ios uitextview 滚动复制

Posted 2023-04-23

参考技术A

UITextView是ios的富文本编辑控件，除了文字还可以插入图片等。今天主要介绍一下UITextView对自定义表情的处理。

1、首先识别出文本中的表情文本，然后在对应的位置插入NSTextAttachment对象，该对象存放的就是自定义表情。

1 static NSString *emojiTextPttern = @"\\\\[[0-9a-zA-Z\\\\u4e00-\\\\u9fa5]+\\\\]"; 2  3 _emojiDic = @@"[大笑]":@"smile",@"[爱心]":@"love"; 4  5 -(NSMutableAttributedString*)getEmojiText:(NSString*)content 6     NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc]initWithString:content attributes:self.typingAttributes]; 7     static NSRegularExpression *regExpress = nil; 8     if(regExpress == nil) 9         regExpress = [[NSRegularExpression alloc]initWithPattern:emojiTextPttern options:0 error:nil];10     11     //通过正则表达式识别出emojiText12     NSArray *matches = [regExpress matchesInString:content options:0 range:NSMakeRange(0, content.length)];13     if(matches.count > 0)14         for(NSTextCheckingResult *result in [matches reverseObjectEnumerator])15             NSString *emojiText = [content substringWithRange:result.range];16             //构造NSTextAttachment对象17             NSTextAttachment *attachment = [self createEmojiAttachment:emojiText];18             if(attachment)19                 NSAttributedString *rep = [NSAttributedString attributedStringWithAttachment:attachment];20                 //在对应的位置替换21                 [attributedString replaceCharactersInRange:result.range withAttributedString:rep];22             23         24     25     return attributedString;26

2、构造NSTextAttachment的过程为：

1 -(NSTextAttachment*)createEmojiAttachment:(NSString*)emojiText 2     if(emojiText.length==0) 3         return nil; 4      5     NSString *imageName = _emojiDic[emojiText]; 6     if(imageName.length == 0) 7         return nil; 8      9     UIImage *image = [UIImage imageNamed:imageName];10     if(image == nil)11         return nil;12     13     //把图片缩放到符合当前textview行高的大小14     CGFloat emojiWHScale = image.size.width/1.0/image.size.height;15     CGSize emojiSize = CGSizeMake(self.font.lineHeight*emojiWHScale, self.font.lineHeight);16     UIImageView *imageView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, emojiSize.width, emojiSize.height)];17     imageView.image = image;18     //防止模糊19     UIGraphicsBeginImageContextWithOptions(imageView.bounds.size, NO, [UIScreen mainScreen].scale);20     [imageView.layer renderInContext:UIGraphicsGetCurrentContext()];21     UIImage *emojiImage = UIGraphicsGetImageFromCurrentImageContext();22     UIGraphicsEndImageContext();23     EmojiTextAttachment *attachment = [[EmojiTextAttachment alloc]init];24     attachment.image = emojiImage;25     attachment.emojiText = emojiText;26     attachment.bounds = CGRectMake(0, -3, emojiImage.size.width, emojiImage.size.height);27     return attachment;28

其中EmojiTextAttachment继承了NSTextAttachment类，主要是为了记住自定义表情对应的emojiText，在后面实现copy和cut需要用到。EmojiTextAttachment声明为：

1 @interface EmojiTextAttachment : NSTextAttachment2 3 /**4  保存emojiText的值5  */6 @property (nonatomic, strong) NSString *emojiText;7 @end

3、实现对自定义表情的粘贴

重新paste方法即可

1 -(void)paste:(id)sender 2     UIPasteboard *defaultPasteboard = [UIPasteboard generalPasteboard]; 3     if(defaultPasteboard.string.length>0) 4         NSRange range = self.selectedRange; 5         if(range.location == NSNotFound) 6             range.location = self.text.length; 7          8         if([self.delegate textView:self shouldChangeTextInRange:range replacementText:defaultPasteboard.string]) 9            NSAttributedString *newAttriString = [self getEmojiText:defaultPasteboard.string];10            [self insertAttriStringToTextview:newAttriString];11         12         return;13     14     [super paste:sender];15 16 17 -(void)insertAttriStringToTextview:(NSAttributedString*)attriString18     NSMutableAttributedString *mulAttriString = [[NSMutableAttributedString alloc]initWithAttributedString:self.attributedText];19     NSRange range = self.selectedRange;20     if(range.location == NSNotFound)21         range.location = self.text.length;22     23     [mulAttriString insertAttributedString:attriString atIndex:range.location];24     self.attributedText = [mulAttriString copy];25     self.selectedRange = NSMakeRange(range.location+attriString.length, 0);26

4、实现自定义表情的拷贝和剪切

拷贝和剪切自定义表情的时候，不是获取自定义表情对应的图片而是自定义表情对应的emojiText，这也是我们在上面要定义EmojiTextAttachment类的原因。具体代码如下：

1 -(void)copy:(id)sender 2     NSRange range = self.selectedRange; 3     NSString *content = [self getStrContentInRange:range]; 4     if(content.length>0) 5         UIPasteboard *defaultPasteboard = [UIPasteboard generalPasteboard]; 6         [defaultPasteboard setString:content]; 7         return; 8      9     [super copy:sender];10 11 -(void)cut:(id)sender12     NSRange range = self.selectedRange;13     NSString *content = [self getStrContentInRange:range];14     if(content.length>0)15         [super cut:sender];16         UIPasteboard *defaultPasteboard = [UIPasteboard generalPasteboard];17         [defaultPasteboard setString:content];18         return;19     20     [super cut:sender];21 22 23 /**24  把textview的attributedText转化为NSString，其中把自定义表情转化为emojiText25 26  @param range 转化的范围27  @return 返回转化后的字符串28  */29 -(NSString*)getStrContentInRange:(NSRange)range30     NSMutableString *result = [[NSMutableString alloc]initWithCapacity:10];31     NSRange effectiveRange = NSMakeRange(range.location,0);32     NSUInteger length = NSMaxRange(range);33     while (NSMaxRange(effectiveRange)<length) 34         NSTextAttachment *attachment = [self.attributedText attribute:NSAttachmentAttributeName atIndex:NSMaxRange(effectiveRange) effectiveRange:&effectiveRange];35         if(attachment)36             if([attachment isKindOfClass:[EmojiTextAttachment class]])37                 EmojiTextAttachment *emojiAttachment = (EmojiTextAttachment*)attachment;38                 [result appendString:emojiAttachment.emojiText];39             40         41         else42             NSString *subStr = [self.text substringWithRange:effectiveRange];43             [result appendString:subStr];44         45     46     return [result copy];47

通过上面的努力，我们已经实现了所有的功能。但是我们用起来的时候，会发现两个问题：

1、在自定义表情的后面输入文本，UITextview设置的属性（比如字体大小，颜色等）都消失，又变成了默认属性；

2、在ios 10.11系统上，长按自定义表情的时候，keyboard会退出，并且弹出保存图片的系统窗口，这样的体验也不好。

解决第一个问题：

我们在初始化的时候保存一下UITextview的typingAttributes属性，然后在每次UITextview的内容将要发生变化的时候，重置一下他的该属性。

1 @interface ViewController ()<UITextViewDelegate> 2 @property (nonatomic, strong)CustomTextView *textView; 3  4 @property (nonatomic, strong)NSDictionary *typingAttributes; 5 @end 6  7 -(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text 8     textView.typingAttributes = self.typingAttributes; 9     return YES;10

解决第二个问题：

只需要实现一个delegate方法就行，直接返回NO

1 -(BOOL)textView:(UITextView *)textView shouldInteractWithTextAttachment:(NSTextAttachment *)textAttachment inRange:(NSRange)characterRange interaction:(UITextItemInteraction)interaction2     return NO;3

swift iOS - Swift - UITextView滚动到底部扩展名

import UIKit

extension UITextView {
    
    func scrollToBotom() {
        let range = NSMakeRange(text.characters.count - 1, 1);
        scrollRangeToVisible(range);
    }
    
}