我正在使用UIAlertController来呈现一个带有UITextField的对话框和一个标有“Ok”的UIAlertAction按钮.如何在UITextField中输入多个字符(例如5个字符)之前禁用该按钮？
解决方法
在头文件中添加以下属性
@property(nonatomic,strong)UIAlertAction *okAction;
然后在ViewController的viewDidLoad方法中复制以下代码
self.okAction = [UIAlertAction actionWithTitle:@"OK"
style:UIAlertActionStyleDefault
handler:nil];
self.okAction.enabled = NO;
UIAlertController *controller = [UIAlertController alertControllerWithTitle:nil
message:@"Enter your text"
preferredStyle:UIAlertControllerStyleAlert];
[controller addTextFieldWithConfigurationHandler:^(UITextField *textField) {
textField.delegate = self;
}];
[controller addAction:self.okAction];
[self presentViewController:controller animated:YES completion:nil];
还要在类中实现以下UITextField委托方法
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
NSString *finalString = [textField.text stringByReplacingCharactersInRange:range withString:string];
[self.okAction setEnabled:(finalString.length >= 5)];
return YES;
}
这应该工作
