大部分
//创建操作
+ (instancetype)actionWithTitle:(nullable NSString *)title style:(UIAlertActionStyle)style handler:(void(^ __nullable)(UIAlertAction *action))handler;
//初始化
+ (instancetype)alertControllerWithTitle:(nullable NSString *)title message:(nullable NSString *)message preferredStyle:(UIAlertControllerStyle)preferredStyle;
//添加操作- (void)addAction:(UIAlertAction *)action;
示例1：最简单的提醒视
//创建操作
UIAlertAction *okAlert = [UIAlertAction actionWithTitle:@"OK"style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){//具体操作内容}];
//初始化UIAlertController *alert = [UIAlertControlleralertControllerWithTitle:@"顶部标题栏"message:@"中间信息"preferredStyle:UIAlertControllerStyleAlert];
//添加操作
[alert addAction:okAlert];
//以model形式，显示警告视图[self presentViewController:alert animated:YES completion:nil];
//等同于NSString *title =@"顶部标题栏";
NSString*message =@"中间信息";
NSString*okAlertButton =@"OK";
UIAlertAction*okAlert =[UIAlertAction
actionWithTitle:okAlertButton style:UIAlertActionStyleDefaulthandler:^(UIAlertAction *_Nonnull action) {
}];
UIAlertController*alert =[UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
示例2：多个按键的提醒视图//取消按键——下次下次 UIAlertActionStyleCancel （粗体）[alert addAction:[UIAlertAction actionWithTitle:@"下次下次"style:UIAlertActionStyleCancel handler:^(UIAlertAction *_Nonnull action) {
NSLog(@"点击取消按钮");
}]];
//红色按键——残忍拒绝 UIAlertActionStyleDestructive
[alert addAction:[UIAlertAction actionWithTitle:@"残忍拒绝"style:UIAlertActionStyleDestructive handler:^(UIAlertAction *_Nonnull action) {
NSLog(@"红色按钮");
}]];
//两个会是这样//3个就挨个往下排//普通按键——立马好评 UIAlertActionStyleDefault[alert addAction:
[UIAlertAction actionWithTitle:@"立马好评"style:UIAlertActionStyleDefault handler:^(UIAlertAction *_Nonnull action) {
NSLog(@"普通按钮");
}]];
示例3：带对话框TextField- (void)addTextFieldWithConfigurationHandler:(void(^ __nullable)(UITextField *textField))configurationHandler;//添加TextField 条栏 addTextFieldWithConfigurationHandler[alert addTextFieldWithConfigurationHandler:^(UITextField *_Nonnull textField) {
NSLog(@"TextField");//中间的提示输入textField.placeholder =@"用来提示你做什么事的";
}];
示例4：提醒图标，在最底部呈现 Sheet//UIAlertControllerStyleAlert改成UIAlertControllerStyleActionSheet (最后面的)UIAlertController *alert =[UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleActionSheet];
UIAlertControllerStyleActionsheet好像不能和TextField在一起，会报错。是这样吗？
