刮刮乐自定义view

说明：该代码是参考鸿洋大神的刮刮乐自定义view来写的。

实现：刮刮乐-刮奖的效果，如下效果

下面直接放代码了：只有一个自定义view，要实现真正的功能还需要进一步封装

 /**
  *    自定义view-刮刮乐
  */
 public class GuaGuaKaView extends View{

     /**
      * 记录用户绘制的Path
      */
     private Path mPath = new Path();

     /**
      * mCanvas绘制内容在其上
      */
     private Bitmap mBitmap;

     /**
      * 内存中创建的Canvas
      */
     private Canvas mCanvas;  

     /**
      * 绘制线条的Paint,即用户手指绘制Path
      */
     private Paint mOutterPaint = new Paint();
     private int mLastX;
     private int mLastY;
     private boolean isComplete=false;

     private int[] mPixels;
     private Paint mBackPint = new Paint();
     private Rect mTextBound = new Rect();
     private String mText = "50,000 元";

     public GuaGuaKaView(Context context)
     {
         this(context, null);
     }  

     public GuaGuaKaView(Context context, AttributeSet attrs)
     {
         this(context, attrs, 0);
     }  

     public GuaGuaKaView(Context context, AttributeSet attrs, int defStyle)
     {
         super(context, attrs, defStyle);
         init();
     }  

     private void init()
     {
         mPath = new Path();
     }

     @Override
     protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
         super.onMeasure(widthMeasureSpec, heightMeasureSpec);
         int width=getMeasuredWidth();
         int height=getMeasuredHeight();
         mBitmap=Bitmap.createBitmap(width, height, Config.ARGB_8888);
         mCanvas=new Canvas(mBitmap);
         setUpBackPaint();
         setUpOutPaint();
         mCanvas.drawColor(Color.parseColor("#c0c0c0"));
         Bitmap bitmap=BitmapFactory.decodeResource(getResources(), R.drawable.s_title);
         mCanvas.drawBitmap(bitmap, null,new RectF(0, 0, width, height), null);
     }

     private void setUpOutPaint() {
         //设置画笔
         mOutterPaint.setColor(Color.RED);
         mOutterPaint.setDither(true);//?
         mOutterPaint.setAntiAlias(true);//设置是否有锯齿
         mOutterPaint.setStyle(Paint.Style.STROKE);
         mOutterPaint.setStrokeJoin(Paint.Join.ROUND);//?
         mOutterPaint.setStrokeCap(Paint.Cap.ROUND);//?

         //设置画笔宽度
         mOutterPaint.setStrokeWidth(50);
     }

     /**
      * 初始化canvas的绘制用的画笔
      */
     private void setUpBackPaint()
     {
         mBackPint.setStyle(Style.FILL);
         mBackPint.setTextScaleX(2f);
         mBackPint.setColor(Color.DKGRAY);
         mBackPint.setTextSize(50);
         mBackPint.getTextBounds(mText, 0, mText.length(), mTextBound);
     }  

     @Override
     protected void onDraw(Canvas canvas) {
         drawBackText(canvas);
         if(!isComplete){
             drawPath();
             canvas.drawBitmap(mBitmap, 0, 0,null);
         }
     }

     private void drawBackText(Canvas canvas) {
         //绘制奖项
         canvas.drawText(mText, getWidth() / 2 - mTextBound.width() / 2,
                 getHeight() / 2 + mTextBound.height() / 2, mBackPint);
     }

     /**
      * 绘制线头
      */
     private void drawPath() {
         mOutterPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_OUT));
         mCanvas.drawPath(mPath, mOutterPaint);
     }

     @Override
     public boolean onTouchEvent(MotionEvent event) {
         int action=event.getAction();
         int x=(int) event.getX();
         int y=(int) event.getY();
         switch (action) {
         case MotionEvent.ACTION_DOWN:
             mLastX=x;
             mLastY=y;
             mPath.moveTo(mLastX, mLastY);
             break;
         case MotionEvent.ACTION_MOVE:
             int dx=Math.abs(x-mLastX);
             int dy=Math.abs(y-mLastY);
             if(dx>3||dy>3){
                 mPath.lineTo(x, y);
             }
             mLastX=x;
             mLastY=y;
             break;
         case MotionEvent.ACTION_UP:
             new Thread(mRunnable).start();
             break;
         default:
             break;
         }
         invalidate();
         return true;
     }

     /*
      * 统计擦除区域的面积
      */
     private Runnable mRunnable=new Runnable() {

         @Override
         public void run() {
             int w=getWidth();
             int h=getHeight();
             float wipeArea=0;
             float totalArea=w*h;//总面积
             Bitmap bitmap=mBitmap;
             mPixels=new int[w*h];
             //拿到所有的像素信息 ？
             bitmap.getPixels(mPixels, 0, w, 0, 0, w, h);

             //遍历统计擦除的区域
             for(int i=0;i<w;i++){
                 for(int j=0;j<h;j++){
                     int index=i+j*w;
                     if(mPixels[index]==0){//擦除后，该点像素值为0
                         wipeArea++;
                     }
                 }
             }

             if(wipeArea>0&&totalArea>0){
                 int percent=(int)(wipeArea*100/totalArea);
                 Log.e("TAG", percent+"");
                 if(percent>70){
                     isComplete=true;
                     postInvalidate();
                 }
             }
         }
     };

 }

至此，完了。