在我的比赛中，我让球直接落下，但是我想实施一种碰撞方法来检测球何时接触网，然后删除球并为我的分数增加一分。我不知道从哪里开始以及如何做到这一点所以任何帮助都非常感激。谢谢。
主要活动.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>
答案 0 :(得分：1)
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);
}
}
答案 1 :(得分：0)
Pixel-Perfect Collision Detection Android
检测两张图片Collision Detection between two images in Java
的碰撞https://www.youtube.com/watch?v=AL92LrbDNY0
https://www.youtube.com/watch?v=xdc_1Pf-jnA
您可以使用控件的坐标检测两个矩形之间的交点，即它们的位置和大小
public boolean Collision(ImageView a, ImageView b)
{
int[] AposXY = new int[2];
a.getLocationOnScreen(AposXY);
int AX = AposXY[0];
int AY = AposXY[1];
int[] BposXY = new int[2];
b.getLocationOnScreen(BposXY);
int BX = BposXY[0];
int BY = BposXY[1];
Rectangle ar = new Rectangle(AX, AY, a.getMeasuredWidth(), a.getMeasuredHeight());
Rectangle br = new Rectangle(BX, BY, b.getMeasuredWidth(), b.getMeasuredHeight());
// Assuming there is an intersect method, otherwise just handcompare the values
// A Collision!
// we know which enemy (e), so we can call e.DoCollision();
//DoCollision();
return ar.Intersects(br);
}