How to create rounded UITextField with inner shadow

Question

I'm customizing a UITextfield to look like a UISearchbar.

I do something like

self.back_textfield = [[UITextField alloc]initWithFrame:CGRectMake(5, 7, 310, 30)];
[self.back_textfield setBorderStyle:UITextBorderStyleRoundedRect];
self.back_textfield.layer.cornerRadius = 15.0;

But I see this:

As you can see the inner shadow doesn't follow the border.

Answer 1

I guess background on a UITextField is an Image, so it no follow to your corner radius.
Creating inner shadow is tricky in iOS. You have 2 options.
1) Use image as background for UITextField
2) Set the shadow programmatically (but it look less attractive than option 1).

Here is the code for setting rounded inner shadow for textfield with solution from @Matt Wilding

_textField.layer.cornerRadius = 10.0f;

CAShapeLayer* shadowLayer = [CAShapeLayer layer];
[shadowLayer setFrame:_textField.bounds];

// Standard shadow stuff
[shadowLayer setShadowColor:[[UIColor colorWithWhite:0 alpha:1] CGColor]];
[shadowLayer setShadowOffset:CGSizeMake(0.0f, 0.0f)];
[shadowLayer setShadowOpacity:1.0f];
[shadowLayer setShadowRadius:4];

// Causes the inner region in this example to NOT be filled.
[shadowLayer setFillRule:kCAFillRuleEvenOdd];

// Create the larger rectangle path.
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, CGRectInset(_textField.bounds, -42, -42));

// Add the inner path so it's subtracted from the outer path.
// someInnerPath could be a simple bounds rect, or maybe
// a rounded one for some extra fanciness.
CGPathRef someInnerPath = [UIBezierPath bezierPathWithRoundedRect:_textField.bounds cornerRadius:10.0f].CGPath;
CGPathAddPath(path, NULL, someInnerPath);
CGPathCloseSubpath(path);

[shadowLayer setPath:path];
CGPathRelease(path);

[[_textField layer] addSublayer:shadowLayer];

CAShapeLayer* maskLayer = [CAShapeLayer layer];
[maskLayer setPath:someInnerPath];
[shadowLayer setMask:maskLayer];

Don't forget to import

#import <QuartzCore/QuartzCore.h>