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这篇博客主要讲限制输入长度的问题，前几天有人问我这个问题，说限制长度会出现无法删除问题，于是正好一块发出来给大家看看。textField的缩进，一张背景图片搞定的事，我这里用了leftView纯属附带。
好了废话少说，贴代码，很简单，大家一看便知。
//先创建一个textField 和 一个button。
#import "ViewController.h"
@interface ViewController ()<UITextFieldDelegate> {
UITextField *currentTextFeild;
UIButton *touchButton;
}
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UITextField *textFields = [[UITextField alloc] initWithFrame:CGRectMake(15, 50, self.view.bounds.size.width-15*2, 40)];
textFields.backgroundColor = [UIColor brownColor];
textFields.layer.cornerRadius = 5;
textFields.leftView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 40)];
textFields.leftViewMode = UITextFieldViewModeAlways;//这两行是为了不让Text太贴textField的左边
textFields.placeholder = @"请输入手机号";
textFields.delegate = self;
[self.view addSubview:textFields];
currentTextFeild = textFields;
UIButton *enableButton = [UIButton buttonWithType:UIButtonTypeCustom];
enableButton.frame = CGRectMake(15, 100, self.view.bounds.size.width-15*2, 40);
enableButton.layer.cornerRadius = 5;
enableButton.backgroundColor = [UIColor grayColor];
[enableButton setTitle:@"没内容不可点击" forState:UIControlStateNormal];
[enableButton setTitle:@"可以按了" forState:UIControlStateSelected];
[enableButton setTitle:@"按下去了" forState:UIControlStateHighlighted];
enableButton.enabled = NO;
[enableButton addTarget:self action:@selector(btnClick) forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:enableButton];
touchButton = enableButton;
}
- (void)btnClick {
}
//设置textField代理
#pragma mark - UITextFieldDelegate
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
return YES;
}
- (void)textFieldDidEndEditing:(UITextField *)textField {
}
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
//用来判断是否可以继续输入， - range.length是为了判断是否可以删除
NSInteger currentLength = textField.text.length - range.length + string.length;
if (currentLength > 11) {
return NO;
}
//判断按钮是否可以enable = YES
if (currentTextFeild.text && currentTextFeild.text.length > 0 && currentLength > 0) {
touchButton.enabled = YES;
touchButton.selected = YES;
}else {
touchButton.enabled = NO;
touchButton.selected = NO;
}
if (currentLength <= 0) {
touchButton.enabled = NO;
touchButton.selected = NO;
}
return YES;
}
- (BOOL)textFieldShouldClear:(UITextField *)textField {
if (currentTextFeild.tag == 11 || currentTextFeild.tag == 12) {
//手机号
touchButton.enabled = NO;
touchButton.selected = NO;;
}
return YES;
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
[textField resignFirstResponder];
return YES;
}
大家看了代码，差不多就明白了。
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原文地址：http://www.cnblogs.com/wly314/p/4682097.html
