加阴影的方法

一、给图片加上阴影 

 UIImageView*pageContenterImageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"onePageApple.png"]];

        

         //添加边框

        

         CALayer*layer = [pageContenterImageView layer];

        

        layer.borderColor= [[UIColor whiteColor]CGColor];

        

        layer.borderWidth=0.0f;

        

        //添加四个边阴影

        

        pageContenterImageView.layer.shadowColor= [UIColor blackColor].CGColor;

        

        pageContenterImageView.layer.shadowOffset=CGSizeMake(0,0);

        

        pageContenterImageView.layer.shadowOpacity=0.5; 

        

        pageContenterImageView.layer.shadowRadius=5.0;

        

        //添加两个边阴影

        

        //pageContenterImageView.layer.shadowColor = [UIColor blackColor].CGColor;

        

        //    pageContenterImageView.layer.shadowOffset = CGSizeMake(2, 2);

        

        //    pageContenterImageView.layer.shadowOpacity = 0.5; 

        

        //    pageContenterImageView.layer.shadowRadius = 2.0;

        

        //-------------

        

        阴影渲染会严重消耗内存 ,导致程序咔叽.

        

         /*阴影效果*/

        

         //添加边框

        

        CALayer*layer = [self.pageContenter layer];

        

        layer.borderColor= [[UIColorwhiteColor]CGColor];

        

        layer.borderWidth=0.0f;

        

        //添加四个边阴影

        

         self.pageContenter.layer.shadowColor= [UIColorblackColor].CGColor;//阴影颜色

        

         self.pageContenter.layer.shadowOffset=CGSizeMake(0,0);//阴影偏移

        

         self.pageContenter.layer.shadowOpacity=0.5;//阴影不透明度

        

         self.pageContenter.layer.shadowRadius=5.0;//阴影半径

        

        //添加两个边阴影

        

        //self.pageContenter.layer.shadowColor = [UIColor blackColor].CGColor;

        

        //self.pageContenter.layer.shadowOffset = CGSizeMake(2, 2);

        

        //self.pageContenter.layer.shadowOpacity = 0.5; 

        

        //self.pageContenter.layer.shadowRadius = 2.0; 



二、给视图加上阴影


 UIView * content=[[UIView alloc] initWithFrame:CGRectMake(100, 250, 503,  500)]; 

    content.backgroundColor=[UIColor orangeColor];

    //content.layer.shadowOffset=10;

    

    

    content.layer.shadowOffset = CGSizeMake(5, 3);

    content.layer.shadowOpacity = 0.6;

    content.layer.shadowColor = [UIColor blackColor].CGColor;

    

    

    [self.window addSubview:content];