UITextView 实现 placeholder 及隐藏键盘

#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

#import "UIPlaceHolderTextView.h"

@implementation UIPlaceHolderTextView

@synthesize placeHolderLabel;

@synthesize placeholder;

@synthesize placeholderColor;

- (void)dealloc

{

    [[NSNotificationCenterdefaultCenter] removeObserver:self];

    [placeHolderLabel release];placeHolderLabel = nil;

    [placeholderColor release];placeholderColor = nil;

    [placeholder release];placeholder = nil;

    [super dealloc];

}

- (void)awakeFromNib

{

    [super awakeFromNib];

    [selfsetPlaceholder:@""];

    [selfsetPlaceholderColor:[UIColor lightGrayColor]];

    [[NSNotificationCenterdefaultCenter] addObserver:self selector:@selector(textChanged:)name:UITextViewTextDidChangeNotification object:nil];

}

- (id)initWithFrame:(CGRect)frame

{

    if( (self = [superinitWithFrame:frame]) )

    {

       [self setPlaceholder:@""];

       [self setPlaceholderColor:[UIColorlightGrayColor]];

       [[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;

           [selfaddSubview: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

 

//隐藏键盘，实现UITextViewDelegate

-(BOOL)textView:(UITextView *)textViewshouldChangeTextInRange:(NSRange)range replacementText:(NSString*)text  

{  

   if ([textisEqualToString:@"\n"]) {  

       [m_textView resignFirstResponder];   

      returnNO;  

   }  

   return YES; 

}

uitextview键盘处理以及字数限制

#pragma ################# textView delegate ###################

- (BOOL)textView:(UITextView*)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString*)text

{

    if(1== range.length) {

        //按下回格键

        returnYES;

    }

    if([text isEqualToString:@"\n"]) {//按下return键

        //这里隐藏键盘，不做任何处理

        [textView resignFirstResponder];

        returnNO;

    }else{

        if([textView.textlength] < 30) {//判断字符个数

            returnYES;

        }

    }

    returnNO;

}

- (BOOL)textViewShouldBeginEditing:(UITextView*)textView

{

    if(_is_first_load){

        textView.text=nil;

        _is_first_load=false;

    }

    returnYES;

}

- (void)textViewDidChange:(UITextView*)textView

{

    intlenth=[textView.textlength];//字数

    NSString*_txt_conten=nil;

    if(lenth>30){

        _txt_conten=[textView.textsubstringToIndex:30];

    }

    else{

        _txt_conten=textView.text;

    }

    textView.text=_txt_conten;

    NSString*txt_length=[NSStringstringWithFormat:@"%d/30",_txt_conten.length];

    lbl_count.text=txt_length;

}