如何在目标C中设置工具栏的高度？

@interface CustomToolbar : UIToolbar

@end

@implementation CustomToolbar

- (void)layoutSubviews {
    [super layoutSubviews];
    CGRect frame = self.bounds;
    frame.size.height = 64; // 设置工具栏的高度
    self.bounds = frame;
}

@end

CustomToolbar *toolbar = [[CustomToolbar alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 64)];
[toolbar setBarStyle:UIBarStyleDefault];

UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(doneButtonTapped)];

[toolbar setItems:@[flexibleSpace, doneButton] animated:NO];

[self.view addSubview:toolbar];

CustomToolbar *toolbar = [[CustomToolbar alloc] init];
[toolbar setBarStyle:UIBarStyleDefault];

UIBarButtonItem *flexibleSpace = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:nil action:nil];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(doneButtonTapped)];

[toolbar setItems:@[flexibleSpace, doneButton] animated:NO];

[self.view addSubview:toolbar];

// 设置约束
[toolbar.translatesAutoresizingMaskIntoConstraints = NO];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[toolbar]|" options:0 metrics:nil views:@{@"toolbar": toolbar}]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[toolbar(==64)]" options:0 metrics:nil views:@{@"toolbar": toolbar}]];