ios 如何左对齐 UISearchBar 占位符文本
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How to left align UISearchBar placeholder text
提问by Chandler De Angelis
I need to make a custom search bar like this. The problem I am having is left aligning the placeholder text, as well as placing the search icon in the right. I have a png of the search icon that I have tried to use in an UIImageView, and set that UIImageViewas the rightViewof the UISearchBar's UITextField. This solution has not worked, and I ran out of ideas. Does anyone have a solution?
我需要制作一个这样的自定义搜索栏。我遇到的问题是左对齐占位符文本，以及将搜索图标放在右边。我有搜索图标的PNG，我曾尝试使用在UIImageView，并设置UIImageView为rightView在的UISearchBar的UITextField。这个解决方案没有奏效，我的想法用完了。有没有人有办法解决吗？
采纳答案by paulrehkugler
Don't use a UISearchBarif you need to do these kinds of customizations. You'll have to make your own using a UITextFieldand a UIImageView, and responding to the delegate calls.
UISearchBar如果您需要进行这些类型的自定义，请不要使用 a 。您必须自己使用 aUITextField和 a UIImageView，并响应委托调用。
回答by Mounika Vangala
SWIFT 3
斯威夫特 3
swift 3 does not allow to override placeholder property. This is the modified version of Drix answer.
swift 3 不允许覆盖占位符属性。这是 Drix 答案的修改版本。
func setPlaceHolder(placeholder: String)-> String
{
var text = placeholder
if text.characters.last! != " " {
// define a max size
let maxSize = CGSize(width: UIScreen.main.bounds.size.width - 97, height: 40)
// let maxSize = CGSizeMake(self.bounds.size.width - 92, 40)
// get the size of the text
let widthText = text.boundingRect( with: maxSize, options: .usesLineFragmentOrigin, attributes:nil, context:nil).size.width
// get the size of one space
let widthSpace = " ".boundingRect( with: maxSize, options: .usesLineFragmentOrigin, attributes:nil, context:nil).size.width
let spaces = floor((maxSize.width - widthText) / widthSpace)
// add the spaces
let newText = text + ((Array(repeating: " ", count: Int(spaces)).joined(separator: "")))
// apply the new text if nescessary
if newText != text {
return newText
}
}
return placeholder;
}
and call the function as :
并将函数调用为：
searchBar.placeholder = self.setPlaceHolder(placeholder: "your placeholder text");
回答by Adriano Spadoni
Based in Mohittomar answer, as asked by @DevC to add spaces to the end of the place holder, here the code in swift:
基于 Mohittomar 的回答，正如@DevC 所要求的那样在占位符的末尾添加空格，这里是 swift 中的代码：
I subclass placeholder in the UISearchBar, after set the value, I check if the last character is a space. then get the size of one space and how many spaces I need to add to align left.
我将 UISearchBar 中的占位符子类化，设置值后，我检查最后一个字符是否为空格。然后获取一个空格的大小以及我需要添加多少空格才能左对齐。
class SearchBar: UISearchBar, UISearchBarDelegate {
override var placeholder:String? {
didSet {
if let text = placeholder {
if text.last != " " {
// get the font attribute
let attr = UITextField.s_appearanceWhenContainedIn(SearchBar).defaultTextAttributes
// define a max size
let maxSize = CGSizeMake(UIScreen.mainScreen().bounds.size.width - 60, 40)
// get the size of the text
var widthText = text.boundingRectWithSize( maxSize, options: .UsesLineFragmentOrigin, attributes:attr, context:nil).size.width
// get the size of one space
var widthSpace = " ".boundingRectWithSize( maxSize, options: .UsesLineFragmentOrigin, attributes:attr, context:nil).size.width
let spaces = floor((maxSize.width - widthText) / widthSpace)
// add the spaces
let newText = text + (" " * spaces)
// apply the new text if nescessary
if newText != text {
placeholder = newText
}
}
}
}
}
回答by fede1608
A working solution for Drix answer
Drix 答案的有效解决方案
import Foundation
import UIKit
class LeftAlignedSearchBar: UISearchBar, UISearchBarDelegate {
override var placeholder:String? {
didSet {
if #available(iOS 9.0, *) {
if let text = placeholder {
if text.characters.last! != " " {
// get the font attribute
let attr = UITextField.appearanceWhenContainedInInstancesOfClasses([LeftAlignedSearchBar.self]).defaultTextAttributes
// define a max size
let maxSize = CGSizeMake(UIScreen.mainScreen().bounds.size.width - 87, 40)
// let maxSize = CGSizeMake(self.bounds.size.width - 92, 40)
// get the size of the text
let widthText = text.boundingRectWithSize( maxSize, options: .UsesLineFragmentOrigin, attributes:attr, context:nil).size.width
// get the size of one space
let widthSpace = " ".boundingRectWithSize( maxSize, options: .UsesLineFragmentOrigin, attributes:attr, context:nil).size.width
let spaces = floor((maxSize.width - widthText) / widthSpace)
// add the spaces
let newText = text + ((Array(count: Int(spaces), repeatedValue: " ").joinWithSeparator("")))
// apply the new text if nescessary
if newText != text {
placeholder = newText
}
}
}
}
}
}
}
This method appearanceWhenContainedInInstancesOfClasses is not available in iOS 8, there is a workaround for iOS 8 here
这种方法appearanceWhenContainedInInstancesOfClasses是不是在iOS的8个可用的，有针对iOS 8一种变通方法在这里
回答by Lion
A working swift 3 solution for Drix answer:
Drix 的一个有效的 swift 3 解决方案：
import Foundation
import UIKit
class LeftAlignedSearchBar: UISearchBar, UISearchBarDelegate {
override var placeholder:String? {
didSet {
if #available(iOS 9.0, *) {
if let text = placeholder {
if text.characters.last! != " " {
// get the font attribute
let attr = UITextField.appearance(whenContainedInInstancesOf: [LeftAlignedSearchBar.self]).defaultTextAttributes
// define a max size
let maxSize = CGSize(width: UIScreen.main.bounds.size.width - 87, height: 40)
// let maxSize = CGSize(width:self.bounds.size.width - 92,height: 40)
// get the size of the text
let widthText = text.boundingRect( with: maxSize, options: .usesLineFragmentOrigin, attributes:attr, context:nil).size.width
// get the size of one space
let widthSpace = " ".boundingRect( with: maxSize, options: .usesLineFragmentOrigin, attributes:attr, context:nil).size.width
let spaces = floor((maxSize.width - widthText) / widthSpace)
// add the spaces
let newText = text + ((Array(repeating: " ", count: Int(spaces)).joined(separator: "")))
// apply the new text if nescessary
if newText != text {
placeholder = newText
}
}
}
}
}
}
/*
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
// Drawing code
}
*/
}
回答by cain
it could be done from story board there is combo box with name semantic on attribute inspector of search bar if you set it to force right to left its done you have right align search bar and it has a similar thing for aligning from left
它可以从故事板完成，搜索栏的属性检查器上有一个带有名称语义的组合框，如果您将其设置为强制从右到左完成，您可以右对齐搜索栏，并且它具有类似的从左对齐的功能
回答by Vlkam
Version for Xamarin
Xamarin 版本
SearchBar.MovePlaceHolderLeft();
public static void MovePlaceHolderLeft(this UISearchBar searchbar)
{
NSAttributedString text = new NSAttributedString(searchbar.Placeholder ?? "");
// define a max size
var maxSize = new CGSize(width: UIScreen.MainScreen.Bounds.Size.Width - 97, height: 40);
// get the size of the text
var widthText = text.GetBoundingRect(maxSize, NSStringDrawingOptions.UsesLineFragmentOrigin, null).Size.Width;
// get the size of one space
var widthSpace = new NSAttributedString(" ").GetBoundingRect(maxSize, NSStringDrawingOptions.UsesLineFragmentOrigin, null).Size.Width;
var spaces = Math.Floor((maxSize.Width - widthText) / widthSpace);
// add the spaces
string newText = searchbar.Placeholder;
for (double i = 0; i < spaces; i++)
{
newText += " ";
}
searchbar.Placeholder = newText;
}
回答by ameunier
If you want your control to respond exactly how you want, you should probably make your own custom control. This control could be separated in three parts :
如果您希望您的控件完全按照您的意愿做出响应，您可能应该制作自己的自定义控件。该控件可以分为三个部分：
- a background
UIImageView - a
UITextField - a
UIButtonfor the the search icon if you want the user to interact with it
- 背景
UIImageView - 一种
UITextField - a
UIButton用于搜索图标，如果您希望用户与之交互
The easiest way to do that is probably to create a new class MySearchBar, with the three parts in the private interface :
最简单的方法可能是创建一个新类MySearchBar，在私有接口中包含三个部分：
@interface MySearchBar ()
@property (nonatomic, strong) UISearchBar* searchBar;
@property (nonatomic, strong) UITextField* textField;
@property (nonatomic, strong) UIButton* button;
@end
In your MySearchBar, you can create your component, customize it, add a better look & feel. To get back the search result, your control can have a delegate id<UISearchBarDelegate>(your UIViewController) which will basically simulate having a standard UISearchBar.
在你的 中MySearchBar，你可以创建你的组件，自定义它，添加更好的外观和感觉。为了取回搜索结果，您的控件可以有一个委托id<UISearchBarDelegate>（您的UIViewController），它基本上模拟拥有一个标准的 UISearchBar。
What remains is to create your MySearchBarin your controller and set the delegate to your view controller. The messages from the UISearchBarDelegatecan either go to your MySearchBarto filter or do pre-treatment before sending to your UIViewController, or go directly to your UIViewController.
剩下的就是MySearchBar在您的控制器中创建您的并将委托设置为您的视图控制器。来自 的消息UISearchBarDelegate可以先到您MySearchBar的过滤器或在发送到您UIViewController的UIViewController.
回答by Mohit Tomar
No need to any customization just do it...
无需任何定制就可以了...
searchBar.placeholder=@"Search ";
searchbar has centeral text alignment for its place-hoder , so just give some big text. and if you text is small then just use some space after place-holder text.
搜索栏的 place-hoder 具有居中文本对齐方式，因此只需提供一些大文本即可。如果您的文本很小，那么只需在占位符文本后使用一些空间。
回答by Faran Rasheed
It's too late, but if anyone is still wondering the solution, then you can follow this.
为时已晚，但是如果有人仍然想知道解决方案，那么您可以按照此操作。
UITextField *searchTextField = [searchBarController.searchBar valueForKey:@"_searchField"];
You can get the search field using above code. Now simply use the properties you want to use, like.
您可以使用上面的代码获取搜索字段。现在只需使用您想要使用的属性，例如。
searchTextField.layer.cornerRadius = 10.0f;
searchTextField.textAlignment = NSTextAlignmentLeft;
PS. Text alignment property is used for text and placeholder both. Thanks.
附注。文本对齐属性用于文本和占位符。谢谢。
