android隨機小球碰撞

• • 1. 通過自定義View繪制小球
  • 2. 定時更新小球位置，讓小球運動
  • 3. 邊界檢測，小球碰撞到布局邊界時更改小球運動方向
  • 4. GitHubDemo
  • 5. 相關(guān)鏈接

1. 通過自定義View繪制小球

創(chuàng)建Ball類，封裝與小球有關(guān)的屬性元素
在構(gòu)造方法中隨機生成0-360的方向值

package com.pcf.randomball.bean;import java.util.HashMap; import java.util.Random;public class Ball {int radius;//半徑大小 單位pxint color;//色值int alpha;//透明度int x;//圓心x坐標int y;//圓心y坐標int degree;//方向int speed//速度 1-3int axisX;//X軸矢量方向值int axisY;//Y軸矢量方向值public Ball() {//生成一個在0-360范圍內(nèi)的隨機數(shù) 為小球的方向this.degree = new Random().nextInt(360);//生成一個在1-3范圍內(nèi)的隨機數(shù) 為小球的速度this.speed = new Random().nextInt(3)+1;}public Ball(int radius, int color, int alpha, int x, int y) {this.radius = radius;this.color = color;this.alpha = alpha;this.x = x;this.y = y;//生成一個在0-360范圍內(nèi)的隨機數(shù) 為小球的方向this.degree = new Random().nextInt(360);//生成一個在1-3范圍內(nèi)的隨機數(shù) 為小球的速度this.speed = new Random().nextInt(3)+1;if (degree == 0) {axisX = 0;axisY = 1;} else if (degree == 90) {axisX = 1;axisY = 0;} else if (degree == 180) {axisX = 0;axisY = -1;} else if (degree == 270) {axisX = -1;axisY = 0;} else if (degree > 0 && degree < 90) {axisX = 1;axisY = 1;} else if (degree > 90 && degree < 180) {axisX = 1;axisY = -1;} else if (degree > 180 && degree < 270) {axisX = -1;axisY = -1;} else if (degree > 270 && degree < 360) {axisX = -1;axisY = 1;}}public int getRadius() {return radius;}public void setRadius(int radius) {this.radius = radius;}public int getColor() {return color;}public void setColor(int color) {this.color = color;}public int getAlpha() {return alpha;}public void setAlpha(int alpha) {this.alpha = alpha;}public int getX() {return x;}public void setX(int x) {this.x = x;}public int getY() {return y;}public void setY(int y) {this.y = y;}public int getDegree() {return degree;}public void setDegree(int degree) {this.degree = degree;}public long getSpeed() {return speed;}public void setSpeed(long speed) {this.speed = speed;}public int getAxisX() {return axisX;}public void setAxisX(int axisX) {this.axisX = axisX;}public int getAxisY() {return axisY;}public void setAxisY(int axisY) {this.axisY = axisY;} }

創(chuàng)建自定義RandomView類繼承自View類
實現(xiàn)構(gòu)造方法與OnDraw OnLayout OnMeasure方法
在OnLayout方法中獲取控件實際寬高
在OnDraw方法里繪制圓形小球

package com.pcf.randomball.bean;import android.content.Context; import android.graphics.Canvas; import android.util.AttributeSet; import android.view.View; /*** 隨機小球View* */ public class RandomView extends View {public RandomView(Context context) {super(context);}public RandomView(Context context, AttributeSet attrs) {super(context, attrs);}public RandomView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);}public RandomView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {super(context, attrs, defStyleAttr, defStyleRes);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);}@Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);Ball ball = new Ball(50, Color.BLUE, 600, width / 2, height / 2)//實例化畫筆對象Paint paint = new Paint();//給畫筆設(shè)置顏色paint.setColor(ball.getColor());paint.setAlpha(ball.getAlpha());//設(shè)置畫筆屬性paint.setStyle(Paint.Style.FILL);//畫筆屬性是實心paint.setStrokeWidth(1);//設(shè)置畫筆粗細/**四個參數(shù)：* 參數(shù)一：圓心的x坐標* 參數(shù)二：圓心的y坐標* 參數(shù)三：圓的半徑* 參數(shù)四：定義好的畫筆**/canvas.drawCircle(ball.getX(), ball.getY(), ball.getRadius(), paint);} }

2. 定時更新小球位置，讓小球運動

在Ball類的構(gòu)造方法里面，通過生成隨機數(shù)0-360賦值運動方向

在直角坐標系中把0-360°分成四等份，均分在四個象限中
通過角度判斷小球的運動方向，每個角限都是90°
無法直接對View進行斜線的移動
把斜線的移動分解成豎向與橫向的移動
沿X軸的，Y軸的進行分解
把90°分成了10等份，并分解到X軸與Y軸
開啟線程定時更新小球位置并重新繪制小球位置

PS：后面會把小球運動的方案改為以速度為基礎(chǔ)

package com.pcf.randomball.view;import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.util.AttributeSet; import android.util.Log; import android.view.View;import com.pcf.randomball.bean.Ball;import java.util.ArrayList; import java.util.HashMap; import java.util.List;public class RandomView extends View {private int height;private int width;private long maxBallNumber = -1;private List<Ball> ballList = new ArrayList();private String TAG = "RandomLayout";private MyThread thread;public RandomView(Context context) {super(context);}public RandomView(Context context, AttributeSet attrs) {super(context, attrs);}public RandomView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);}public RandomView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {super(context, attrs, defStyleAttr, defStyleRes);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);Log.d(TAG, "onMeasure ");width = getMeasuredWidth();height = getMeasuredHeight();Log.d(TAG, "width " + width);Log.d(TAG, "height " + height);}@Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {Log.d(TAG, "onLayout ");ballList.add(new Ball(50, Color.BLUE, 600, width / 2, height / 2));//避免重復(fù)創(chuàng)建線程if (thread == null) {thread = new MyThread();}thread.start();}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);Log.d(TAG, "onDraw ");for (int i = 0; i < ballList.size(); i++) {Ball ball = ballList.get(i);//實例化畫筆對象Paint paint = new Paint();//給畫筆設(shè)置顏色paint.setColor(ball.getColor());paint.setAlpha(ball.getAlpha());//設(shè)置畫筆屬性paint.setStyle(Paint.Style.FILL);//畫筆屬性是實心paint.setStrokeWidth(1);//設(shè)置畫筆粗細/*四個參數(shù)：參數(shù)一：圓心的x坐標參數(shù)二：圓心的y坐標參數(shù)三：圓的半徑參數(shù)四：定義好的畫筆*/canvas.drawCircle(ball.getX(), ball.getY(), ball.getRadius(), paint);}}public long getMaxBallNumber() {return maxBallNumber;}public void setMaxBallNumber(long maxBallNumber) {this.maxBallNumber = maxBallNumber;}/*** 往布局添加小球*/public void addBall(Ball ball) {if (ball != null && ballList.size()<maxBallNumber) {ballList.add(ball);}}/*** 從布局移除小球*/public void removeBall(Ball ball) {if (ball != null)ballList.remove(ball);}public void actionBall() {for (int i = 0; i < ballList.size(); i++) {Ball ball1 = ballList.get(i);int x1 = ball1.getX();int y1 = ball1.getY();int degree = ball1.getDegree();//按照0-360度劃分四個象限if (degree >= 0 && degree < 90) {//按10等份去分配X軸與Y軸的位移值int xL = degree / 9;int yL = 10 - degree / 9;//第一象限ball1.setX(x1 + xL);ball1.setY(y1 + yL);} else if (degree >= 90 && degree < 180) {//第二象限 碰撞到布局邊界int xL = 10 - (degree / 9 - 10);int yL = (degree / 9 - 10);ball1.setX(x1 + xL);ball1.setY(y1 + yL);} else if (degree >= 180 && degree < 270) {//第三象限 碰撞到布局邊界int xL = (degree / 9 - 20);int yL = 10 - (degree / 9 - 20);ball1.setX(x1 - xL);ball1.setY(y1 + yL);} else if (degree >= 270 && degree < 360) {//第四象限 碰撞到布局邊界int xL = 10 - (degree / 9 - 30);int yL = (degree / 9 - 30);ball1.setX(x1 - xL);ball1.setY(y1 - yL);}}}private class MyThread extends Thread {@Overridepublic void run() {while (true) {actionBall();//通知更新界面，會重新調(diào)用onDraw()函數(shù)postInvalidate(); try {sleep(10);} catch (Exception e) {e.printStackTrace();}}}}@Overrideprotected void onDetachedFromWindow() {super.onDetachedFromWindow();if(thread!=null)thread.stop();} }

3. 邊界檢測，小球碰撞到布局邊界時更改小球運動方向

根據(jù)入射角與反射角與平面夾角大小相等的原理
可以計算出在不同象限與邊界碰撞后的運動方向

package com.pcf.randomball.view;import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.util.AttributeSet; import android.util.Log; import android.view.View;import com.pcf.randomball.bean.Ball;import java.util.ArrayList; import java.util.HashMap; import java.util.List;public class RandomView extends View {private int height;private int width;private long maxBallNumber = -1;private List<Ball> ballList = new ArrayList();private String TAG = "RandomLayout";private MyThread thread;public RandomView(Context context) {super(context);}public RandomView(Context context, AttributeSet attrs) {super(context, attrs);}public RandomView(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);}public RandomView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {super(context, attrs, defStyleAttr, defStyleRes);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);Log.d(TAG, "onMeasure ");width = getMeasuredWidth();height = getMeasuredHeight();Log.d(TAG, "width " + width);Log.d(TAG, "height " + height);}@Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {Log.d(TAG, "onLayout ");ballList.add(new Ball(50, Color.BLUE, 600, width / 2, height / 2));//避免重復(fù)創(chuàng)建線程if (thread == null) {thread = new MyThread();}thread.start();}@Overrideprotected void onDraw(Canvas canvas) {super.onDraw(canvas);Log.d(TAG, "onDraw ");for (int i = 0; i < ballList.size(); i++) {Ball ball = ballList.get(i);//實例化畫筆對象Paint paint = new Paint();//給畫筆設(shè)置顏色paint.setColor(ball.getColor());paint.setAlpha(ball.getAlpha());//設(shè)置畫筆屬性paint.setStyle(Paint.Style.FILL);//畫筆屬性是實心paint.setStrokeWidth(1);//設(shè)置畫筆粗細/*四個參數(shù)：參數(shù)一：圓心的x坐標參數(shù)二：圓心的y坐標參數(shù)三：圓的半徑參數(shù)四：定義好的畫筆*/canvas.drawCircle(ball.getX(), ball.getY(), ball.getRadius(), paint);}}public long getMaxBallNumber() {return maxBallNumber;}public void setMaxBallNumber(long maxBallNumber) {this.maxBallNumber = maxBallNumber;}/*** 往布局添加小球*/public void addBall(Ball ball) {if (ball != null && ballList.size()<maxBallNumber) {ballList.add(ball);}}/*** 從布局移除小球*/public void removeBall(Ball ball) {if (ball != null)ballList.remove(ball);}public void actionBall() {for (int i = 0; i < ballList.size(); i++) {Ball ball1 = ballList.get(i);int x1 = ball1.getX();int y1 = ball1.getY();int degree = ball1.getDegree();//按照0-360度劃分四個象限if (degree >= 0 && degree < 90) {//按10等份去分配X軸與Y軸的位移值int xL = degree / 9;int yL = 10 - degree / 9;//第一象限 碰撞到布局右邊界if (ball1.getX() + ball1.getRadius() >= width) {ball1.setDegree(360 - degree);ball1.setX(x1 - ball1.getRadius());} else {if (x1 + ball1.getRadius() + 1 + xL >= width) {ball1.setX(width - ball1.getRadius());} else {ball1.setX(x1 + 1 + xL);}}//碰撞到布局上邊界if (ball1.getY() - ball1.getRadius() <= 0) {ball1.setDegree(180 - degree);ball1.setY(y1 + 1 + yL);} else {if (y1 - ball1.getRadius() - 1 - yL <= 0) {ball1.setY(ball1.getRadius());} else {ball1.setY(y1 - 1 - yL);}}} else if (degree >= 90 && degree < 180) {//第二象限 碰撞到布局邊界int xL = 10 - (degree / 9 - 10);int yL = (degree / 9 - 10);if (ball1.getX() + ball1.getRadius() >= width) {ball1.setDegree(180 - degree + 180);ball1.setX(x1 - ball1.getRadius());} else {if (x1 + ball1.getRadius() + 1 + xL >= width) {ball1.setX(width - ball1.getRadius());} else {ball1.setX(x1 + 1 + xL);}}//碰撞到布局邊界if (ball1.getY() + ball1.getRadius() >= height) {ball1.setDegree(90 - degree + 90);ball1.setY(y1 - 1 - yL);} else {if (y1 + ball1.getRadius() + 1 + yL >= height) {ball1.setY(height - ball1.getRadius());} else {ball1.setY(y1 + 1 + yL);}}} else if (degree >= 180 && degree < 270) {//第三象限 碰撞到布局邊界int xL = (degree / 9 - 20);int yL = 10 - (degree / 9 - 20);if (ball1.getX() - ball1.getRadius() <= 0) {ball1.setDegree(360 - degree);ball1.setX(x1 + 1 + xL);} else {if (x1 - ball1.getRadius() - 1 - xL <= 0) {ball1.setX(ball1.getRadius());} else {ball1.setX(x1 - 1 - xL);}}//碰撞到布局邊界if (ball1.getY() + ball1.getRadius() >= height) {ball1.setDegree(270 + 270 - degree);ball1.setY(y1 - 1 - yL);} else {if (x1 + ball1.getRadius() + 1 + yL >= height) {ball1.setY(height - ball1.getRadius());} else {ball1.setY(y1 + 1 + yL);}}} else if (degree >= 270 && degree < 360) {//第四象限 碰撞到布局邊界int xL = 10 - (degree / 9 - 30);int yL = (degree / 9 - 30);if (ball1.getX() - ball1.getRadius() <= 0) {ball1.setDegree(360 - degree);ball1.setX(x1 + 1 + xL);} else {if (x1 - ball1.getRadius() - 1 - xL <= 0) {ball1.setX(ball1.getRadius());} else {ball1.setX(x1 - 1 - xL);}}//碰撞到布局邊界if (ball1.getY() - ball1.getRadius() <= 0) {ball1.setDegree(360 - degree + 180);ball1.setY(y1 + 1 + yL);} else {if (y1 - ball1.getRadius() - 1 - yL <= 0) {ball1.setY(ball1.getRadius());} else {ball1.setY(y1 - 1 - yL);}}}}}private class MyThread extends Thread {@Overridepublic void run() {while (true) {actionBall();//通知更新界面，會重新調(diào)用onDraw()函數(shù)postInvalidate(); try {sleep(10);} catch (Exception e) {e.printStackTrace();}}}}@Overrideprotected void onDetachedFromWindow() {super.onDetachedFromWindow();if(thread!=null)thread.stop();} }

4. GitHubDemo

GitHubDemo
https://github.com/pengchengfuGit/randomball

5. 相關(guān)鏈接

https://www.cnblogs.com/xieyuan/archive/2012/11/27/3787450.html

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