android游戏开发虚拟方向键

 

 闲暇时 弄了个例子实现 360°随便控制 打印坐标 角色转动角度计算；首次下博客代码有点乱 希望大家支持一下共同学习共同进步

点击源代码下载：http://download.csdn.net/detail/chizhafengyun_1314/4565038

java代码：

 

package com.rp;

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;

public class Rocker { 
double degreesByNormalSystem = Double.NaN;//一般坐标系下的角度
double rad = Double.NaN;//当前遥感的弧度
int rockerColor = Color.GREEN;
//定义两个圆形的中心点坐标与半径 
private static final float rockerCenterXMarginRight4ScreenWidthPercent = 0.05f;//摇杆右边界宽度相对于屏幕宽度百分比
private static final float rockerCenterYMarginBottom4ScreenHeightPercent = 0.05f;//摇杆右边界高度相对于屏幕百分比
private static final float rockerR4ScreenWidthPercent = 0.1f; 
private float smallCenterX = 120, smallCenterY = 120, smallCenterR = 20;
private float BigCenterX = 120, BigCenterY = 120, BigCenterR = 40; 
Paint paint; 
/*
* 因为要考虑适应屏幕，所以需要将屏幕宽高放进来
* */

public Rocker(int screenWidth,int screenHeight) {
super();
paint = new Paint();
paint.setAntiAlias(true); 
BigCenterR = screenWidth*rockerR4ScreenWidthPercent; 
BigCenterX = smallCenterX = screenWidth - BigCenterR*1.5f - rockerCenterXMarginRight4ScreenWidthPercent*screenWidth;
BigCenterY = smallCenterY = screenHeight - BigCenterR*1.5f - rockerCenterYMarginBottom4ScreenHeightPercent*screenHeight; 
smallCenterR = BigCenterR/2;
}

void draw(Canvas canvas){ 
paint.setColor(rockerColor);
paint.setAlpha(0x77);
canvas.drawCircle(BigCenterX, BigCenterY, BigCenterR, paint); 
canvas.drawCircle(smallCenterX, smallCenterY, smallCenterR, paint); 
paint.setColor(Color.BLACK);
canvas.drawText("原点在左上坐标系下的弧度:"+rad, 20, 20, paint);
canvas.drawText("由该弧度计算得出角度:"+(rad*180/Math.PI), 20, 40, paint);
canvas.drawText("原点在左下坐标系角度:"+degreesByNormalSystem, 20, 60, paint); 
}


float getDegrees(float firstX,float firstY,float secondX,float secondY ){ 
float ret = (float)Math.atan((firstY-secondY)/(firstX-secondX))*180/(float)Math.PI; 
if(firstX= 360 ? ret - 360: ret; 
return ret;
} 

/** 
* 小圆针对于大圆做圆周运动时，设置小圆中心点的坐标位置
* @param centerX 
* 围绕的圆形(大圆)中心点X坐标
* @param centerY 
* 围绕的圆形(大圆)中心点Y坐标
* @param R
* 围绕的圆形(大圆)半径
* @param rad 
* 旋转的弧度 
*/
public void setSmallCircleXY(float centerX, float centerY, float R, double rad) {
//获取圆周运动的X坐标 
smallCenterX = (float) (R * Math.cos(rad)) + centerX;
//获取圆周运动的Y坐标 
smallCenterY = (float) (R * Math.sin(rad)) + centerY;
}

/**
* 得到两点之间的弧度
* @param px1 第一个点的X坐标
* @param py1 第一个点的Y坐标
* @param px2 第二个点的X坐标
* @param py2 第二个点的Y坐标
* @return
*/
public double getRad(float px1, float py1, float px2, float py2) {
//得到两点X的距离 
float dx = px2 - px1;
//得到两点Y的距离 
float dy = py1 - py2;
//算出斜边长 
float Hypotenuse = (float) Math.sqrt(Math.pow(dx, 2) + Math.pow(dy, 2));
//得到这个角度的余弦值（通过三角函数中的定理 ：邻边/斜边=角度余弦值） 
float cosAngle = dx / Hypotenuse;
//通过反余弦定理获取到其角度的弧度 
float rad = (float) Math.acos(cosAngle);
//当触屏的位置Y坐标<摇杆的Y坐标我们要取反值-0~-180 ？？？？
if (py2 < py1) {
rad = -rad;
}
return rad;
}

boolean WORKING = false;

public void reset() {
smallCenterX = BigCenterX;
smallCenterY = BigCenterY;
WORKING = false;
}

public void update(int pointX,int pointY) { 
if(WORKING){ 
//判断用户点击的位置是否在大圆内
if (Math.sqrt(Math.pow((BigCenterX - pointX), 2) + Math.pow((BigCenterY - pointY), 2)) <= (BigCenterR )) {
//让小圆跟随用户触点位置移动 
smallCenterX = pointX;
smallCenterY = pointY; 
this.rad = getRad(BigCenterX, BigCenterY, pointX, pointY); 
} 
else { 
this.rad = getRad(BigCenterX, BigCenterY, pointX, pointY); 
setSmallCircleXY(BigCenterX, BigCenterY, BigCenterR, rad);
} 
degreesByNormalSystem = getDegrees(BigCenterX,BigCenterY,smallCenterX,smallCenterY); 
}
}

public void begin(int pointX,int pointY) {
if (Math.sqrt(Math.pow((BigCenterX - pointX), 2) + Math.pow((BigCenterY - pointY), 2)) <= (BigCenterR )) {
WORKING = true;
update(pointX,pointY);
} else{
WORKING = false;
}
} 
}

 

点击源代码下载：http://download.csdn.net/detail/chizhafengyun_1314/4565038