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)
 }
}

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)
    }
}

就像这样子类UITextField (Swift版本):

import UIKit

class CustomTextField: UITextField {

    override func textRectForBounds(bounds: CGRect) -> CGRect {
       return CGRectInset(bounds, 25.0, 0)
    }

    override func editingRectForBounds(bounds: CGRect) -> CGRect {
       return self.textRectForBounds(bounds)
    }

}

这增加了25.0点的水平填充两边。

编辑:在iOS 11.3.1中仍然有效

在iOS 6 myTextField。leftView = paddingView;引起了问题

这就解决了问题

myTextField.layer.sublayerTransform = CATransform3DMakeTranslation(5, 0, 0)

对于右对齐的文本字段使用CATransform3DMakeTranslation(- 5,0,0)，正如latenitecoder在注释中提到的那样

@Evil trout的回答很棒。我使用这种方法已经有一段时间了。它唯一缺少的是“处理大量文本字段”。我尝试了其他方法，但似乎不奏效。

子类化UITextField只是为了添加填充对我来说没有任何意义。因此，我迭代了所有UITextFields来添加填充。

-(void) addPaddingToAllTextFields:(UIView*)view {

    for(id currentView in [view subviews]){
        if([currentView isKindOfClass:[UITextField class]]) {
            // Change value of CGRectMake to fit ur need
            [currentView setLeftView:[[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 20)]];
            [currentView setLeftViewMode:UITextFieldViewModeAlways];
        }

        if([currentView respondsToSelector:@selector(subviews)]){
            [textfieldarray addObjectsFromArray:[self addPaddingToAllTextFields:currentView]];
        }
    }
}

我发现使用不可编辑的UITextView并设置contenttoffset要容易得多

uiTextView.contentOffset = CGPointMake(8, 7);