最近在做一個專案的時候，發現沒有獲取游標的方法。進過研究後，出來分享給大家：

1、新建一個工程，我使用的Xcode 7.2 也就是 iOS9.2，託轉一個TextField；

2、新建一個類別，對TextFIeld進行一個擴充套件，也就是新建一個類別；

這是.h檔案

#import <UIKit/UIKit.h>

@interface UITextField (ExtentRange)

- (NSRange)selectedRange;

- (void)setSelectedRange:(NSRange)range;

@end

#import "UITextField+ExtentRange.h"

@implementation UITextField (ExtentRange)

- (NSRange) selectedRange
{
    UITextPosition* beginning = self.beginningOfDocument;
    
    UITextRange* selectedRange = self.selectedTextRange;
    UITextPosition* selectionStart = selectedRange.start;
    UITextPosition* selectionEnd = selectedRange.end;
    
    const NSInteger location = [self offsetFromPosition:beginning toPosition:selectionStart];
    const NSInteger length = [self offsetFromPosition:selectionStart toPosition:selectionEnd];
    
    return NSMakeRange(location, length);
}

- (void) setSelectedRange:(NSRange) range
{
    UITextPosition* beginning = self.beginningOfDocument;
    
    UITextPosition* startPosition = [self positionFromPosition:beginning offset:range.location];
    UITextPosition* endPosition = [self positionFromPosition:beginning offset:range.location + range.length];
    UITextRange* selectionRange = [self textRangeFromPosition:startPosition toPosition:endPosition];
    
    [self setSelectedTextRange:selectionRange];
}

@end
 

selectedRange

那麼我們現在來對這個方法進行測試：

#import "ViewController.h"
#import "UITextField+ExtentRange.h"

@interface ViewController ()

@property (weak, nonatomic) IBOutlet UITextField *textField;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    UITextField *tmpTextField = [[UITextField alloc]initWithFrame:CGRectMake(30, 30, 100, 40)];
    
    [self.view addSubview:tmpTextField];
    
    tmpTextField.text = @"121";
    [tmpTextField becomeFirstResponder];
    
    NSRange range = [tmpTextField selectedRange];
    
    NSLog(@"%lu and %lu", (unsigned long)range.location, (unsigned long)range.length);
    
    self.textField.text = @"ddwa";

    NSLog(@"localhost is %lu, length is %lu", (unsigned long)[self.textField selectedRange].location, (unsigned long)[self.textField selectedRange].length);
    
    [self.textField setSelectedRange:NSMakeRange(0, 1)];
    
    NSLog(@"localhost is %lu, length is %lu", (unsigned long)[self.textField selectedRange].location, (unsigned long)[self.textField selectedRange].length);
    
    [self.textField addTarget:self action:@selector(didChangeWithTextField:) forControlEvents:UIControlEventEditingChanged];
}


- (void)didChangeWithTextField:(UITextField *)textField{
    
    NSRange range = textField.selectedRange;
    
    NSLog(@"%lu and %lu", (unsigned long)range.location, (unsigned long)range.length);
    
    NSLog(@" ... ");
    
}

 

然後我對這個textField添加了一個當值改變的一個監聽，每次輸入數值的時候，會有看到打印出來資料的變化。