如何在UITextField leftView图像上获得左边距？

Question

我在UIImageView上设置leftView为UITextField，如此：

UIImageView *envelopeView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.height*.1, self.height*.1)];
envelopeView.image = [UIImage imageNamed:@"envelope.png"];
envelopeView.contentMode = UIViewContentModeScaleAspectFit;
envelopeView.bounds = CGRectInset(envelopeView.frame, 15, 10);
self.emailAddress.leftView = envelopeView;
self.emailAddress.leftViewMode = UITextFieldViewModeAlways;

让我得到以下信息：

正如您所见，即使我尝试设置插图，图像的左侧大小也会一直向上移动到按钮的左边缘。如何移动这个信封，使其四面都有填充物？

更新：我尝试了如此更改UIImageView框架的建议答案，但信封仍然排列在UITextField边框的左侧：

CGFloat padding = 20;
UIImageView *envelopeView = [[UIImageView alloc] initWithFrame:CGRectMake(3*padding, padding, self.height*.1-padding, self.height*.1-padding)];

Answer 1

适用于Swift 3用户

这对我有用：

extension UITextField {

 /// set icon of 20x20 with left padding of 8px 
 func setLeftIcon(_ icon: UIImage) {

    let padding = 8
    let size = 20

    let outerView = UIView(frame: CGRect(x: 0, y: 0, width: size+padding, height: size) )
    let iconView  = UIImageView(frame: CGRect(x: padding, y: 0, width: size, height: size))
    iconView.image = icon
    outerView.addSubview(iconView)

    leftView = outerView
    leftViewMode = .always  
  }
}

试验：

txOrigin.setLeftIcon(icon_location)

结果：

Answer 2

对于Swift 4.2 +

您可以使用此扩展名：

extension UITextField {
    func leftImage(_ image: UIImage?, imageWidth: CGFloat, padding: CGFloat) {
        let imageView = UIImageView(image: image)
        imageView.frame = CGRect(x: padding, y: 0, width: imageWidth, height: frame.height)
        imageView.contentMode = .center
        
        let containerView = UIView(frame: CGRect(x: 0, y: 0, width: imageWidth + 2 * padding, height: frame.height))
        containerView.addSubview(imageView)
        leftView = containerView
        leftViewMode = .always
    }
}

Answer 3

你可以试试这个：

    UIImageView *envelopeView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 0, 30, 30)];
    envelopeView.image = [UIImage imageNamed:@"comment-128.png"];
    envelopeView.contentMode = UIViewContentModeScaleAspectFit;
  UIView *test=  [[UIView alloc]initWithFrame:CGRectMake(20, 0, 30, 30)];
    [test addSubview:envelopeView];
    [self.textField.leftView setFrame:envelopeView.frame];
    self.textField.leftView =test;
        self.textField.leftViewMode = UITextFieldViewModeAlways;

Answer 4

你可以用它。根据需要改变你的框架。

NSTextAttachment*   placeholderImageTextAttachment = [[NSTextAttachment alloc] init];
placeholderImageTextAttachment.image = [UIImage imageNamed:@"Search"];
placeholderImageTextAttachment.bounds = CGRectMake(0, -2, 16, 16);
NSMutableAttributedString*  placeholderImageString = [[NSAttributedString attributedStringWithAttachment:placeholderImageTextAttachment] mutableCopy];
 NSMutableAttributedString*  placeholderString = [[NSMutableAttributedString alloc] initWithString:NSLocalizedString(@"   Search", nil)];
[placeholderImageString appendAttributedString:placeholderString];
 _txtFieldSearch.attributedPlaceholder = placeholderImageString;
_txtFieldSearch.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;