ImageView 之间的碰撞检测

Question

我需要帮助让两个 ImageView 发生碰撞，我环顾了这个网站和许多 youtube 视频，并认为我找到了解决问题的方法。我从另一个人的帖子中找到了一些代码，

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

我只是想知道我应该将该代码放在我的程序中的哪个位置，因为当它位于底部时，我尝试 log.d 以显示我是否成功地尝试检测 imageViews 是否发生碰撞并且没有任何显示。无论如何，这是我的代码，我在另一个问题中使用的代码位于最底部并用作注释。非常感谢您的帮助，如果您帮助了我，谢谢！

Main.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;

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
    final 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);


    //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;
        }
    });
}

}



/*
private boolean viewsOverlap(ImageView net, ImageView ball) {

    int[] net_coords = new int[2];
    net.getLocationOnScreen(net_coords);
    int net_w = net.getWidth();
    int net_h = net.getHeight();
    Rect net_rect = new Rect(net_coords[0], net_coords[1], net_coords[0] + 
net_w, net_coords[1] + net_h);

    int[] ball_coords = new int[2];
    ball.getLocationOnScreen(ball_coords);
    int ball_w = ball.getWidth();
    int ball_h = ball.getHeight();
    Rect ball_rect = new Rect(ball_coords[0], ball_coords[1], ball_coords[0] 
+ ball_w, ball_coords[1] + ball_h);

    return net_rect.intersect(ball_rect) || net_rect.contains(ball_rect) || 
ball_rect.contains(net_rect);

}*/

Answer 1

碰撞检测和分数增加 ;-)

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);
    }
}

Answer 2

让我举个例子，我是如何仅在 10 行代码中实现有效的碰撞检测的。这不是完全相同的问题，但它可以让您了解如何根据坐标操作对象。

 // update the canvas in order to display the game action
    @Override
    public void onDraw(Canvas canvas) {

        super.onDraw(canvas);
        int xx = 200;
        int yy = 0;
        if (persons != null) {
            synchronized (persons) {
                Iterator<Person> iterate = persons.iterator();
                while (iterate.hasNext()) {
                    Person p = iterate.next();
                    if (p.getImage() != 0) {
                        bitmap = BitmapFactory.decodeResource(getResources(), p.getImage()); //load a character image
                        // Draw the visible person's appearance
                        if(xx > canvas.getWidth())
                            xx = 0;
                        canvas.drawBitmap(bitmap, xx , canvas.getHeight()- bitmap.getHeight() , null);
                        // Draw the name
                        Paint paint = new Paint();
                        paint.setStyle(Paint.Style.FILL);
                        canvas.save();
                        paint.setStrokeWidth(1);
                        paint.setColor(Color.WHITE);
                        paint.setTextSize(50);
                        canvas.drawText(p.name, (float)(xx+0.25*bitmap.getWidth()), (float) (canvas.getHeight() ), paint);
                        xx += bitmap.getWidth()*0.75;
                    }
                }
            }
        }
        canvas.save(); //Save the position of the canvas.
        canvas.restore();
        //Call the next frame.
        invalidate();
    }
}

在上面的代码中，我只是检查xx 是否与其他图像数组冲突，然后我只是相应地更新xx。欢迎您使用此代码查看我的open source repository。