at 03:53
@NBAMIXTAPE3 You say that before it fell? – Héctor M. Mar 17 '18 at 04:15
@NBAMIXTAPE3 Before, did it fall? – Héctor M. Mar 17 '18 at 04:16
-Yes, this was back before you reformatted the code. – NBA MIXTAPE3 Mar 17 '18 at 04:21
@NBAMIXTAPE3 Well, the Handler is the error, try now – Héctor M. Mar 17 '18 at 04:29
Héctor Manuel Martinez Durán, ball is not falling but text view score is going up very fast – NBA MIXTAPE3 Mar 17 '18 at 04:51
@NBAMIXTAPE3 mmmmm, this error is more serious than I thought, well, we go in parts – Héctor M. Mar 17 '18 at 04:56
@NBAMIXTAPE3 Well, perfect, I have returned a part of the code to its previous state, check if the ball moves – Héctor M. Mar 17 '18 at 05:09
works good,and the ball is back, points are increasing fast , but the ball is moving down a bit slower, maybe just because it's an emulator – NBA MIXTAPE3 Mar 17 '18 at 05:12
@NBAMIXTAPE3 Perfect, I think the points increase quickly because Collision always returns true, let's try investing the collision – Héctor M. Mar 17 '18 at 05:14
@NBAMIXTAPE3 Copy and paste, then check if collision works – Héctor M. Mar 17 '18 at 05:15
so the ball is moving, net is moving but when both the views overlap score doesn't increase so now collision code is returning false, i think – NBA MIXTAPE3 Mar 17 '18 at 05:18
@NBAMIXTAPE3 Let's try several methods until we find one that works – Héctor M. Mar 17 '18 at 05:22
@NBAMIXTAPE3 First test, copy paste and tell me if it detects the collision – Héctor M. Mar 17 '18 at 05:28
points are increasing very fast, ball and net are still moving, collision is still returning true continuosly – NBA MIXTAPE3 Mar 17 '18 at 05:31
@NBAMIXTAPE3 That method does not work, confrimed, let's try another, copy, paste and tell me if the collision works – Héctor M. Mar 17 '18 at 05:37
Wow man you really solved my problem, thanks it means alot, you have a bright future ahead. – NBA MIXTAPE3 Mar 17 '18 at 05:41
@NBAMIXTAPE3 Well, thanks to you for helping me develop more my programming logic, I wish you luck and hopefully we'll see you later – Héctor M. Mar 17 '18 at 05:43
@NBAMIXTAPE3 Also remember that I promised you to do everything possible to help you – Héctor M. Mar 17 '18 at 05:45
@NBAMIXTAPE3 ;-) – Héctor M. Mar 17 '18 at 05:49
@NBAMIXTAPE3 Happy to help you, hey, could you attach a capture of your game to your question? Just to see how I stay – Héctor M. Mar 17 '18 at 05:51

Intersect method not working, keeps returning true

2 Answers2

I have reformed your code, try now