UITextField 는 placeholder 프로퍼티가 존재한다.
입력전에 grayColor로 보여주다가 입력이 시작되면 사라지는 것이다.
근데 멀티라인을 입력 할수 있는 UITextView는 이러한 placeholder프로퍼티가 없다.
UITextView 를 상속 받고 NSString *placeholder, 와 UIColor *placeholderColor 를
가지고 있는 UIPlaceHolderTextView를 만들어 사용할수 있다.
UIPlaceHolderTextView.h
#import <Foundation/Foundation.h>
@interface UIPlaceHolderTextView : UITextView {
NSString *placeholder;
UIColor *placeholderColor;
@private
UILabel *placeHolderLabel;
}
@property (nonatomic, retain) UILabel *placeHolderLabel;
@property (nonatomic, retain) NSString *placeholder;
@property (nonatomic, retain) UIColor *placeholderColor;
-(void)textChanged:(NSNotification*)notification;
@end
UIPlaceHolderTextView.m
#import "UIPlaceHolderTextView.h"
@implementation UIPlaceHolderTextView
@synthesize placeHolderLabel;
@synthesize placeholder;
@synthesize placeholderColor;
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
[placeHolderLabel release]; placeHolderLabel = nil;
[placeholderColor release]; placeholderColor = nil;
[placeholder release]; placeholder = nil;
[super dealloc];
}
- (void)awakeFromNib
{
[super awakeFromNib];
[self setPlaceholder:@""];
[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;
}
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 = UILineBreakModeWordWrap;
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
참고 : http://stackoverflow.com/questions/1328638/placeholder-in-uitextview
