编辑代码

#import "ViewController.h"
@interface ViewController()
@end

@implemntation ViewController

-(void)viewDidLoad
{
    [super viewDidLoad];
    [self addTextField];
}

-(void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarining];
}

-(void)addTextField
{
    UILabel *prefixLabel =[[UILabel alloc]initWithFrame:CGRectZero];
    prefixLabel.text=@"##";
    [prefixLabel setFont:[UIFont boldSystemFontOfSize:14]];
    [prefixLabel sizeToFit];

    UITextField *textField =[[UITextField alloc] initWithFrame:CGRectMake(20,50,280,30)];
    textField.borderStyle =UITextBorderStyleRounderRect;
    textField.contentVerticalAlignment = UiControlContentVerticalAlignmentCenter;
    [textField setFont:[UIFont boldSystemFontOfSize:12]];

    textField.placeholder=@"Simple Text field";
    textField.leftView = prefixLabel;
    textField.leftViewMode = UITextFieldViewModeAlways;
    [self.view addSubview:textField];
    textField.delegate =self;
}

#pragma mark - TextField Delegates

-(void)textFieldDidBeginEditing:(UITextField *)textField{
    NSLog(@"Text field disbegi editing");
}

-(BOOL) textFieldShouldReturn:(UITextField *)textField{
    [textField resignFirestResponder];
    return Yes;
}

-(void)vieDidUnload
{
    label = nil;
    [super viewDidUnload];
}
#end