先上图,本文用自定义View简单实现一个这样的效果,动态图看着有点卡卡的,帧率问题,运行起来是很流畅的 ----- 文末添加用SerfaceView的实现方式
思路
N个小球随机方向,随机速度,在视图中移动;任意两个小球靠近到一定距离就连线,距离越近,线越粗
分以下步骤实现
1.创建小球类,这里我用点来表示 取类名Po
2.创建一个定时器,16ms 刷新一次小球的位置,并重绘视图
这里定义的Po类有X,Y坐标,X,Y方向移动速度,以及绘制的半径,(半径是预留出来改变球的大小的,这个字段暂时没使用,球大小固定,就写了个固定值)
package com.zcy.mycanvas.view;
public class Po implements Runnable {
private boolean isRemove;
float x;//x坐标(有效范围0-1,0-1代表在承载视图左到右 , 用这个值乘以视图宽度就得到X方向坐标 , 下面同理)
float y;//Y坐标
float r;//半径
float vx;//X方向速度
float vy;//Y方向速度
public Po(float x, float y, float r, float vx, float vy) {
this.x = x;
this.y = y;
this.r = r;
this.vx = vx;
this.vy = vy;
}
/**
* 用来刷新位置
*/
@Override
public void run() {
if ((x < - 0.01f && vx < 0f) || ( x > 1.01f && vx > 0f)) vx = - vx;//超出显示边缘百分之1回弹
if ((y < - 0.01f && vy < 0f) || ( y > 1.01f && vy > 0f)) vy = - vy;//超出显示边缘百分之1回弹
x += vx;
y += vy;
}
/**
* 计算本点和目标点的距离,
* @param o
* @return
*/
public float lenght(Po o){
float lx = x - o.x;
float ly = y - o.y;
return (float) Math.sqrt(lx*lx + ly*ly);
}
public boolean isRemove() {
return isRemove;
}
public void setRemove(boolean remove) {
isRemove = remove;
}
}
下面自定义一个GravitationView 继承View ,贴上代码,看init 和onDraw,的实现就行了,然后再布局中运行出来就是上图的效果
package com.zcy.mycanvas.view;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
public class GravitationView extends View implements Runnable{
private List<Po> pos;//点集
private Paint p;//画笔
private Random random;
protected void init(Context context, AttributeSet attrs) {
p = new Paint(Paint.ANTI_ALIAS_FLAG);
p.setStrokeWidth(10);
p.setStrokeCap(Paint.Cap.ROUND);
p.setColor(Color.WHITE);
random = new Random();
pos = new ArrayList<>();
//模拟随机生成50个点
for (int i = 0 ; i < 50 ; i++ ){
Po po = new Po(nextFloat(),nextFloat(),nextFloat(),random.nextBoolean() ? nextFloat()/1000f : -nextFloat()/1000f,random.nextBoolean() ? nextFloat()/1000f : -nextFloat()/1000f );
pos.add(po);
}
TimerUtils.addR(this);//这个TimerUtils类会每隔16毫秒调用一次run方法
}
private float nextFloat(){
return random.nextFloat();
}
public GravitationView(Context context) {
super(context);
init(context,null);
}
public GravitationView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init(context,attrs);
}
public GravitationView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context,attrs);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float width = getWidth();
float height = getHeight();
//外层循环绘制每一个点
for (int i = 0 ; i < pos.size() ; i++){
Po po = pos.get(i);
p.setStrokeWidth(10);//设置点的大小
canvas.drawPoint(po.x * width , po.y* height ,p);//绘制点
//内层循环会将该点与后面的点逐一比较,计算距离
for (int j = i+ 1; j < pos.size() ; j++){
Po poj = pos.get(j);
float lenght = po.lenght(poj);
//距离在0f 和 0.2f之间的点就会被连线(这个值可根据需求随意调整)
if (lenght > 0f && lenght < 0.2f){
p.setStrokeWidth(5*(0.2f - lenght));//距离越近,线越粗
canvas.drawLine(po.x*width,po.y*height,poj.x*width,poj.y*height,p);//绘制线
}
}
}
}
@Override
public void run() {
for (Po o : pos)o.run();
postInvalidate();
}
}
*****************************surfaceView实现 *********************************
代码可直接运行,注释写的很清楚了
package com.zcy.mycanvas.view;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
/*
* zcy 1084204954@qq.com
* */
public class MySurfaceView extends SurfaceView implements SurfaceHolder.Callback,Runnable{
private List<Po> pos;//点集
private Paint p;//画笔
private Random random;
private SurfaceHolder mHolder;
private Canvas mCanvas;//绘图的画布
private boolean mIsDrawing;//控制绘画线程的标志位
public MySurfaceView(Context context) {
super(context);
init();
}
public MySurfaceView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public MySurfaceView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init(){
mHolder = getHolder();
mHolder.addCallback(this);
setFocusable(true);
setFocusableInTouchMode(true);
this.setKeepScreenOn(true);
p = new Paint(Paint.ANTI_ALIAS_FLAG);
p.setStrokeWidth(10);
p.setStrokeCap(Paint.Cap.ROUND);
p.setColor(Color.WHITE);
random = new Random();
pos = new ArrayList<>();
//模拟随机生成50个点
for (int i = 0 ; i < 50 ; i++ ){
Po po = new Po(nextFloat(),nextFloat(),nextFloat(),random.nextBoolean() ? nextFloat()/1000f : -nextFloat()/1000f,random.nextBoolean() ? nextFloat()/1000f : -nextFloat()/1000f );
pos.add(po);
}
}
private float nextFloat(){
return random.nextFloat();
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mIsDrawing = true;
new Thread(this).start();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
mIsDrawing = false;
}
@Override
public void run() {
while (mIsDrawing){
long startTime = System.currentTimeMillis();
for (Po o: pos){
o.run();
}
draw();
while (System.currentTimeMillis() - startTime < 30L){
Thread.yield();//耗时少于刷新间隔,线程等待
}
}
}
private void draw(){
try {
mCanvas = mHolder.lockCanvas();
}catch (Exception e){
e.printStackTrace();
}finally {
if (null != mCanvas){
mCanvas.drawColor(Color.BLACK);
float width = getWidth();
float height = getHeight();
//外层循环绘制每一个点
for (int i = 0 ; i < pos.size() ; i++){
Po po = pos.get(i);
p.setStrokeWidth(10);//设置点的大小
mCanvas.drawPoint(po.x * width , po.y* height ,p);//绘制点
//内层循环会将该点与后面的点逐一比较,计算距离
for (int j = i+ 1; j < pos.size() ; j++){
Po poj = pos.get(j);
float lenght = po.lenght(poj);
//距离在0f 和 0.2f之间的点就会被连线(这个值可根据需求随意调整)
if (lenght > 0f && lenght < 0.2f){
p.setStrokeWidth(5*(0.2f - lenght));//距离越近,线越粗
mCanvas.drawLine(po.x*width,po.y*height,poj.x*width,poj.y*height,p);//绘制线
}
}
}
mHolder.unlockCanvasAndPost(mCanvas);
}
}
}
}