Android自定义View实现游戏摇杆键盘的方法示例

前言

本文主要给大家介绍的是关于Android自定义View实现游戏摇杆键盘的相关内容，为什么会有这篇文章呢？因为在之前的一个项目，操作方向的方式为上下左右，左上需要同时按住左键和右键的方式进行操作。

如下图：

近来需要升级项目，操作方式改为类似王者荣耀的摇杆操作。

如下图：

好了，下面话不多说了，跟着小编来一起看看是如何实现的吧。

绘制背景

实现遥感按钮，需要绘制背景，绘制中心的遥感按钮。绘制遥感背景，需要创建一个RemoteViewBg类，存储背景图，减少重复创建bitmap。

RemoteViewBg类代码如下：

public class RemoteViewBg {
private Bitmap bitmapBg;
public RemoteViewBg(Bitmap bitmap) {
 bitmapBg = bitmap;
}

//背景的绘图函数
public void draw(Canvas canvas, Paint paint, Rect src0 ,Rect dst0 ) {
 canvas.drawBitmap(bitmapBg, src0, dst0, paint);
}
}

点击触摸事件

重写系统的触摸时间，判断触摸点在背景范围内还是背景范围外

 @Override
public boolean onTouchEvent(MotionEvent event) {
 if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() ==  MotionEvent.ACTION_MOVE) {
 //   // 在范围外触摸
  if (Math.sqrt(Math.pow((bigCircleX - (int) event.getX()), 2) + Math.pow((bigCircleY - (int) event.getY()), 2)) >= bigCircleR) {

   double tempRad = getRad(bigCircleX, bigCircleY, event.getX(), event.getY());

   getXY(bigCircleX, bigCircleY, bigCircleR, tempRad);
  } else {//范围内触摸
   smallCircleX = (int) event.getX();
   smallCircleY = (int) event.getY();
  }
 } else if (event.getAction() == MotionEvent.ACTION_UP) {
  smallCircleX = bigCircleX;
  smallCircleY = bigCircleY;

 }
 return true;
}

弧度计算

通过 event.getX() , event.getY()获得当前的触摸点，与圆点进行计算，获取弧度

/***
 * 得到两点之间的弧度
 */
public float getRad(float px1, float py1, float px2, float py2) {
 float x = px2 - px1;

 float y = py1 - py2;
 //斜边的长
 float z = (float) Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
 float cosAngle = x / z;
 float rad = (float) Math.acos(cosAngle);

 if (py2 < py1) {
  rad = -rad;
 }
 return rad;
}

图形绘制

通过 canvas.drawCircle()和 canvas.drawBitmap()分别进行遥感按钮和遥感背景的绘制，注意对遥感背景的保存，如果在绘制的时候每次BitmapFactory.decodeResource()会增加耗时，因此只需在surfaceCreated（）中进行bitmap的生成即可。

public void draw() {
 try {
  canvas = sfh.lockCanvas();
  canvas.drawColor(getResources().getColor(R.color.ghostwhite));


 // 指定图片绘制区域(左上角的四分之一)
  Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());

  // 指定图片在屏幕上显示的区域
  Rect dst = new Rect(bigCircleX - bigCircleR, bigCircleY - bigCircleR, bigCircleX + bigCircleR, bigCircleY + bigCircleR);
  // 绘制图片
  remoteViewBg.draw(canvas, paint, src, dst);
  paint.setColor(0x70ff0000);
  //绘制摇杆
  canvas.drawCircle(smallCircleX, smallCircleY, smallCircleR, paint);
 } catch (Exception e) {
  // TODO: handle exception
 } finally {
  try {
   if (canvas != null)
    sfh.unlockCanvasAndPost(canvas);
  } catch (Exception e2) {
   e2.printStackTrace();
  }
 }
}

使用

在activity中动态添加

 RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.dance_relative_layout);
 remoteSurfaceView = new RemoteSurfaceView(this);
 params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, 
 RelativeLayout.LayoutParams.MATCH_PARENT);
 remoteSurfaceView.setLayoutParams(params);
 relativeLayout.addView(remoteSurfaceView);

全部代码

public class RemoteSurfaceView extends SurfaceView implements Callback, Runnable {
private float scale = this.getResources().getDisplayMetrics().density;
private Thread th;
private SurfaceHolder sfh;
private Canvas canvas;
private Paint paint;
private boolean flag;

private int bigCircleX = 0;
private int bigCircleY =0;
private int bigCircleR = 0;
//摇杆的X,Y坐标以及摇杆的半径
private float smallCircleX = 0;
private float smallCircleY = 0;
private float smallCircleR = 0;


private Bitmap bitmap;
private RemoteViewBg remoteViewBg;

public RemoteSurfaceView(Context context) {
 super(context);
 sfh = this.getHolder();
 sfh.addCallback(this);
 paint = new Paint();
 paint.setAntiAlias(true);
 setFocusable(true);
 setFocusableInTouchMode(true);
 setZOrderOnTop(true);
 getHolder().setFormat(PixelFormat.TRANSPARENT);

}

public void surfaceCreated(SurfaceHolder holder) {
 int width = getWidth();
 int height = getHeight();
 bigCircleX = width / 2;
 bigCircleY = height / 2;
 bigCircleR = width / 4;
 smallCircleX = width / 2;
 smallCircleY = height / 2;
 smallCircleR = width / 8;
 bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.fangxiang);
 remoteViewBg = new RemoteViewBg(bitmap);
 th = new Thread(this);
 flag = true;
 th.start();


}

/***
 * 得到两点之间的弧度
 */
public float getRad(float px1, float py1, float px2, float py2) {
 float x = px2 - px1;

 float y = py1 - py2;
 //斜边的长
 float z = (float) Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2));
 float cosAngle = x / z;
 float rad = (float) Math.acos(cosAngle);

 if (py2 < py1) {
  rad = -rad;
 }
 return rad;
}

@Override
public boolean onTouchEvent(MotionEvent event) {
 if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() == MotionEvent.ACTION_MOVE) {
  // 在范围外触摸
  if (Math.sqrt(Math.pow((bigCircleX - (int) event.getX()), 2) + Math.pow((bigCircleY - (int) event.getY()), 2)) >= bigCircleR) {

   double tempRad = getRad(bigCircleX, bigCircleY, event.getX(), event.getY());

   getXY(bigCircleX, bigCircleY, bigCircleR, tempRad);
  } else {//范围内触摸
   smallCircleX = (int) event.getX();
   smallCircleY = (int) event.getY();
  }
 } else if (event.getAction() == MotionEvent.ACTION_UP) {
  smallCircleX = bigCircleX;
  smallCircleY = bigCircleY;

 }
 return true;
}




public void getXY(float x, float y, float R, double rad) {
 //获取圆周运动的X坐标
 smallCircleX = (float) (R * Math.cos(rad)) + x;
 //获取圆周运动的Y坐标
 smallCircleY = (float) (R * Math.sin(rad)) + y;
}

public void draw() {
 try {
  canvas = sfh.lockCanvas();
  canvas.drawColor(getResources().getColor(R.color.ghostwhite));


  // 指定图片绘制区域(左上角的四分之一)
  Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());

  // 指定图片在屏幕上显示的区域
  Rect dst = new Rect(bigCircleX - bigCircleR, bigCircleY - bigCircleR, bigCircleX + bigCircleR, bigCircleY + bigCircleR);
  // 绘制图片
  remoteViewBg.draw(canvas, paint, src, dst);
  paint.setColor(0x70ff0000);
  //绘制摇杆
  canvas.drawCircle(smallCircleX, smallCircleY, smallCircleR, paint);
 } catch (Exception e) {
  // TODO: handle exception
 } finally {
  try {
   if (canvas != null)
    sfh.unlockCanvasAndPost(canvas);
  } catch (Exception e2) {
   e2.printStackTrace();
  }
 }
}

public void run() {

 while (flag) {
  draw();
  try {
   Thread.sleep(50);
  } catch (Exception ex) {
   ex.printStackTrace();
  }
 }
}

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


}

public void surfaceDestroyed(SurfaceHolder holder) {
 flag = false;

}
 }

总结

以上就是这篇文章的全部内容，希望本文的内容对大家的学习或者工作能带来一定的帮助，如果有疑问大家可以留言交流，谢谢大家对呐喊教程的支持。

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