学步园

MainActivity：

package potter.back;</p> <p>import android.app.Activity;</p> <p>public class Main extends Activity {<br /> /** Called when the activity is first created. */<br /> @Override<br /> public void onCreate(Bundle savedInstanceState) {<br /> super.onCreate(savedInstanceState);<br /> //隐藏标题栏<br /> requestWindowFeature(Window.FEATURE_NO_TITLE);<br /> //设置成全屏<br /> getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);<br /> //设置为上面的MTView<br /> setContentView(new MySurfaceView(this));<br /> }<br /> }

SurfaceView：

package potter.back;</p> <p>import android.content.Context;<br /> import android.graphics.Canvas;<br /> import android.graphics.Color;<br /> import android.graphics.Paint;<br /> import android.view.MotionEvent;<br /> import android.view.SurfaceHolder;<br /> import android.view.SurfaceHolder.Callback;<br /> import android.view.SurfaceView;</p> <p>public class MySurfaceView extends SurfaceView implements Callback{<br /> private static final int MAX_TOUCHPOINTS = 10;<br /> private static final String START_TEXT = "请随便触摸屏幕进行测试";<br /> private Paint textPaint = new Paint();<br /> private Paint touchPaints[] = new Paint[MAX_TOUCHPOINTS];<br /> private int colors[] = new int[MAX_TOUCHPOINTS];<br /> private int width, height;<br /> private float scale = 1.0f;</p> <p> public MySurfaceView(Context context) {<br /> super(context);<br /> SurfaceHolder holder = getHolder();<br /> holder.addCallback(this);<br /> setFocusable(true); // 确保我们的View能获得输入焦点<br /> setFocusableInTouchMode(true); // 确保能接收到触屏事件<br /> init();<br /> }<br /> public void init(){<br /> // 初始化10个不同颜色的画笔<br /> textPaint.setColor(Color.WHITE);<br /> colors[0] = Color.BLUE;<br /> colors[1] = Color.RED;<br /> colors[2] = Color.GREEN;<br /> colors[3] = Color.YELLOW;<br /> colors[4] = Color.CYAN;<br /> colors[5] = Color.MAGENTA;<br /> colors[6] = Color.DKGRAY;<br /> colors[7] = Color.WHITE;<br /> colors[8] = Color.LTGRAY;<br /> colors[9] = Color.GRAY;<br /> for(int i=0;i<MAX_TOUCHPOINTS;i++){<br /> touchPaints[i]=new Paint();<br /> touchPaints[i].setColor(colors[i]);<br /> }<br /> }</p> <p> @Override<br /> public boolean onTouchEvent(MotionEvent event) {<br /> int pointerCount=event.getPointerCount();<br /> if(pointerCount>MAX_TOUCHPOINTS){<br /> pointerCount=MAX_TOUCHPOINTS;<br /> }<br /> Canvas c=getHolder().lockCanvas();<br /> if(c!=null){<br /> c.drawColor(Color.BLACK);<br /> if(event.getAction()==MotionEvent.ACTION_UP){<br /> // 当手离开屏幕时，清屏<br /> c.drawColor(Color.BLACK);<br /> }else{<br /> // 先在屏幕上画一个十字，然后画一个圆<br /> for(int i=0;i<pointerCount;i++){<br /> //获取一个触点的坐标，然后开始绘制<br /> int id=event.getPointerId(i);<br /> int x=(int)event.getX(i);<br /> int y=(int)event.getY(i);<br /> drawCrosshairsAndText(x, y, touchPaints[id], i, id, c);<br /> }<br /> for(int i=0;i<pointerCount;i++){<br /> int id=event.getPointerId(i);<br /> int x=(int)event.getX(i);<br /> int y=(int)event.getY(i);<br /> drawCircle(x, y, touchPaints[id],c);<br /> }<br /> }<br /> getHolder().unlockCanvasAndPost(c);<br /> }<br /> return true;<br /> }</p> <p> private void drawCrosshairsAndText(int x, int y, Paint paint, int ptr,int id, Canvas c) {<br /> c.drawLine(0, y, width, y, paint);<br /> c.drawLine(x, 0, x, height, paint);<br /> int textY = (int) ((15 + 20 * ptr) * scale);<br /> c.drawText("x" + ptr + "=" + x, 10 * scale, textY, textPaint);<br /> c.drawText("y" + ptr + "=" + y, 70 * scale, textY, textPaint);<br /> c.drawText("id" + ptr + "=" + id, width - 55 * scale, textY, textPaint);<br /> } </p> <p> private void drawCircle(int x, int y, Paint paint, Canvas c) {<br /> c.drawCircle(x, y, 40 * scale, paint);<br /> } </p> <p> @Override<br /> public void surfaceChanged(SurfaceHolder holder, int format, int width,<br /> int height) {<br /> this.width = width;<br /> this.height = height;<br /> if (width > height){<br /> this.scale = width / 480f;<br /> } else {<br /> this.scale = height / 480f;<br /> }<br /> textPaint.setTextSize(14 * scale);<br /> Canvas c = getHolder().lockCanvas();<br /> if (c != null) { // 背景黑色<br /> c.drawColor(Color.BLACK);<br /> float tWidth = textPaint.measureText(START_TEXT);<br /> c.drawText(START_TEXT, width / 2 - tWidth / 2, height / 2,textPaint);<br /> getHolder().unlockCanvasAndPost(c);<br /> }<br /> }<br /> @Override<br /> public void surfaceCreated(SurfaceHolder holder) {<br /> // TODO Auto-generated method stub</p> <p> }<br /> @Override<br /> public void surfaceDestroyed(SurfaceHolder holder) {<br /> // TODO Auto-generated method stub</p> <p> } </p> <p>}<br />