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。

Swift 3解决方案

class CustomTextField: UITextField {

 override func textRect(forBounds bounds: CGRect) -> CGRect {
  return CGRect(x: bounds.origin.x + 10, y: bounds.origin.y + 8, width: bounds.size.width - 20, height: bounds.size.height - 16)
 }

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

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)

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)
    }
}

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

以下是如何在SWIFT中实现这一点

@IBOutlet weak var yourTextField: UITextField!

override func viewDidLoad() {
super.viewDidLoad()
let paddingView = UIView(frame: CGRectMake(0, 0, 10, self.yourTextField.frame.height))
yourTextField.leftView = paddingView
yourTextField.leftViewMode = UITextFieldViewMode.Always
}
}

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