Uitextview Word limit

Original address: Detailed explanation (common uitextview input word limit) one---Fixed length

Limit the number of words uitextview input, commonly used Uitextview delegate:

-(BOOL) TextView: (Uitextview *) TextView Shouldchangetextinrange: (nsrange) range   *) text; // there is a touch on the input, but it does not trigger    for the Chinese keyboard to show the legend selection -(void) Textviewdidchange: (Uitextview *) TextView; // triggered when the input and the above code returns YES. or triggered when you select a legend on the keyboard. 

The first is for restricting input and the second is for dynamic calculation of the remaining word count.

#define Max_limit_nums     // to limit maximum input of 100 characters only

Full code:

-(BOOL) TextView: (Uitextview *) TextView Shouldchangetextinrange: (nsrange) Range Replacementtext: (NSString*) Text {uitextrange*selectedrange =[TextView Markedtextrange]; //get highlighted partsUitextposition *pos = [TextView positionFromPosition:selectedRange.start offset:0]; //get highlighted parts of the content//NSString * SelectedText = [TextView textinrange:selectedrange]; //allow input If there is a highlight and the current word start position is less than the maximum limit    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); if(Offsetrange.location <max_limit_nums) {              returnYES; }          Else          {              returnNO; }} nsstring*comcatstr =[Textview.text Stringbyreplacingcharactersinrange:range Withstring:text]; Nsinteger Caninputlen= Max_limit_nums-comcatstr.length; if(Caninputlen >=0)      {          returnYES; }      Else{Nsinteger len= Text.length +Caninputlen; //prevents error when Text.length + Caninputlen < 0 o'clock, making rg.length an illegal maximum positive numberNsrange RG = {0, MAX (Len,0)}; if(Rg.length >0) {NSString*s =@""; //determine if only normal characters or ASC codes (for Chinese and Emoticons return no)BOOL ASC =[text canbeconvertedtoencoding:nsasciistringencoding]; if(ASC) {s= [text Substringwithrange:rg];//because it's ASCII, it's not wrong to take it directly.            }              Else{__block Nsinteger idx=0; __block NSString*trimstring =@"";//the truncated string//using string traversal, this method can know exactly whether each emoji is a Unicode or two[Text Enumeratesubstringsinrange:nsmakerange (0, [text length]) options:nsstringenumerationbycomposedcharactersequence S Usingblock:^ (nsstring* substring, nsrange substringrange, Nsrange Enclosingrange, bool*stop) {                                                                                                  if(IDX >=rg.length) {*stop = YES;//remove the need to break, improve efficiency                                                   return ; } trimstring=[trimstring stringbyappendingstring:substring]; IDX++;                                    }]; S=trimstring; }              //rang refers to the substitution process from the current cursor (note that if yes is returned after this sentence is executed, the Didchange event is triggered)[TextView settext:[textview.text stringbyreplacingcharactersinrange:range withstring:s]; //since it is out of the partial interception, which must be the maximum limit. Self.lbNums.text = [NSString stringWithFormat:@"%d/%ld",0,(Long) Max_limit_nums]; }          returnNO; }    }    - (void) Textviewdidchange: (Uitextview *) TextView {uitextrange*selectedrange =[TextView Markedtextrange]; //get highlighted partsUitextposition *pos = [TextView positionFromPosition:selectedRange.start offset:0]; //If the highlight is changing in the change, don't count the characters.    if(Selectedrange &&POS) {          return; } nsstring*nstextcontent =Textview.text; Nsinteger Existtextnum=nstextcontent.length; if(Existtextnum >max_limit_nums) {          //The character that is intercepted to the maximum position (because the outside section is processed at should, which is where the efficiency is no longer judged)NSString *s =[Nstextcontent substringtoindex:max_limit_nums];      [TextView settext:s]; }            //do not let display negative mouth daySelf.lbNums.text = [NSString stringWithFormat:@"%ld/%d", MAX (0, Max_limit_nums-existtextnum), max_limit_nums]; }  

Places to be aware of:

1. In, English characters are limited when entering.

2. Take emoji when the interception shows half or garbled character processing.

Modification of the above code for emoji length:

[Text Enumeratesubstringsinrange:nsmakerange (0, [text length]) options:nsstringenumerationbycomposedcharactersequences Usingblock:^ (nsstring* substring, nsrange substringrange, Nsrange Enclosingrange, bool*stop) {Nsinteger Steplen=substring.length; if(IDX >=rg.length) {*stop = YES;//remove the need to break, improve efficiency                                   return ; } trimstring=[trimstring stringbyappendingstring:substring]; IDX= idx + Steplen;//This changes, using the length of the string as the step}];

Treat a emoji of length 2 as 1 characters:

[Text Enumeratesubstringsinrange:nsmakerange (0, [text length])                                                options: Nsstringenumerationbycomposedcharactersequences                                             

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The article is very useful for the discussion of all kinds of text content.

Uitextview Word limit