默認狀態(tài)下TextField字體是這個樣子的

QQ20160603-0@2x.png

但是當切換到密文狀態(tài)再切換回來之后，就變成了下面的樣子

QQ20160603-1@2x.png

不知道為什么蘋果默認在切換secure狀態(tài)是要改變TextField的字體，其實在切換完secure狀態(tài)變?yōu)榉敲芪臓顟B(tài)的時候默認給TextField設置下字體就好可以解決了，大概就是這樣

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITextField *textField;
@property (weak, nonatomic) IBOutlet UIButton *changeBtn;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.textField.font = [UIFont fontWithName:@"System" size:15];
}

- (IBAction)changeSecure:(id)sender {
    self.textField.secureTextEntry = !self.textField.secureTextEntry;
    self.textField.font = [UIFont fontWithName:@"System" size:15];
}