标签：ios ios开发 uitextfield uilabel ios7
//// SSTextView.h// SSToolkit//// Created by Sam Soffes on 8/18/10.// Copyright 2010-2011 Sam Soffes. All rights reserved.///** UITextView subclass that adds placeholder support like UITextField has. */@interface
SSTextView : UITextView/** The string that is displayed when there is no other text in the text view. The default value is `nil`. */@property
(nonatomic, retain)
NSString *placeholder;/** The color of the placeholder. The default is `[UIColor lightGrayColor]`. */@property
(nonatomic, retain)
UIColor *placeholderColor;@end//// SSTextView.m// SSToolkit//// Created by Sam Soffes on 8/18/10.// Copyright 2010-2011 Sam Soffes. All rights reserved.//#import "SSTextView.h"@interface
SSTextView ()- (void)_initialize;- (void)_updateShouldDrawPlaceholder;- (void)_textChanged:(NSNotification
*)notification;@end@implementation
SSTextView { BOOL
_shouldDrawPlaceholder;}#pragma mark - Accessors@synthesize
placeholder = _placeholder;@synthesize
placeholderColor = _placeholderColor;- (void)setText:(NSString
*)string { [super
setText:string]; [self
_updateShouldDrawPlaceholder];}- (void)setPlaceholder:(NSString
*)string { if
([string isEqual:_placeholder]) { return; } [_placeholder
release]; _placeholder = [string
retain]; [self
_updateShouldDrawPlaceholder];}#pragma mark - NSObject- (void)dealloc { [[NSNotificationCenter
defaultCenter]
removeObserver:self
name:UITextViewTextDidChangeNotification
object:self]; [_placeholder
release]; [_placeholderColor
release]; [super
dealloc];}#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
(_shouldDrawPlaceholder) { [_placeholderColor
set]; [_placeholder
drawInRect:CGRectMake(8.0f,
8.0f,
self.frame.size.width
- 16.0f,
self.frame.size.height
- 16.0f)
withFont:self.font]; }}#pragma mark - Private- (void)_initialize { [[NSNotificationCenter
defaultCenter]
addObserver:self
selector:@selector(_textChanged:)
name:UITextViewTextDidChangeNotification
object:self]; self.placeholderColor
= [UIColor
colorWithWhite:0.702f
alpha:1.0f]; _shouldDrawPlaceholder =
NO;}- (void)_updateShouldDrawPlaceholder { BOOL
prev = _shouldDrawPlaceholder; _shouldDrawPlaceholder =
self.placeholder
&& self.placeholderColor
&& self.text.length
== 0; if
(prev != _shouldDrawPlaceholder) { [self
setNeedsDisplay]; }}- (void)_textChanged:(NSNotification
*)notificaiton { [self
_updateShouldDrawPlaceholder];
}
@end
#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//.m file#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标签：ios ios开发 uitextfield uilabel ios7
原文地址：http://blog.csdn.net/wanglongblog/article/details/41853627
