自定义textview

#import <UIKit/UIKit.h>

@class FSTextView;

typedef void(^FSTextViewHandler)(FSTextView *textView);

IB_DESIGNABLE

@interface FSTextView : UITextView

/**

便利构造器.

*/

+ (instancetype)textView;

/**

设定文本改变Block回调. (切记弱化引用, 以免造成内存泄露.)

*/

- (void)addTextDidChangeHandler:(FSTextViewHandler)eventHandler;

/**

设定达到最大长度Block回调. (切记弱化引用, 以免造成内存泄露.)

*/

- (void)addTextLengthDidMaxHandler:(FSTextViewHandler)maxHandler;

/**

最大限制文本长度, 默认为无穷大, 即不限制, 如果被设为 0 也同样表示不限制字符数.

*/

@property (nonatomic, assign) IBInspectable NSUInteger maxLength;

/**

圆角半径.

*/

@property (nonatomic, assign) IBInspectable CGFloat cornerRadius;

/**

边框宽度.

*/

@property (nonatomic, assign) IBInspectable CGFloat borderWidth;

/**

边框颜色.

*/

@property (nonatomic, strong) IBInspectable UIColor *borderColor;

/**

placeholder, 会自适应TextView宽高以及横竖屏切换, 字体默认和TextView一致.

*/

@property (nonatomic, copy)   IBInspectable NSString *placeholder;

/**

placeholder文本颜色, 默认为#C7C7CD.

*/

@property (nonatomic, strong) IBInspectable UIColor *placeholderColor;

/**

placeholder文本字体, 默认为UITextView的默认字体.

*/

@property (nonatomic, strong) UIFont *placeholderFont;

/**

是否允许长按弹出UIMenuController, 默认为YES.

*/

@property (nonatomic, assign, getter=isCanPerformAction) BOOL canPerformAction;

/**

该属性返回一个经过处理的 `self.text` 的值, 去除了首位的空格和换行.

*/

@property (nonatomic, readonly) NSString *formatText;

@end

#import "FSTextView.h"

CGFloat const kFSTextViewPlaceholderVerticalMargin = 8.0; ///< placeholder垂直方向边距

CGFloat const kFSTextViewPlaceholderHorizontalMargin = 6.0; ///< placeholder水平方向边距

@interface FSTextView ()

@property (nonatomic, copy) FSTextViewHandler changeHandler; ///< 文本改变Block

@property (nonatomic, copy) FSTextViewHandler maxHandler; ///< 达到最大限制字符数Block

@property (nonatomic, strong) UILabel *placeholderLabel; ///< placeholderLabel

@end

@implementation FSTextView

#pragma mark - Override

- (void)dealloc

{

[[NSNotificationCenter defaultCenter] removeObserver:self];

_changeHandler = NULL;

_maxHandler = NULL;

}

- (instancetype)initWithCoder:(NSCoder *)aDecoder

{

if (!(self = [super initWithCoder:aDecoder])) return nil;

if ([[[UIDevice currentDevice] systemVersion] compare:@"10.0" options:NSNumericSearch] != NSOrderedAscending) {

[self layoutIfNeeded];

}

[self initialize];

return self;

}

- (instancetype)initWithFrame:(CGRect)frame

{

if (!(self = [super initWithFrame:frame])) return nil;

[self initialize];

return self;

}

- (BOOL)becomeFirstResponder

{

BOOL become = [super becomeFirstResponder];

// 成为第一响应者时注册通知监听文本变化

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textDidChange:) name:UITextViewTextDidChangeNotification object:nil];

return become;

}

- (BOOL)resignFirstResponder

{

BOOL resign = [super resignFirstResponder];

// 注销第一响应者时移除文本变化的通知, 以免影响其它的`UITextView`对象.

[[NSNotificationCenter defaultCenter] removeObserver:self name:UITextViewTextDidChangeNotification object:nil];

return resign;

}

- (BOOL)canPerformAction:(SEL)action withSender:(id)sender

{

BOOL result = [super canPerformAction:action withSender:sender];

if (result) {

if (![self respondsToSelector:action]) {

result = NO;

} else {

result = _canPerformAction;

}

}

return result;

}

#pragma mark - Private

- (void)initialize

{

// 基本配置 (需判断是否在Storyboard中设置了值)

_canPerformAction = YES;

if (_maxLength == 0 || _maxLength == NSNotFound) {

_maxLength = NSUIntegerMax;

}

if (!_placeholderColor) {

_placeholderColor = [UIColor colorWithRed:0.780 green:0.780 blue:0.804 alpha:1.000];

}

// 基本设定 (需判断是否在Storyboard中设置了值)

if (!self.backgroundColor) {

self.backgroundColor = [UIColor whiteColor];

}

if (!self.font) {

self.font = [UIFont systemFontOfSize:15.f];

}

// placeholderLabel

self.placeholderLabel.font = self.font;

self.placeholderLabel.text = _placeholder; // 可能在Storyboard中设置了Placeholder

self.placeholderLabel.textColor = _placeholderColor;

[self addSubview:self.placeholderLabel];

// constraint

[self addConstraint:[NSLayoutConstraint constraintWithItem:self.placeholderLabel

attribute:NSLayoutAttributeTop

relatedBy:NSLayoutRelationEqual

toItem:self

attribute:NSLayoutAttributeTop

multiplier:1.0

constant:kFSTextViewPlaceholderVerticalMargin]];

[self addConstraint:[NSLayoutConstraint constraintWithItem:self.placeholderLabel

attribute:NSLayoutAttributeLeft

relatedBy:NSLayoutRelationEqual

toItem:self

attribute:NSLayoutAttributeLeft

multiplier:1.0

constant:kFSTextViewPlaceholderHorizontalMargin]];

[self addConstraint:[NSLayoutConstraint constraintWithItem:self.placeholderLabel

attribute:NSLayoutAttributeWidth

relatedBy:NSLayoutRelationLessThanOrEqual

toItem:self

attribute:NSLayoutAttributeWidth

multiplier:1.0

constant:-kFSTextViewPlaceholderHorizontalMargin*2]];

[self addConstraint:[NSLayoutConstraint constraintWithItem:self.placeholderLabel

attribute:NSLayoutAttributeHeight

relatedBy:NSLayoutRelationLessThanOrEqual

toItem:self

attribute:NSLayoutAttributeHeight

multiplier:1.0

constant:-kFSTextViewPlaceholderVerticalMargin*2]];

}

#pragma mark - Getter

/// 返回一个经过处理的 `self.text` 的值, 去除了首位的空格和换行.

- (NSString *)formatText

{

return [[super text] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]]; // 去除首尾的空格和换行.

}

- (UILabel *)placeholderLabel

{

if (!_placeholderLabel) {

_placeholderLabel = [[UILabel alloc] init];

_placeholderLabel.numberOfLines = 0;

_placeholderLabel.translatesAutoresizingMaskIntoConstraints = NO;

}

return _placeholderLabel;

}

#pragma mark - Setter

- (void)setText:(NSString *)text

{

[super setText:text];

self.placeholderLabel.hidden = [@(text.length) boolValue];

// 手动模拟触发通知

NSNotification *notification = [NSNotification notificationWithName:UITextViewTextDidChangeNotification object:self];

[self textDidChange:notification];

}

- (void)setFont:(UIFont *)font

{

[super setFont:font];

self.placeholderLabel.font = font;

}

- (void)setMaxLength:(NSUInteger)maxLength

{

_maxLength = fmax(0, maxLength);

self.text = self.text;

}

- (void)setCornerRadius:(CGFloat)cornerRadius

{

_cornerRadius = cornerRadius;

self.layer.cornerRadius = _cornerRadius;

}

- (void)setBorderColor:(UIColor *)borderColor

{

if (!borderColor) return;

_borderColor = borderColor;

self.layer.borderColor = _borderColor.CGColor;

}

- (void)setBorderWidth:(CGFloat)borderWidth

{

_borderWidth = borderWidth;

self.layer.borderWidth = _borderWidth;

}

- (void)setPlaceholder:(NSString *)placeholder

{

if (!placeholder) return;

_placeholder = [placeholder copy];

if (_placeholder.length > 0) {

self.placeholderLabel.text = _placeholder;

}

}

- (void)setPlaceholderColor:(UIColor *)placeholderColor

{

if (!placeholderColor) return;

_placeholderColor = placeholderColor;

self.placeholderLabel.textColor = _placeholderColor;

}

- (void)setPlaceholderFont:(UIFont *)placeholderFont

{

if (!placeholderFont) return;

_placeholderFont = placeholderFont;

self.placeholderLabel.font = _placeholderFont;

}

#pragma mark - NSNotification

- (void)textDidChange:(NSNotification *)notification

{

// 通知回调的实例的不是当前实例的话直接返回

if (notification.object != self) return;

// 根据字符数量显示或者隐藏 `placeholderLabel`

self.placeholderLabel.hidden = [@(self.text.length) boolValue];

// 禁止第一个字符输入空格或者换行

if (self.text.length == 1) {

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

self.text = @"";

}

}

// 只有当maxLength字段的值不为无穷大整型也不为0时才计算限制字符数.

if (_maxLength != NSUIntegerMax && _maxLength != 0 && self.text.length > 0) {

if (!self.markedTextRange && self.text.length > _maxLength) {

!_maxHandler ?: _maxHandler(self); // 回调达到最大限制的Block.

self.text = [self.text substringToIndex:_maxLength]; // 截取最大限制字符数.

[self.undoManager removeAllActions]; // 达到最大字符数后清空所有 undoaction, 以免 undo 操作造成crash.

}

}

// 回调文本改变的Block.

!_changeHandler ?: _changeHandler(self);

}

#pragma mark - Public

+ (instancetype)textView

{

return [[self alloc] init];

}

- (void)addTextDidChangeHandler:(FSTextViewHandler)changeHandler

{

_changeHandler = [changeHandler copy];

}

- (void)addTextLengthDidMaxHandler:(FSTextViewHandler)maxHandler

{

_maxHandler = [maxHandler copy];

}

@end