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。