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javaandroidcollision-detectioncollisionandroid-studio-3.0

Detect Collision between two objects and make points increase on collision


In my game I got the ball to fall straight down but I want to implement a collision method that detects when the ball touches the net, then deletes the ball and adds one point to my score. I dont know where to start and how to do this so any help is extremely appreciated. thank you.

Main activity.java

package com.example.admin.basketball;

import android.graphics.Point;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Display;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

import java.util.Timer;
import java.util.TimerTask;

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
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);




    //give points for getting ball through net






    //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;
        }
    });
}

}

ActivityMain.xml

 <?xml version="1.0" encoding="utf-8"?>
<android.widget.RelativeLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/myLayout"
android:background="@drawable/bbackground"
tools:context="com.example.admin.basketball.MainActivity">

<ImageView
    android:id="@+id/net"
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="70dp"
    app:srcCompat="@drawable/thenet"
    />

<ImageView
    android:id="@+id/ball"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:layout_alignTop="@+id/score"
    android:layout_centerHorizontal="true"
    app:srcCompat="@drawable/theball" />

<TextView
    android:id="@+id/score"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="true"
    android:layout_marginStart="11dp"
    android:layout_marginTop="11dp"
    android:textSize="25sp"
    android:textStyle="italic"
    android:textColor="@android:color/black"
    android:text="Score: 0" />
</android.widget.RelativeLayout>

Solution

  • Collision detection?

    Try with this ;-)

    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);
        }
    }