//

// QMUITextView.m

// qmui

//

// Created by QQMail on 14-8-5.

// Copyright (c) 2014年 QMUI Team. All rights reserved.

//

#import "QMUITextView.h"

#import "QMUICore.h"

#import "QMUILabel.h"

#import "NSObject+QMUI.h"

#import "NSString+QMUI.h"

#import "UITextView+QMUI.h"

/// 系统 textView 默认的字号大小，用于 placeholder 默认的文字大小。实测得到，请勿修改。

const CGFloat kSystemTextViewDefaultFontPointSize = 12.0f;

/// 当系统的 textView.textContainerInset 为 UIEdgeInsetsZero 时，文字与 textView 边缘的间距。实测得到，请勿修改（在输入框font大于13时准确，小于等于12时，y有-1px的偏差）。

const UIEdgeInsets kSystemTextViewFixTextInsets = {0, 5, 0, 5};

@interface QMUITextView ()

@property(nonatomic, assign) BOOL debug;

@property(nonatomic, assign) BOOL shouldRejectSystemScroll;// 如果在 handleTextChanged: 里主动调整 contentOffset，则为了避免被系统的自动调整覆盖，会利用这个标记去屏蔽系统对 setContentOffset: 的调用

@property(nonatomic, strong) UILabel *placeholderLabel;

@property(nonatomic, weak) id<QMUITextViewDelegate> originalDelegate;

@end

@implementation QMUITextView

@dynamic delegate;

- (instancetype)initWithFrame:(CGRect)frame {

self = [super initWithFrame:frame];

if (self) {

[self didInitialized];

self.tintColor = TextFieldTintColor;

}

return self;

}

- (instancetype)initWithCoder:(NSCoder *)aDecoder {

if (self = [super initWithCoder:aDecoder]) {

[self didInitialized];

}

return self;

}

- (void)didInitialized {

self.debug = NO;

self.delegate = self;

self.scrollsToTop = NO;

self.placeholderColor = UIColorPlaceholder;

self.placeholderMargins = UIEdgeInsetsZero;

self.autoResizable = NO;

self.maximumTextLength = NSUIntegerMax;

self.shouldResponseToProgrammaticallyTextChanges = YES;

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

self.placeholderLabel.font = UIFontMake(kSystemTextViewDefaultFontPointSize);

self.placeholderLabel.textColor = self.placeholderColor;

self.placeholderLabel.numberOfLines = 0;

self.placeholderLabel.alpha = 0;

[self addSubview:self.placeholderLabel];

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

}

- (void)dealloc {

[[NSNotificationCenter defaultCenter] removeObserver:self];

self.delegate = nil;

self.originalDelegate = nil;

}

- (NSString *)description {

return [NSString stringWithFormat:@"%@; text.length: %@ | %@; markedTextRange: %@", [super description], @(self.text.length), @([self lengthWithString:self.text]), self.markedTextRange];

}

- (BOOL)isCurrentTextDifferentOfText:(NSString *)text {

NSString *textBeforeChange = self.text;// UITextView 如果文字为空，self.text 永远返回 @"" 而不是 nil（即便你设置为 nil 后立即 get 出来也是）

if ([textBeforeChange isEqualToString:text] || (textBeforeChange.length == 0 && !text)) {

return NO;

}

return YES;

}

- (void)setText:(NSString *)text {

NSString *textBeforeChange = self.text;

BOOL textDifferent = [self isCurrentTextDifferentOfText:text];

// 如果前后文字没变化，则什么都不做

if (!textDifferent) {

[super setText:text];

return;

}

// 前后文字发生变化，则要根据是否主动接管 delegate 来决定是否要询问 delegate

if (self.shouldResponseToProgrammaticallyTextChanges) {

BOOL shouldChangeText = YES;

if ([self.delegate respondsToSelector:@selector(textView:shouldChangeTextInRange:replacementText:)]) {

shouldChangeText = [self.delegate textView:self shouldChangeTextInRange:NSMakeRange(0, textBeforeChange.length) replacementText:text];

}

if (!shouldChangeText) {

// 不应该改变文字，所以连 super 都不调用，直接结束方法

return;

}

// 应该改变文字，则调用 super 来改变文字，然后主动调用 textViewDidChange:

[super setText:text];

if ([self.delegate respondsToSelector:@selector(textViewDidChange:)]) {

[self.delegate textViewDidChange:self];

}

[[NSNotificationCenter defaultCenter] postNotificationName:UITextViewTextDidChangeNotification object:self];

} else {

[super setText:text];

// 如果不需要主动接管事件，则只要触发内部的监听即可，不用调用 delegate 系列方法

[self handleTextChanged:self];

}

}

- (void)setAttributedText:(NSAttributedString *)attributedText {

NSString *textBeforeChange = self.attributedText.string;

BOOL textDifferent = [self isCurrentTextDifferentOfText:attributedText.string];

// 如果前后文字没变化，则什么都不做

if (!textDifferent) {

[super setAttributedText:attributedText];

return;

}

// 前后文字发生变化，则要根据是否主动接管 delegate 来决定是否要询问 delegate

if (self.shouldResponseToProgrammaticallyTextChanges) {

BOOL shouldChangeText = YES;

if ([self.delegate respondsToSelector:@selector(textView:shouldChangeTextInRange:replacementText:)]) {

shouldChangeText = [self.delegate textView:self shouldChangeTextInRange:NSMakeRange(0, textBeforeChange.length) replacementText:attributedText.string];

}

if (!shouldChangeText) {

// 不应该改变文字，所以连 super 都不调用，直接结束方法

return;

}

// 应该改变文字，则调用 super 来改变文字，然后主动调用 textViewDidChange:

[super setAttributedText:attributedText];

if ([self.delegate respondsToSelector:@selector(textViewDidChange:)]) {

[self.delegate textViewDidChange:self];

}

[[NSNotificationCenter defaultCenter] postNotificationName:UITextViewTextDidChangeNotification object:self];

} else {

[super setAttributedText:attributedText];

// 如果不需要主动接管事件，则只要触发内部的监听即可，不用调用 delegate 系列方法

[self handleTextChanged:self];

}

}

- (void)setTypingAttributes:(NSDictionary<NSString *,id> *)typingAttributes {

[super setTypingAttributes:typingAttributes];

[self updatePlaceholderStyle];

}

- (void)setFont:(UIFont *)font {

[super setFont:font];

[self updatePlaceholderStyle];

}

- (void)setTextColor:(UIColor *)textColor {

[super setTextColor:textColor];

[self updatePlaceholderStyle];

}

- (void)setTextAlignment:(NSTextAlignment)textAlignment {

[super setTextAlignment:textAlignment];

[self updatePlaceholderStyle];

}

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

_placeholder = placeholder;

self.placeholderLabel.attributedText = [[NSAttributedString alloc] initWithString:_placeholder attributes:self.typingAttributes];

if (self.placeholderColor) {

self.placeholderLabel.textColor = self.placeholderColor;

}

[self sendSubviewToBack:self.placeholderLabel];

}

- (void)setPlaceholderColor:(UIColor *)placeholderColor {

_placeholderColor = placeholderColor;

self.placeholderLabel.textColor = _placeholderColor;

}

- (void)updatePlaceholderStyle {

self.placeholder = self.placeholder;// 触发文字样式的更新

}

- (void)handleTextChanged:(id)sender {

// 输入字符的时候，placeholder隐藏

if(self.placeholder.length > 0) {

[self updatePlaceholderLabelHidden];

}

QMUITextView *textView = nil;

if ([sender isKindOfClass:[NSNotification class]]) {

id object = ((NSNotification *)sender).object;

if (object == self) {

textView = (QMUITextView *)object;

}

} else if ([sender isKindOfClass:[QMUITextView class]]) {

textView = (QMUITextView *)sender;

}

if (textView) {

// 计算高度

if (self.autoResizable) {

CGFloat resultHeight = [textView sizeThatFits:CGSizeMake(CGRectGetWidth(self.bounds), CGFLOAT_MAX)].height;

if (self.debug) NSLog(@"handleTextDidChange, text = %@, resultHeight = %f", textView.text, resultHeight);

// 通知delegate去更新textView的高度

if ([textView.originalDelegate respondsToSelector:@selector(textView:newHeightAfterTextChanged:)] && resultHeight != CGRectGetHeight(self.bounds)) {

[textView.originalDelegate textView:self newHeightAfterTextChanged:resultHeight];

}

}

// textView 尚未被展示到界面上时，此时过早进行光标调整会计算错误

if (!textView.window) {

return;

}

self.shouldRejectSystemScroll = YES;

// 用 dispatch 延迟一下，因为在文字发生换行时，系统自己会做一些滚动，我们要延迟一点才能避免被系统的滚动覆盖

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{

self.shouldRejectSystemScroll = NO;

[self qmui_scrollCaretVisibleAnimated:NO];

});

}

}

- (void)layoutSubviews {

[super layoutSubviews];

if (self.placeholder.length > 0) {

UIEdgeInsets labelMargins = UIEdgeInsetsConcat(UIEdgeInsetsConcat(self.textContainerInset, self.placeholderMargins), kSystemTextViewFixTextInsets);

CGFloat limitWidth = CGRectGetWidth(self.bounds) - UIEdgeInsetsGetHorizontalValue(self.contentInset) - UIEdgeInsetsGetHorizontalValue(labelMargins);

CGFloat limitHeight = CGRectGetHeight(self.bounds) - UIEdgeInsetsGetVerticalValue(self.contentInset) - UIEdgeInsetsGetVerticalValue(labelMargins);

CGSize labelSize = [self.placeholderLabel sizeThatFits:CGSizeMake(limitWidth, limitHeight)];

labelSize.height = fminf(limitHeight, labelSize.height);

self.placeholderLabel.frame = CGRectFlatMake(labelMargins.left, labelMargins.top, limitWidth, labelSize.height);

}

}

- (void)drawRect:(CGRect)rect {

[super drawRect:rect];

[self updatePlaceholderLabelHidden];

}

- (void)updatePlaceholderLabelHidden {

if (self.text.length == 0 && self.placeholder.length > 0) {

self.placeholderLabel.alpha = 1;

} else {

self.placeholderLabel.alpha = 0;// 用alpha来让placeholder隐藏，从而尽量避免因为显隐 placeholder 导致 layout

}

}

- (NSUInteger)lengthWithString:(NSString *)string {

return self.shouldCountingNonASCIICharacterAsTwo ? string.qmui_lengthWhenCountingNonASCIICharacterAsTwo : string.length;

}

#pragma mark - <QMUITextViewDelegate>

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

if (self.debug) NSLog(@"textView.text(%@ | %@) = %@\nmarkedTextRange = %@\nrange = %@\ntext = %@", @(textView.text.length), @(textView.text.qmui_lengthWhenCountingNonASCIICharacterAsTwo), textView.text, textView.markedTextRange, NSStringFromRange(range), text);

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

if ([self.delegate respondsToSelector:@selector(textViewShouldReturn:)]) {

BOOL shouldReturn = [self.delegate textViewShouldReturn:self];

if (shouldReturn) {

return NO;

}

}

}

if (textView.maximumTextLength < NSUIntegerMax) {

// 如果是中文输入法正在输入拼音的过程中（markedTextRange 不为 nil），是不应该限制字数的（例如输入“huang”这5个字符，其实只是为了输入“黄”这一个字符），所以在 shouldChange 这里不会限制，而是放在 didChange 那里限制。

BOOL isDeleting = range.length > 0 && text.length <= 0;

if (isDeleting || textView.markedTextRange) {

if ([textView.originalDelegate respondsToSelector:_cmd]) {

return [textView.originalDelegate textView:textView shouldChangeTextInRange:range replacementText:text];

}

return YES;

}

NSUInteger rangeLength = self.shouldCountingNonASCIICharacterAsTwo ? [textView.text substringWithRange:range].qmui_lengthWhenCountingNonASCIICharacterAsTwo : range.length;

BOOL textWillOutofMaximumTextLength = [self lengthWithString:textView.text] - rangeLength + [self lengthWithString:text] > textView.maximumTextLength;

if (textWillOutofMaximumTextLength) {

// 当输入的文本达到最大长度限制后，此时继续点击 return 按钮（相当于尝试插入“\n”），就会认为总文字长度已经超过最大长度限制，所以此次 return 按钮的点击被拦截，外界无法感知到有这个 return 事件发生，所以这里为这种情况做了特殊保护

if ([self lengthWithString:textView.text] - rangeLength == textView.maximumTextLength && [text isEqualToString:@"\n"]) {

if ([textView.originalDelegate respondsToSelector:_cmd]) {

// 不管外面 return YES 或 NO，都不允许输入了，否则会超出 maximumTextLength。

[textView.originalDelegate textView:textView shouldChangeTextInRange:range replacementText:text];

return NO;

}

}

// 将要插入的文字裁剪成多长，就可以让它插入了

NSInteger substringLength = textView.maximumTextLength - [self lengthWithString:textView.text] + rangeLength;

if (substringLength > 0 && [self lengthWithString:text] > substringLength) {

NSString *allowedText = [text qmui_substringAvoidBreakingUpCharacterSequencesWithRange:NSMakeRange(0, substringLength) lessValue:YES countingNonASCIICharacterAsTwo:self.shouldCountingNonASCIICharacterAsTwo];

if ([self lengthWithString:allowedText] <= substringLength) {

textView.text = [textView.text stringByReplacingCharactersInRange:range withString:allowedText];

textView.selectedRange = NSMakeRange(range.location + substringLength, 0);

if (!textView.shouldResponseToProgrammaticallyTextChanges) {

[textView.originalDelegate textViewDidChange:textView];

}

}

}

if ([self.originalDelegate respondsToSelector:@selector(textView:didPreventTextChangeInRange:replacementText:)]) {

[self.originalDelegate textView:textView didPreventTextChangeInRange:range replacementText:text];

}

return NO;

}

}

if ([textView.originalDelegate respondsToSelector:_cmd]) {

return [textView.originalDelegate textView:textView shouldChangeTextInRange:range replacementText:text];

}

return YES;

}

- (void)textViewDidChange:(QMUITextView *)textView {

// 1、iOS 10 以下的版本，从中文输入法的候选词里选词输入，是不会走到 textView:shouldChangeTextInRange:replacementText: 的，所以要在这里截断文字

// 2、如果是中文输入法正在输入拼音的过程中（markedTextRange 不为 nil），是不应该限制字数的（例如输入“huang”这5个字符，其实只是为了输入“黄”这一个字符），所以在 shouldChange 那边不会限制，而是放在 didChange 这里限制。

if (!textView.markedTextRange) {

if ([self lengthWithString:textView.text] > textView.maximumTextLength) {

textView.text = [textView.text qmui_substringAvoidBreakingUpCharacterSequencesWithRange:NSMakeRange(0, textView.maximumTextLength) lessValue:YES countingNonASCIICharacterAsTwo:self.shouldCountingNonASCIICharacterAsTwo];

if ([self.originalDelegate respondsToSelector:@selector(textView:didPreventTextChangeInRange:replacementText:)]) {

// 如果是在这里被截断，是无法得知截断前光标所处的位置及要输入的文本的，所以只能将当前的 selectedRange 传过去，而 replacementText 为 nil

[self.originalDelegate textView:textView didPreventTextChangeInRange:textView.selectedRange replacementText:nil];

}

if (textView.shouldResponseToProgrammaticallyTextChanges) {

return;

}

}

}

if ([textView.originalDelegate respondsToSelector:_cmd]) {

[textView.originalDelegate textViewDidChange:textView];

}

}

#pragma mark - Delegate Proxy

- (void)setDelegate:(id<QMUITextViewDelegate>)delegate {

self.originalDelegate = delegate != self ? delegate : nil;

[super setDelegate:delegate ? self : nil];

}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector {

NSMethodSignature *a = [super methodSignatureForSelector:aSelector];

NSMethodSignature *b = [(id)self.originalDelegate methodSignatureForSelector:aSelector];

NSMethodSignature *result = a ? a : b;

return result;

}

- (void)forwardInvocation:(NSInvocation *)anInvocation {

if ([(id)self.originalDelegate respondsToSelector:anInvocation.selector]) {

[anInvocation invokeWithTarget:(id)self.originalDelegate];

}

}

- (BOOL)respondsToSelector:(SEL)aSelector {

BOOL a = [super respondsToSelector:aSelector];

BOOL c = [self.originalDelegate respondsToSelector:aSelector];

BOOL result = a || c;

return result;

}

// 下面这两个方法比较特殊，无法通过 forwardInvocation: 的方式把消息发送给 self.originalDelegate，只会直接被调用，所以只能在 QMUITextView 内部实现这连个方法然后调用 originalDelegate 的对应方法

// 注意，测过 UITextView 默认没有实现任何 UIScrollViewDelegate 方法 from 2016-11-01 in iOS 10.1 by molice

- (void)scrollViewDidScroll:(UIScrollView *)scrollView {

if ([self.originalDelegate respondsToSelector:_cmd]) {

[self.originalDelegate scrollViewDidScroll:scrollView];

}

}

- (void)setContentOffset:(CGPoint)contentOffset animated:(BOOL)animated {

if (!self.shouldRejectSystemScroll) {

[super setContentOffset:contentOffset animated:animated];

if (self.debug) NSLog(@"%@, contentOffset.y = %.2f", NSStringFromSelector(_cmd), contentOffset.y);

} else {

if (self.debug) NSLog(@"被屏蔽的 %@, contentOffset.y = %.2f", NSStringFromSelector(_cmd), contentOffset.y);

}

}

- (void)setContentOffset:(CGPoint)contentOffset {

if (!self.shouldRejectSystemScroll) {

[super setContentOffset:contentOffset];

if (self.debug) NSLog(@"%@, contentOffset.y = %.2f", NSStringFromSelector(_cmd), contentOffset.y);

} else {

if (self.debug) NSLog(@"被屏蔽的 %@, contentOffset.y = %.2f", NSStringFromSelector(_cmd), contentOffset.y);

}

}

- (void)scrollViewDidZoom:(UIScrollView *)scrollView {

if ([self.originalDelegate respondsToSelector:_cmd]) {

[self.originalDelegate scrollViewDidZoom:scrollView];

}

}

@end