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
在h课上
@interface RateCommentViewController : UIViewController<UITextViewDelegate>{IBoutlet UITextview *commentTxtView;}
在。m类
- (void)viewDidLoad{
commentTxtView.text = @"Comment";
commentTxtView.textColor = [UIColor lightGrayColor];
commentTxtView.delegate = self;
}
- (BOOL) textViewShouldBeginEditing:(UITextView *)textView
{
commentTxtView.text = @"";
commentTxtView.textColor = [UIColor blackColor];
return YES;
}
-(void) textViewDidChange:(UITextView *)textView
{
if(commentTxtView.text.length == 0){
commentTxtView.textColor = [UIColor lightGrayColor];
commentTxtView.text = @"Comment";
[commentTxtView resignFirstResponder];
}
}
其他回答
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
}
}
如果有人需要Swift的解决方案:
添加UITextViewDelegate到类中
var placeHolderText = "Placeholder Text..."
override func viewDidLoad() {
super.viewDidLoad()
textView.delegate = self
}
func textViewShouldBeginEditing(textView: UITextView) -> Bool {
self.textView.textColor = .black
if(self.textView.text == placeHolderText) {
self.textView.text = ""
}
return true
}
func textViewDidEndEditing(textView: UITextView) {
if(textView.text == "") {
self.textView.text = placeHolderText
self.textView.textColor = .lightGray
}
}
override func viewWillAppear(animated: Bool) {
if(currentQuestion.answerDisplayValue == "") {
self.textView.text = placeHolderText
self.textView.textColor = .lightGray
} else {
self.textView.text = "xxx" // load default text / or stored
self.textView.textColor = .black
}
}
在h课上
@interface RateCommentViewController : UIViewController<UITextViewDelegate>{IBoutlet UITextview *commentTxtView;}
在。m类
- (void)viewDidLoad{
commentTxtView.text = @"Comment";
commentTxtView.textColor = [UIColor lightGrayColor];
commentTxtView.delegate = self;
}
- (BOOL) textViewShouldBeginEditing:(UITextView *)textView
{
commentTxtView.text = @"";
commentTxtView.textColor = [UIColor blackColor];
return YES;
}
-(void) textViewDidChange:(UITextView *)textView
{
if(commentTxtView.text.length == 0){
commentTxtView.textColor = [UIColor lightGrayColor];
commentTxtView.text = @"Comment";
[commentTxtView resignFirstResponder];
}
}
我遵循了这个链接的代码。只有7个简单的步骤。它添加了一个UILabel的textView和隐藏/显示标签时,文本输入或从textView通过textView的textViewDidChangeSelection(_ textView: UITextView)委托方法。我将步骤放在代码上方的注释中。
// 1. make sure to include the UITextViewDelegate
class YourClass: UITextViewDelegate {
@IBOutlet weak var textView : UITextView!
// 2. create placeholder textLabel
let placeHolderTextLabel: UILabel = {
let placeholderLabel = UILabel()
placeholderLabel.text = "Placeholder text..."
placeholderLabel.sizeToFit()
placeholderLabel.textColor = UIColor.lightGray
return placeholderLabel
}()
override func viewDidLoad() {
super.viewDidLoad()
// 3. set textView delegate
textView.delegate = self
configurePlaceholderTextLabel()
}
func configurePlaceholderTextLabel() {
// 4. add placeholder label to textView, set it's frame and font
textView.addSubview(placeHolderTextLabel)
placeHolderTextLabel.frame.origin = CGPoint(x: 5, y: (textView.font?.pointSize)! / 2)
placeHolderTextLabel.font = UIFont.systemFont(ofSize: (textView.font?.pointSize)!)
// 5. decide wether the placeHolderTextLabel is hidden or not depending on if there is or isn't text inside the textView
placeHolderTextLabel.isHidden = !textView.text.isEmpty
}
// 6. implement textView delegate method to update the placeHolderTextLabel when the text is changed
func textViewDidChangeSelection(_ textView: UITextView) {
// 7. decide wether the placeHolderTextLabel is hidden or not depending on if there is or isn't text inside the textView when text in textView is changed
placeHolderTextLabel.isHidden = !textView.text.isEmpty
}
}
好吧,我的阴沟有点不同 我创建了一个小班来为你做这件事。
TextViewShader。m文件
#import "TextViewShader.h"
@implementation TextViewShader
-(id)initWithShadedTextView:(NSString *)text textViewToShade:(UITextView *)textview {
self = [super initWithFrame:textview.frame];
if (self) {
if (shadeLabel==nil)
{
shadeLabel= [[UILabel alloc]initWithFrame:CGRectMake(10, 0, textview.frame.size.width, 30)];
}
shadeLabel.text =text;// @"Enter Your Support Request";
shadeLabel.textColor = [UIColor lightGrayColor];
[textview setDelegate: self];
[textview addSubview:shadeLabel];
}
return self;
}
-(void)textViewDidChange:(UITextView *)textView{
if (textView.text.length==0)
{
shadeLabel.hidden=false;
}
else
{
shadeLabel.hidden=true;
}
}
@end
TextViewShader.h文件
#import <UIKit/UIKit.h>
@interface TextViewShader : UIView<UITextViewDelegate>{
UILabel *shadeLabel;
}
-(id)initWithShadedTextView:(NSString *)text textViewToShade:(UITextView *)textview ;
@end
这是简单的一行代码使用(不要忘记添加#import "TextViewShader.h")
TextViewShader* shader = [[TextViewShader alloc]initWithShadedTextView:@"Enter Your Support Request" textViewToShade: youruitextviewToshade];
玩得开心!