iOS TextField 获取光标的位置

来源：互联网发布：纸箱厂专业软件编辑：程序博客网时间：2024/05/21 14:25

最近在做一个项目的时候，发现没有获取光标的方法。进过研究后，出来分享给大家：

1、新建一个工程，我使用的Xcode 7.2 也就是 iOS9.2，托转一个TextField；

2、新建一个类别，对TextFIeld进行一个扩展，也就是新建一个类别；

这是.h文件

#import <UIKit/UIKit.h>@interface UITextField (ExtentRange)- (NSRange)selectedRange;- (void)setSelectedRange:(NSRange)range;@end

然后.m文件：

#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

大家也看到了，就是基本上一个重写的Set 和 Get 方法，值得一提的是这里所定义的

selectedRange

变量，它在UITextView是有这个属性的，但是在UItextField中确实没有的。

那么我们现在来对这个方法进行测试：

#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(@" ... ");    }

可以看到我在UIVIewDidLoad中写的变量，所得到的坐标位置都是（0 ， 0）；

然后我对这个textField添加了一个当值改变的一个监听，每次输入数值的时候，会有看到打印出来数据的变化。

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