A single virtual joystick development

Mainly includes three parts, respectively is the calling class, touch handler class, utility class.

Touch handler class: AppSingleRocker

package com.seuic;

import com.seuic.util.MathUtils;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Point;
import android.graphics.PorterDuff.Mode;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.SurfaceHolder.Callback;

public class AppSingleRocker extends SurfaceView implements Callback{

 private SurfaceHolder mHolder;
 private Paint mPaint;
 public Point mRockerPosition; // Rocker position
 private Point mCtrlPoint = new Point(80, 80);// Rocker starting position
 private int mRudderRadius = 20;//Rocker arm radius
 private int mWheelRadius = 60;//Rocker range radius

int isHide = 0;
 private SingleRudderListener listener = null; //事件回調介面
 public static final int ACTION_RUDDER = 1, ACTION_ATTACK_DEVICEMOVE = 2, ACTION_STOP = 3,  ACTION_ATTACK_CAMERAMOVE = 4;
 public AppSingleRocker(Context context) {
  super(context);
  this.setKeepScreenOn(true);
        mHolder = getHolder();
        mHolder.addCallback(this);
        mPaint = new Paint();
        mPaint.setColor(Color.GREEN);
        mPaint.setAntiAlias(true);//消除鋸齒
        mRockerPosition = new Point(mCtrlPoint);
        setFocusable(true);
        setFocusableInTouchMode(true);
        setZOrderOnTop(true);
        mHolder.setFormat(PixelFormat.TRANSPARENT);//設定背景透明
 }

 //回調介面
    public interface SingleRudderListener {
        void onSteeringWheelChanged(int action,int angle);
    }
   
 //設定回調介面
    public void setSingleRudderListener(SingleRudderListener rockerListener) {
        listener = rockerListener;
    }
   
    int len;
 @Override
 public boolean onTouchEvent(MotionEvent event) {
  try {
   if (isHide == 0) {
    switch (event.getAction()) {
    case MotionEvent.ACTION_DOWN:
     len = MathUtils.getLength(mCtrlPoint.x, mCtrlPoint.y, event.getX(), event.getY());
      //如果螢幕接觸點不在搖杆揮動範圍內,則不處理
              if(len >mWheelRadius) {
                  return true;
              }
     break;
    case MotionEvent.ACTION_MOVE:
     len = MathUtils.getLength(mCtrlPoint.x, mCtrlPoint.y, event.getX(), event.getY());
     if(len <= mWheelRadius) {
                  //如果手指在搖杆活動範圍內，則搖杆處於手指觸摸位置
                  mRockerPosition.set((int)event.getX(), (int)event.getY());
                 
              }else{
                  //設定搖杆位置，使其處於手指觸摸方向的 搖杆活動範圍邊緣
                  mRockerPosition = MathUtils.getBorderPoint(mCtrlPoint, new Point((int)event.getX(), (int)event.getY()), mWheelRadius);
              }
              if(listener != null) {
                  float radian = MathUtils.getRadian(mCtrlPoint, new Point((int)event.getX(), (int)event.getY()));
                  listener.onSteeringWheelChanged(ACTION_RUDDER, getAngleCouvert(radian));
              }
     break;
    case MotionEvent.ACTION_UP:
      mRockerPosition = new Point(mCtrlPoint);
      listener.onSteeringWheelChanged(ACTION_STOP, 0);
     break;
    }
    Canvas_OK();
    Thread.sleep(60);
   }else {
    Thread.sleep(200);
   }
  } catch (Exception e) {

  }
  return true;
 }

 //擷取搖杆位移角度 0-360°
    private int getAngleCouvert(float radian) {
        int tmp = (int)Math.round(radian/Math.PI*180);
        if(tmp < 0) {
            return -tmp;
        }else{
            return 180 + (180 - tmp);
        }
    }

 public void surfaceCreated(SurfaceHolder holder) {
  Canvas_OK();
 }

 public void surfaceChanged(SurfaceHolder holder, int format, int width,
   int height) {
  
 }

 public void surfaceDestroyed(SurfaceHolder holder) {
  
 }
 // 設定是否隱藏
  public void Hided(int opt)
  {
   isHide = opt;
   Canvas_OK();
  }
 
 //繪製映像
 public void Canvas_OK(){
   Canvas canvas = null;
   try {
             canvas = mHolder.lockCanvas();
             canvas.drawColor(Color.TRANSPARENT,Mode.CLEAR);//清除螢幕
             mPaint.setColor(Color.CYAN);
             mPaint.setAlpha(100);
             canvas.drawCircle(mCtrlPoint.x, mCtrlPoint.y, mWheelRadius, mPaint);//繪製範圍
             mPaint.setColor(Color.RED);
             mPaint.setAlpha(100);
             canvas.drawCircle(mRockerPosition.x, mRockerPosition.y, mRudderRadius, mPaint);//繪製搖杆
         } catch (Exception e) {
             e.printStackTrace();
         } finally {
             if(canvas != null) {
                 mHolder.unlockCanvasAndPost(canvas);
             }
         }
 }

}

 

utility class:MathUtils

package com.seuic.util;

import android.graphics.Point;
 public class MathUtils {
     //擷取兩點間直線距離
     public static int getLength(float x1,float y1,float x2,float y2) {
         return (int)Math.sqrt(Math.pow(x1-x2, 2) + Math.pow(y1-y2, 2));
     }
     /**
      * 擷取線段上某個點的座標，長度為a.x - cutRadius
      * @param a 點A
      * @param b 點B
      * @param cutRadius 截斷距離
      * @return 截斷點
      */
     public static Point getBorderPoint(Point a, Point b,int cutRadius) {
         float radian = getRadian(a, b);
         return new Point(a.x + (int)(cutRadius * Math.cos(radian)), a.x + (int)(cutRadius * Math.sin(radian)));
     }
    
     //擷取水平線夾角弧度
     public static float getRadian (Point a, Point b) {
         float lenA = b.x-a.x;
         float lenB = b.y-a.y;
         float lenC = (float)Math.sqrt(lenA*lenA+lenB*lenB);
         float ang = (float)Math.acos(lenA/lenC);
         ang = ang * (b.y < a.y ? -1 : 1);
         return ang;
     }
 }

calling class:SingleRocker

package com.seuic;

import com.seuic.AppSingleRocker.SingleRudderListener;

import android.os.Bundle;
import android.util.Log;
import android.widget.RelativeLayout;
import android.app.Activity;

public class SingleRocker extends Activity {
 
 RelativeLayout Parent;
 AppSingleRocker appSingleRocker;
 public static final String Main = "SingleRocker";
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  Parent = new RelativeLayout(this);
  RelativeLayout.LayoutParams RockerCanvasParams = new RelativeLayout.LayoutParams(160,160);
  RockerCanvasParams.addRule(RelativeLayout.CENTER_VERTICAL);
  appSingleRocker = new AppSingleRocker(this);
  Parent.addView(appSingleRocker,RockerCanvasParams);
  setContentView(Parent);
  appSingleRocker.setSingleRudderListener(new SingleRudderListener() {
   
   @Override
   public void onSteeringWheelChanged(int action, int angle) {
    Log.e(Main, angle+"");
   }
  });
 }

}

 

 

source address:

http://download.csdn.net/download/jwzhangjie/5184324