Android五子棋课程，画出的线有的透明有的不透明，求解

Question

public 
WuziqiPanel(Context context, AttributeSet attrs) {    
super
(context, attrs);
    setBackgroundColor(
0x44ff0000
);
    init();
}
private void 
init() {    
mPaint
.setColor(
0x88000000
);    
mPaint
.setAntiAlias(
true
);    
mPaint
.setDither(
true
);    
mPaint
.setStyle(Paint.Style.
STROKE
);    
mWhitePiece
= BitmapFactory.
decodeResource
(getResources(),R.drawable.
stone_w2
);    
mBlackPiece
= BitmapFactory.
decodeResource
(getResources(),R.drawable.
stone_b1
);

}