Deduct square from view

-(Void) drawRect :( CGRect) rect {[super drawRect: rect]; CGContextRef ctx = UIGraphicsGetCurrentContext (); CGContextSetRGBFillColor (ctx ,. 3 ,. 3 ,. 3 ,. 1); CGContextFillRect (ctx, self. bounds); CGContextSetStrokeColorWithColor (ctx, [UIColor whiteColor]. CGColor); CGContextStrokeRectWithWidth (ctx, _ clearRect, 2); CGContextClearRect (ctx, _ clearRect );}

A mask layer problem occurs in the project. The entire view is transparent in the middle of the light gray area. You can see the content displayed on the view below!