你不能设置填充。而是有一个UIView，里面有你的背景图像和UITextField。设置UITextField的宽度为UIViewWidth-(paddingSize x 2)和高度相似，然后设置它在点paddingSize,paddingSize。

我创建了这个类别实现，并将其添加到.m文件的顶部。

@implementation UITextField (custom)
    - (CGRect)textRectForBounds:(CGRect)bounds {
        return CGRectMake(bounds.origin.x + 10, bounds.origin.y + 8,
                          bounds.size.width - 20, bounds.size.height - 16);
    }
    - (CGRect)editingRectForBounds:(CGRect)bounds {
        return [self textRectForBounds:bounds];
    }
@end

根据彼得·布拉斯亚克提供的链接。这似乎比创建一个全新的子类更简单，也比添加额外的UIView更简单。不过，似乎缺少了一些东西，无法控制文本字段内的填充。

Swift 4解决方案:

class CustomTextField: UITextField {
    struct Constants {
        static let sidePadding: CGFloat = 10
        static let topPadding: CGFloat = 8
    }

    override func textRect(forBounds bounds: CGRect) -> CGRect {
        return CGRect(
            x: bounds.origin.x + Constants.sidePadding,
            y: bounds.origin.y + Constants.topPadding,
            width: bounds.size.width - Constants.sidePadding * 2,
            height: bounds.size.height - Constants.topPadding * 2
        )
    }

    override func editingRect(forBounds bounds: CGRect) -> CGRect {
        return self.textRect(forBounds: bounds)
    }
}

你可以使用分类。设置左填充和右填充

UITextField+Padding.h

@interface UITextField (Padding)
@property (nonatomic, assign) CGFloat paddingValue;
@property (nonatomic, assign) CGFloat leftPadding;
@property (nonatomic, assign) CGFloat rightPadding;

//overwrite
-(CGRect)textRectForBounds:(CGRect)bounds;
-(CGRect)editingRectForBounds:(CGRect)bounds;
@end

UITextField+Padding.m

#import "UITextField+Padding.h"
#import <objc/runtime.h>

static char TAG_LeftPaddingKey;
static char TAG_RightPaddingKey;
static char TAG_Left_RightPaddingKey;

@implementation UITextField (Padding)

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wobjc-protocol-method-implementation"
-(CGRect)textRectForBounds:(CGRect)bounds {

CGFloat offset_Left=0;
CGFloat offset_Right=0;
if (self.paddingValue>0) {
    offset_Left=self.paddingValue;
    offset_Right=offset_Left;
}else{
    if (self.leftPadding>0){
        offset_Left=self.leftPadding;
    }
    if (self.rightPadding>0){
        offset_Right=self.rightPadding;
    }
}

if (offset_Left>0||offset_Right>0) {
    return CGRectMake(bounds.origin.x+ offset_Left ,bounds.origin.y ,
                      bounds.size.width- (offset_Left+offset_Right), bounds.size.height-2 );
 }else{
    return bounds;
 }
}



-(CGRect)editingRectForBounds:(CGRect)bounds {
    return [self textRectForBounds:bounds];
}
#pragma clang diagnostic pop


#pragma maek -setter&&getter
- (CGFloat)paddingValue
{
    return [objc_getAssociatedObject(self,&TAG_Left_RightPaddingKey) floatValue];
}
-(void)setPaddingValue:(CGFloat)paddingValue
{
    objc_setAssociatedObject(self, &TAG_Left_RightPaddingKey, @(paddingValue), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

-(CGFloat)leftPadding
{
    return [objc_getAssociatedObject(self,&TAG_LeftPaddingKey) floatValue];
}

-(void)setLeftPadding:(CGFloat)leftPadding
{
    objc_setAssociatedObject(self, &TAG_LeftPaddingKey, @(leftPadding), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

-(CGFloat)rightPadding
{
    return [objc_getAssociatedObject(self,&TAG_RightPaddingKey) floatValue];
}

-(void)setRightPadding:(CGFloat)rightPadding
{
    objc_setAssociatedObject(self, &TAG_RightPaddingKey, @(rightPadding), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

@end

你可以像这样设置填充 self.phoneNumTF.paddingValue f = 10.; 或 self.phoneNumTF.leftPadding f = 10.;

到目前为止，我找到的最佳解决方案是分类。这就是我如何在左右两侧添加5点填充:

@implementation UITextField (Padding)

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wobjc-protocol-method-implementation"
- (CGRect)textRectForBounds:(CGRect)bounds {
    return CGRectMake(bounds.origin.x + 5, bounds.origin.y,
                      bounds.size.width - 10, bounds.size.height);
}
- (CGRect)editingRectForBounds:(CGRect)bounds {
    return [self textRectForBounds:bounds];
}
#pragma clang diagnostic pop

@end

#pragma’s只是用来删除恼人的警告

下面是一个Swift代码，在UITextfield中提供填充

 func txtPaddingVw(txt:UITextField) {
     let paddingView = UIView(frame: CGRectMake(0, 0, 10, 10))
     txt.leftViewMode = .Always
     txt.leftView = paddingView
 }

调用using

self.txtPaddingVw(txtPin)

Swift 3的更新版本:

@IBDesignable
class FormTextField: UITextField {

    @IBInspectable var paddingLeft: CGFloat = 0
    @IBInspectable var paddingRight: CGFloat = 0

    override func textRect(forBounds bounds: CGRect) -> CGRect {
        return CGRect(x: bounds.origin.x + paddingLeft, y: bounds.origin.y, width: bounds.size.width - paddingLeft - paddingRight, height: bounds.size.height)
    }

    override func editingRect(forBounds bounds: CGRect) -> CGRect {
        return textRect(forBounds: bounds)
    }
}