UI基础_UIAlertController/UIAlertView使用和字体大小颜色

1.UIAlertView在iOS9.0后被抛弃

UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:nil message:NSLocalizedString(@"请核对后重新输入",nil) delegate:self cancelButtonTitle:NSLocalizedString(@"知道了",nil) otherButtonTitles:nil, nil];
    [alertView show];

2.UIAlertController

NSString *message = NSLocalizedString(@"请核对后重新输入",nil);
    NSString *title = @"提示";
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
    //改变title的大小和颜色
    NSMutableAttributedString *titleAtt = [[NSMutableAttributedString alloc] initWithString:title];
    [titleAtt addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:16] range:NSMakeRange(0, title.length)];
    [titleAtt addAttribute:NSForegroundColorAttributeName value:[UIColor orangeColor] range:NSMakeRange(0, title.length)];
    [alertController setValue:titleAtt forKey:@"attributedTitle"];
    //改变message的大小和颜色
    NSMutableAttributedString *messageAtt = [[NSMutableAttributedString alloc] initWithString:message];
    [messageAtt addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:13] range:NSMakeRange(0, message.length)];
    [messageAtt addAttribute:NSForegroundColorAttributeName value:[UIColor darkTextColor] range:NSMakeRange(0, message.length)];
    [alertController setValue:messageAtt forKey:@"attributedMessage"];
    
    UIAlertAction *alertAction = [UIAlertAction actionWithTitle:NSLocalizedString(@"知道了",nil) style:UIAlertActionStyleCancel handler:nil];
    [alertController addAction:alertAction];
    [self presentViewController:alertController animated:YES completion:nil];

注：当title设置为nil时，message的字体大小会是标题的大小，如果单纯只是希望message小些，可设置title = @ "" 即可
注：UIAlertAction的字体也可改变，打印属性即可查看。取消按钮字体颜色的key是@"titleTextColor"

3.属性可通过runtime打印

unsigned int count = 0;
    Ivar *ivars = class_copyIvarList([UIAlertController class], &count);
    for (int i = 0; i