给普通的view添加边框和背景 （关于layer的一些属性）

UIImageView *imgvPhoto  = [UIImageView alloc] init];

//添加边框
CALayer *layer = [_imgvPhoto layer];
layer.borderColor = [[UIColor whiteColor] CGColor];
layer.borderWidth = 5.0f;
//添加四个边阴影
_imgvPhoto.layer.shadowColor = [UIColor blackColor].CGColor;
_imgvPhoto.layer.shadowOffset = CGSizeMake(0, 0);
_imgvPhoto.layer.shadowOpacity = 0.5;
_imgvPhoto.layer.shadowRadius = 10.0;
//添加两个边阴影
_imgvPhoto.layer.shadowColor = [UIColor blackColor].CGColor;
_imgvPhoto.layer.shadowOffset = CGSizeMake(4, 4);
_imgvPhoto.layer.shadowOpacity = 0.5;
_imgvPhoto.layer.shadowRadius = 2.0;

layer.backgroundColor = [UIColor cyanColor].CGColor; // 给图层添加背景色
layer.contents = (id)[UIImage imageNamed:@"view_BG.png"].CGImage; // 给图层添加背景图片
layer.cornerRadius = 8;  // 将图层的边框设置为圆脚
layer.masksToBounds = YES; // 隐藏边界
layer.borderWidth = 5;  // 给图层添加一个有色边框
layer.borderColor = [UIColor colorWithRed:0.52 green:0.09 blue:0.07 alpha:1].CGColor;
layer.shadowOffset = CGSizeMake(0, 3);  // 设置阴影的偏移量
layer.shadowRadius = 10.0;  // 设置阴影的半径
layer.shadowColor = [UIColor blackColor].CGColor; // 设置阴影的颜色为黑色
layer.shadowOpacity = 0.9; // 设置阴影的不透明度