Ios uitextview滚动副本
1.首先在文本中标识表达式文本，然后在相应位置插入NSTextAttachment对象，该对象存储自定义表达式。
1 static ns string * emojiTextPttern = @ " \ \[[0-9a-zA-Z \ \ u4e 00-\ \ u9fa 5]+\ \]"；2 ?3 _ e mojic = @ { @"[笑]":@ "笑" ,@ "[爱]":@ "爱" }；4 ?5-(NSMutableAttributedString *)getEmojiText:(NSString *)content { 6 NSMutableAttributedString * attributedString =[[NSMutableAttributedString alloc]init with string:content attributes:self . typing attributes]；7静态ns regular expression * reg express = nil；8 if(reg express = = nil){ 9 reg express =[[ns regular expression alloc]init with pattern:emojitextptern options:0 error:nil]；10 } 11//emojitex 12 nsarray * matches =[regexpressmatches索引:内容选项:0范围:nsmakerange (0，内容。长度)]由正则表达式识别；13 if(matches . count & gt；0){ 14 for(NSTextCheckingResult * result in[matches reverseobjectenumerate]){ 15 ns string * emojiText =[content substring with range:result . range]；16 //构造NSTextAttachment对象17 NSTextAttachment * attachment =[self-createmojiattachment:emojitext]；18 if(attachment){ 19 NSAttributedString * rep =[NSAttributedString attachment:attachment]；20//Replace 21[属性化字符串replacecharactersinrange:result。相应位置没有attributedstring: rep]的范围；22 }23 }24 }25返回attributedString26 }
2.构建NSTextAttachment的过程如下:
1-(NSTextAttachment *)createEmojiAttachment:(ns string *)emoji text { 2 if(emoji text . length = = 0){ 3 return nil；4 } 5 ns string * imageName = _ e mojidic[emojiText]；6 if(imagename . length = = 0){ 7 return nil；8 } 9 ui image * image =[ui image image named:imageName]；10 if(image = = nil){ 11返回nil；12 }13 //缩放图片以适合当前的textview行高14 cgfloat emojiWHScale = image.size.width/1.0/image.size.height;. 15 CGSize e mojisize = CGSizeMake(self . font . line height * emojiWHScale，self . font . line height)；16 ui imageView * imageView =[[ui imageView alloc]initWithFrame:CGRectMake(0，0，emojiSize.width，e moji size . height)]；17 imageview . image = image；18 //防模糊19 ui graphics begin imagecontext with options(imageview . bounds . size，no，[uiscreen主屏]。尺度)；20[imageview . layer render in context:UIGraphicsGetCurrentContext()]；21 ui image * emoji image = UIGraphicsGetImageFromCurrentImageContext()；22 UIGraphicsEndImageContext()；23 EmojiTextAttachment * attachment =[[EmojiTextAttachment alloc]init]；24 attachment.image = emojiImage25 attachment . emojiText = emojiText；26 attachment . bounds = CGRectMake(0，-3，emojiImage.size.width，emojiimage . size . height)；27返回附件；28 }
其中EmojiTextAttachment继承了NSTextAttachment类，主要是记住自定义表达式对应的emojiText，后面实现复制和剪切需要用到。EmojiTextAttachment声明为:
1 @ interface EmojiTextAttachment:nstextattachment 2 3/* * 4？保存emojiText 5的值？*/6 @property(非原子，强)NSString * emojiText7 @结束
3.粘贴自定义表达式。
重新粘贴该方法
1 -(void)paste:(id)发件人{ 2 UIPasteboard * default pasteboard =[UIPasteboard general pasteboard]；3 if(defaultpasteboard . string . length & gt；0){ 4 ns range range = self . selected range；5 if(range . location = = NSNotFound){ 6 range . location = self . text . length；7 } 8 if([self . delegate textView:self should change textinrange:range replacement text:defaultpasteboard . string]){ 9 NSAttributedString * newAttriString =[self getEmojiText:defaultpasteboard . string]；10 ?[self insertattributestringtotextview:newAttriString]；11 }12返回；13 }14【超级贴:发件人】；15 } 16 17-(void)insertattributestringtotextview:(NSAttributedString *)attributestring { 18 NSMutableAttributedString * multitristring =[[NSMutableAttributedString alloc]initWithAttributedString:self . attributedtext]；19 ns range range = self . selected range；20 if(range . location = = NSNotFound){ 21 range . location = self . text . length；22 } 23[mulat tristring insertAttributedString:attributestring at index:range . location]；24 self . attributed text =[mulat tristring copy]；25 self . selected range = NSMakeRange(range . location+attribute string . length，0)；26 }
4.复制和剪切自定义表达式。
在复制剪切自定义表达式时，我们得到的不是自定义表达式对应的图片，而是自定义表达式对应的emojiText，这也是为什么我们要定义上面的EmojiTextAttachment类。具体代码如下:
1 -(void)copy:(id)发件人{ 2 ns range range = self . selected range；3 ns string * content =[self getStrContentInRange:range]；4 if(content . length & gt；0){ 5 UIPasteboard * default pasteboard =[UIPasteboard general pasteboard]；6[defaultPasteboard setString:content]；7返回；8 } 9[超级副本:发件人]；10 } 11-(void)cut:(id)sender { 12 ns range range = selected range；13 ns string * content =[self getStrContentInRange:range]；14 if(content . length & gt；0){ 15[超切:发件人]；16 UIPasteboard * default pasteboard =[UIPasteboard general pasteboard]；17[defaultPasteboard setString:content]；18返回；19 } 20[超切:发件人]；21 }22 23 /**24 ?将textview的attributedText转换成NSString，将自定义表达式转换成emojiText25 26？@param range变换范围27？@return返回转换后的字符串28？*/29-(ns string *)getStrContentInRange:(ns range)range { 30 NSMutableString * result =[[NSMutableString alloc]initwithcapability:10]；31 ns range effective range = NSMakeRange(range . location，0)；32 nsu integer length = NSMaxRange(range)；33 while(NSMaxRange(effective range)& lt；length){ 34 NSTextAttachment * attachment =[self . attributed text attribute:nstachmentattributename at index:ns maxrange(effective range)effective range:& amp；effective range]；35 if(attachment){ 36 if([attachment is kindof class:[EmojiTextAttachment class]]){ 37 EmojiTextAttachment * emojiAttachment =(EmojiTextAttachment *)attachment；38[result appendString:emojiattachment . emojitext]；39 } 40 } 41 else { 42 ns string * subStr =[self . text substring with range:effective range]；43[result append string:subStr]；44 }45 }46返回【结果副本】；47 }
通过以上的努力，我们实现了所有的功能。但是当我们使用它的时候，我们会发现两个问题:
1.当在自定义表达式后输入文本时，UITextview设置的属性(如字体大小、颜色)消失，重新成为默认属性；
2.在ios 10.11系统上，长按自定义表达式时，键盘会退出并弹出保存图片的系统窗口，这不是一个好的体验。
解决第一个问题:
我们在初始化时保存UITextview的typingAttributes属性，然后在UITextview的内容每次即将发生变化时重置它。
1 @ interface view controller()& lt；UITextViewDelegate & gt2 @property(非原子，强)CustomTextView * textView3 ?4 @property(非原子，强)NSDictionary * typingAttributes5 @end 6？7-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(ns range)range replacement text:(ns string *)text { 8 textView . typing attributes = self . typing attributes；9返回YES10 }
解决第二个问题:
只需要实现一个委托方法，直接返回NO。
1-(BOOL)textView:(UITextView *)textView should interactwithtextattachment:(NSTextAttachment *)text attachment in range:(ns range)character range interaction:(uitextiteminaction)interaction { 2 return NO；3 }