iOS 带有placeholder、clearButton和自动

由于项目中许多地方用到textView，并且要有placeholder和自动计数、字数限制，所以自己就想着写一个，可以方便很多地方调用。

1.先新建一个继承UITextView的文件，主要是在这里实现placeholder、clearButton以及自动计数控件的通用类设置，还有一些代理方法:

@property (nonatomic, strong) NSString *placeholder;
@property (nonatomic, strong) UIColor *placeholderColor;
@property (nonatomic, strong) UIFont *placeholderFont;

//允许输入的最大长度
@property (nonatomic, assign) NSInteger maxLength;
//是否显示 计数器 label
@property (nonatomic, assign) BOOL showWordCountLabel;

-(void)setPlaceholder:(NSString *)placeholder
{
    _placeholder = placeholder;
    [self setNeedsDisplay];
}

-(void)setPlaceholderFont:(UIFont *)placeholderFont
{
    _placeholderFont = placeholderFont;
    [self setNeedsDisplay];
}

-(void)setPlaceholderColor:(UIColor *)placeholderColor
{
    _placeholderColor = placeholderColor;
    [self setNeedsDisplay];
}

2.建一个继承UIView的文件，在这里设置属性和回调方法，把上面创建的头文件导入进来，如下方法：

-(void)textViewDidChange:(UITextView *)textView
{
    [self textViewTextLengthChange:textView.text.length];
    
    self.maxTextCount = 60;
    
    NSString *toBeString = textView.text;
    
    NSString *lang = [(UITextInputMode*)[[UITextInputMode activeInputModes] firstObject] 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 = [textView markedTextRange];
        //获取高亮部分
        UITextPosition *position = [textView 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 (toBeString.length >= self.maxTextCount) {
                textView.text = [toBeString substringToIndex:self.maxTextCount];
            }
            self.countLabel.text=[NSString stringWithFormat:@"(%lu/%@)",(unsigned long)_textView.text.length, @(self.maxTextCount)];
            [self changeTextWithTextColor:[UIColor orangeColor] OfLabel:self.countLabel withLocation:1 andLength:self.countLabel.text.length-5];
            
            
        } // 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 (toBeString.length >= self.maxTextCount) {
            textView.text = [toBeString substringToIndex:self.maxTextCount];
        }
        self.countLabel.text=[NSString stringWithFormat:@"(%lu/%@)",(unsigned long)_textView.text.length, @(self.maxTextCount)];
        [self changeTextWithTextColor:[UIColor orangeColor] OfLabel:self.countLabel withLocation:1 andLength:self.countLabel.text.length-5];
    }
    
    if ([_delegate respondsToSelector:@selector(textViewDidChange:)]) {
        [_delegate textViewDidChange:textView];
    }
}

• 这里进行了一个高亮判断和输入法的判断，主要是在计数的时候，能够在选中高亮文字之后再执行，这样就不会造成输入字数达到最大限制时计数label显示不正确，或者是键盘直接不能用了,达到的效果就是字数达到限制时，键盘还能输入，textView不再输入或高亮选中无效

3.在需要的地方调用就可以了

 //textView
    LALCustomTextView *customTextView =[[NSBundle mainBundle] loadNibNamed:@"LALCustomTextView" owner:self options:nil].lastObject;
    
    [self.view addSubview:customTextView];
    customTextView.delegate = self;
    customTextView.clearButtonType = ClearButtonAppearWhenEditing;
    [customTextView setPlaceholder:@"编辑新通知,60字以内..." contentText:_inputText maxTextCount:60];
    __weak typeof (self) weakSelf = self;
    customTextView.frame = CGRectMake(weakSelf.view.frame.origin.x, 0, weakSelf.view.frame.size.width, 200);

具体代码可直接去下载，有错误或改进的地方，请直接@我，不吝赐教。
代码传送门：demo