前言
本文主要給大家介紹的是關于Android自定義View實現游戲搖桿鍵盤的相關內容，為什么會有這篇文章呢？因為在之前的一個項目，操作方向的方式為上下左右，左上需要同時按住左鍵和右鍵的方式進行操作。
如下圖：
近來需要升級項目，操作方式改為類似王者榮耀的搖桿操作。
如下圖：
好了，下面話不多說了，跟著小編來一起看看是如何實現的吧。
繪制背景
實現遙感按鈕，需要繪制背景，繪制中心的遙感按鈕。繪制遙感背景，需要創(chuàng)建一個RemoteViewBg類，存儲背景圖，減少重復創(chuàng)建bitmap。
RemoteViewBg類代碼如下：
public class RemoteViewBg {private Bitmap bitmapBg;public RemoteViewBg(Bitmap bitmap) { bitmapBg = bitmap;}//背景的繪圖函數public void draw(Canvas canvas, Paint paint, Rect src0 ,Rect dst0 ) { canvas.drawBitmap(bitmapBg, src0, dst0, paint);}}點擊觸摸事件
重寫系統(tǒng)的觸摸時間，判斷觸摸點在背景范圍內還是背景范圍外
@Overridepublic boolean onTouchEvent(MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() == MotionEvent.ACTION_MOVE) { // // 在范圍外觸摸 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 {//范圍內觸摸 smallCircleX = (int) event.getX(); smallCircleY = (int) event.getY(); } } else if (event.getAction() == MotionEvent.ACTION_UP) { smallCircleX = bigCircleX; smallCircleY = bigCircleY; } return true;}弧度計算
通過 event.getX() , event.getY()獲得當前的觸摸點，與圓點進行計算，獲取弧度
/*** * 得到兩點之間的弧度 */public float getRad(float px1, float py1, float px2, float py2) { float x = px2 - px1; float y = py1 - py2; //斜邊的長 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;}圖形繪制
通過 canvas.drawCircle()和 canvas.drawBitmap()分別進行遙感按鈕和遙感背景的繪制，注意對遙感背景的保存，如果在繪制的時候每次BitmapFactory.decodeResource()會增加耗時，因此只需在surfaceCreated（）中進行bitmap的生成即可。
public void draw() { try { canvas = sfh.lockCanvas(); canvas.drawColor(getResources().getColor(R.color.ghostwhite)); // 指定圖片繪制區(qū)域(左上角的四分之一) Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); // 指定圖片在屏幕上顯示的區(qū)域 Rect dst = new Rect(bigCircleX - bigCircleR, bigCircleY - bigCircleR, bigCircleX + bigCircleR, bigCircleY + bigCircleR); // 繪制圖片 remoteViewBg.draw(canvas, paint, src, dst); paint.setColor(0x70ff0000); //繪制搖桿 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中動態(tài)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);
全部代碼
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;//搖桿的X,Y坐標以及搖桿的半徑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();}/*** * 得到兩點之間的弧度 */public float getRad(float px1, float py1, float px2, float py2) { float x = px2 - px1; float y = py1 - py2; //斜邊的長 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;}@Overridepublic boolean onTouchEvent(MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN || event.getAction() == MotionEvent.ACTION_MOVE) { // 在范圍外觸摸 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 {//范圍內觸摸 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) { //獲取圓周運動的X坐標 smallCircleX = (float) (R * Math.cos(rad)) + x; //獲取圓周運動的Y坐標 smallCircleY = (float) (R * Math.sin(rad)) + y;}public void draw() { try { canvas = sfh.lockCanvas(); canvas.drawColor(getResources().getColor(R.color.ghostwhite)); // 指定圖片繪制區(qū)域(左上角的四分之一) Rect src = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); // 指定圖片在屏幕上顯示的區(qū)域 Rect dst = new Rect(bigCircleX - bigCircleR, bigCircleY - bigCircleR, bigCircleX + bigCircleR, bigCircleY + bigCircleR); // 繪制圖片 remoteViewBg.draw(canvas, paint, src, dst); paint.setColor(0x70ff0000); //繪制搖桿 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;} }總結
以上就是這篇文章的全部內容，希望本文的內容對大家的學習或者工作能帶來一定的幫助，如果有疑問大家可以留言交流，謝謝大家對武林網的支持。
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