IOS8之后增加了UIAlertController类,它可以表示UIAlertView和UIActionSheet.它继承自UIViewController。

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window.backgroundColor=[UIColor whiteColor];
    [self.window makeKeyAndVisible];
     
    ViewController *vc=[[ViewController alloc]init];
    UINavigationController *nvc=[[UINavigationController alloc]initWithRootViewController:vc];
    self.window.rootViewController=nvc;
    return YES;
}

//
//  ViewController.m
//  AlertVC
//
//  Created by City--Online on 15/5/25.
//  Copyright (c) 2015年 XQB. All rights reserved.
//
 
#import "ViewController.h"
 
@interface ViewController ()
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *btn=[UIButton buttonWithType:UIButtonTypeCustom];
    btn.frame=CGRectMake(100, 100, 50, 50);
    [btn setTitle:@"按钮" forState:UIControlStateNormal];
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    btn.layer.borderWidth=2.0;
    [btn addTarget:self action:@selector(btnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
     
     
     
     
} 
-(void)btnClick:(id)sender
{
//    UIAlertController *alert=[UIAlertController alertControllerWithTitle:@"Title" message:@"message" preferredStyle:UIAlertControllerStyleAlert];
//    
//    [alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
//        textField.text=@"name";
//        textField.clearsOnBeginEditing=YES;
//    }];
//    [alert addTextFieldWithConfigurationHandler:^(UITextField *textField) {
//        textField.text=@"password";
//        textField.clearsOnBeginEditing=YES;
//    }];
     
    UIAlertController *alert=[UIAlertController alertControllerWithTitle:@"Title" message:@"message" preferredStyle:UIAlertControllerStyleActionSheet];
     
    UIAlertAction *actionOk=[UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
        NSLog(@"确定");
    }];
    UIAlertAction *actionCancel=[UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
        NSLog(@"取消");
    }];
    [alert addAction:actionOk];
    [alert addAction:actionCancel];
    [self presentViewController:alert animated:YES completion:nil];
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
 
@end