textField textView輸入限制

1、小數點後兩位，隻能輸入數字和小數點 @property (nonatomic, assign) BOOL isHaveDian; @property (nonatomic, assign) BOOL isFirstZero; if ([textField.text rangeOfString:@"."].location==NSNotFound) { _isHaveDian = NO; } if ([textField.text rangeOfString:@"0"].location==NSNotFound) { _isFirstZero = NO; }

if ([string length]>0)
{
    if (textField.text.length > 12) {
        return NO;
    }
    unichar single=[string characterAtIndex:0];//目前輸入的字元
    if ((single >='0' && single<='9') || single=='.')//資料格式正确
    {
        
        if([textField.text length]==0){
            if(single == '.'){
                //首字母不能為小數點
                return NO;
            }
            if (single == '0') {
                _isFirstZero = YES;
                return YES;
            }
        }
        
        if (single=='.'){
            if(!_isHaveDian)//text中還沒有小數點
            {
                _isHaveDian=YES;
                return YES;
            }else{
                return NO;
            }
        }else if(single=='0'){
            if ((_isFirstZero&&_isHaveDian)||(!_isFirstZero&&_isHaveDian)) {
                //首位有0有.（0.01）或首位沒0有.（10200.00）可輸入兩位數的0
                if([textField.text isEqualToString:@"0.0"]){
                    return NO;
                }
                NSRange ran=[textField.text rangeOfString:@"."];
                int tt=(int)(range.location-ran.location);
                if (tt <= 2){
                    return YES;
                }else{
                    return NO;
                }
            }else if (_isFirstZero&&!_isHaveDian){
                //首位有0沒.不能再輸入0
                return NO;
            }else{
                return YES;
            }
        }else{
            if (_isHaveDian){
                //存在小數點，保留兩位小數
                NSRange ran=[textField.text rangeOfString:@"."];
                int tt= (int)(range.location-ran.location);
                if (tt <= 2){
                    return YES;
                }else{
                    return NO;
                }
            }else if(_isFirstZero&&!_isHaveDian){
                //首位有0沒點
                return NO;
            }else{
                return YES;
            }
        }
    }else{
        //輸入的資料格式不正确
        return NO;
    }
}else{
    return YES;
}
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2、textView輸入位數的限制

• (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text { UITextRange *selectedRange = [textView markedTextRange]; //擷取高亮部分 UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0]; //擷取高亮部分内容 //NSString * selectedtext = [textView textInRange:selectedRange];

  //如果有高亮且目前字數開始位置小于最大限制時允許輸入 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);

  if (offsetRange.location < maxNum) {
        return YES;
    }
    else
    {
        return NO;
    }
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  }

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

  NSInteger caninputlen = maxNum - comcatstr.length;

  if (caninputlen >= 0) { return YES; } else { NSInteger len = text.length + caninputlen; //防止當text.length + caninputlen < 0時，使得rg.length為一個非法最大正數出錯 NSRange rg = {0,MAX(len,0)};

  if (rg.length > 0)
    {
        NSString *s = @"";
        //判斷是否隻普通的字元或asc碼(對于中文和表情傳回NO)
        BOOL asc = [text canBeConvertedToEncoding:NSASCIIStringEncoding];
        if (asc) {
            s = [text substringWithRange:rg];//因為是ascii碼直接取就可以了不會錯
        }
        else
        {
            __block NSInteger idx = 0;
            __block NSString  *trimString = @"";//截取出的字串
            //使用字元串周遊，這個方法能準确知道每個emoji是占一個unicode還是兩個
            [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是指從目前光标處進行替換處理(注意如果執行此句後面傳回的是YES會觸發didchange事件)
        [textView setText:[textView.text stringByReplacingCharactersInRange:range withString:s]];
        //既然是超出部分截取了，哪一定是最大限制了。
        NSLog(@"%@",[NSString stringWithFormat:@"%d/%ld",0,(long)maxNum]);
    }
    return NO;
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  }

}

• (void)textViewDidChange:(UITextView *)textView { UITextRange *selectedRange = [textView markedTextRange]; //擷取高亮部分 UITextPosition *pos = [textView positionFromPosition:selectedRange.start offset:0];

  //如果在變化中是高亮部分在變，就不要計算字元了 if (selectedRange && pos) { return; }

  NSString *nsTextContent = textView.text; NSInteger existTextNum = nsTextContent.length;

  if (existTextNum > maxNum) { //截取到最大位置的字元(由于超出截部分在should時被處理了所在這裡這了提高效率不再判斷) NSString *s = [nsTextContent substringToIndex:maxNum];

  [textView setText:s];
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  }

  NSLog(@"%@",[NSString stringWithFormat:@"%ld/%ld",MAX(0,maxNum - existTextNum),(long)maxNum]); }