一个带有 PlaceHolder 的BRPlaceholderTextView

#import <UIKit/UIKit.h>@interface BRPlaceholderTextView : UITextView@property(copy,nonatomic)   NSString *placeholder;@property(strong,nonatomic) NSIndexPath * indexPath;//最大长度设置@property(assign,nonatomic) NSInteger maxTextLength;//更新高度的时候@property(assign,nonatomic) float updateHeight;/** *  增加text 长度限制 * *  @param maxLength <#maxLength description#> *  @param limit     <#limit description#> */-(void)addMaxTextLengthWithMaxLength:(NSInteger)maxLength andEvent:(void(^)(BRPlaceholderTextView*text))limit;/** *  开始编辑 的 回调 * *  @param begin <#begin description#> */-(void)addTextViewBeginEvent:(void(^)(BRPlaceholderTextView*text))begin;/** *  结束编辑 的 回调 * *  @param begin <#begin description#> */-(void)addTextViewEndEvent:(void(^)(BRPlaceholderTextView*text))End;/** *  设置Placeholder 颜色 * *  @param color <#color description#> */-(void)setPlaceholderColor:(UIColor*)color;/** *  设置Placeholder 字体 * *  @param font <#font description#> */-(void)setPlaceholderFont:(UIFont*)font;/** *  设置透明度 * *  @param opacity <#opacity description#> */-(void)setPlaceholderOpacity:(float)opacity;@end

#import "BRPlaceholderTextView.h"#define kTopY 7.0#define kLeftX 5.0@interface BRPlaceholderTextView()<UITextViewDelegate>@property(strong,nonatomic) UIColor *placeholder_color;@property(strong,nonatomic) UIFont * placeholder_font;/** *   显示 Placeholder */@property(strong,nonatomic,readonly)  UILabel *PlaceholderLabel;@property(assign,nonatomic) float placeholdeWidth;@property(copy,nonatomic) id eventBlock;@property(copy,nonatomic) id BeginBlock;@property(copy,nonatomic) id EndBlock;@end@implementation BRPlaceholderTextView// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.#pragma mark - life cycle- (id) initWithFrame:(CGRect)frame {    if ((self = [super initWithFrame:frame])) {        [self awakeFromNib];    }    return self;}- (void)awakeFromNib {    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(DidChange:) name:UITextViewTextDidChangeNotification object:self];    //UITextViewTextDidBeginEditingNotification    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textViewBeginNoti:) name:UITextViewTextDidBeginEditingNotification object:self];    //UITextViewTextDidEndEditingNotification    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textViewEndNoti:) name:UITextViewTextDidEndEditingNotification object:self];    float left=kLeftX,top=kTopY,hegiht=30;    self.placeholdeWidth=CGRectGetWidth(self.frame)-2*left;    _PlaceholderLabel=[[UILabel alloc] initWithFrame:CGRectMake(left, top                                                                , _placeholdeWidth, hegiht)];    _PlaceholderLabel.numberOfLines=0;    _PlaceholderLabel.lineBreakMode=NSLineBreakByCharWrapping|NSLineBreakByWordWrapping;    [self addSubview:_PlaceholderLabel];    [self defaultConfig];}-(void)layoutSubviews{    float left=kLeftX,top=kTopY,hegiht=self.bounds.size.height;    self.placeholdeWidth=CGRectGetWidth(self.frame)-2*left;    CGRect frame=_PlaceholderLabel.frame;    frame.origin.x=left;    frame.origin.y=top;    frame.size.height=hegiht;    frame.size.width=self.placeholdeWidth;    _PlaceholderLabel.frame=frame;    [_PlaceholderLabel sizeToFit];}-(void)dealloc{    [_PlaceholderLabel removeFromSuperview];    [[NSNotificationCenter defaultCenter] removeObserver:self];}#pragma mark - System Delegate#pragma mark - custom Delegate#pragma mark - Event response-(void)defaultConfig{    self.placeholder_color = [UIColor lightGrayColor];    self.placeholder_font  = [UIFont systemFontOfSize:15];    self.maxTextLength=1000;    self.layoutManager.allowsNonContiguousLayout=NO;}-(void)addMaxTextLengthWithMaxLength:(NSInteger)maxLength andEvent:(void (^)(BRPlaceholderTextView *text))limit{    if (maxLength>0) {        _maxTextLength=maxLength;    }    if (limit) {        _eventBlock=limit;    }}-(void)addTextViewBeginEvent:(void (^)(BRPlaceholderTextView *))begin{    _BeginBlock=begin;}-(void)addTextViewEndEvent:(void (^)(BRPlaceholderTextView *))End{    _EndBlock=End;}-(void)setUpdateHeight:(float)updateHeight{    CGRect frame=self.frame;    frame.size.height=updateHeight;    self.frame=frame;    _updateHeight=updateHeight;} //供外部使用的 api-(void)setPlaceholderFont:(UIFont *)font{    self.placeholder_font=font;}-(void)setPlaceholderColor:(UIColor *)color{    self.placeholder_color=color;}-(void)setPlaceholderOpacity:(float)opacity{    if (opacity<0) {        opacity=1;    }    self.PlaceholderLabel.layer.opacity=opacity;}#pragma mark - Noti Event-(void)textViewBeginNoti:(NSNotification*)noti{    if (_BeginBlock) {        void(^begin)(BRPlaceholderTextView*text)=_BeginBlock;        begin(self);    }}-(void)textViewEndNoti:(NSNotification*)noti{    if (_EndBlock) {        void(^end)(BRPlaceholderTextView*text)=_EndBlock;        end(self);    }}-(void)DidChange:(NSNotification*)noti{    if (self.placeholder.length == 0 || [self.placeholder isEqualToString:@""]) {        _PlaceholderLabel.hidden=YES;    }    if (self.text.length > 0) {        _PlaceholderLabel.hidden=YES;    }    else{        _PlaceholderLabel.hidden=NO;    }    NSString *lang = [[self.nextResponder textInputMode] primaryLanguage]; // 键盘输入模式    if ([lang isEqualToString:@"zh-Hans"]) { // 简体中文输入，包括简体拼音，健体五笔，简体手写        UITextRange *selectedRange = [self markedTextRange];        //获取高亮部分        UITextPosition *position = [self positionFromPosition:selectedRange.start offset:0];        // 没有高亮选择的字，则对已输入的文字进行字数统计和限制        if (!position) {            if (self.text.length > self.maxTextLength) {                self.text = [self.text substringToIndex:self.maxTextLength];            }        }        // 有高亮选择的字符串，则暂不对文字进行统计和限制        else{        }    }    // 中文输入法以外的直接对其统计限制即可，不考虑其他语种情况    else{        if (self.text.length > self.maxTextLength) {             self.text = [ self.text substringToIndex:self.maxTextLength];        }    }    if (_eventBlock && self.text.length > self.maxTextLength) {        void (^limint)(BRPlaceholderTextView*text) =_eventBlock;        limint(self);    }}#pragma mark - private method+(float)boundingRectWithSize:(CGSize)size withLabel:(NSString *)label withFont:(UIFont *)font{    NSDictionary *attribute = @{NSFontAttributeName:font};    // CGSize retSize;    CGSize retSize = [label boundingRectWithSize:size                                         options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading                                      attributes:attribute                                         context:nil].size;    return retSize.height;}#pragma mark - getters and Setters-(void)setText:(NSString *)tex{    if (tex.length>0) {        _PlaceholderLabel.hidden=YES;    }    [super setText:tex];}-(void)setPlaceholder:(NSString *)placeholder{    if (placeholder.length == 0 || [placeholder isEqualToString:@""]) {        _PlaceholderLabel.hidden=YES;    }    else    {        _PlaceholderLabel.text=placeholder;        _placeholder=placeholder;//        float  height=  [BRPlaceholderTextView boundingRectWithSize:CGSizeMake(_placeholdeWidth, MAXFLOAT) withLabel:_placeholder withFont:_PlaceholderLabel.font];//        if (height>CGRectGetHeight(_PlaceholderLabel.frame) && height< CGRectGetHeight(self.frame)) {//            //            CGRect frame=_PlaceholderLabel.frame;//            frame.size.height=height;//            _PlaceholderLabel.frame=frame;//            //        }    }}-(void)setPlaceholder_font:(UIFont *)placeholder_font{    _placeholder_font=placeholder_font;    _PlaceholderLabel.font=placeholder_font;}-(void)setPlaceholder_color:(UIColor *)placeholder_color{    _placeholder_color=placeholder_color;    _PlaceholderLabel.textColor=placeholder_color;}