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
你也可以创建一个新的类TextViewWithPlaceholder作为UITextView的子类。
(这段代码有点粗糙——但我认为它在正确的轨道上。)
@interface TextViewWithPlaceholder : UITextView
{
NSString *placeholderText; // make a property
UIColor *placeholderColor; // make a property
UIColor *normalTextColor; // cache text color here whenever you switch to the placeholderColor
}
- (void) setTextColor: (UIColor*) color
{
normalTextColor = color;
[super setTextColor: color];
}
- (void) updateForTextChange
{
if ([self.text length] == 0)
{
normalTextColor = self.textColor;
self.textColor = placeholderColor;
self.text = placeholderText;
}
else
{
self.textColor = normalTextColor;
}
}
在委托中,添加以下内容:
- (void)textViewDidChange:(UITextView *)textView
{
if ([textView respondsToSelector: @selector(updateForTextChange)])
{
[textView updateForTextChange];
}
}
其他回答
你可以在textview上设置一个标签。
MyUITextView.h
@interface MyUITextView : UITextView {
UILabel* _placeholderLabel;
}
@property(nonatomic, assign)NSString *placeholder;
MyUITextView.m
@implementation MyUITextView
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
// Create placeholder
viewFrame = CGRectMake(0, 0, frame.size.width, 15);
_placeholderLabel = [[UILabel alloc] initWithFrame:viewFrame];
_placeholderLabel.textColor = [UIColor lightGrayColor];
[self addSubview:_placeholderLabel];
// Add text changed notification
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
}
return self;
}
- (void)setPlaceholder:(NSString *)placeholder {
_placeholderLabel.text = placeholder;
}
- (NSString*)placeholder {
return _placeholderLabel.text;
}
#pragma mark UITextViewTextDidChangeNotification
- (void)textChanged:(NSNotification *)notification {
_placeholderLabel.hidden = ([self.text lenght] == 0);
}
@end
嗨,你可以使用IQTextView可用的IQKeyboard管理器,这是简单的使用和集成只是设置类你的textview到IQTextView,你可以使用它的属性设置占位符标签与你想要的颜色。 您可以从IQKeyboardManager下载该库
或者你也可以从cocoapods上安装。
让我们简单点
创建一个UILabel并把它放在你的文本视图上(给文本作为占位符-设置颜色为灰色-你可以在你的xib中做这一切) 现在在头文件中声明UILabel和textviewDelegate 现在你可以简单地隐藏标签,当你点击textview
完整代码如下
头
@interface ViewController :UIViewController<UITextViewDelegate>{
}
@property (nonatomic,strong) IBOutlet UILabel *PlceHolder_label;
@property (nonatomic,strong) IBOutlet UITextView *TextView;
@end
实现
@implementation UploadFoodImageViewController
@synthesize PlceHolder_label,TextView;
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (BOOL)textViewShouldBeginEditing:(UITextView *)textView{
if([textView isEqual:TextView]){
[PlceHolder_label setHidden:YES];
[self.tabScrlVw setContentOffset:CGPointMake(0,150) animated:YES];
}
return YES;
}
@end
别忘了连接textView和UILabel文件所有者从xib
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。
这是我的版本的UITextView与占位符支持。斯威夫特4.2 https://gist.github.com/hlung/c5dda3a0c2087e5ae6c1fce8822c4713
一个支持占位符文本的UITextView子类。它使用另一个 UILabel显示占位符,当文本为空时显示。