#import "NETextView.h"

@interface NETextView ()<UITextViewDelegate>

@property (strong, nonatomic) UILabel * placeholderLabel;

@property (strong, nonatomic) UITextView * textView;

@implementation NETextView

- (id)initWithFrame:(CGRect)frame {

if (self = [super initWithFrame:frame]) {

[self initSet];

}

return self;

}

- (void)awakeFromNib

{

[self initSet];

}

- (id)init {

if (self = [super init]) {

[self initSet];

}

return self;

}

-(void)initSet

{

_textView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];

_textView.delegate = self;

[self addSubview:_textView];

//设置placeholderLabel

self.placeholderLabel = [[UILabel alloc]init];

self.placeholderLabel.backgroundColor = [UIColor clearColor];

self.placeholderLabel.numberOfLines = 0;

[self addSubview:self.placeholderLabel];

self.placeholderColor = [UIColor lightGrayColor]; //设置 颜色

self.placeholderFont = [UIFont systemFontOfSize:15]; //设置字体大小

self.textView.font = self.placeholderFont;

self.maxLength = MAXFLOAT;

}

#pragma mark 设置占位字符

- (void)setPlaceholder:(NSString *)placeholder{

_placeholder = placeholder;

_placeholderLabel.text = placeholder;

// 计算子控件

[self setNeedsLayout];

}

#pragma mark 颜色

- (void)setPlaceholderColor:(UIColor *)placeholderColor

{

_placeholderColor = placeholderColor;

_placeholderLabel.textColor = placeholderColor;

}

#pragma mark 字体

- (void)setPlaceholderFont:(UIFont *)placeholderFont

{

_placeholderFont = placeholderFont;

_placeholderLabel.font = placeholderFont;

_textView.font = placeholderFont;

[self setNeedsLayout];

}

#pragma 布局加载时设置Label的frame

- (void)layoutSubviews

{

// 设置坐标

CGFloat labelX = 5;

CGFloat labelY = 8;

CGFloat labelW = self.frame.size.width - labelX*2;

// 根据文字计算高度

CGSize maxSize = CGSizeMake(labelW, MAXFLOAT);

CGSize textSize = [_placeholder boundingRectWithSize:maxSize options:NSStringDrawingUsesFontLeading|NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:_placeholderFont} context:nil].size;

CGFloat labelH = textSize.height;

// 设置Frame

_placeholderLabel.frame = CGRectMake(labelX, labelY, labelW, labelH);

}

#pragma mark UITextViewDelegate

- (BOOL)textViewShouldEndEditing:(UITextView *)textView

{

[textView resignFirstResponder];

return YES;

}

-(BOOL)textFieldShouldReturn:(UITextField *)textField

{

[textField resignFirstResponder];

return YES;

}

- (void)textViewDidChange:(UITextView *)textView

{

_placeholderLabel.hidden = [textView.text length];

UITextRange *selectedRange = [textView markedTextRange];

//获取高亮部分

UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];

//如果在变化中是高亮部分在变，就不要计算字符了

if (selectedRange && pos) {

return;

}

NSInteger length = [self countInputWordNum:textView.text];

NSRange cursorRange=textView.selectedRange;

if(length >self.maxLength){

textView.text=[textView.text substringToIndex:[self lastInputIndex:textView.text]];

}

else{

//删除emoji符号，输入框内图形残留

textView.text=textView.text;

}

textView.selectedRange = cursorRange;

}

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

{

if ([text isEqualToString:@"\n"]) {

[textView resignFirstResponder];

return NO;

}

UITextRange *selectedRange = [textView markedTextRange];

//获取高亮部分

UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];

//获取高亮部分内容

//NSString * selectedtext = [textView textInRange:selectedRange];

//如果有高亮且当前字数开始位置小于最大限制时允许输入

if (selectedRange && pos) {

NSInteger startOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.start];

NSInteger endOffset = [textView offsetFromPosition:textView.beginningOfDocument toPosition:selectedRange.end];

NSRange offsetRange = NSMakeRange(startOffset, endOffset - startOffset);

NSString *preTextViewStr = [textView.text substringToIndex:offsetRange.location];

if ([self countInputWordNum:preTextViewStr] < self.maxLength) {

return YES;

}

else

{

return NO;

}

}

NSString *comcatstr = [textView.text stringByReplacingCharactersInRange:range withString:text];

//caninputlen 还可以输入多少个字

NSInteger caninputlen = self.maxLength -[self countInputWordNum:comcatstr];

if (caninputlen >= 0)

{

return YES;

}

else

{

NSInteger len = [self countInputWordNum:text] + caninputlen;

//防止当text.length + caninputlen < 0时，使得rg.length为一个非法最大正数出错

NSRange rg = {0,MAX(len,0)};

if (rg.length > 0)

{

NSString *s = @"";

//判断是否只普通的字符或asc码(对于中文和表情返回NO)

BOOL asc = [text canBeConvertedToEncoding:NSASCIIStringEncoding];

if (asc) {

s = [text substringWithRange:rg];//因为是ascii码直接取就可以了不会错

}

else

{

__block NSInteger idx = 0;

__block NSString *trimString = @"";//截取出的字串

//使用字符串遍历，这个方法能准确知道每个emoji是占一个unicode还是两个

[text enumerateSubstringsInRange:NSMakeRange(0, [text length])

options:NSStringEnumerationByComposedCharacterSequences

usingBlock: ^(NSString* substring, NSRange substringRange, NSRange enclosingRange, BOOL* stop) {

if (idx >= rg.length) {

*stop = YES; //取出所需要就break，提高效率

return ;

}

trimString = [trimString stringByAppendingString:substring];

idx++;

}];

s = trimString;

}

//rang是指从当前光标处进行替换处理(注意如果执行此句后面返回的是YES会触发didchange事件)

[textView setText:[textView.text stringByReplacingCharactersInRange:range withString:s]];

}

return NO;

}

}

- (NSInteger)countInputWordNum:(NSString*)text{

__block NSInteger count = 0;

[text enumerateSubstringsInRange:NSMakeRange(0, [text length])

options:NSStringEnumerationByComposedCharacterSequences

usingBlock: ^(NSString* substring, NSRange substringRange, NSRange enclosingRange, BOOL* stop) {

if (*stop) {

return;

}

count++;

}];

return count;

}

- (NSInteger)lastInputIndex:(NSString*)text{

__block NSInteger count = 0;

__block NSInteger lastIndex = 0;

[text enumerateSubstringsInRange:NSMakeRange(0, [text length])

options:NSStringEnumerationByComposedCharacterSequences

usingBlock: ^(NSString* substring, NSRange substringRange, NSRange enclosingRange, BOOL* stop) {

if (count >=self.maxLength) {

*stop = YES;

return;

}

count++;

lastIndex = substringRange.location+substringRange.length;

}];

return lastIndex;

}