我的应用程序使用UITextView。现在我想让UITextView有一个占位符,类似于你可以为UITextField设置的占位符。
如何做到这一点?
我的应用程序使用UITextView。现在我想让UITextView有一个占位符,类似于你可以为UITextField设置的占位符。
如何做到这一点?
当前回答
斯威夫特3.1
在尝试了所有快速的答案之后,这个答案将为我节省3个小时的研究时间。希望这能有所帮助。
确保你的textField(不管你有什么自定义名称)指向它在Storyboard中的委托,并且有一个@IBOutlet和你的customtextfield 将以下内容添加到viewDidLoad()中,加载视图时会出现:
告诉我什么看起来是占位符:
yourCustomTextField = "Start typing..."
yourCustomTextField.textColor = .lightGray
在viewDidLoad外部但在同一个类内部添加以下声明:UIViewController, UITextViewDelegate, UINavigationControllerDelegate
这段代码将使yourCustomTextField在输入textField时消失:
func textViewDidBeginEditing (_ textView: UITextView) {
if (textView.text == "Start typing...") {
textView.text = ""
textView.textColor = .black
}
textView.becomeFirstResponder()
}
func textViewDidEndEditing(_ textView: UITextView) {
if (textView.text == "") {
textView.text = "Start typing..."
textView.textColor = .lightGray
}
textView.resignFirstResponder()
}
其他回答
修改占位符文本颜色最简单的方法是通过XCode故事板接口构建器。选择感兴趣的UITextField并打开右侧的标识检查器。单击User Defined Runtime Attributes中的加号,并添加一个新行,其中Key Path为_placeholderLabel。输入颜色和值到你想要的颜色。
在代码行中使用它的简单方法:
取一个标签到。nib中的UITextView 将这个标签连接到你的代码, 在它。
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
if (range.location>0 || text.length!=0) {
placeholderLabel1.hidden = YES;
}else{
placeholderLabel1.hidden = NO;
}
return YES;
}
我刚刚发现,在iOS 10中,你现在可以将UITextView转换为方法的UITextField,并在方法中设置占位符。刚试过,它不需要子类化UITextView就能工作。
下面是一个对我有用的例子:
-(void)customizeTextField:(UITextField *)textField placeholder:(NSString *)pText withColor:(UIColor *)pTextColor{
textField.attributedPlaceholder = [[NSAttributedString alloc]
initWithString:pText
attributes:@{NSForegroundColorAttributeName:pTextColor}];
}
为了将它用于UITextView,你只需要将它传递给方法,使用像这样的类型转换:
[self customizeTextField:(UITextField*)_myTextView placeholder:@"Placeholder" withColor:[UIColor blackColor]];
注:经过测试,我发现这个解决方案在iOS9上也很好。但是会在iOS8.x上导致崩溃
我对发布的任何解决方案都不太满意,因为它们有点重。向视图中添加视图并不理想(尤其是在drawRect:)。它们都有漏洞,这也是不可接受的。
这是我的解决方案:SAMTextView
SAMTextView.h
//
// SAMTextView.h
// SAMTextView
//
// Created by Sam Soffes on 8/18/10.
// Copyright 2010-2013 Sam Soffes. All rights reserved.
//
#import <UIKit/UIKit.h>
/**
UITextView subclass that adds placeholder support like UITextField has.
*/
@interface SAMTextView : UITextView
/**
The string that is displayed when there is no other text in the text view.
The default value is `nil`.
*/
@property (nonatomic, strong) NSString *placeholder;
/**
The color of the placeholder.
The default is `[UIColor lightGrayColor]`.
*/
@property (nonatomic, strong) UIColor *placeholderTextColor;
/**
Returns the drawing rectangle for the text views’s placeholder text.
@param bounds The bounding rectangle of the receiver.
@return The computed drawing rectangle for the placeholder text.
*/
- (CGRect)placeholderRectForBounds:(CGRect)bounds;
@end
SAMTextView.m
//
// SAMTextView.m
// SAMTextView
//
// Created by Sam Soffes on 8/18/10.
// Copyright 2010-2013 Sam Soffes. All rights reserved.
//
#import "SAMTextView.h"
@implementation SAMTextView
#pragma mark - Accessors
@synthesize placeholder = _placeholder;
@synthesize placeholderTextColor = _placeholderTextColor;
- (void)setText:(NSString *)string {
[super setText:string];
[self setNeedsDisplay];
}
- (void)insertText:(NSString *)string {
[super insertText:string];
[self setNeedsDisplay];
}
- (void)setAttributedText:(NSAttributedString *)attributedText {
[super setAttributedText:attributedText];
[self setNeedsDisplay];
}
- (void)setPlaceholder:(NSString *)string {
if ([string isEqual:_placeholder]) {
return;
}
_placeholder = string;
[self setNeedsDisplay];
}
- (void)setContentInset:(UIEdgeInsets)contentInset {
[super setContentInset:contentInset];
[self setNeedsDisplay];
}
- (void)setFont:(UIFont *)font {
[super setFont:font];
[self setNeedsDisplay];
}
- (void)setTextAlignment:(NSTextAlignment)textAlignment {
[super setTextAlignment:textAlignment];
[self setNeedsDisplay];
}
#pragma mark - NSObject
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self name:UITextViewTextDidChangeNotification object:self];
}
#pragma mark - UIView
- (id)initWithCoder:(NSCoder *)aDecoder {
if ((self = [super initWithCoder:aDecoder])) {
[self initialize];
}
return self;
}
- (id)initWithFrame:(CGRect)frame {
if ((self = [super initWithFrame:frame])) {
[self initialize];
}
return self;
}
- (void)drawRect:(CGRect)rect {
[super drawRect:rect];
if (self.text.length == 0 && self.placeholder) {
rect = [self placeholderRectForBounds:self.bounds];
UIFont *font = self.font ? self.font : self.typingAttributes[NSFontAttributeName];
// Draw the text
[self.placeholderTextColor set];
[self.placeholder drawInRect:rect withFont:font lineBreakMode:NSLineBreakByTruncatingTail alignment:self.textAlignment];
}
}
#pragma mark - Placeholder
- (CGRect)placeholderRectForBounds:(CGRect)bounds {
// Inset the rect
CGRect rect = UIEdgeInsetsInsetRect(bounds, self.contentInset);
if (self.typingAttributes) {
NSParagraphStyle *style = self.typingAttributes[NSParagraphStyleAttributeName];
if (style) {
rect.origin.x += style.headIndent;
rect.origin.y += style.firstLineHeadIndent;
}
}
return rect;
}
#pragma mark - Private
- (void)initialize {
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:self];
self.placeholderTextColor = [UIColor colorWithWhite:0.702f alpha:1.0f];
}
- (void)textChanged:(NSNotification *)notification {
[self setNeedsDisplay];
}
@end
它比其他的要简单得多,因为它不使用子视图(或有泄漏)。请随意使用。
更新11/10/11:它现在是文档化的,并支持在接口生成器中使用。
更新11/24/13:指向新的回购。
我建议使用pod 'UITextView+Placeholder'
pod 'UITextView+Placeholder'
在代码中
#import "UITextView+Placeholder.h"
////
UITextView *textView = [[UITextView alloc] init];
textView.placeholder = @"How are you?";
textView.placeholderColor = [UIColor lightGrayColor];