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
我找到了自己的解决方案
- (void)textViewDidBeginEditing:(UITextView *)textView
{
if ([textView.text isEqualToString:PLACEHOLDER_TEXT])
{
textView.textColor = [UIColor lightGrayColor];
dispatch_async(dispatch_get_main_queue(), ^
{
textView.selectedRange = NSMakeRange(0, 0);
});
}
else
{
textView.textColor = [UIColor blackColor];
}
[textView becomeFirstResponder];
}
- (void)textViewDidEndEditing:(UITextView *)textView
{
if ([textView.text isEqualToString:@""])
{
textView.text = PLACEHOLDER_TEXT;
textView.textColor = [UIColor lightGrayColor];
}
[textView resignFirstResponder];
}
- (BOOL)textView:(UITextView *)textView
shouldChangeTextInRange:(NSRange)range
replacementText:(NSString *)text
{
if (range.location == 0 && range.length == [[textView text] length] && [text isEqualToString:@""])
{
textView.text = PLACEHOLDER_TEXT;
textView.textColor = [UIColor lightGrayColor];
dispatch_async(dispatch_get_main_queue(), ^
{
textView.selectedRange = NSMakeRange(0, 0);
});
return NO;
}
if ([textView.text isEqualToString:PLACEHOLDER_TEXT])
{
textView.text = @"";
textView.textColor = [UIColor blackColor];
}
return YES;
}
其他回答
我对bcd的解决方案做了一些小修改,以允许从Xib文件初始化、文本包装和保持背景颜色。希望它能为其他人省去麻烦。
UIPlaceHolderTextView.h:
#import <Foundation/Foundation.h>
IB_DESIGNABLE
@interface UIPlaceHolderTextView : UITextView
@property (nonatomic, retain) IBInspectable NSString *placeholder;
@property (nonatomic, retain) IBInspectable UIColor *placeholderColor;
-(void)textChanged:(NSNotification*)notification;
@end
UIPlaceHolderTextView.m:
#import "UIPlaceHolderTextView.h"
@interface UIPlaceHolderTextView ()
@property (nonatomic, retain) UILabel *placeHolderLabel;
@end
@implementation UIPlaceHolderTextView
CGFloat const UI_PLACEHOLDER_TEXT_CHANGED_ANIMATION_DURATION = 0.25;
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
#if __has_feature(objc_arc)
#else
[_placeHolderLabel release]; _placeHolderLabel = nil;
[_placeholderColor release]; _placeholderColor = nil;
[_placeholder release]; _placeholder = nil;
[super dealloc];
#endif
}
- (void)awakeFromNib
{
[super awakeFromNib];
// Use Interface Builder User Defined Runtime Attributes to set
// placeholder and placeholderColor in Interface Builder.
if (!self.placeholder) {
[self setPlaceholder:@""];
}
if (!self.placeholderColor) {
[self setPlaceholderColor:[UIColor lightGrayColor]];
}
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
}
- (id)initWithFrame:(CGRect)frame
{
if( (self = [super initWithFrame:frame]) )
{
[self setPlaceholder:@""];
[self setPlaceholderColor:[UIColor lightGrayColor]];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
}
return self;
}
- (void)textChanged:(NSNotification *)notification
{
if([[self placeholder] length] == 0)
{
return;
}
[UIView animateWithDuration:UI_PLACEHOLDER_TEXT_CHANGED_ANIMATION_DURATION animations:^{
if([[self text] length] == 0)
{
[[self viewWithTag:999] setAlpha:1];
}
else
{
[[self viewWithTag:999] setAlpha:0];
}
}];
}
- (void)setText:(NSString *)text {
[super setText:text];
[self textChanged:nil];
}
- (void)drawRect:(CGRect)rect
{
if( [[self placeholder] length] > 0 )
{
if (_placeHolderLabel == nil )
{
_placeHolderLabel = [[UILabel alloc] initWithFrame:CGRectMake(8,8,self.bounds.size.width - 16,0)];
_placeHolderLabel.lineBreakMode = NSLineBreakByWordWrapping;
_placeHolderLabel.numberOfLines = 0;
_placeHolderLabel.font = self.font;
_placeHolderLabel.backgroundColor = [UIColor clearColor];
_placeHolderLabel.textColor = self.placeholderColor;
_placeHolderLabel.alpha = 0;
_placeHolderLabel.tag = 999;
[self addSubview:_placeHolderLabel];
}
_placeHolderLabel.text = self.placeholder;
[_placeHolderLabel sizeToFit];
[self sendSubviewToBack:_placeHolderLabel];
}
if( [[self text] length] == 0 && [[self placeholder] length] > 0 )
{
[[self viewWithTag:999] setAlpha:1];
}
[super drawRect:rect];
}
@end
我建议使用SZTextView。
https://github.com/glaszig/SZTextView
从storyboard中添加默认的UITextView,然后将其自定义类更改为SZTextView,如下所示
然后您将在属性检查器中看到两个新选项
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。
基于这里已经给出的一些很好的建议,我能够将以下轻量级的、与接口生成器兼容的UITextView子类组合在一起,它是:
包括可配置的占位符文本,样式就像UITextField一样。 不需要任何额外的子视图或约束。 不需要来自ViewController的任何委托或其他行为。 不需要任何通知。 保持该文本与查看字段的文本属性的任何外部类完全分离。
欢迎提出改进建议。
编辑1:更新为重置占位符格式,如果实际文本以编程方式设置。
编辑2:现在可以以编程方式检索占位符文本颜色。
斯威夫特v5:
import UIKit
@IBDesignable class TextViewWithPlaceholder: UITextView {
override var text: String! { // Ensures that the placeholder text is never returned as the field's text
get {
if showingPlaceholder {
return "" // When showing the placeholder, there's no real text to return
} else { return super.text }
}
set {
if showingPlaceholder {
removePlaceholderFormatting() // If the placeholder text is what's being changed, it's no longer the placeholder
}
super.text = newValue
}
}
@IBInspectable var placeholderText: String = ""
@IBInspectable var placeholderTextColor: UIColor = .placeholderText
private var showingPlaceholder: Bool = true // Keeps track of whether the field is currently showing a placeholder
override func didMoveToWindow() {
super.didMoveToWindow()
if text.isEmpty {
showPlaceholderText() // Load up the placeholder text when first appearing, but not if coming back to a view where text was already entered
}
}
override public func becomeFirstResponder() -> Bool {
// If the current text is the placeholder, remove it
if showingPlaceholder {
text = nil
removePlaceholderFormatting()
}
return super.becomeFirstResponder()
}
override public func resignFirstResponder() -> Bool {
// If there's no text, put the placeholder back
if text.isEmpty {
showPlaceholderText()
}
return super.resignFirstResponder()
}
private func showPlaceholderText() {
text = placeholderText
showingPlaceholder = true
textColor = placeholderTextColor
}
private func removePlaceholderFormatting() {
showingPlaceholder = false
textColor = nil // Put the text back to the default, unmodified color
}
}
我是这样做的:
UITextView2.h
#import <UIKit/UIKit.h>
@interface UITextView2 : UITextView <UITextViewDelegate> {
NSString *placeholder;
UIColor *placeholderColor;
}
@property(nonatomic, retain) NSString *placeholder;
@property(nonatomic, retain) UIColor *placeholderColor;
-(void)textChanged:(NSNotification*)notif;
@end
UITextView2.m
@implementation UITextView2
@synthesize placeholder, placeholderColor;
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
[self setPlaceholder:@""];
[self setPlaceholderColor:[UIColor lightGrayColor]];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
}
return self;
}
-(void)textChanged:(NSNotification*)notif {
if ([[self placeholder] length]==0)
return;
if ([[self text] length]==0) {
[[self viewWithTag:999] setAlpha:1];
} else {
[[self viewWithTag:999] setAlpha:0];
}
}
- (void)drawRect:(CGRect)rect {
if ([[self placeholder] length]>0) {
UILabel *l = [[UILabel alloc] initWithFrame:CGRectMake(8, 8, 0, 0)];
[l setFont:self.font];
[l setTextColor:self.placeholderColor];
[l setText:self.placeholder];
[l setAlpha:0];
[l setTag:999];
[self addSubview:l];
[l sizeToFit];
[self sendSubviewToBack:l];
[l release];
}
if ([[self text] length]==0 && [[self placeholder] length]>0) {
[[self viewWithTag:999] setAlpha:1];
}
[super drawRect:rect];
}
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
[super dealloc];
}
@end