UIImage *image = [UIImage imageNamed:@"playing"];
_layerView.layer.contents = (__bridge id)image.CGImage;
_layerView.layer.contentsCenter = CGRectMake(0.25, 0.25, 0.5, 0.5);
//同樣可以設(shè)置顯示的圖片范圍
//不過此處略有不同,這里的四個(gè)值均為0-1之間;對應(yīng)的依然是寫x,y,widt,height