searchBar的搜索图标靠左

# UISearchBar
## searchBar****的图标靠左

 SEL centerSelector = NSSelectorFromString([NSString stringWithFormat:@"%@%@", @"setCenter", @"Placeholder:"]);
    if ([seachBar respondsToSelector:centerSelector]){
        NSMethodSignature *signature = [[UISearchBar class] instanceMethodSignatureForSelector:centerSelector];
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
        [invocation setTarget:seachBar];
        [invocation setSelector:centerSelector];
        [invocation invoke];
    }

serchBar改变cancel字体

 searchBar.showsCancelButton = YES;
    for(UIView *view in  [[[searchBar subviews] objectAtIndex:0] subviews]) {
        if([view isKindOfClass:[NSClassFromString(@"UINavigationButton") class]]) {
            UIButton * cancel =(UIButton *)view;
            [cancel setTitle:@"搜索" forState:UIControlStateNormal];
            cancel.titleLabel.font = [UIFont systemFontOfSize:14];
        }
    }