ios UITextField

#import "ViewController.h"

@interface ViewController () <UITextFieldDelegate>
@property (strong) IBOutlet UITextField *f;
@end

@implementation ViewController

-(void)viewDidLoad{
    [super viewDidLoad];
    [self.f addTarget:self
               action:@selector(valueChangeCallback:)
     forControlEvents:UIControlEventEditingChanged];
}

//文本变更后触发
-(void) valueChangeCallback:(UITextField *) sender{
    NSLog(@"f.text %@",sender.text);
}

-(IBAction) changeByCode:(id)sender{
    self.f.text = @"1234";
    //不会触发下面如何方法
}

#pragma mark - delegate

//清除按钮的回调
-(BOOL)textFieldShouldClear:(UITextField *)textField{
    NSLog(@"textFieldShouldClear");
    return YES;
}

//Return 按键的回调  返回yes表示 开发人员自己来处理Return时间
//Return yes/no 跟关键键盘没有直接关系
-(BOOL)textFieldShouldReturn:(UITextField *)textField{
    NSLog(@"textFieldShouldReturn");
    [textField resignFirstResponder];
    return NO;
}

-(void)textFieldDidBeginEditing:(UITextField *)textField{

}

//停止编辑前调用 返回yes继续编辑 返回no取消"停止编辑"
-(BOOL)textFieldShouldEndEditing:(UITextField *)textField{
    return YES;
}


//停止编辑后调用
-(void)textFieldDidEndEditing:(UITextField *)textField{
    
}

//ios 10的方法 替换上面这个方法
-(void)textFieldDidEndEditing:(UITextField *)textField reason:(UITextFieldDidEndEditingReason)reason{
    NSLog(@"textFieldDidEndEditing:reason %zd",reason);

}

//文本变更之前的方法
//range是影响的文本范围
//replacementString是range范围文本的替换内容
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    NSLog(@"-----------------");
    NSLog(@"current [%@]",textField.text);
    NSLog(@"range %zd, %zd",range.location, range.length);
    NSLog(@"replacementString [%@]",string);
    NSLog(@"-----------------");
    return YES;
}
#pragma mark end - 
@end