iOS UITextView 首行縮進(jìn) 撤銷輸入 反撤銷輸入的實現(xiàn)代碼
最近公司涉及到作家助手的功能,能撤銷輸入的文字,并能反撤銷被撤銷掉的文字。
該功能類似ios系統(tǒng)的搖一搖撤銷輸入。
當(dāng)時也特迷茫,不知道從何下手,后來搜索了大量的資料,終于完成了這個功能,現(xiàn)在就將該功能的實現(xiàn)寫出來,共勉。
這個功能涉及到ios原生類:NSUndomanager。這個類挺強(qiáng)大。廢話不多說,直接上代碼。
#import "ViewController.h" @interface ViewController ()<UITextViewDelegate>{ UITextView *_textView; NSUndoManager *_undomanager; NSInteger _length; UIButton *undobutton; UIButton *redobutton; } @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; UIBarButtonItem *undoItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemUndo target:self action:@selector(undoitem)]; UIBarButtonItem *redoItem = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemRedo target:self action:@selector(redoitem)]; self.navigationItem.leftBarButtonItem = undoItem; self.navigationItem.rightBarButtonItem = redoItem; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardShow:) name:UIKeyboardWillShowNotification object:nil]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyBoardHidden:) name:UIKeyboardWillHideNotification object:nil]; _length = 0; //初始化NSUndoManager _undomanager = [[NSUndoManager alloc] init]; _textView = [[UITextView alloc]initWithFrame:CGRectMake(0, 200, self.view.frame.size.width, 400)]; _textView.backgroundColor = [UIColor yellowColor]; _textView.delegate = self; _textView.font = [UIFont systemFontOfSize:15]; _textView.layer.cornerRadius = 5; _textView.layer.masksToBounds = YES; _textView.textColor = [UIColor blackColor]; _textView.text = @" ";//要設(shè)置初始文本,不然段落體現(xiàn)不出來。 NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init]; paragraphStyle.lineSpacing = 5; //行間距 paragraphStyle.firstLineHeadIndent = 30; /**首行縮進(jìn)寬度*/ paragraphStyle.alignment = NSTextAlignmentLeft; NSDictionary *attributes = @{ NSFontAttributeName:[UIFont systemFontOfSize:13], NSParagraphStyleAttributeName:paragraphStyle }; _textView.attributedText = [[NSAttributedString alloc] initWithString:_textView.text attributes:attributes]; //監(jiān)聽textview文本改動的通知 [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(changeTextViewText) name:UITextViewTextDidChangeNotification object:nil]; [self.view addSubview:_textView]; } -(void)redoitem{ //反撤銷 [_undomanager redo]; } -(void)undoitem{ //撤銷 [_undomanager undo]; } -(void)keyBoardShow:(NSNotification *)noti{ NSDictionary *dic = noti.userInfo; NSValue *aValue = [dic objectForKey:UIKeyboardFrameEndUserInfoKey]; CGRect keyboardRect = [aValue CGRectValue]; int height = keyboardRect.size.height; [_textView setContentInset:UIEdgeInsetsMake(0, 0, height, 0)]; } -(void)keyBoardHidden:(NSNotification *)noti{ [_textView setContentInset:UIEdgeInsetsMake(0, 0, 0, 0)]; } - (void)setMyObjectTitle:(NSString *)newTitle{ //判斷當(dāng)前NSUndoManager的狀態(tài),是處于撤銷或者反撤銷的狀態(tài) -(void)textViewDidChange:(UITextView *)textView if (_undomanager.isUndoing) { NSInteger length = newTitle.length; if (_textView.text.length>0) { //獲取 _textView.text = [_textView.text substringWithRange:NSMakeRange(0, _textView.text.length - length)]; [_undomanager registerUndoWithTarget:self selector:@selector(setMyObjectTitle:) object:newTitle]; } }else if (_undomanager.isRedoing){ _textView.text = [_textView.text stringByAppendingString:newTitle]; [_undomanager registerUndoWithTarget:self selector:@selector(setMyObjectTitle:) object:newTitle]; }else{ NSString *currentText = _textView.text; if (newTitle != currentText) { _textView.text = currentText; [_undomanager registerUndoWithTarget:self selector:@selector(setMyObjectTitle:) object:newTitle]; }else{ _textView.text = newTitle; } } } -(void)changeTextViewText{ if (_textView.text.length>0) { undobutton.enabled = YES; }else{ undobutton.enabled = NO; redobutton.enabled = NO; } NSString *text ; if (_length != 0) { NSInteger textLength = _textView.text.length; if (textLength > _length) { NSInteger newLength = textLength - _length; text = [NSString stringWithFormat:@"%@",[_textView.text substringWithRange:NSMakeRange(_length, newLength)]]; }else{ text = _textView.text; } }else{ text = _textView.text; } _length = _textView.text.length; [self setMyObjectTitle:text]; }
總結(jié)
以上所述是小編給大家介紹的iOS UITextView 首行縮進(jìn) 撤銷輸入 反撤銷輸入的實現(xiàn)代碼,希望對大家有所幫助,如果大家有任何疑問請給我留言,小編會及時回復(fù)大家的。在此也非常感謝大家對腳本之家網(wǎng)站的支持!
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